diff mbox series

[v12,2/2] i2c: aspeed: support ast2600 i2c new register mode driver

Message ID 20230714074522.23827-3-ryan_chen@aspeedtech.com
State New
Headers show
Series Add ASPEED AST2600 I2Cv2 controller driver | expand

Commit Message

Ryan Chen July 14, 2023, 7:45 a.m. UTC
Add i2c new register mode driver to support AST2600 i2c
new register mode. AST2600 i2c controller have legacy and
new register mode. The new register mode have global register
support 4 base clock for scl clock selection, and new clock
divider mode. The i2c new register mode have separate register
set to control i2c master and slave.

Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
---
 MAINTAINERS                      |    9 +
 drivers/i2c/busses/Kconfig       |   11 +
 drivers/i2c/busses/Makefile      |    1 +
 drivers/i2c/busses/i2c-ast2600.c | 1576 ++++++++++++++++++++++++++++++
 4 files changed, 1597 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-ast2600.c

Comments

Ryan Chen July 14, 2023, 8:08 a.m. UTC | #1
Hello,

On 14/07/2023 09:45, Ryan Chen wrote:
> Add i2c new register mode driver to support AST2600 i2c new register 
> mode. AST2600 i2c controller have legacy and new register mode. The 
> new register mode have global register support 4 base clock for scl 
> clock selection, and new clock divider mode. The i2c new register mode 
> have separate register set to control i2c master and slave.
> 
> Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
> ---

...

> +	ret = devm_i2c_add_adapter(dev, &i2c_bus->adap);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int ast2600_i2c_remove(struct platform_device *pdev) {
> +	struct ast2600_i2c_bus *i2c_bus = platform_get_drvdata(pdev);
> +
> +	/* Disable everything. */
> +	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> +	writel(0, i2c_bus->reg_base + AST2600_I2CM_IER);
> +
> +	i2c_del_adapter(&i2c_bus->adap);

> I have doubts that you tested this. I think you have here double free/del of the adapter.
Sorry, i can't catch your point for double free the adapter.
It should use i2c_del_adapter in driver remove function.
All the driver doing this 
https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-npcm7xx.c#L2373
https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-altera.c#L473

Do you mean it is not necessary? 

> +	devm_free_irq(&pdev->dev, i2c_bus->irq, i2c_bus);
> +


Best regards,
Krzysztof
Andy Shevchenko July 14, 2023, 8:56 a.m. UTC | #2
On Fri, Jul 14, 2023 at 08:08:48AM +0000, Ryan Chen wrote:
> On 14/07/2023 09:45, Ryan Chen wrote:

...

> > +	ret = devm_i2c_add_adapter(dev, &i2c_bus->adap);
> > +	if (ret)
> > +		return ret;

...

> > +	i2c_del_adapter(&i2c_bus->adap);
> 
> > I have doubts that you tested this. I think you have here double free/del of the adapter.
> Sorry, i can't catch your point for double free the adapter.
> It should use i2c_del_adapter in driver remove function.
> All the driver doing this 
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-npcm7xx.c#L2373
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-altera.c#L473
> 
> Do you mean it is not necessary? 

I'm wondering if you understand what you are doing...
Ryan Chen July 14, 2023, 9:26 a.m. UTC | #3
Hello,
> 
> On 14/07/2023 09:45, Ryan Chen wrote:
>> Add i2c new register mode driver to support AST2600 i2c new register 
>> mode. AST2600 i2c controller have legacy and new register mode. The 
>> new register mode have global register support 4 base clock for scl 
>> clock selection, and new clock divider mode. The i2c new register 
>> mode have separate register set to control i2c master and slave.
>>
>> Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
>> ---
> 
> ...
> 
>> +	ret = devm_i2c_add_adapter(dev, &i2c_bus->adap);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ast2600_i2c_remove(struct platform_device *pdev) {
>> +	struct ast2600_i2c_bus *i2c_bus = platform_get_drvdata(pdev);
>> +
>> +	/* Disable everything. */
>> +	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
>> +	writel(0, i2c_bus->reg_base + AST2600_I2CM_IER);
>> +
>> +	i2c_del_adapter(&i2c_bus->adap);
> 
>> I have doubts that you tested this. I think you have here double free/del of the adapter.
> Sorry, i can't catch your point for double free the adapter.
> It should use i2c_del_adapter in driver remove function.
> All the driver doing this
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-n
> pcm7xx.c#L2373
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-a
> ltera.c#L473
> 
> Do you mean it is not necessary? 

>Instead of giving you the fish, I think much more learning experience is to teach you how to fish. Please unbind your driver (echo the device name to proper unbind file in sysfs). The best if you build your kernel with KASAN.

Thanks, will do this test with unbind to understand your point.
Ryan Chen July 26, 2023, 3:38 a.m. UTC | #4
Hello,
> 
> On 14/07/2023 09:45, Ryan Chen wrote:
>> Add i2c new register mode driver to support AST2600 i2c new register 
>> mode. AST2600 i2c controller have legacy and new register mode. The 
>> new register mode have global register support 4 base clock for scl 
>> clock selection, and new clock divider mode. The i2c new register 
>> mode have separate register set to control i2c master and slave.
>>
>> Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
>> ---
> 
> ...
> 
>> +	ret = devm_i2c_add_adapter(dev, &i2c_bus->adap);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ast2600_i2c_remove(struct platform_device *pdev) {
>> +	struct ast2600_i2c_bus *i2c_bus = platform_get_drvdata(pdev);
>> +
>> +	/* Disable everything. */
>> +	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
>> +	writel(0, i2c_bus->reg_base + AST2600_I2CM_IER);
>> +
>> +	i2c_del_adapter(&i2c_bus->adap);
> 
>> I have doubts that you tested this. I think you have here double free/del of the adapter.
> Sorry, i can't catch your point for double free the adapter.
> It should use i2c_del_adapter in driver remove function.
> All the driver doing this
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-n
> pcm7xx.c#L2373
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-a
> ltera.c#L473
> 
> Do you mean it is not necessary? 

>Instead of giving you the fish, I think much more learning experience is to teach you how to fish. Please unbind your driver (echo the device name to proper unbind file in sysfs). The best if you build your kernel with KASAN.

>Thanks, will do this test with unbind to understand your point. 
I do my the test with enable kernel config KASAN.
I don't see any error dump. You can see the following. It use i2c-0 bind/unbind.
Did I miss some test ??

root@ast2600-default:/sys/bus/platform/drivers/i2c_ast2600# i2cdetect -l
i2c-0   i2c             1e78a080.i2c-bus                        I2C adapter
i2c-1   i2c             1e78a100.i2c-bus                        I2C adapter
i2c-2   i2c             1e78a180.i2c-bus                        I2C adapter
i2c-3   i2c             1e78a200.i2c-bus                        I2C adapter
i2c-4   i2c             1e78a280.i2c-bus                        I2C adapter
i2c-5   i2c             1e78a300.i2c-bus                        I2C adapter
i2c-6   i2c             1e78a380.i2c-bus                        I2C adapter
i2c-7   i2c             1e78a400.i2c-bus                        I2C adapter
i2c-8   i2c             1e78a480.i2c-bus                        I2C adapter
i2c-9   i2c             1e78a500.i2c-bus                        I2C adapter
i2c-12  i2c             1e78a680.i2c-bus                        I2C adapter
i2c-13  i2c             1e78a700.i2c-bus                        I2C adapter
i2c-14  i2c             1e78a780.i2c-bus                        I2C adapter
i2c-15  i2c             1e78a800.i2c-bus                        I2C adapter
root@ast2600-default:/sys/bus/platform/drivers/i2c_ast2600# echo 1e78a080.i2c-bus > unbind
root@ast2600-default:/sys/bus/platform/drivers/i2c_ast2600# i2cdetect -l
i2c-1   i2c             1e78a100.i2c-bus                        I2C adapter
i2c-2   i2c             1e78a180.i2c-bus                        I2C adapter
i2c-3   i2c             1e78a200.i2c-bus                        I2C adapter
i2c-4   i2c             1e78a280.i2c-bus                        I2C adapter
i2c-5   i2c             1e78a300.i2c-bus                        I2C adapter
i2c-6   i2c             1e78a380.i2c-bus                        I2C adapter
i2c-7   i2c             1e78a400.i2c-bus                        I2C adapter
i2c-8   i2c             1e78a480.i2c-bus                        I2C adapter
i2c-9   i2c             1e78a500.i2c-bus                        I2C adapter
i2c-12  i2c             1e78a680.i2c-bus                        I2C adapter
i2c-13  i2c             1e78a700.i2c-bus                        I2C adapter
i2c-14  i2c             1e78a780.i2c-bus                        I2C adapter
i2c-15  i2c             1e78a800.i2c-bus                        I2C adapter
root@ast2600-default:/sys/bus/platform/drivers/i2c_ast2600# echo 1e78a080.i2c-bus > bind
[  388.177413] i2c_ast2600 1e78a080.i2c-bus: i2c-bus [0]: adapter [100 khz] mode [0]
root@ast2600-default:/sys/bus/platform/drivers/i2c_ast2600# i2cdetect -l
i2c-0   i2c             1e78a080.i2c-bus                        I2C adapter
i2c-1   i2c             1e78a100.i2c-bus                        I2C adapter
i2c-2   i2c             1e78a180.i2c-bus                        I2C adapter
i2c-3   i2c             1e78a200.i2c-bus                        I2C adapter
i2c-4   i2c             1e78a280.i2c-bus                        I2C adapter
i2c-5   i2c             1e78a300.i2c-bus                        I2C adapter
i2c-6   i2c             1e78a380.i2c-bus                        I2C adapter
i2c-7   i2c             1e78a400.i2c-bus                        I2C adapter
i2c-8   i2c             1e78a480.i2c-bus                        I2C adapter
i2c-9   i2c             1e78a500.i2c-bus                        I2C adapter
i2c-12  i2c             1e78a680.i2c-bus                        I2C adapter
i2c-13  i2c             1e78a700.i2c-bus                        I2C adapter
i2c-14  i2c             1e78a780.i2c-bus                        I2C adapter
i2c-15  i2c             1e78a800.i2c-bus                        I2C adapter
Ryan Chen July 26, 2023, 6:19 a.m. UTC | #5
Hello,
	After do more study about devm_i2c_add_adapter, I will remove i2c_del_adapter in driver remove. Thanks your input.

> 
> On 14/07/2023 09:45, Ryan Chen wrote:
>> Add i2c new register mode driver to support AST2600 i2c new register 
>> mode. AST2600 i2c controller have legacy and new register mode. The 
>> new register mode have global register support 4 base clock for scl 
>> clock selection, and new clock divider mode. The i2c new register 
>> mode have separate register set to control i2c master and slave.
>>
>> Signed-off-by: Ryan Chen <ryan_chen@aspeedtech.com>
>> ---
> 
> ...
> 
>> +	ret = devm_i2c_add_adapter(dev, &i2c_bus->adap);
>> +	if (ret)
>> +		return ret;
>> +
>> +	return 0;
>> +}
>> +
>> +static int ast2600_i2c_remove(struct platform_device *pdev) {
>> +	struct ast2600_i2c_bus *i2c_bus = platform_get_drvdata(pdev);
>> +
>> +	/* Disable everything. */
>> +	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
>> +	writel(0, i2c_bus->reg_base + AST2600_I2CM_IER);
>> +
>> +	i2c_del_adapter(&i2c_bus->adap);
> 
>> I have doubts that you tested this. I think you have here double free/del of the adapter.
> Sorry, i can't catch your point for double free the adapter.
> It should use i2c_del_adapter in driver remove function.
> All the driver doing this
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-n
> pcm7xx.c#L2373
> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-a
> ltera.c#L473
> 
> Do you mean it is not necessary? 

>Instead of giving you the fish, I think much more learning experience is to teach you how to fish. Please unbind your driver (echo the device name to proper unbind file in sysfs). The best if you build your kernel with KASAN.

Thanks, will do this test with unbind to understand your point.
Krzysztof Kozlowski July 26, 2023, 6:31 a.m. UTC | #6
On 26/07/2023 05:38, Ryan Chen wrote:
>>> +
>>> +static int ast2600_i2c_remove(struct platform_device *pdev) {
>>> +	struct ast2600_i2c_bus *i2c_bus = platform_get_drvdata(pdev);
>>> +
>>> +	/* Disable everything. */
>>> +	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
>>> +	writel(0, i2c_bus->reg_base + AST2600_I2CM_IER);
>>> +
>>> +	i2c_del_adapter(&i2c_bus->adap);
>>
>>> I have doubts that you tested this. I think you have here double free/del of the adapter.
>> Sorry, i can't catch your point for double free the adapter.
>> It should use i2c_del_adapter in driver remove function.
>> All the driver doing this
>> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-n
>> pcm7xx.c#L2373
>> https://github.com/torvalds/linux/blob/master/drivers/i2c/busses/i2c-a
>> ltera.c#L473
>>
>> Do you mean it is not necessary? 
> 
>> Instead of giving you the fish, I think much more learning experience is to teach you how to fish. Please unbind your driver (echo the device name to proper unbind file in sysfs). The best if you build your kernel with KASAN.
> 
>> Thanks, will do this test with unbind to understand your point. 
> I do my the test with enable kernel config KASAN.
> I don't see any error dump. You can see the following. It use i2c-0 bind/unbind.
> Did I miss some test ??
> 
> root@ast2600-default:/sys/bus/platform/drivers/i2c_ast2600# i2cdetect -l
> i2c-0   i2c             1e78a080.i2c-bus                        I2C adapter
> i2c-1   i2c             1e78a100.i2c-bus                        I2C adapter
> i2c-2   i2c             1e78a180.i2c-bus                        I2C adapter
> i2c-3   i2c             1e78a200.i2c-bus                        I2C adapter
> i2c-4   i2c             1e78a280.i2c-bus                        I2C adapter
> i2c-5   i2c             1e78a300.i2c-bus                        I2C adapter
> i2c-6   i2c             1e78a380.i2c-bus                        I2C adapter
> i2c-7   i2c             1e78a400.i2c-bus                        I2C adapter
> i2c-8   i2c             1e78a480.i2c-bus                        I2C adapter
> i2c-9   i2c             1e78a500.i2c-bus                        I2C adapter
> i2c-12  i2c             1e78a680.i2c-bus                        I2C adapter
> i2c-13  i2c             1e78a700.i2c-bus                        I2C adapter
> i2c-14  i2c             1e78a780.i2c-bus                        I2C adapter
> i2c-15  i2c             1e78a800.i2c-bus                        I2C adapter
> root@ast2600-default:/sys/bus/platform/drivers/i2c_ast2600# echo 1e78a080.i2c-bus > unbind

It should fail... if it doesn't, maybe you can tell why?

Best regards,
Krzysztof
Ryan Chen Aug. 31, 2023, 6:04 a.m. UTC | #7
Hello Andy,
> 
> On Fri, Jul 14, 2023 at 03:45:22PM +0800, Ryan Chen wrote:
> > Add i2c new register mode driver to support AST2600 i2c new register
> > mode. AST2600 i2c controller have legacy and new register mode. The
> > new register mode have global register support 4 base clock for scl
> > clock selection, and new clock divider mode. The i2c new register mode
> > have separate register set to control i2c master and slave.
> 
> ...
> 
> + bits.h
> 
> > +#include <linux/clk.h>
> > +#include <linux/completion.h>
> > +#include <linux/delay.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/err.h>
> > +#include <linux/i2c.h>
> > +#include <linux/i2c-smbus.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/io.h>
> > +#include <linux/module.h>
> > +#include <linux/mfd/syscon.h>
> 
> > +#include <linux/of.h>
> > +#include <linux/of_device.h>
> > +#include <linux/of_irq.h>
> 
> You missed property.h
> and these of*.h probably not needed at all, see below.
> 
> > +#include <linux/regmap.h>
> > +#include <linux/reset.h>
> > +#include <linux/slab.h>
> > +#include <linux/string_helpers.h>
> 
> ...
> 
> > +#define AST2600_I2CC_GET_RX_BUFF(x)			(((x) >> 8) &
> GENMASK(7, 0))
> 
> > +#define AST2600_I2CC_GET_RX_BUF_LEN(x)		(((x) >> 24) &
> GENMASK(5, 0))
> 
> > +#define AST2600_I2CC_GET_TX_BUF_LEN(x)		((((x) >> 8) &
> GENMASK(4, 0)) + 1)
> 
> With right shifts it's better to have GENMASK to be applied first, it will show
> exact MSB of the bitfield.
> 
> (Ditto for other cases similar to these)
> 
> ...
> 
> > +static u32 ast2600_select_i2c_clock(struct ast2600_i2c_bus *i2c_bus)
> > +{
> > +	unsigned long base_clk[4];
> > +	int baseclk_idx;
> > +	u32 clk_div_reg;
> > +	u32 scl_low;
> > +	u32 scl_high;
> > +	int divisor;
> > +	int inc = 0;
> > +	u32 data;
> > +
> > +	regmap_read(i2c_bus->global_regs, AST2600_I2CG_CLK_DIV_CTRL,
> &clk_div_reg);
> > +	for (int i = 0; i < 4; i++) {
> 
> See below.
> 
> > +		base_clk[i] = (i2c_bus->apb_clk * 10) /
> > +		(((((clk_div_reg >> (i * 8)) & GENMASK(7, 0)) + 2) * 10) / 2);
> 
> Second line is wrongly indented.
> 
> > +	}
> 
> > +	if ((i2c_bus->apb_clk / i2c_bus->bus_frequency) <= 32) {
> > +		baseclk_idx = 0;
> > +		divisor = DIV_ROUND_UP(i2c_bus->apb_clk,
> i2c_bus->bus_frequency);
> > +	} else {
> 
> > +		int i;
> > +
> 
> Just add to the definition block:
> 
> 	unsigned int i;
> 
> > +		for (i = 0; i < 4; i++) {
> > +			if ((base_clk[i] / i2c_bus->bus_frequency) <= 32) {
> 
> > +				baseclk_idx = i + 1;
> > +				divisor = DIV_ROUND_UP(base_clk[i],
> i2c_bus->bus_frequency);
> 
> These two can be moved outside of the loop
> 
> > +				break;
> > +			}
> 
> 			if ((base_clk[i] / i2c_bus->bus_frequency) <= 32)
> 				break;
> 
> > +		}
> > +		if (i == 4) {
> > +			baseclk_idx = 4;
> > +			divisor = DIV_ROUND_UP(base_clk[3],
> i2c_bus->bus_frequency);
> 
> > +			while ((divisor + inc) > 32) {
> > +				inc |= divisor & 0x1;
> > +				divisor >>= 1;
> 
> 	unsigned long divisor;
> 
> 			for_each_set_bit(divisor, ...)
> 
> I.o.w. think about this, maybe you can refactor with the above.
> 
> > +				baseclk_idx++;
> > +			}
> > +			divisor += inc;
> 
> 		} else {
> 			...those two lines...
> 
> > +		}
> 
> > +	}
> > +
> > +	divisor = min_t(int, divisor, 32);
> > +	baseclk_idx &= GENMASK(3, 0);
> 
> > +	scl_low = ((divisor * 9) / 16) - 1;
> > +	scl_low = min_t(u32, scl_low, GENMASK(3, 0));
> 
> (with the divisor being unsigned long) this can be rewritten as
> 
> 	scl_low = min(divisor * 9 / 16 - 1, GENMASK(3, 0));
> 
> which improves type checking and readability.
> 
> > +	scl_high = (divisor - scl_low - 2) & GENMASK(3, 0);
> > +	data = (scl_high - 1) << 20 | scl_high << 16 | scl_low << 12 |
> > +baseclk_idx;
> > +
> > +	if (i2c_bus->timeout) {
> > +		data |= AST2600_I2CC_TOUTBASECLK(AST_I2C_TIMEOUT_CLK);
> > +		data |= AST2600_I2CC_TTIMEOUT(i2c_bus->timeout);
> > +	}
> > +
> > +	return data;
> > +}
> 
> ...
> 
> > +static u8 ast2600_i2c_recover_bus(struct ast2600_i2c_bus *i2c_bus) {
> > +	int ret = 0;
> > +	u32 ctrl;
> > +	u32 state;
> > +	int r;
> 
> > +	dev_dbg(i2c_bus->dev, "%d-bus recovery bus [%x]\n", i2c_bus->adap.nr,
> > +		readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
> 
> Why you can't reuse "state" (assigned below)?
> If not, then something like
> 
> 	/* ...comment that state can be changed... */
> 	state = ...
> 	dev_dbg(state);
> 
> > +	ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +
> > +	writel(ctrl & ~(AST2600_I2CC_MASTER_EN | AST2600_I2CC_SLAVE_EN),
> > +	       i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +
> > +	writel(readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL) |
> > +AST2600_I2CC_MASTER_EN,
> 
> will it be different from ctrl value?
> 
> > +	       i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +
> > +	reinit_completion(&i2c_bus->cmd_complete);
> > +	i2c_bus->cmd_err = 0;
> > +
> > +	/* Check 0x14's SDA and SCL status */
> > +	state = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
> > +	if (!(state & AST2600_I2CC_SDA_LINE_STS) && (state &
> AST2600_I2CC_SCL_LINE_STS)) {
> > +		writel(AST2600_I2CM_RECOVER_CMD_EN, i2c_bus->reg_base +
> AST2600_I2CM_CMD_STS);
> > +		r = wait_for_completion_timeout(&i2c_bus->cmd_complete,
> i2c_bus->adap.timeout);
> > +		if (r == 0) {
> > +			dev_dbg(i2c_bus->dev, "recovery timed out\n");
> > +			ret = -ETIMEDOUT;
> 
> > +		} else {
> > +			if (i2c_bus->cmd_err) {
> 
> 		} else if (...) {
> 
> > +				dev_dbg(i2c_bus->dev, "recovery error\n");
> > +				ret = -EPROTO;
> > +			}
> > +		}
> > +	}
> > +
> > +	dev_dbg(i2c_bus->dev, "Recovery done [%x]\n",
> > +		readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
> 
> As above.
> 
> > +	if (readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF) &
> > +AST2600_I2CC_BUS_BUSY_STS) {
> 
> Two sequential reads may give you different values?
> 
> > +		dev_dbg(i2c_bus->dev, "Can't recover bus [%x]\n",
> > +			readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
> 
> Again? With this inconsistency it will be "nice" to debug.
> 
> > +		ret = -EPROTO;
> > +	}
> > +
> > +	writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +	return ret;
> > +}
> 
> ...
> 
> > +#ifdef CONFIG_I2C_SLAVE
> 
> For (at least) review purposes I recommend to split slave out to the separate
> change. This driver is 16 hundreds LoCs long...
> 
> > +#endif
> 
> ...
> 
> > +		} else if (i2c_bus->mode == BUFF_MODE) {
> > +			/* buff mode */
> > +			cmd |= AST2600_I2CM_RX_BUFF_EN;
> 
> > +			if (msg->flags & I2C_M_RECV_LEN) {
> > +				dev_dbg(i2c_bus->dev, "smbus read\n");
> > +				xfer_len = 1;
> > +			} else {
> > +				if (msg->len > i2c_bus->buf_size) {
> > +					xfer_len = i2c_bus->buf_size;
> > +				} else {
> > +					xfer_len = msg->len;
> > +					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
> > +						cmd |= MASTER_TRIGGER_LAST_STOP;
> > +				}
> > +			}
> 
> This...
> 
> > +			writel(AST2600_I2CC_SET_RX_BUF_LEN(xfer_len),
> > +			       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
> > +		} else {
> 
> > +			/* byte mode */
> > +			xfer_len = 1;
> > +			if (msg->flags & I2C_M_RECV_LEN) {
> > +				dev_dbg(i2c_bus->dev, "smbus read\n");
> > +			} else {
> > +				if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count) {
> > +					if (msg->len == 1)
> > +						cmd |= MASTER_TRIGGER_LAST_STOP;
> > +				}
> > +			}
> 
> ...and this have a lot in common, can it be deduplicated?
> 
> > +		}
> 
> ...
> 
> > +			if (msg->len > AST2600_I2C_DMA_SIZE) {
> > +				xfer_len = AST2600_I2C_DMA_SIZE;
> > +			} else {
> > +				if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
> > +					cmd |= AST2600_I2CM_STOP_CMD;
> > +				xfer_len = msg->len;
> > +			}
> 
> See above.
> 
> ...
> 
> > +			u8 wbuf[4];
> > +			/* buff mode */
> > +			if (msg->len > i2c_bus->buf_size) {
> > +				xfer_len = i2c_bus->buf_size;
> > +			} else {
> > +				if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
> > +					cmd |= AST2600_I2CM_STOP_CMD;
> > +				xfer_len = msg->len;
> > +			}
> > +			if (xfer_len) {
> > +				cmd |= AST2600_I2CM_TX_BUFF_EN |
> AST2600_I2CM_TX_CMD;
> > +				if (readl(i2c_bus->reg_base + AST2600_I2CS_ISR))
> > +					return -ENOMEM;
> > +				writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
> > +				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
> > +				if (readl(i2c_bus->reg_base + AST2600_I2CS_ISR))
> > +					return -ENOMEM;
> > +				for (i = 0; i < xfer_len; i++) {
> > +					wbuf[i % 4] = msg->buf[i];
> > +					if (i % 4 == 3)
> 
> > +						writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
> 
> This is incorrect memory accessor.
> 
> > +				}
> > +				if (--i % 4 != 3)
> > +					writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
> 
> Ditto.
> 
> > +			}
> 
> ...
> 
> > +static int ast2600_i2c_is_irq_error(u32 irq_status)
> 
> This function is not boolean, so "_is_" seems misleading.
> 
> This is basically error code conversion, something like
> 
> ast2600_i2c_irq_err_to_errno(u32 irq_status)
> 
> > +{
> > +	if (irq_status & AST2600_I2CM_ARBIT_LOSS)
> > +		return -EAGAIN;
> > +	if (irq_status & (AST2600_I2CM_SDA_DL_TO |
> AST2600_I2CM_SCL_LOW_TO))
> > +		return -EBUSY;
> > +	if (irq_status & (AST2600_I2CM_ABNORMAL))
> > +		return -EPROTO;
> > +
> > +	return 0;
> > +}
> 
> ...
> 
> > +				u8 wbuf[4];
> > +
> > +				cmd |= AST2600_I2CM_TX_BUFF_EN;
> > +				xfer_len = msg->len - i2c_bus->master_xfer_cnt;
> > +				if (xfer_len > i2c_bus->buf_size) {
> > +					xfer_len = i2c_bus->buf_size;
> > +				} else {
> > +					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
> > +						cmd |= AST2600_I2CM_STOP_CMD;
> > +				}
> > +				for (i = 0; i < xfer_len; i++) {
> > +					wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
> > +					if (i % 4 == 3)
> > +						writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
> > +				}
> > +				if (--i % 4 != 3)
> > +					writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
> > +				writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
> > +				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
> 
> Wrong memory accessors. You should use something from asm/byteorder.h
> which includes linux/byteorder/generic.h.
> 

Are you preferring add comment to explain more by following?
				/*
				 * The controller's buffer register supports dword writes only.
				 * Therefore, write dwords to the buffer register in a 4-byte aligned,
				 * and write the remaining unaligned data at the end.
				 */
				for (i = 0; i < xfer_len; i++) {
					wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
					/* accumulating 4 bytes of data, write as a Dword to the buffer register */
					if (i % 4 == 3)
						writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
				}
				/* less than 4 bytes of remaining data, write the remaining part as a Dword */
				if (--i % 4 != 3)
					writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
				writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);

Or more columns (use get_unaligned_le32(wbuf); ) by following.

	for (i = 0; i < xfer_len; i++) {
		wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
		if (i % 4 == 3) {
			wbuf_dword = get_unaligned_le32(wbuf);
			writel(wbuf_dword, i2c_bus->buf_base + i - 3);
		}
	}

	if (--i % 4 != 3) {
		wbuf_dword = get_unaligned_le32(wbuf);
		writel(wbuf_dword, i2c_bus->buf_base + i - (i % 4));
	}

> ...
> 
> > +#ifdef CONFIG_I2C_SLAVE
> > +		/* Workaround for master/slave package mode enable rx done stuck
> issue
> > +		 * When master go for first read (RX_DONE), slave mode will also
> effect
> > +		 * Then controller will send nack, not operate anymore.
> > +		 */
> 
> /*
>  * Wrong style of multi-line
>  * comments. You need to fix
>  * them in the entire driver.
>  */
> 
> > +		if (readl(i2c_bus->reg_base + AST2600_I2CS_CMD_STS) &
> AST2600_I2CS_PKT_MODE_EN) {
> > +			u32 slave_cmd = readl(i2c_bus->reg_base +
> AST2600_I2CS_CMD_STS);
> > +
> > +			writel(0, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
> > +			writel(slave_cmd, i2c_bus->reg_base +
> AST2600_I2CS_CMD_STS);
> > +		}
> > +		fallthrough;
> > +#endif
> 
> ...
> 
> > +static int ast2600_i2c_master_irq(struct ast2600_i2c_bus *i2c_bus) {
> > +	u32 sts = readl(i2c_bus->reg_base + AST2600_I2CM_ISR);
> > +	u32 ier = readl(i2c_bus->reg_base + AST2600_I2CM_IER);
> > +	u32 ctrl = 0;
> 
> Redundant assignment.
> 
> > +	if (!i2c_bus->alert_enable)
> > +		sts &= ~AST2600_I2CM_SMBUS_ALT;
> > +
> > +	if (AST2600_I2CM_BUS_RECOVER_FAIL & sts) {
> > +		writel(AST2600_I2CM_BUS_RECOVER_FAIL, i2c_bus->reg_base +
> AST2600_I2CM_ISR);
> > +		ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +		writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +		writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
> > +		i2c_bus->cmd_err = -EPROTO;
> > +		complete(&i2c_bus->cmd_complete);
> > +		return 1;
> > +	}
> > +
> > +	if (AST2600_I2CM_BUS_RECOVER & sts) {
> > +		writel(AST2600_I2CM_BUS_RECOVER, i2c_bus->reg_base +
> AST2600_I2CM_ISR);
> > +		i2c_bus->cmd_err = 0;
> > +		complete(&i2c_bus->cmd_complete);
> > +		return 1;
> > +	}
> > +
> > +	if (AST2600_I2CM_SMBUS_ALT & sts) {
> > +		if (ier & AST2600_I2CM_SMBUS_ALT) {
> > +			/* Disable ALT INT */
> > +			writel(ier & ~AST2600_I2CM_SMBUS_ALT, i2c_bus->reg_base +
> AST2600_I2CM_IER);
> > +			i2c_handle_smbus_alert(i2c_bus->ara);
> > +			writel(AST2600_I2CM_SMBUS_ALT, i2c_bus->reg_base +
> AST2600_I2CM_ISR);
> > +			dev_err(i2c_bus->dev,
> > +				"ast2600_master_alert_recv bus id %d, Disable Alt, Please
> Imple\n",
> > +				i2c_bus->adap.nr);
> > +			return 1;
> > +		}
> > +	}
> > +
> > +	i2c_bus->cmd_err = ast2600_i2c_is_irq_error(sts);
> > +	if (i2c_bus->cmd_err) {
> > +		writel(AST2600_I2CM_PKT_DONE, i2c_bus->reg_base +
> AST2600_I2CM_ISR);
> > +		complete(&i2c_bus->cmd_complete);
> > +		return 1;
> > +	}
> > +
> > +	if (AST2600_I2CM_PKT_DONE & sts) {
> > +		ast2600_i2c_master_package_irq(i2c_bus, sts);
> > +		return 1;
> > +	}
> > +
> > +	return 0;
> > +}
> 
> ...
> 
> > +	if (of_property_read_bool(pdev->dev.of_node, "multi-master"))
> > +		i2c_bus->multi_master = true;
> > +	else
> > +		fun_ctrl |= AST2600_I2CC_MULTI_MASTER_DIS;
> 
> 	i2c_bus->multi_master = device_property_read_bool(&pdev->dev,
> "multi-master");
> 	if (!i2c_bus->multi_master)
> 		fun_ctrl |= AST2600_I2CC_MULTI_MASTER_DIS;
> 
> ...
> 
> > +	struct device_node *np = pdev->dev.of_node;
> 
> It should use dev, but see below.
> 
> > +	struct device *dev = &pdev->dev;
> > +	struct ast2600_i2c_bus *i2c_bus;
> > +	struct resource *res;
> > +	u32 global_ctrl;
> 
> > +	int ret = 0;
> 
> Do you need this assignment?
> 
> ...
> 
> > +		i2c_bus->buf_base = devm_platform_ioremap_resource(pdev, 1);
> 
> > +		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
> 
> Why not positive check?
> 
> > +			i2c_bus->buf_size = resource_size(res) / 2;
> > +		else
> > +			i2c_bus->mode = BYTE_MODE;
> > +	}
> 
> ...
> 
> > +	ret = of_property_read_u32(dev->of_node,
> > +				   "i2c-scl-clk-low-timeout-us",
> > +				   &i2c_bus->timeout);
> 
> 	device_property_read_u32()
> 
> > +	if (!ret)
> > +		i2c_bus->timeout /= 4096;
> 
> ...
> 
> > +	ret = device_property_read_u32(&pdev->dev, "clock-frequency",
> &i2c_bus->bus_frequency);
> > +	if (ret < 0) {
> > +		dev_warn(dev, "Could not read clock-frequency property\n");
> > +		i2c_bus->bus_frequency = I2C_MAX_STANDARD_MODE_FREQ;
> > +	}
> 
> Use standard API from I2C core for this.
> 
> ...
> 
> > +	if (of_property_read_bool(dev->of_node, "smbus-alert")) {
> 
> device_property_read_bool()
> 
> Doesn't I2C core handle this property?
> 
> > +		i2c_bus->alert_enable = true;
> > +		i2c_bus->ara = i2c_new_smbus_alert_device(&i2c_bus->adap,
> &i2c_bus->alert_data);
> > +		if (!i2c_bus->ara)
> > +			dev_warn(dev, "Failed to register ARA client\n");
> > +
> > +		writel(AST2600_I2CM_PKT_DONE | AST2600_I2CM_BUS_RECOVER |
> AST2600_I2CM_SMBUS_ALT,
> > +		       i2c_bus->reg_base + AST2600_I2CM_IER);
> > +	} else {
> > +		i2c_bus->alert_enable = false;
> > +		/* Set interrupt generation of I2C master controller */
> > +		writel(AST2600_I2CM_PKT_DONE | AST2600_I2CM_BUS_RECOVER,
> > +		       i2c_bus->reg_base + AST2600_I2CM_IER);
> > +	}
> 
> ...
> 
> > +	devm_free_irq(&pdev->dev, i2c_bus->irq, i2c_bus);
> 
> Why explicit call?
> 
> ...
> 
> > +		dmam_free_coherent(i2c_bus->dev, I2C_SLAVE_MSG_BUF_SIZE,
> > +				   i2c_bus->slave_dma_buf, i2c_bus->slave_dma_addr);
> 
> Ditto.
> 
> ...
> 
> It looks to me like you ignored part of my comments. If so, I would like to know
> why.
> 
> --
> With Best Regards,
> Andy Shevchenko
>
Andy Shevchenko Aug. 31, 2023, 2:18 p.m. UTC | #8
On Thu, Aug 31, 2023 at 06:04:30AM +0000, Ryan Chen wrote:
> > On Fri, Jul 14, 2023 at 03:45:22PM +0800, Ryan Chen wrote:

Stop overquoting! Remove the context you are not answering to.

...

> > > +				if (--i % 4 != 3)
> > > +					writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
> > > +				writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
> > > +				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
> > 
> > Wrong memory accessors. You should use something from asm/byteorder.h
> > which includes linux/byteorder/generic.h.
> > 
> 
> Are you preferring add comment to explain more by following?
> 				/*
> 				 * The controller's buffer register supports dword writes only.
> 				 * Therefore, write dwords to the buffer register in a 4-byte aligned,
> 				 * and write the remaining unaligned data at the end.
> 				 */

This does not explain endianess bug (or feature) it has.
You are using CPU side byteorder for the aligned data.
This is not okay, on top of the code looking ugly and
prone to errors. Note, that somebody may refer to your
code, once accepted, in educational purposes, but since
the code is not good written, it makes a false positive
impression that this is the right thing to do in the similar
case elsewhere.

Please, fix this.

> 				for (i = 0; i < xfer_len; i++) {
> 					wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
> 					/* accumulating 4 bytes of data, write as a Dword to the buffer register */
> 					if (i % 4 == 3)
> 						writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
> 				}
> 				/* less than 4 bytes of remaining data, write the remaining part as a Dword */
> 				if (--i % 4 != 3)
> 					writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
> 				writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
> 				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
> 
> Or more columns (use get_unaligned_le32(wbuf); ) by following.
> 
> 	for (i = 0; i < xfer_len; i++) {
> 		wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
> 		if (i % 4 == 3) {
> 			wbuf_dword = get_unaligned_le32(wbuf);
> 			writel(wbuf_dword, i2c_bus->buf_base + i - 3);
> 		}
> 	}
> 
> 	if (--i % 4 != 3) {
> 		wbuf_dword = get_unaligned_le32(wbuf);
> 		writel(wbuf_dword, i2c_bus->buf_base + i - (i % 4));
> 	}
Andy Shevchenko Sept. 5, 2023, 11:55 a.m. UTC | #9
On Tue, Sep 05, 2023 at 06:52:37AM +0000, Ryan Chen wrote:
> > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Sent: Friday, July 14, 2023 4:55 PM
> > On Fri, Jul 14, 2023 at 03:45:22PM +0800, Ryan Chen wrote:

...

> > > +#define AST2600_I2CC_GET_RX_BUFF(x)			(((x) >> 8) &
> > GENMASK(7, 0))
> > 
> > > +#define AST2600_I2CC_GET_RX_BUF_LEN(x)		(((x) >> 24) &
> > GENMASK(5, 0))
> > 
> > > +#define AST2600_I2CC_GET_TX_BUF_LEN(x)		((((x) >> 8) &
> > GENMASK(4, 0)) + 1)
> > 
> > With right shifts it's better to have GENMASK to be applied first, it will show
> > exact MSB of the bitfield.
> > 
> > (Ditto for other cases similar to these)

> It will update next version.
> #define AST2600_I2CC_GET_RX_BUF_LEN(x)      (((x) & GENMASK(29, 24)) >> 24)
> #define AST2600_I2CC_GET_TX_BUF_LEN(x)      ((((x) & GENMASK(12, 8)) >> 8) + 1)

Note, these were just an example, check _all_ of the similar cases.

In general any reviewer's comment should be considered for the entire code where
it makes sense.

...

> 			divisor = DIV_ROUND_UP(base_clk[3], i2c_bus->timing_info.bus_freq_hz);
> 			for_each_set_bit(divisor, &divisor, 32) {

This is wrong.

> 				if ((divisor + 1) <= 32)
> 					break;

> 				divisor >>= 1;

And this.

> 				baseclk_idx++;

> 			}

for_each_set_bit() should use two different variables.

> 		} else {
> 			baseclk_idx = i + 1;
> 			divisor = DIV_ROUND_UP(base_clk[i], i2c_bus->timing_info.bus_freq_hz);
> 		}
> 	}

...

> 	divisor = min_t(unsigned long, divisor, 32);

Can't you use min()? min_t is a beast with some subtle corner cases.

...

> Sorry I don't catch this split slave out to separate change?
> Do you mean go for another file name example ast2600_i2c_slave.c ?

No, I mean

 patch 1: Introduce the driver with only master support
 patch 2: Add slave capability (all what is under ifdeffery for I2C_SLAVE)

...

> static int ast2600_i2c_do_start(struct ast2600_i2c_bus *i2c_bus)
> {
> 	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];

> 	int ret;

This is not needed, you may return directly.

> 	/* send start */
> 	dev_dbg(i2c_bus->dev, "[%d] %sing %d byte%s %s 0x%02x\n",
> 		i2c_bus->msgs_index, str_read_write(msg->flags & I2C_M_RD),
> 		msg->len, msg->len > 1 ? "s" : "",
> 		msg->flags & I2C_M_RD ? "from" : "to", msg->addr);
> 
> 	i2c_bus->master_xfer_cnt = 0;
> 	i2c_bus->buf_index = 0;

> 	if (msg->flags & I2C_M_RD) {
> 		if (i2c_bus->mode == DMA_MODE)
> 			ret = ast2600_i2c_setup_dma_rx(i2c_bus);

			return ...;
		if ...


> 		else if (i2c_bus->mode == BUFF_MODE)
> 			ret = ast2600_i2c_setup_buff_rx(i2c_bus);
> 		else
> 			ret = ast2600_i2c_setup_byte_rx(i2c_bus);

> 	} else {
> 		if (i2c_bus->mode == DMA_MODE)
> 			ret = ast2600_i2c_setup_dma_tx(AST2600_I2CM_START_CMD, i2c_bus);
> 		else if (i2c_bus->mode == BUFF_MODE)
> 			ret = ast2600_i2c_setup_buff_tx(AST2600_I2CM_START_CMD, i2c_bus);
> 		else
> 			ret = ast2600_i2c_setup_byte_tx(AST2600_I2CM_START_CMD, i2c_bus);

Same way.

> 	}
> 
> 	return ret;
> }

...

> > Wrong memory accessors. You should use something from asm/byteorder.h
> > which includes linux/byteorder/generic.h.
> 
> Sorry, about these parts. I quit no idea.
> This is chip register limited, it only support dword write, not support byte write.
> So the only way I have is use get_unaligned_le32 function get the byte buffer to align dword write.
> Or I may need your help point me a good way.

>  	for (i = 0; i < xfer_len; i++) {
>  		wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
>  		if (i % 4 == 3) {
>  			wbuf_dword = get_unaligned_le32(wbuf);
>  			writel(wbuf_dword, i2c_bus->buf_base + i - 3);
>  		}
>  	}
>  
>  	if (--i % 4 != 3) {
>  		wbuf_dword = get_unaligned_le32(wbuf);
>  		writel(wbuf_dword, i2c_bus->buf_base + i - (i % 4));
>  	} 

Something like that. The most problematic part in your original code is
dereferencing byte memory as 32-bit memory with all possible problems behind.
With this code it's gone. The code itself might be improved even more,
you can think about it, you still have time (we are now in v6.7 cycle).
Ryan Chen Oct. 5, 2023, 6:21 a.m. UTC | #10
Hello Andy,
	appreciate your review and comments.

> -----Original Message-----
> From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> Sent: Tuesday, September 5, 2023 7:55 PM
> To: Ryan Chen <ryan_chen@aspeedtech.com>
> Cc: jk@codeconstruct.com.au; Brendan Higgins <brendan.higgins@linux.dev>;
> Benjamin Herrenschmidt <benh@kernel.crashing.org>; Joel Stanley
> <joel@jms.id.au>; Rob Herring <robh+dt@kernel.org>; Krzysztof Kozlowski
> <krzysztof.kozlowski+dt@linaro.org>; Andrew Jeffery <andrew@aj.id.au>;
> Philipp Zabel <p.zabel@pengutronix.de>; Wolfram Sang <wsa@kernel.org>;
> linux-i2c@vger.kernel.org; Florian Fainelli <f.fainelli@gmail.com>; Jean
> Delvare <jdelvare@suse.de>; William Zhang <william.zhang@broadcom.com>;
> Tyrone Ting <kfting@nuvoton.com>; Tharun Kumar P
> <tharunkumar.pasumarthi@microchip.com>; Conor Dooley
> <conor.dooley@microchip.com>; Phil Edworthy <phil.edworthy@renesas.com>;
> openbmc@lists.ozlabs.org; devicetree@vger.kernel.org;
> linux-arm-kernel@lists.infradead.org; linux-aspeed@lists.ozlabs.org;
> =linux-kernel@vger.kernel.org; Andi Shyti <andi.shyti@kernel.org>
> Subject: Re: [PATCH v12 2/2] i2c: aspeed: support ast2600 i2c new register
> mode driver
> 
> On Tue, Sep 05, 2023 at 06:52:37AM +0000, Ryan Chen wrote:
> > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > Sent: Friday, July 14, 2023 4:55 PM
> > > On Fri, Jul 14, 2023 at 03:45:22PM +0800, Ryan Chen wrote:
> 
> ...
> 
> > > > +#define AST2600_I2CC_GET_RX_BUFF(x)			(((x) >> 8) &
> > > GENMASK(7, 0))
> > >
> > > > +#define AST2600_I2CC_GET_RX_BUF_LEN(x)		(((x) >> 24) &
> > > GENMASK(5, 0))
> > >
> > > > +#define AST2600_I2CC_GET_TX_BUF_LEN(x)		((((x) >> 8) &
> > > GENMASK(4, 0)) + 1)
> > >
> > > With right shifts it's better to have GENMASK to be applied first,
> > > it will show exact MSB of the bitfield.
> > >
> > > (Ditto for other cases similar to these)
> 
> > It will update next version.
> > #define AST2600_I2CC_GET_RX_BUF_LEN(x)      (((x) & GENMASK(29, 24))
> >> 24)
> > #define AST2600_I2CC_GET_TX_BUF_LEN(x)      ((((x) & GENMASK(12, 8))
> >> 8) + 1)
> 
> Note, these were just an example, check _all_ of the similar cases.
> 
> In general any reviewer's comment should be considered for the entire code
> where it makes sense.
> 

Sure, will check entire code.

> ...
> 
> > 			divisor = DIV_ROUND_UP(base_clk[3],
> i2c_bus->timing_info.bus_freq_hz);
> > 			for_each_set_bit(divisor, &divisor, 32) {
> 
> This is wrong.
> 
> > 				if ((divisor + 1) <= 32)
> > 					break;
> 
> > 				divisor >>= 1;
> 
> And this.
> 
> > 				baseclk_idx++;
> 
> > 			}
> 
> for_each_set_bit() should use two different variables.

Will update by following.

for_each_set_bit(bit, &divisor, 32) {
    divisor >>= 1;
    baseclk_idx++;
}

> 
> > 		} else {
> > 			baseclk_idx = i + 1;
> > 			divisor = DIV_ROUND_UP(base_clk[i],
> i2c_bus->timing_info.bus_freq_hz);
> > 		}
> > 	}
> 
> ...
> 
> > 	divisor = min_t(unsigned long, divisor, 32);
> 
> Can't you use min()? min_t is a beast with some subtle corner cases.
> 
Will update to 
divisor = min(divisor, (unsigned long)32);

> ...
> 
> > Sorry I don't catch this split slave out to separate change?
> > Do you mean go for another file name example ast2600_i2c_slave.c ?
> 
> No, I mean
> 
>  patch 1: Introduce the driver with only master support  patch 2: Add slave
> capability (all what is under ifdeffery for I2C_SLAVE)
> 
Got your point, will be separate patch. master -> slave added.
> ...
> 
> > static int ast2600_i2c_do_start(struct ast2600_i2c_bus *i2c_bus) {
> > 	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
> 
> > 	int ret;
> 
> This is not needed, you may return directly.
> 
> > 	/* send start */
> > 	dev_dbg(i2c_bus->dev, "[%d] %sing %d byte%s %s 0x%02x\n",
> > 		i2c_bus->msgs_index, str_read_write(msg->flags & I2C_M_RD),
> > 		msg->len, msg->len > 1 ? "s" : "",
> > 		msg->flags & I2C_M_RD ? "from" : "to", msg->addr);
> >
> > 	i2c_bus->master_xfer_cnt = 0;
> > 	i2c_bus->buf_index = 0;
> 
> > 	if (msg->flags & I2C_M_RD) {
> > 		if (i2c_bus->mode == DMA_MODE)
> > 			ret = ast2600_i2c_setup_dma_rx(i2c_bus);
> 
> 			return ...;
> 		if ...
> 
> 
> > 		else if (i2c_bus->mode == BUFF_MODE)
> > 			ret = ast2600_i2c_setup_buff_rx(i2c_bus);
> > 		else
> > 			ret = ast2600_i2c_setup_byte_rx(i2c_bus);
> 
> > 	} else {
> > 		if (i2c_bus->mode == DMA_MODE)
> > 			ret = ast2600_i2c_setup_dma_tx(AST2600_I2CM_START_CMD,
> i2c_bus);
> > 		else if (i2c_bus->mode == BUFF_MODE)
> > 			ret = ast2600_i2c_setup_buff_tx(AST2600_I2CM_START_CMD,
> i2c_bus);
> > 		else
> > 			ret = ast2600_i2c_setup_byte_tx(AST2600_I2CM_START_CMD,
> i2c_bus);
> 
> Same way.
> 
Yes, will update it.

> > 	}
> >
> > 	return ret;
> > }
> 
> ...
> 
> > > Wrong memory accessors. You should use something from
> > > asm/byteorder.h which includes linux/byteorder/generic.h.
> >
> > Sorry, about these parts. I quit no idea.
> > This is chip register limited, it only support dword write, not support byte
> write.
> > So the only way I have is use get_unaligned_le32 function get the byte buffer
> to align dword write.
> > Or I may need your help point me a good way.
> 
> >  	for (i = 0; i < xfer_len; i++) {
> >  		wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
> >  		if (i % 4 == 3) {
> >  			wbuf_dword = get_unaligned_le32(wbuf);
> >  			writel(wbuf_dword, i2c_bus->buf_base + i - 3);
> >  		}
> >  	}
> >
> >  	if (--i % 4 != 3) {
> >  		wbuf_dword = get_unaligned_le32(wbuf);
> >  		writel(wbuf_dword, i2c_bus->buf_base + i - (i % 4));
> >  	}
> 
> Something like that. The most problematic part in your original code is
> dereferencing byte memory as 32-bit memory with all possible problems
> behind.
> With this code it's gone. The code itself might be improved even more, you can
> think about it, you still have time (we are now in v6.7 cycle).
> 
Got it, let me find a better way, and also readable. 

> --
> With Best Regards,
> Andy Shevchenko
>
Andy Shevchenko Oct. 5, 2023, 11:56 a.m. UTC | #11
On Thu, Oct 05, 2023 at 06:21:35AM +0000, Ryan Chen wrote:
> > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > Sent: Tuesday, September 5, 2023 7:55 PM
> > On Tue, Sep 05, 2023 at 06:52:37AM +0000, Ryan Chen wrote:
> > > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > > Sent: Friday, July 14, 2023 4:55 PM
> > > > On Fri, Jul 14, 2023 at 03:45:22PM +0800, Ryan Chen wrote:

...

> > > 			divisor = DIV_ROUND_UP(base_clk[3],
> > i2c_bus->timing_info.bus_freq_hz);
> > > 			for_each_set_bit(divisor, &divisor, 32) {
> > 
> > This is wrong.
> > 
> > > 				if ((divisor + 1) <= 32)
> > > 					break;
> > 
> > > 				divisor >>= 1;
> > 
> > And this.
> > 
> > > 				baseclk_idx++;
> > 
> > > 			}
> > 
> > for_each_set_bit() should use two different variables.
> 
> Will update by following.
> 
> for_each_set_bit(bit, &divisor, 32) {
>     divisor >>= 1;
>     baseclk_idx++;
> }

It's unclear what you are trying to achieve here as the code is not equivalent
to the above.

> > > 		} else {
> > > 			baseclk_idx = i + 1;
> > > 			divisor = DIV_ROUND_UP(base_clk[i],
> > i2c_bus->timing_info.bus_freq_hz);
> > > 		}
> > > 	}

...

> > > 	divisor = min_t(unsigned long, divisor, 32);
> > 
> > Can't you use min()? min_t is a beast with some subtle corner cases.
> > 
> Will update to 
> divisor = min(divisor, (unsigned long)32);

No, the idea behind min() is that _both_ arguments are of the same type,
the proposed above is wrong.
Ryan Chen Oct. 11, 2023, 7:36 a.m. UTC | #12
> On Thu, Oct 05, 2023 at 06:21:35AM +0000, Ryan Chen wrote:
> > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > Sent: Tuesday, September 5, 2023 7:55 PM On Tue, Sep 05, 2023 at
> > > 06:52:37AM +0000, Ryan Chen wrote:
> > > > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > > > Sent: Friday, July 14, 2023 4:55 PM On Fri, Jul 14, 2023 at
> > > > > 03:45:22PM +0800, Ryan Chen wrote:
> 
> ...
> 
> > > > 			divisor = DIV_ROUND_UP(base_clk[3],
> > > i2c_bus->timing_info.bus_freq_hz);
> > > > 			for_each_set_bit(divisor, &divisor, 32) {
> > >
> > > This is wrong.
> > >
> > > > 				if ((divisor + 1) <= 32)
> > > > 					break;
> > >
> > > > 				divisor >>= 1;
> > >
> > > And this.
> > >
> > > > 				baseclk_idx++;
> > >
> > > > 			}
> > >
> > > for_each_set_bit() should use two different variables.
> >
> > Will update by following.
> >
> > for_each_set_bit(bit, &divisor, 32) {
> >     divisor >>= 1;
> >     baseclk_idx++;
> > }
> 
> It's unclear what you are trying to achieve here as the code is not equivalent to
> the above.
> 
> > > > 		} else {
> > > > 			baseclk_idx = i + 1;
> > > > 			divisor = DIV_ROUND_UP(base_clk[i],
> > > i2c_bus->timing_info.bus_freq_hz);
> > > > 		}
> > > > 	}
> 
Hello Andy, 
	I modify it to be simple way by following.
	Because baseclk_idx will be set to register [I2CD04[3:0]] that is indicate the 0~15 different base clk selection.
	So I initial the base_clk[15] array and assign initial clk value, and then find which clk idx will be right SCL clk selection.

	000: pclk
	001: base_clk1
	002: base_clk2
	003: base_clk3
	004: base_clk4
	005: base_clk4/2
	006: base_clk4/4 
	006: base_clk4/8
	.....

static u32 ast2600_select_i2c_clock(struct ast2600_i2c_bus *i2c_bus)
{
	unsigned long base_clk[15];
	int baseclk_idx;
	u32 clk_div_reg;
	u32 scl_low;
	u32 scl_high;
	int divisor = 0;
	u32 data;
	int i;

	regmap_read(i2c_bus->global_regs, AST2600_I2CG_CLK_DIV_CTRL, &clk_div_reg);
	base_clk[0] = i2c_bus->apb_clk;
	for (i = 1; i < 5; i++) {
		base_clk[i] = (i2c_bus->apb_clk * 2) /
			(((clk_div_reg >> (i * 8)) & GENMASK(7, 0)) + 2);
	}
	for (i = 5; i < 16; i++) {
		base_clk[i] = base_clk[4] / (1 << (i - 5));
	}

	for (i = 0; i < 16; i++) {
		if ((base_clk[i] / i2c_bus->timing_info.bus_freq_hz) <= 32)
			break;
	}
	baseclk_idx = i;
	baseclk_idx = min(baseclk_idx, 15);
	divisor = min(divisor, 32);
	scl_low = min(divisor * 9 / 16 - 1, 15);
	scl_high = (divisor - scl_low - 2) & GENMASK(3, 0);
	data = (scl_high - 1) << 20 | scl_high << 16 | scl_low << 12 | baseclk_idx;
	if (i2c_bus->timeout) {
		data |= AST2600_I2CC_TOUTBASECLK(AST_I2C_TIMEOUT_CLK);
		data |= AST2600_I2CC_TTIMEOUT(i2c_bus->timeout);
	}

	return data;
}
> ...
> 
> > > > 	divisor = min_t(unsigned long, divisor, 32);
> > >
> > > Can't you use min()? min_t is a beast with some subtle corner cases.
> > >
> > Will update to
> > divisor = min(divisor, (unsigned long)32);
> 
> No, the idea behind min() is that _both_ arguments are of the same type, the
> proposed above is wrong.
> 
> --
> With Best Regards,
> Andy Shevchenko
>
Ryan Chen Oct. 11, 2023, 8:17 a.m. UTC | #13
> 
> > On Thu, Oct 05, 2023 at 06:21:35AM +0000, Ryan Chen wrote:
> > > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > > Sent: Tuesday, September 5, 2023 7:55 PM On Tue, Sep 05, 2023 at
> > > > 06:52:37AM +0000, Ryan Chen wrote:
> > > > > > From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> > > > > > Sent: Friday, July 14, 2023 4:55 PM On Fri, Jul 14, 2023 at
> > > > > > 03:45:22PM +0800, Ryan Chen wrote:
> >
> > ...
> >
> > > > > 			divisor = DIV_ROUND_UP(base_clk[3],
> > > > i2c_bus->timing_info.bus_freq_hz);
> > > > > 			for_each_set_bit(divisor, &divisor, 32) {
> > > >
> > > > This is wrong.
> > > >
> > > > > 				if ((divisor + 1) <= 32)
> > > > > 					break;
> > > >
> > > > > 				divisor >>= 1;
> > > >
> > > > And this.
> > > >
> > > > > 				baseclk_idx++;
> > > >
> > > > > 			}
> > > >
> > > > for_each_set_bit() should use two different variables.
> > >
> > > Will update by following.
> > >
> > > for_each_set_bit(bit, &divisor, 32) {
> > >     divisor >>= 1;
> > >     baseclk_idx++;
> > > }
> >
> > It's unclear what you are trying to achieve here as the code is not
> > equivalent to the above.
> >
> > > > > 		} else {
> > > > > 			baseclk_idx = i + 1;
> > > > > 			divisor = DIV_ROUND_UP(base_clk[i],
> > > > i2c_bus->timing_info.bus_freq_hz);
> > > > > 		}
> > > > > 	}
> >
> Hello Andy,
> 	I modify it to be simple way by following.
> 	Because baseclk_idx will be set to register [I2CD04[3:0]] that is indicate
> the 0~15 different base clk selection.
> 	So I initial the base_clk[15] array and assign initial clk value, and then find
> which clk idx will be right SCL clk selection.
> 
> 	000: pclk
> 	001: base_clk1
> 	002: base_clk2
> 	003: base_clk3
> 	004: base_clk4
> 	005: base_clk4/2
> 	006: base_clk4/4
> 	006: base_clk4/8
> 	.....
> 

Sorry updated.

> static u32 ast2600_select_i2c_clock(struct ast2600_i2c_bus *i2c_bus) {
> 	unsigned long base_clk[15];
	unsigned long base_clk[16];

> 	int baseclk_idx;
> 	u32 clk_div_reg;
> 	u32 scl_low;
> 	u32 scl_high;
> 	int divisor = 0;
> 	u32 data;
> 	int i;
> 
> 	regmap_read(i2c_bus->global_regs, AST2600_I2CG_CLK_DIV_CTRL,
> &clk_div_reg);
> 	base_clk[0] = i2c_bus->apb_clk;
> 	for (i = 1; i < 5; i++) {
> 		base_clk[i] = (i2c_bus->apb_clk * 2) /
> 			(((clk_div_reg >> (i * 8)) & GENMASK(7, 0)) + 2);
> 	}
> 	for (i = 5; i < 16; i++) {
> 		base_clk[i] = base_clk[4] / (1 << (i - 5));
> 	}
> 
> 	for (i = 0; i < 16; i++) {
> 		if ((base_clk[i] / i2c_bus->timing_info.bus_freq_hz) <= 32)
		{
			baseclk_idx = i;
			divisor = DIV_ROUND_UP(i2c_bus->apb_clk, i2c_bus->timing_info.bus_freq_hz);
		}
> 			break;
> 	}
> 	baseclk_idx = i;
> 	baseclk_idx = min(baseclk_idx, 15);
> 	divisor = min(divisor, 32);
> 	scl_low = min(divisor * 9 / 16 - 1, 15);
> 	scl_high = (divisor - scl_low - 2) & GENMASK(3, 0);
> 	data = (scl_high - 1) << 20 | scl_high << 16 | scl_low << 12 | baseclk_idx;
> 	if (i2c_bus->timeout) {
> 		data |= AST2600_I2CC_TOUTBASECLK(AST_I2C_TIMEOUT_CLK);
> 		data |= AST2600_I2CC_TTIMEOUT(i2c_bus->timeout);
> 	}
> 
> 	return data;
> }
> > ...
> >
> > > > > 	divisor = min_t(unsigned long, divisor, 32);
> > > >
> > > > Can't you use min()? min_t is a beast with some subtle corner cases.
> > > >
> > > Will update to
> > > divisor = min(divisor, (unsigned long)32);
> >
> > No, the idea behind min() is that _both_ arguments are of the same
> > type, the proposed above is wrong.
> >
> > --
> > With Best Regards,
> > Andy Shevchenko
> >
diff mbox series

Patch

diff --git a/MAINTAINERS b/MAINTAINERS
index 3be1bdfe8ecc..8428094cd216 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1945,6 +1945,15 @@  F:	Documentation/devicetree/bindings/interrupt-controller/aspeed,ast2400-i2c-ic.
 F:	drivers/i2c/busses/i2c-aspeed.c
 F:	drivers/irqchip/irq-aspeed-i2c-ic.c
 
+ARM/ASPEED I2CV2 DRIVER
+M:	Ryan Chen <ryan_chen@aspeedtech.com>
+R:	Andrew Jeffery <andrew@aj.id.au>
+L:	linux-i2c@vger.kernel.org
+L:	openbmc@lists.ozlabs.org (moderated for non-subscribers)
+S:	Maintained
+F:	Documentation/devicetree/bindings/i2c/aspeed,i2c.yaml
+F:	drivers/i2c/busses/i2c-ast2600.c
+
 ARM/ASPEED MACHINE SUPPORT
 M:	Joel Stanley <joel@jms.id.au>
 R:	Andrew Jeffery <andrew@aj.id.au>
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 9cfe8fc509d7..a430a9f45994 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -389,6 +389,17 @@  config I2C_ALTERA
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-altera.
 
+config I2C_AST2600
+	tristate "Aspeed I2C v2 Controller"
+	depends on ARCH_ASPEED || COMPILE_TEST
+	select I2C_SMBUS
+	help
+	  If you say yes to this option, support will be included for the
+	  Aspeed I2C controller with new register set.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-ast2600.
+
 config I2C_ASPEED
 	tristate "Aspeed I2C Controller"
 	depends on ARCH_ASPEED || COMPILE_TEST
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index af56fe2c75c0..67e8e6ca44fb 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -38,6 +38,7 @@  obj-$(CONFIG_I2C_POWERMAC)	+= i2c-powermac.o
 obj-$(CONFIG_I2C_ALTERA)	+= i2c-altera.o
 obj-$(CONFIG_I2C_AMD_MP2)	+= i2c-amd-mp2-pci.o i2c-amd-mp2-plat.o
 obj-$(CONFIG_I2C_ASPEED)	+= i2c-aspeed.o
+obj-$(CONFIG_I2C_AST2600)	+= i2c-ast2600.o
 obj-$(CONFIG_I2C_AT91)		+= i2c-at91.o
 i2c-at91-objs			:= i2c-at91-core.o i2c-at91-master.o
 ifeq ($(CONFIG_I2C_AT91_SLAVE_EXPERIMENTAL),y)
diff --git a/drivers/i2c/busses/i2c-ast2600.c b/drivers/i2c/busses/i2c-ast2600.c
new file mode 100644
index 000000000000..d9a4ca0ecca6
--- /dev/null
+++ b/drivers/i2c/busses/i2c-ast2600.c
@@ -0,0 +1,1576 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ASPEED AST2600 new register set I2C controller driver
+ *
+ * Copyright (C) ASPEED Technology Inc.
+ */
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/i2c-smbus.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mfd/syscon.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/regmap.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/string_helpers.h>
+
+#define AST2600_I2CG_ISR			0x00
+#define AST2600_I2CG_SLAVE_ISR		0x04
+#define AST2600_I2CG_OWNER		0x08
+#define AST2600_I2CG_CTRL		0x0C
+#define AST2600_I2CG_CLK_DIV_CTRL	0x10
+
+#define AST2600_I2CG_SLAVE_PKT_NAK	BIT(4)
+#define AST2600_I2CG_M_S_SEPARATE_INTR	BIT(3)
+#define AST2600_I2CG_CTRL_NEW_REG	BIT(2)
+#define AST2600_I2CG_CTRL_NEW_CLK_DIV	BIT(1)
+#define AST2600_GLOBAL_INIT	\
+	(AST2600_I2CG_CTRL_NEW_REG | AST2600_I2CG_CTRL_NEW_CLK_DIV)
+/*
+ * APB clk : 100Mhz
+ * div	: scl		: baseclk [APB/((div/2) + 1)] : tBuf [1/bclk * 16]
+ * I2CG10[31:24] base clk4 for i2c auto recovery timeout counter (0xC6)
+ * I2CG10[23:16] base clk3 for Standard-mode (100Khz) min tBuf 4.7us
+ * 0x3c : 100.8Khz	: 3.225Mhz					  : 4.96us
+ * 0x3d : 99.2Khz	: 3.174Mhz					  : 5.04us
+ * 0x3e : 97.65Khz	: 3.125Mhz					  : 5.12us
+ * 0x40 : 97.75Khz	: 3.03Mhz					  : 5.28us
+ * 0x41 : 99.5Khz	: 2.98Mhz					  : 5.36us (default)
+ * I2CG10[15:8] base clk2 for Fast-mode (400Khz) min tBuf 1.3us
+ * 0x12 : 400Khz	: 10Mhz						  : 1.6us
+ * I2CG10[7:0] base clk1 for Fast-mode Plus (1Mhz) min tBuf 0.5us
+ * 0x08 : 1Mhz		: 20Mhz						  : 0.8us
+ */
+#define I2CCG_DIV_CTRL 0xC6411208
+
+/* 0x00 : I2CC Master/Slave Function Control Register  */
+#define AST2600_I2CC_FUN_CTRL		0x00
+#define AST2600_I2CC_SLAVE_ADDR_RX_EN		BIT(20)
+#define AST2600_I2CC_MASTER_RETRY_MASK		GENMASK(19, 18)
+#define AST2600_I2CC_MASTER_RETRY(x)		(((x) & GENMASK(1, 0)) << 18)
+#define AST2600_I2CC_BUS_AUTO_RELEASE		BIT(17)
+#define AST2600_I2CC_M_SDA_LOCK_EN			BIT(16)
+#define AST2600_I2CC_MULTI_MASTER_DIS		BIT(15)
+#define AST2600_I2CC_M_SCL_DRIVE_EN			BIT(14)
+#define AST2600_I2CC_MSB_STS				BIT(9)
+#define AST2600_I2CC_SDA_DRIVE_1T_EN		BIT(8)
+#define AST2600_I2CC_M_SDA_DRIVE_1T_EN		BIT(7)
+#define AST2600_I2CC_M_HIGH_SPEED_EN		BIT(6)
+/* reserver 5 : 2 */
+#define AST2600_I2CC_SLAVE_EN			BIT(1)
+#define AST2600_I2CC_MASTER_EN			BIT(0)
+
+/* 0x04 : I2CC Master/Slave Clock and AC Timing Control Register #1 */
+#define AST2600_I2CC_AC_TIMING		0x04
+#define AST2600_I2CC_TTIMEOUT(x)			(((x) & GENMASK(4, 0)) << 24)
+#define AST2600_I2CC_TCKHIGHMIN(x)			(((x) & GENMASK(3, 0)) << 20)
+#define AST2600_I2CC_TCKHIGH(x)			(((x) & GENMASK(3, 0)) << 16)
+#define AST2600_I2CC_TCKLOW(x)			(((x) & GENMASK(3, 0)) << 12)
+#define AST2600_I2CC_THDDAT(x)			(((x) & GENMASK(1, 0)) << 10)
+#define AST2600_I2CC_TOUTBASECLK(x)			(((x) & GENMASK(1, 0)) << 8)
+#define AST2600_I2CC_TBASECLK(x)			((x) & GENMASK(3, 0))
+
+/* 0x08 : I2CC Master/Slave Transmit/Receive Byte Buffer Register */
+#define AST2600_I2CC_STS_AND_BUFF		0x08
+#define AST2600_I2CC_TX_DIR_MASK			GENMASK(31, 29)
+#define AST2600_I2CC_SDA_OE				BIT(28)
+#define AST2600_I2CC_SDA_O				BIT(27)
+#define AST2600_I2CC_SCL_OE				BIT(26)
+#define AST2600_I2CC_SCL_O				BIT(25)
+
+#define AST2600_I2CC_SCL_LINE_STS			BIT(18)
+#define AST2600_I2CC_SDA_LINE_STS			BIT(17)
+#define AST2600_I2CC_BUS_BUSY_STS			BIT(16)
+
+#define AST2600_I2CC_GET_RX_BUFF(x)			(((x) >> 8) & GENMASK(7, 0))
+
+/* 0x0C : I2CC Master/Slave Pool Buffer Control Register  */
+#define AST2600_I2CC_BUFF_CTRL		0x0C
+#define AST2600_I2CC_GET_RX_BUF_LEN(x)		(((x) >> 24) & GENMASK(5, 0))
+#define AST2600_I2CC_SET_RX_BUF_LEN(x)		(((((x) - 1) & GENMASK(4, 0)) << 16) | BIT(0))
+#define AST2600_I2CC_SET_TX_BUF_LEN(x)		(((((x) - 1) & GENMASK(4, 0)) << 8) | BIT(0))
+#define AST2600_I2CC_GET_TX_BUF_LEN(x)		((((x) >> 8) & GENMASK(4, 0)) + 1)
+
+/* 0x10 : I2CM Master Interrupt Control Register */
+#define AST2600_I2CM_IER			0x10
+/* 0x14 : I2CM Master Interrupt Status Register   : WC */
+#define AST2600_I2CM_ISR			0x14
+
+#define AST2600_I2CM_PKT_TIMEOUT			BIT(18)
+#define AST2600_I2CM_PKT_ERROR			BIT(17)
+#define AST2600_I2CM_PKT_DONE			BIT(16)
+
+#define AST2600_I2CM_BUS_RECOVER_FAIL		BIT(15)
+#define AST2600_I2CM_SDA_DL_TO			BIT(14)
+#define AST2600_I2CM_BUS_RECOVER			BIT(13)
+#define AST2600_I2CM_SMBUS_ALT			BIT(12)
+
+#define AST2600_I2CM_SCL_LOW_TO			BIT(6)
+#define AST2600_I2CM_ABNORMAL			BIT(5)
+#define AST2600_I2CM_NORMAL_STOP			BIT(4)
+#define AST2600_I2CM_ARBIT_LOSS			BIT(3)
+#define AST2600_I2CM_RX_DONE			BIT(2)
+#define AST2600_I2CM_TX_NAK				BIT(1)
+#define AST2600_I2CM_TX_ACK				BIT(0)
+
+/* 0x18 : I2CM Master Command/Status Register   */
+#define AST2600_I2CM_CMD_STS		0x18
+#define AST2600_I2CM_PKT_ADDR(x)			(((x) & GENMASK(6, 0)) << 24)
+#define AST2600_I2CM_PKT_EN				BIT(16)
+#define AST2600_I2CM_SDA_OE_OUT_DIR			BIT(15)
+#define AST2600_I2CM_SDA_O_OUT_DIR			BIT(14)
+#define AST2600_I2CM_SCL_OE_OUT_DIR			BIT(13)
+#define AST2600_I2CM_SCL_O_OUT_DIR			BIT(12)
+#define AST2600_I2CM_RECOVER_CMD_EN			BIT(11)
+
+#define AST2600_I2CM_RX_DMA_EN			BIT(9)
+#define AST2600_I2CM_TX_DMA_EN			BIT(8)
+/* Command Bit */
+#define AST2600_I2CM_RX_BUFF_EN			BIT(7)
+#define AST2600_I2CM_TX_BUFF_EN			BIT(6)
+#define AST2600_I2CM_STOP_CMD			BIT(5)
+#define AST2600_I2CM_RX_CMD_LAST			BIT(4)
+#define AST2600_I2CM_RX_CMD				BIT(3)
+
+#define AST2600_I2CM_TX_CMD				BIT(1)
+#define AST2600_I2CM_START_CMD			BIT(0)
+
+/* 0x1C : I2CM Master DMA Transfer Length Register	 */
+#define AST2600_I2CM_DMA_LEN		0x1C
+/* Tx Rx support length 1 ~ 4096 */
+#define AST2600_I2CM_SET_RX_DMA_LEN(x)	((((x) & GENMASK(11, 0)) << 16) | BIT(31))
+#define AST2600_I2CM_SET_TX_DMA_LEN(x)	(((x) & GENMASK(11, 0)) | BIT(15))
+
+/* 0x20 : I2CS Slave Interrupt Control Register   */
+#define AST2600_I2CS_IER			0x20
+/* 0x24 : I2CS Slave Interrupt Status Register	 */
+#define AST2600_I2CS_ISR			0x24
+
+#define AST2600_I2CS_ADDR_INDICATE_MASK	GENMASK(31, 30)
+#define AST2600_I2CS_SLAVE_PENDING			BIT(29)
+
+#define AST2600_I2CS_WAIT_TX_DMA			BIT(25)
+#define AST2600_I2CS_WAIT_RX_DMA			BIT(24)
+
+#define AST2600_I2CS_ADDR3_NAK			BIT(22)
+#define AST2600_I2CS_ADDR2_NAK			BIT(21)
+#define AST2600_I2CS_ADDR1_NAK			BIT(20)
+
+#define AST2600_I2CS_ADDR_MASK			GENMASK(19, 18)
+#define AST2600_I2CS_PKT_ERROR			BIT(17)
+#define AST2600_I2CS_PKT_DONE			BIT(16)
+#define AST2600_I2CS_INACTIVE_TO			BIT(15)
+
+#define AST2600_I2CS_SLAVE_MATCH			BIT(7)
+#define AST2600_I2CS_ABNOR_STOP			BIT(5)
+#define AST2600_I2CS_STOP				BIT(4)
+#define AST2600_I2CS_RX_DONE_NAK			BIT(3)
+#define AST2600_I2CS_RX_DONE			BIT(2)
+#define AST2600_I2CS_TX_NAK				BIT(1)
+#define AST2600_I2CS_TX_ACK				BIT(0)
+
+/* 0x28 : I2CS Slave CMD/Status Register   */
+#define AST2600_I2CS_CMD_STS		0x28
+#define AST2600_I2CS_ACTIVE_ALL			GENMASK(18, 17)
+#define AST2600_I2CS_PKT_MODE_EN			BIT(16)
+#define AST2600_I2CS_AUTO_NAK_NOADDR		BIT(15)
+#define AST2600_I2CS_AUTO_NAK_EN			BIT(14)
+
+#define AST2600_I2CS_ALT_EN				BIT(10)
+#define AST2600_I2CS_RX_DMA_EN			BIT(9)
+#define AST2600_I2CS_TX_DMA_EN			BIT(8)
+#define AST2600_I2CS_RX_BUFF_EN			BIT(7)
+#define AST2600_I2CS_TX_BUFF_EN			BIT(6)
+#define AST2600_I2CS_RX_CMD_LAST			BIT(4)
+
+#define AST2600_I2CS_TX_CMD				BIT(2)
+
+#define AST2600_I2CS_DMA_LEN		0x2C
+#define AST2600_I2CS_SET_RX_DMA_LEN(x)	(((((x) - 1) & GENMASK(11, 0)) << 16) | BIT(31))
+#define AST2600_I2CS_RX_DMA_LEN_MASK	(GENMASK(11, 0) << 16)
+
+#define AST2600_I2CS_SET_TX_DMA_LEN(x)	((((x) - 1) & GENMASK(11, 0)) | BIT(15))
+#define AST2600_I2CS_TX_DMA_LEN_MASK	GENMASK(11, 0)
+
+/* I2CM Master DMA Tx Buffer Register   */
+#define AST2600_I2CM_TX_DMA			0x30
+/* I2CM Master DMA Rx Buffer Register	*/
+#define AST2600_I2CM_RX_DMA			0x34
+/* I2CS Slave DMA Tx Buffer Register   */
+#define AST2600_I2CS_TX_DMA			0x38
+/* I2CS Slave DMA Rx Buffer Register   */
+#define AST2600_I2CS_RX_DMA			0x3C
+
+#define AST2600_I2CS_ADDR_CTRL		0x40
+
+#define	AST2600_I2CS_ADDR3_MASK		GENMASK(22, 16)
+#define	AST2600_I2CS_ADDR2_MASK		GENMASK(14, 8)
+#define	AST2600_I2CS_ADDR1_MASK		GENMASK(6, 0)
+
+#define AST2600_I2CM_DMA_LEN_STS		0x48
+#define AST2600_I2CS_DMA_LEN_STS		0x4C
+
+#define AST2600_I2C_GET_TX_DMA_LEN(x)		((x) & GENMASK(12, 0))
+#define AST2600_I2C_GET_RX_DMA_LEN(x)		(((x) >> 16) & GENMASK(12, 0))
+
+/* 0x40 : Slave Device Address Register */
+#define AST2600_I2CS_ADDR3_ENABLE			BIT(23)
+#define AST2600_I2CS_ADDR3(x)			((x) << 16)
+#define AST2600_I2CS_ADDR2_ENABLE			BIT(15)
+#define AST2600_I2CS_ADDR2(x)			((x) << 8)
+#define AST2600_I2CS_ADDR1_ENABLE			BIT(7)
+#define AST2600_I2CS_ADDR1(x)			(x)
+
+#define I2C_SLAVE_MSG_BUF_SIZE		256
+
+#define AST2600_I2C_DMA_SIZE		4096
+
+#define MASTER_TRIGGER_LAST_STOP	(AST2600_I2CM_RX_CMD_LAST | AST2600_I2CM_STOP_CMD)
+#define SLAVE_TRIGGER_CMD	(AST2600_I2CS_ACTIVE_ALL | AST2600_I2CS_PKT_MODE_EN)
+
+#define AST_I2C_TIMEOUT_CLK		0x2
+
+enum xfer_mode {
+	BYTE_MODE,
+	BUFF_MODE,
+	DMA_MODE,
+};
+
+struct ast2600_i2c_bus {
+	struct i2c_adapter		adap;
+	struct device			*dev;
+	void __iomem			*reg_base;
+	struct regmap			*global_regs;
+	struct reset_control		*rst;
+	int				irq;
+	enum xfer_mode			mode;
+	struct clk			*clk;
+	u32				apb_clk;
+	u32				bus_frequency;
+	int				slave_operate;
+	u32				timeout;
+	/* smbus alert */
+	bool			alert_enable;
+	struct i2c_smbus_alert_setup	alert_data;
+	struct i2c_client		*ara;
+	/* Multi-master */
+	bool				multi_master;
+	/* master structure */
+	int				cmd_err;
+	struct completion		cmd_complete;
+	struct i2c_msg			*msgs;
+	size_t				buf_index;
+	/* cur xfer msgs index*/
+	int				msgs_index;
+	int				msgs_count;
+	u8				*master_safe_buf;
+	dma_addr_t			master_dma_addr;
+	/*total xfer count */
+	int				master_xfer_cnt;
+	/* Buffer mode */
+	void __iomem			*buf_base;
+	size_t				buf_size;
+	/* Slave structure */
+	int				slave_xfer_len;
+	int				slave_xfer_cnt;
+#ifdef CONFIG_I2C_SLAVE
+	unsigned char			*slave_dma_buf;
+	dma_addr_t			slave_dma_addr;
+	struct i2c_client		*slave;
+#endif
+};
+
+static u32 ast2600_select_i2c_clock(struct ast2600_i2c_bus *i2c_bus)
+{
+	unsigned long base_clk[4];
+	int baseclk_idx;
+	u32 clk_div_reg;
+	u32 scl_low;
+	u32 scl_high;
+	int divisor;
+	int inc = 0;
+	u32 data;
+
+	regmap_read(i2c_bus->global_regs, AST2600_I2CG_CLK_DIV_CTRL, &clk_div_reg);
+	for (int i = 0; i < 4; i++) {
+		base_clk[i] = (i2c_bus->apb_clk * 10) /
+		(((((clk_div_reg >> (i * 8)) & GENMASK(7, 0)) + 2) * 10) / 2);
+	}
+
+	if ((i2c_bus->apb_clk / i2c_bus->bus_frequency) <= 32) {
+		baseclk_idx = 0;
+		divisor = DIV_ROUND_UP(i2c_bus->apb_clk, i2c_bus->bus_frequency);
+	} else {
+		int i;
+
+		for (i = 0; i < 4; i++) {
+			if ((base_clk[i] / i2c_bus->bus_frequency) <= 32) {
+				baseclk_idx = i + 1;
+				divisor = DIV_ROUND_UP(base_clk[i], i2c_bus->bus_frequency);
+				break;
+			}
+		}
+		if (i == 4) {
+			baseclk_idx = 4;
+			divisor = DIV_ROUND_UP(base_clk[3], i2c_bus->bus_frequency);
+			while ((divisor + inc) > 32) {
+				inc |= divisor & 0x1;
+				divisor >>= 1;
+				baseclk_idx++;
+			}
+			divisor += inc;
+		}
+	}
+
+	divisor = min_t(int, divisor, 32);
+	baseclk_idx &= GENMASK(3, 0);
+	scl_low = ((divisor * 9) / 16) - 1;
+	scl_low = min_t(u32, scl_low, GENMASK(3, 0));
+	scl_high = (divisor - scl_low - 2) & GENMASK(3, 0);
+	data = (scl_high - 1) << 20 | scl_high << 16 | scl_low << 12 | baseclk_idx;
+
+	if (i2c_bus->timeout) {
+		data |= AST2600_I2CC_TOUTBASECLK(AST_I2C_TIMEOUT_CLK);
+		data |= AST2600_I2CC_TTIMEOUT(i2c_bus->timeout);
+	}
+
+	return data;
+}
+
+static u8 ast2600_i2c_recover_bus(struct ast2600_i2c_bus *i2c_bus)
+{
+	int ret = 0;
+	u32 ctrl;
+	u32 state;
+	int r;
+
+	dev_dbg(i2c_bus->dev, "%d-bus recovery bus [%x]\n", i2c_bus->adap.nr,
+		readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
+
+	ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	writel(ctrl & ~(AST2600_I2CC_MASTER_EN | AST2600_I2CC_SLAVE_EN),
+	       i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	writel(readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL) | AST2600_I2CC_MASTER_EN,
+	       i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	reinit_completion(&i2c_bus->cmd_complete);
+	i2c_bus->cmd_err = 0;
+
+	/* Check 0x14's SDA and SCL status */
+	state = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+	if (!(state & AST2600_I2CC_SDA_LINE_STS) && (state & AST2600_I2CC_SCL_LINE_STS)) {
+		writel(AST2600_I2CM_RECOVER_CMD_EN, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+		r = wait_for_completion_timeout(&i2c_bus->cmd_complete, i2c_bus->adap.timeout);
+		if (r == 0) {
+			dev_dbg(i2c_bus->dev, "recovery timed out\n");
+			ret = -ETIMEDOUT;
+		} else {
+			if (i2c_bus->cmd_err) {
+				dev_dbg(i2c_bus->dev, "recovery error\n");
+				ret = -EPROTO;
+			}
+		}
+	}
+
+	dev_dbg(i2c_bus->dev, "Recovery done [%x]\n",
+		readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
+	if (readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF) & AST2600_I2CC_BUS_BUSY_STS) {
+		dev_dbg(i2c_bus->dev, "Can't recover bus [%x]\n",
+			readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
+		ret = -EPROTO;
+	}
+
+	writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+	return ret;
+}
+
+#ifdef CONFIG_I2C_SLAVE
+static void ast2600_i2c_slave_packet_dma_irq(struct ast2600_i2c_bus *i2c_bus, u32 sts)
+{
+	int slave_rx_len;
+	u32 cmd = 0;
+	u8 value;
+	int i;
+
+	sts &= ~(AST2600_I2CS_SLAVE_PENDING);
+	/* Handle i2c slave timeout condition */
+	if (AST2600_I2CS_INACTIVE_TO & sts) {
+		cmd = SLAVE_TRIGGER_CMD;
+		cmd |= AST2600_I2CS_RX_DMA_EN;
+		writel(AST2600_I2CS_SET_RX_DMA_LEN(I2C_SLAVE_MSG_BUF_SIZE),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+		writel(cmd, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+		writel(AST2600_I2CS_PKT_DONE, i2c_bus->reg_base + AST2600_I2CS_ISR);
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		return;
+	}
+
+	sts &= ~(AST2600_I2CS_PKT_DONE | AST2600_I2CS_PKT_ERROR);
+
+	switch (sts) {
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE | AST2600_I2CS_WAIT_RX_DMA:
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_WAIT_RX_DMA:
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+		slave_rx_len = AST2600_I2C_GET_RX_DMA_LEN(readl(i2c_bus->reg_base +
+						      AST2600_I2CS_DMA_LEN_STS));
+		for (i = 0; i < slave_rx_len; i++) {
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED,
+					&i2c_bus->slave_dma_buf[i]);
+		}
+		writel(AST2600_I2CS_SET_RX_DMA_LEN(I2C_SLAVE_MSG_BUF_SIZE),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_RX_DMA_EN;
+		break;
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_STOP:
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		writel(AST2600_I2CS_SET_RX_DMA_LEN(I2C_SLAVE_MSG_BUF_SIZE),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_RX_DMA_EN;
+		break;
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE_NAK |
+			AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_WAIT_RX_DMA |
+			AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+	case AST2600_I2CS_RX_DONE_NAK | AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+	case AST2600_I2CS_RX_DONE | AST2600_I2CS_WAIT_RX_DMA | AST2600_I2CS_STOP:
+	case AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+	case AST2600_I2CS_RX_DONE | AST2600_I2CS_WAIT_RX_DMA:
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+		if (sts & AST2600_I2CS_SLAVE_MATCH)
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+
+		slave_rx_len = AST2600_I2C_GET_RX_DMA_LEN(readl(i2c_bus->reg_base +
+						      AST2600_I2CS_DMA_LEN_STS));
+		for (i = 0; i < slave_rx_len; i++) {
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED,
+					&i2c_bus->slave_dma_buf[i]);
+		}
+		writel(AST2600_I2CS_SET_RX_DMA_LEN(I2C_SLAVE_MSG_BUF_SIZE),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+		if (sts & AST2600_I2CS_STOP)
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_RX_DMA_EN;
+		break;
+
+	/* it is Mw data Mr coming -> it need send tx */
+	case AST2600_I2CS_RX_DONE | AST2600_I2CS_WAIT_TX_DMA:
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE | AST2600_I2CS_WAIT_TX_DMA:
+		/* it should be repeat start read */
+		if (sts & AST2600_I2CS_SLAVE_MATCH)
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+
+		slave_rx_len = AST2600_I2C_GET_RX_DMA_LEN(readl(i2c_bus->reg_base +
+						      AST2600_I2CS_DMA_LEN_STS));
+		for (i = 0; i < slave_rx_len; i++) {
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED,
+					&i2c_bus->slave_dma_buf[i]);
+		}
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_READ_REQUESTED,
+				&i2c_bus->slave_dma_buf[0]);
+		writel(0, i2c_bus->reg_base + AST2600_I2CS_DMA_LEN_STS);
+		writel(AST2600_I2CS_SET_TX_DMA_LEN(1),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_TX_DMA_EN;
+		break;
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_WAIT_TX_DMA:
+		/* First Start read */
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_READ_REQUESTED,
+				&i2c_bus->slave_dma_buf[0]);
+		writel(AST2600_I2CS_SET_TX_DMA_LEN(1),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_TX_DMA_EN;
+		break;
+	case AST2600_I2CS_WAIT_TX_DMA:
+		/* it should be next start read */
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_READ_PROCESSED,
+				&i2c_bus->slave_dma_buf[0]);
+		writel(0, i2c_bus->reg_base + AST2600_I2CS_DMA_LEN_STS);
+		writel(AST2600_I2CS_SET_TX_DMA_LEN(1),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_TX_DMA_EN;
+		break;
+	case AST2600_I2CS_TX_NAK | AST2600_I2CS_STOP:
+		/* it just tx complete */
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		writel(0, i2c_bus->reg_base + AST2600_I2CS_DMA_LEN_STS);
+		writel(AST2600_I2CS_SET_RX_DMA_LEN(I2C_SLAVE_MSG_BUF_SIZE),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_RX_DMA_EN;
+		break;
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE:
+		cmd = 0;
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+		break;
+	case AST2600_I2CS_STOP:
+		cmd = 0;
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		break;
+	default:
+		dev_dbg(i2c_bus->dev, "unhandled slave isr case %x, sts %x\n", sts,
+			readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
+		break;
+	}
+
+	if (cmd)
+		writel(cmd, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+	writel(AST2600_I2CS_PKT_DONE, i2c_bus->reg_base + AST2600_I2CS_ISR);
+	readl(i2c_bus->reg_base + AST2600_I2CS_ISR);
+}
+
+static void ast2600_i2c_slave_packet_buff_irq(struct ast2600_i2c_bus *i2c_bus, u32 sts)
+{
+	int slave_rx_len = 0;
+	u32 cmd = 0;
+	u8 value;
+	int i;
+
+	/* due to master slave is common buffer, so need force the master stop not issue */
+	if (readl(i2c_bus->reg_base + AST2600_I2CM_CMD_STS) & GENMASK(15, 0)) {
+		writel(0, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+		i2c_bus->cmd_err = -EBUSY;
+		writel(0, i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		complete(&i2c_bus->cmd_complete);
+	}
+
+	/* Handle i2c slave timeout condition */
+	if (AST2600_I2CS_INACTIVE_TO & sts) {
+		writel(SLAVE_TRIGGER_CMD, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+		writel(AST2600_I2CS_PKT_DONE, i2c_bus->reg_base + AST2600_I2CS_ISR);
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		i2c_bus->slave_operate = 0;
+		return;
+	}
+
+	sts &= ~(AST2600_I2CS_PKT_DONE | AST2600_I2CS_PKT_ERROR);
+
+	if (sts & AST2600_I2CS_SLAVE_MATCH)
+		i2c_bus->slave_operate = 1;
+
+	switch (sts) {
+	case AST2600_I2CS_SLAVE_PENDING | AST2600_I2CS_WAIT_RX_DMA |
+		 AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+	case AST2600_I2CS_SLAVE_PENDING |
+		 AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+	case AST2600_I2CS_SLAVE_PENDING |
+		 AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_STOP:
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		fallthrough;
+	case AST2600_I2CS_SLAVE_PENDING |
+		 AST2600_I2CS_WAIT_RX_DMA | AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE:
+	case AST2600_I2CS_WAIT_RX_DMA | AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE:
+	case AST2600_I2CS_WAIT_RX_DMA | AST2600_I2CS_SLAVE_MATCH:
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+		cmd = SLAVE_TRIGGER_CMD;
+		if (sts & AST2600_I2CS_RX_DONE) {
+			slave_rx_len = AST2600_I2CC_GET_RX_BUF_LEN(readl(i2c_bus->reg_base +
+							       AST2600_I2CC_BUFF_CTRL));
+			for (i = 0; i < slave_rx_len; i++) {
+				value = readb(i2c_bus->buf_base + 0x10 + i);
+				i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+			}
+		}
+		if (readl(i2c_bus->reg_base + AST2600_I2CS_CMD_STS) & AST2600_I2CS_RX_BUFF_EN)
+			cmd = 0;
+		else
+			cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_RX_BUFF_EN;
+
+		writel(AST2600_I2CC_SET_RX_BUF_LEN(i2c_bus->buf_size),
+		       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		break;
+	case AST2600_I2CS_WAIT_RX_DMA | AST2600_I2CS_RX_DONE:
+		cmd = SLAVE_TRIGGER_CMD;
+		slave_rx_len = AST2600_I2CC_GET_RX_BUF_LEN(readl(i2c_bus->reg_base +
+						       AST2600_I2CC_BUFF_CTRL));
+		for (i = 0; i < slave_rx_len; i++) {
+			value = readb(i2c_bus->buf_base + 0x10 + i);
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+		}
+		cmd |= AST2600_I2CS_RX_BUFF_EN;
+		writel(AST2600_I2CC_SET_RX_BUF_LEN(i2c_bus->buf_size),
+		       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		break;
+	case AST2600_I2CS_SLAVE_PENDING | AST2600_I2CS_WAIT_RX_DMA |
+				AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+		cmd = SLAVE_TRIGGER_CMD;
+		slave_rx_len = AST2600_I2CC_GET_RX_BUF_LEN(readl(i2c_bus->reg_base +
+								 AST2600_I2CC_BUFF_CTRL));
+		for (i = 0; i < slave_rx_len; i++) {
+			value = readb(i2c_bus->buf_base + 0x10 + i);
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+		}
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		cmd |= AST2600_I2CS_RX_BUFF_EN;
+		writel(AST2600_I2CC_SET_RX_BUF_LEN(i2c_bus->buf_size),
+		       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		break;
+	case AST2600_I2CS_SLAVE_PENDING | AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+		cmd = SLAVE_TRIGGER_CMD;
+		slave_rx_len = AST2600_I2CC_GET_RX_BUF_LEN(readl(i2c_bus->reg_base +
+								 AST2600_I2CC_BUFF_CTRL));
+		for (i = 0; i < slave_rx_len; i++) {
+			value = readb(i2c_bus->buf_base + 0x10 + i);
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+		}
+		/* workaround for avoid next start with len != 0 */
+		writel(BIT(0), i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		break;
+	case AST2600_I2CS_RX_DONE | AST2600_I2CS_STOP:
+		cmd = SLAVE_TRIGGER_CMD;
+		slave_rx_len = AST2600_I2CC_GET_RX_BUF_LEN(readl(i2c_bus->reg_base +
+								 AST2600_I2CC_BUFF_CTRL));
+		for (i = 0; i < slave_rx_len; i++) {
+			value = readb(i2c_bus->buf_base + 0x10 + i);
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+		}
+		/* workaround for avoid next start with len != 0 */
+		writel(BIT(0), i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		break;
+	case AST2600_I2CS_WAIT_TX_DMA | AST2600_I2CS_SLAVE_MATCH:
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_READ_REQUESTED, &value);
+		writeb(value, i2c_bus->buf_base);
+		writel(AST2600_I2CC_SET_TX_BUF_LEN(1),
+		       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_TX_BUFF_EN;
+		break;
+	case AST2600_I2CS_WAIT_TX_DMA | AST2600_I2CS_RX_DONE:
+	case AST2600_I2CS_WAIT_TX_DMA:
+		if (sts & AST2600_I2CS_RX_DONE) {
+			slave_rx_len = AST2600_I2CC_GET_RX_BUF_LEN(readl(i2c_bus->reg_base +
+							AST2600_I2CC_BUFF_CTRL));
+			for (i = 0; i < slave_rx_len; i++) {
+				value = readb(i2c_bus->buf_base + 0x10 + i);
+				i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED, &value);
+			}
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_READ_REQUESTED, &value);
+		} else {
+			i2c_slave_event(i2c_bus->slave, I2C_SLAVE_READ_PROCESSED, &value);
+		}
+		writeb(value, i2c_bus->buf_base);
+		writel(AST2600_I2CC_SET_TX_BUF_LEN(1),
+		       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_TX_BUFF_EN;
+		break;
+	/* workaround : trigger the cmd twice to fix next state keep 1000000 */
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE:
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+		cmd = SLAVE_TRIGGER_CMD | AST2600_I2CS_RX_BUFF_EN;
+		writel(cmd, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+		break;
+
+	case AST2600_I2CS_TX_NAK | AST2600_I2CS_STOP:
+	case AST2600_I2CS_STOP:
+		cmd = SLAVE_TRIGGER_CMD;
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		break;
+	default:
+		dev_dbg(i2c_bus->dev, "unhandled slave isr case %x, sts %x\n", sts,
+			readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF));
+		break;
+	}
+
+	if (cmd)
+		writel(cmd, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+	writel(AST2600_I2CS_PKT_DONE, i2c_bus->reg_base + AST2600_I2CS_ISR);
+	readl(i2c_bus->reg_base + AST2600_I2CS_ISR);
+
+	if ((sts & AST2600_I2CS_STOP) && !(sts & AST2600_I2CS_SLAVE_PENDING))
+		i2c_bus->slave_operate = 0;
+}
+
+static void ast2600_i2c_slave_byte_irq(struct ast2600_i2c_bus *i2c_bus, u32 sts)
+{
+	u32 i2c_buff = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+	u32 cmd = AST2600_I2CS_ACTIVE_ALL;
+	u8 byte_data;
+	u8 value;
+
+	switch (sts) {
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE | AST2600_I2CS_WAIT_RX_DMA:
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_REQUESTED, &value);
+		/* first address match is address */
+		byte_data = AST2600_I2CC_GET_RX_BUFF(i2c_buff);
+		break;
+	case AST2600_I2CS_RX_DONE | AST2600_I2CS_WAIT_RX_DMA:
+		byte_data = AST2600_I2CC_GET_RX_BUFF(i2c_buff);
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_WRITE_RECEIVED, &byte_data);
+		break;
+	case AST2600_I2CS_SLAVE_MATCH | AST2600_I2CS_RX_DONE | AST2600_I2CS_WAIT_TX_DMA:
+		cmd |= AST2600_I2CS_TX_CMD;
+		byte_data = AST2600_I2CC_GET_RX_BUFF(i2c_buff);
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_READ_REQUESTED, &byte_data);
+		writel(byte_data, i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+		break;
+	case AST2600_I2CS_TX_ACK | AST2600_I2CS_WAIT_TX_DMA:
+		cmd |= AST2600_I2CS_TX_CMD;
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_READ_PROCESSED, &byte_data);
+		writel(byte_data, i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+		break;
+	case AST2600_I2CS_STOP:
+	case AST2600_I2CS_STOP | AST2600_I2CS_TX_NAK:
+		i2c_slave_event(i2c_bus->slave, I2C_SLAVE_STOP, &value);
+		break;
+	default:
+		dev_dbg(i2c_bus->dev, "unhandled pkt isr %x\n", sts);
+		break;
+	}
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+	writel(sts, i2c_bus->reg_base + AST2600_I2CS_ISR);
+	readl(i2c_bus->reg_base + AST2600_I2CS_ISR);
+}
+
+static int ast2600_i2c_slave_irq(struct ast2600_i2c_bus *i2c_bus)
+{
+	u32 ier = readl(i2c_bus->reg_base + AST2600_I2CS_IER);
+	u32 isr = readl(i2c_bus->reg_base + AST2600_I2CS_ISR);
+
+	if (!(isr & ier))
+		return 0;
+
+	/* Slave interrupt coming after Master package done
+	 * So need handle master first.
+	 */
+	if (readl(i2c_bus->reg_base + AST2600_I2CM_ISR) & AST2600_I2CM_PKT_DONE)
+		return 0;
+
+	isr &= ~(AST2600_I2CS_ADDR_INDICATE_MASK);
+
+	if (AST2600_I2CS_ADDR1_NAK & isr)
+		isr &= ~AST2600_I2CS_ADDR1_NAK;
+
+	if (AST2600_I2CS_ADDR2_NAK & isr)
+		isr &= ~AST2600_I2CS_ADDR2_NAK;
+
+	if (AST2600_I2CS_ADDR3_NAK & isr)
+		isr &= ~AST2600_I2CS_ADDR3_NAK;
+
+	if (AST2600_I2CS_ADDR_MASK & isr)
+		isr &= ~AST2600_I2CS_ADDR_MASK;
+
+	if (AST2600_I2CS_PKT_DONE & isr) {
+		if (i2c_bus->mode == DMA_MODE)
+			ast2600_i2c_slave_packet_dma_irq(i2c_bus, isr);
+		else
+			ast2600_i2c_slave_packet_buff_irq(i2c_bus, isr);
+	} else {
+		ast2600_i2c_slave_byte_irq(i2c_bus, isr);
+	}
+
+	return 1;
+}
+#endif
+
+static int ast2600_i2c_do_start(struct ast2600_i2c_bus *i2c_bus)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	int xfer_len = 0;
+	int i;
+	u32 cmd;
+
+	cmd = AST2600_I2CM_PKT_EN | AST2600_I2CM_PKT_ADDR(msg->addr) | AST2600_I2CM_START_CMD;
+
+	/* send start */
+	dev_dbg(i2c_bus->dev, "[%d] %sing %d byte%s %s 0x%02x\n",
+		i2c_bus->msgs_index, str_read_write(msg->flags & I2C_M_RD),
+		msg->len, msg->len > 1 ? "s" : "",
+		msg->flags & I2C_M_RD ? "from" : "to", msg->addr);
+
+	i2c_bus->master_xfer_cnt = 0;
+	i2c_bus->buf_index = 0;
+
+	if (msg->flags & I2C_M_RD) {
+		cmd |= AST2600_I2CM_RX_CMD;
+		if (i2c_bus->mode == DMA_MODE) {
+			/* dma mode */
+			cmd |= AST2600_I2CM_RX_DMA_EN;
+
+			if (msg->flags & I2C_M_RECV_LEN) {
+				xfer_len = 1;
+			} else {
+				if (msg->len > AST2600_I2C_DMA_SIZE) {
+					xfer_len = AST2600_I2C_DMA_SIZE;
+				} else {
+					xfer_len = msg->len;
+					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+						cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+			}
+			writel(AST2600_I2CM_SET_RX_DMA_LEN(xfer_len - 1),
+			       i2c_bus->reg_base + AST2600_I2CM_DMA_LEN);
+			i2c_bus->master_safe_buf = i2c_get_dma_safe_msg_buf(msg, 1);
+			if (!i2c_bus->master_safe_buf)
+				return -ENOMEM;
+			i2c_bus->master_dma_addr =
+				dma_map_single(i2c_bus->dev,
+					       i2c_bus->master_safe_buf, msg->len, DMA_FROM_DEVICE);
+			if (dma_mapping_error(i2c_bus->dev, i2c_bus->master_dma_addr)) {
+				i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf, msg, false);
+				i2c_bus->master_safe_buf = NULL;
+				return -ENOMEM;
+			}
+			writel(i2c_bus->master_dma_addr, i2c_bus->reg_base + AST2600_I2CM_RX_DMA);
+		} else if (i2c_bus->mode == BUFF_MODE) {
+			/* buff mode */
+			cmd |= AST2600_I2CM_RX_BUFF_EN;
+			if (msg->flags & I2C_M_RECV_LEN) {
+				dev_dbg(i2c_bus->dev, "smbus read\n");
+				xfer_len = 1;
+			} else {
+				if (msg->len > i2c_bus->buf_size) {
+					xfer_len = i2c_bus->buf_size;
+				} else {
+					xfer_len = msg->len;
+					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+						cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+			}
+			writel(AST2600_I2CC_SET_RX_BUF_LEN(xfer_len),
+			       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+		} else {
+			/* byte mode */
+			xfer_len = 1;
+			if (msg->flags & I2C_M_RECV_LEN) {
+				dev_dbg(i2c_bus->dev, "smbus read\n");
+			} else {
+				if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count) {
+					if (msg->len == 1)
+						cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+			}
+		}
+	} else {
+		if (i2c_bus->mode == DMA_MODE) {
+			/* dma mode */
+			if (msg->len > AST2600_I2C_DMA_SIZE) {
+				xfer_len = AST2600_I2C_DMA_SIZE;
+			} else {
+				if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+					cmd |= AST2600_I2CM_STOP_CMD;
+				xfer_len = msg->len;
+			}
+
+			if (xfer_len) {
+				cmd |= AST2600_I2CM_TX_DMA_EN | AST2600_I2CM_TX_CMD;
+				writel(AST2600_I2CM_SET_TX_DMA_LEN(xfer_len - 1),
+				       i2c_bus->reg_base + AST2600_I2CM_DMA_LEN);
+				i2c_bus->master_safe_buf = i2c_get_dma_safe_msg_buf(msg, 1);
+				if (!i2c_bus->master_safe_buf)
+					return -ENOMEM;
+				i2c_bus->master_dma_addr =
+					dma_map_single(i2c_bus->dev, i2c_bus->master_safe_buf,
+						       msg->len, DMA_TO_DEVICE);
+				if (dma_mapping_error(i2c_bus->dev, i2c_bus->master_dma_addr)) {
+					i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf,
+								 msg, false);
+					i2c_bus->master_safe_buf = NULL;
+					return -ENOMEM;
+				}
+				writel(i2c_bus->master_dma_addr,
+				       i2c_bus->reg_base + AST2600_I2CM_TX_DMA);
+			}
+		} else if (i2c_bus->mode == BUFF_MODE) {
+			u8 wbuf[4];
+			/* buff mode */
+			if (msg->len > i2c_bus->buf_size) {
+				xfer_len = i2c_bus->buf_size;
+			} else {
+				if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+					cmd |= AST2600_I2CM_STOP_CMD;
+				xfer_len = msg->len;
+			}
+			if (xfer_len) {
+				cmd |= AST2600_I2CM_TX_BUFF_EN | AST2600_I2CM_TX_CMD;
+				if (readl(i2c_bus->reg_base + AST2600_I2CS_ISR))
+					return -ENOMEM;
+				writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
+				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+				if (readl(i2c_bus->reg_base + AST2600_I2CS_ISR))
+					return -ENOMEM;
+				for (i = 0; i < xfer_len; i++) {
+					wbuf[i % 4] = msg->buf[i];
+					if (i % 4 == 3)
+						writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
+				}
+				if (--i % 4 != 3)
+					writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
+			}
+			if (readl(i2c_bus->reg_base + AST2600_I2CS_ISR))
+				return -ENOMEM;
+		} else {
+			/* byte mode */
+			if (msg->len <= 1 && (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count))
+				cmd |= AST2600_I2CM_STOP_CMD;
+
+			if (msg->len) {
+				cmd |= AST2600_I2CM_TX_CMD;
+				xfer_len = 1;
+				writel(msg->buf[0], i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+			} else {
+				xfer_len = 0;
+			}
+		}
+	}
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+	return 0;
+}
+
+static int ast2600_i2c_is_irq_error(u32 irq_status)
+{
+	if (irq_status & AST2600_I2CM_ARBIT_LOSS)
+		return -EAGAIN;
+	if (irq_status & (AST2600_I2CM_SDA_DL_TO | AST2600_I2CM_SCL_LOW_TO))
+		return -EBUSY;
+	if (irq_status & (AST2600_I2CM_ABNORMAL))
+		return -EPROTO;
+
+	return 0;
+}
+
+static void ast2600_i2c_master_package_irq(struct ast2600_i2c_bus *i2c_bus, u32 sts)
+{
+	struct i2c_msg *msg = &i2c_bus->msgs[i2c_bus->msgs_index];
+	u32 cmd = AST2600_I2CM_PKT_EN;
+	int xfer_len;
+	int i;
+
+	sts &= ~AST2600_I2CM_PKT_DONE;
+	writel(AST2600_I2CM_PKT_DONE, i2c_bus->reg_base + AST2600_I2CM_ISR);
+	switch (sts) {
+	case AST2600_I2CM_PKT_ERROR:
+		i2c_bus->cmd_err = -EAGAIN;
+		complete(&i2c_bus->cmd_complete);
+		break;
+	case AST2600_I2CM_PKT_ERROR | AST2600_I2CM_TX_NAK: /* a0 fix for issue */
+		fallthrough;
+	case AST2600_I2CM_PKT_ERROR | AST2600_I2CM_TX_NAK | AST2600_I2CM_NORMAL_STOP:
+		i2c_bus->cmd_err = -ENXIO;
+		complete(&i2c_bus->cmd_complete);
+		break;
+	case AST2600_I2CM_NORMAL_STOP:
+		/* write 0 byte only have stop isr */
+		i2c_bus->msgs_index++;
+		if (i2c_bus->msgs_index < i2c_bus->msgs_count) {
+			if (ast2600_i2c_do_start(i2c_bus)) {
+				i2c_bus->cmd_err = -ENOMEM;
+				complete(&i2c_bus->cmd_complete);
+			}
+		} else {
+			i2c_bus->cmd_err = i2c_bus->msgs_index;
+			complete(&i2c_bus->cmd_complete);
+		}
+		break;
+	case AST2600_I2CM_TX_ACK:
+	case AST2600_I2CM_TX_ACK | AST2600_I2CM_NORMAL_STOP:
+		if (i2c_bus->mode == DMA_MODE)
+			xfer_len = AST2600_I2C_GET_TX_DMA_LEN(readl(i2c_bus->reg_base +
+							  AST2600_I2CM_DMA_LEN_STS));
+		else if (i2c_bus->mode == BUFF_MODE)
+			xfer_len = AST2600_I2CC_GET_TX_BUF_LEN(readl(i2c_bus->reg_base +
+							   AST2600_I2CC_BUFF_CTRL));
+		else
+			xfer_len = 1;
+
+		i2c_bus->master_xfer_cnt += xfer_len;
+
+		if (i2c_bus->master_xfer_cnt == msg->len) {
+			if (i2c_bus->mode == DMA_MODE) {
+				dma_unmap_single(i2c_bus->dev, i2c_bus->master_dma_addr, msg->len,
+						 DMA_TO_DEVICE);
+				i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf, msg, true);
+				i2c_bus->master_safe_buf = NULL;
+			}
+			i2c_bus->msgs_index++;
+			if (i2c_bus->msgs_index == i2c_bus->msgs_count) {
+				i2c_bus->cmd_err = i2c_bus->msgs_index;
+				complete(&i2c_bus->cmd_complete);
+			} else {
+				if (ast2600_i2c_do_start(i2c_bus)) {
+					i2c_bus->cmd_err = -ENOMEM;
+					complete(&i2c_bus->cmd_complete);
+				}
+			}
+		} else {
+			/* do next tx */
+			cmd |= AST2600_I2CM_TX_CMD;
+			if (i2c_bus->mode == DMA_MODE) {
+				cmd |= AST2600_I2CM_TX_DMA_EN;
+				xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+				if (xfer_len > AST2600_I2C_DMA_SIZE) {
+					xfer_len = AST2600_I2C_DMA_SIZE;
+				} else {
+					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+						cmd |= AST2600_I2CM_STOP_CMD;
+				}
+				writel(AST2600_I2CM_SET_TX_DMA_LEN(xfer_len - 1),
+				       i2c_bus->reg_base + AST2600_I2CM_DMA_LEN);
+				writel(i2c_bus->master_dma_addr + i2c_bus->master_xfer_cnt,
+				       i2c_bus->reg_base + AST2600_I2CM_TX_DMA);
+			} else if (i2c_bus->mode == BUFF_MODE) {
+				u8 wbuf[4];
+
+				cmd |= AST2600_I2CM_TX_BUFF_EN;
+				xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+				if (xfer_len > i2c_bus->buf_size) {
+					xfer_len = i2c_bus->buf_size;
+				} else {
+					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+						cmd |= AST2600_I2CM_STOP_CMD;
+				}
+				for (i = 0; i < xfer_len; i++) {
+					wbuf[i % 4] = msg->buf[i2c_bus->master_xfer_cnt + i];
+					if (i % 4 == 3)
+						writel(*(u32 *)wbuf, i2c_bus->buf_base + i - 3);
+				}
+				if (--i % 4 != 3)
+					writel(*(u32 *)wbuf, i2c_bus->buf_base + i - (i % 4));
+				writel(AST2600_I2CC_SET_TX_BUF_LEN(xfer_len),
+				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+			} else {
+				/* byte */
+				if ((i2c_bus->msgs_index + 1 == i2c_bus->msgs_count) &&
+				    ((i2c_bus->master_xfer_cnt + 1) == msg->len)) {
+					cmd |= AST2600_I2CM_STOP_CMD;
+				}
+				writel(msg->buf[i2c_bus->master_xfer_cnt],
+				       i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+			}
+			writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+		}
+		break;
+	case AST2600_I2CM_RX_DONE:
+#ifdef CONFIG_I2C_SLAVE
+		/* Workaround for master/slave package mode enable rx done stuck issue
+		 * When master go for first read (RX_DONE), slave mode will also effect
+		 * Then controller will send nack, not operate anymore.
+		 */
+		if (readl(i2c_bus->reg_base + AST2600_I2CS_CMD_STS) & AST2600_I2CS_PKT_MODE_EN) {
+			u32 slave_cmd = readl(i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+
+			writel(0, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+			writel(slave_cmd, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+		}
+		fallthrough;
+#endif
+	case AST2600_I2CM_RX_DONE | AST2600_I2CM_NORMAL_STOP:
+		/* do next rx */
+		if (i2c_bus->mode == DMA_MODE) {
+			xfer_len = AST2600_I2C_GET_RX_DMA_LEN(readl(i2c_bus->reg_base +
+								    AST2600_I2CM_DMA_LEN_STS));
+		} else if (i2c_bus->mode == BUFF_MODE) {
+			xfer_len = AST2600_I2CC_GET_RX_BUF_LEN(readl(i2c_bus->reg_base +
+								     AST2600_I2CC_BUFF_CTRL));
+			for (i = 0; i < xfer_len; i++)
+				msg->buf[i2c_bus->master_xfer_cnt + i] =
+					readb(i2c_bus->buf_base + 0x10 + i);
+		} else {
+			xfer_len = 1;
+			msg->buf[i2c_bus->master_xfer_cnt] =
+				AST2600_I2CC_GET_RX_BUFF(readl(i2c_bus->reg_base +
+						     AST2600_I2CC_STS_AND_BUFF));
+		}
+
+		if (msg->flags & I2C_M_RECV_LEN) {
+			msg->len = msg->buf[0] + ((msg->flags & I2C_CLIENT_PEC) ? 2 : 1);
+			msg->len = min_t(unsigned int, msg->len, I2C_SMBUS_BLOCK_MAX);
+			msg->flags &= ~I2C_M_RECV_LEN;
+		}
+		i2c_bus->master_xfer_cnt += xfer_len;
+
+		if (i2c_bus->master_xfer_cnt == msg->len) {
+			if (i2c_bus->mode == DMA_MODE) {
+				dma_unmap_single(i2c_bus->dev, i2c_bus->master_dma_addr, msg->len,
+						 DMA_FROM_DEVICE);
+				i2c_put_dma_safe_msg_buf(i2c_bus->master_safe_buf, msg, true);
+				i2c_bus->master_safe_buf = NULL;
+			}
+
+			i2c_bus->msgs_index++;
+			if (i2c_bus->msgs_index == i2c_bus->msgs_count) {
+				i2c_bus->cmd_err = i2c_bus->msgs_index;
+				complete(&i2c_bus->cmd_complete);
+			} else {
+				if (ast2600_i2c_do_start(i2c_bus)) {
+					i2c_bus->cmd_err = -ENOMEM;
+					complete(&i2c_bus->cmd_complete);
+				}
+			}
+		} else {
+			/* next rx */
+			cmd |= AST2600_I2CM_RX_CMD;
+			if (i2c_bus->mode == DMA_MODE) {
+				cmd |= AST2600_I2CM_RX_DMA_EN;
+				xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+				if (xfer_len > AST2600_I2C_DMA_SIZE) {
+					xfer_len = AST2600_I2C_DMA_SIZE;
+				} else {
+					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+						cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+				writel(AST2600_I2CM_SET_RX_DMA_LEN(xfer_len - 1),
+				       i2c_bus->reg_base + AST2600_I2CM_DMA_LEN);
+				writel(i2c_bus->master_dma_addr + i2c_bus->master_xfer_cnt,
+				       i2c_bus->reg_base + AST2600_I2CM_RX_DMA);
+			} else if (i2c_bus->mode == BUFF_MODE) {
+				cmd |= AST2600_I2CM_RX_BUFF_EN;
+				xfer_len = msg->len - i2c_bus->master_xfer_cnt;
+				if (xfer_len > i2c_bus->buf_size) {
+					xfer_len = i2c_bus->buf_size;
+				} else {
+					if (i2c_bus->msgs_index + 1 == i2c_bus->msgs_count)
+						cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+				writel(AST2600_I2CC_SET_RX_BUF_LEN(xfer_len),
+				       i2c_bus->reg_base + AST2600_I2CC_BUFF_CTRL);
+			} else {
+				if ((i2c_bus->msgs_index + 1 == i2c_bus->msgs_count) &&
+				    ((i2c_bus->master_xfer_cnt + 1) == msg->len)) {
+					cmd |= MASTER_TRIGGER_LAST_STOP;
+				}
+			}
+			writel(cmd, i2c_bus->reg_base + AST2600_I2CM_CMD_STS);
+		}
+		break;
+	default:
+		dev_dbg(i2c_bus->dev, "unhandled sts %x\n", sts);
+		break;
+	}
+}
+
+static int ast2600_i2c_master_irq(struct ast2600_i2c_bus *i2c_bus)
+{
+	u32 sts = readl(i2c_bus->reg_base + AST2600_I2CM_ISR);
+	u32 ier = readl(i2c_bus->reg_base + AST2600_I2CM_IER);
+	u32 ctrl = 0;
+
+	if (!i2c_bus->alert_enable)
+		sts &= ~AST2600_I2CM_SMBUS_ALT;
+
+	if (AST2600_I2CM_BUS_RECOVER_FAIL & sts) {
+		writel(AST2600_I2CM_BUS_RECOVER_FAIL, i2c_bus->reg_base + AST2600_I2CM_ISR);
+		ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+		writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+		writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+		i2c_bus->cmd_err = -EPROTO;
+		complete(&i2c_bus->cmd_complete);
+		return 1;
+	}
+
+	if (AST2600_I2CM_BUS_RECOVER & sts) {
+		writel(AST2600_I2CM_BUS_RECOVER, i2c_bus->reg_base + AST2600_I2CM_ISR);
+		i2c_bus->cmd_err = 0;
+		complete(&i2c_bus->cmd_complete);
+		return 1;
+	}
+
+	if (AST2600_I2CM_SMBUS_ALT & sts) {
+		if (ier & AST2600_I2CM_SMBUS_ALT) {
+			/* Disable ALT INT */
+			writel(ier & ~AST2600_I2CM_SMBUS_ALT, i2c_bus->reg_base + AST2600_I2CM_IER);
+			i2c_handle_smbus_alert(i2c_bus->ara);
+			writel(AST2600_I2CM_SMBUS_ALT, i2c_bus->reg_base + AST2600_I2CM_ISR);
+			dev_err(i2c_bus->dev,
+				"ast2600_master_alert_recv bus id %d, Disable Alt, Please Imple\n",
+				i2c_bus->adap.nr);
+			return 1;
+		}
+	}
+
+	i2c_bus->cmd_err = ast2600_i2c_is_irq_error(sts);
+	if (i2c_bus->cmd_err) {
+		writel(AST2600_I2CM_PKT_DONE, i2c_bus->reg_base + AST2600_I2CM_ISR);
+		complete(&i2c_bus->cmd_complete);
+		return 1;
+	}
+
+	if (AST2600_I2CM_PKT_DONE & sts) {
+		ast2600_i2c_master_package_irq(i2c_bus, sts);
+		return 1;
+	}
+
+	return 0;
+}
+
+static irqreturn_t ast2600_i2c_bus_irq(int irq, void *dev_id)
+{
+	struct ast2600_i2c_bus *i2c_bus = dev_id;
+
+#ifdef CONFIG_I2C_SLAVE
+	if (readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL) & AST2600_I2CC_SLAVE_EN) {
+		if (ast2600_i2c_slave_irq(i2c_bus))
+			return IRQ_HANDLED;
+	}
+#endif
+	return IRQ_RETVAL(ast2600_i2c_master_irq(i2c_bus));
+}
+
+static int ast2600_i2c_master_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num)
+{
+	struct ast2600_i2c_bus *i2c_bus = i2c_get_adapdata(adap);
+	unsigned long timeout;
+	int ret;
+
+	/* If bus is busy in a single master environment, attempt recovery. */
+	if (!i2c_bus->multi_master &&
+	    (readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF) & AST2600_I2CC_BUS_BUSY_STS)) {
+		ret = ast2600_i2c_recover_bus(i2c_bus);
+		if (ret)
+			return ret;
+	}
+
+#ifdef CONFIG_I2C_SLAVE
+	if (i2c_bus->mode == BUFF_MODE) {
+		if (i2c_bus->slave_operate)
+			return -EBUSY;
+		/* disable slave isr */
+		writel(0, i2c_bus->reg_base + AST2600_I2CS_IER);
+		if (readl(i2c_bus->reg_base + AST2600_I2CS_ISR) || i2c_bus->slave_operate) {
+			writel(AST2600_I2CS_PKT_DONE, i2c_bus->reg_base + AST2600_I2CS_IER);
+			return -EBUSY;
+		}
+	}
+#endif
+
+	i2c_bus->cmd_err = 0;
+	i2c_bus->msgs = msgs;
+	i2c_bus->msgs_index = 0;
+	i2c_bus->msgs_count = num;
+	reinit_completion(&i2c_bus->cmd_complete);
+	ret = ast2600_i2c_do_start(i2c_bus);
+#ifdef CONFIG_I2C_SLAVE
+	/* avoid race condication slave is wait and master wait 1st slave operate */
+	if (i2c_bus->mode == BUFF_MODE)
+		writel(AST2600_I2CS_PKT_DONE, i2c_bus->reg_base + AST2600_I2CS_IER);
+#endif
+	if (ret)
+		goto master_out;
+	timeout = wait_for_completion_timeout(&i2c_bus->cmd_complete, i2c_bus->adap.timeout);
+	if (timeout == 0) {
+		u32 isr = readl(i2c_bus->reg_base + AST2600_I2CM_ISR);
+		u32 i2c_status = readl(i2c_bus->reg_base + AST2600_I2CC_STS_AND_BUFF);
+
+		dev_dbg(i2c_bus->dev, "timeout isr[%x], sts[%x]\n", isr, i2c_status);
+		if (isr || (i2c_status & AST2600_I2CC_TX_DIR_MASK)) {
+			u32 ctrl = readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+			writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+			writel(ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+#ifdef CONFIG_I2C_SLAVE
+			if (ctrl & AST2600_I2CC_SLAVE_EN) {
+				u32 cmd = SLAVE_TRIGGER_CMD;
+
+				if (i2c_bus->mode == DMA_MODE) {
+					cmd |= AST2600_I2CS_RX_DMA_EN;
+					writel(i2c_bus->slave_dma_addr,
+					       i2c_bus->reg_base + AST2600_I2CS_RX_DMA);
+					writel(i2c_bus->slave_dma_addr,
+					       i2c_bus->reg_base + AST2600_I2CS_TX_DMA);
+					writel(AST2600_I2CS_SET_RX_DMA_LEN(I2C_SLAVE_MSG_BUF_SIZE),
+					       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+				} else if (i2c_bus->mode == BUFF_MODE) {
+					cmd = SLAVE_TRIGGER_CMD;
+				} else {
+					cmd &= ~AST2600_I2CS_PKT_MODE_EN;
+				}
+				writel(cmd, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+			}
+#endif
+		}
+		ret = -ETIMEDOUT;
+	} else {
+		ret = i2c_bus->cmd_err;
+	}
+
+	dev_dbg(i2c_bus->dev, "bus%d-m: %d end\n", i2c_bus->adap.nr, i2c_bus->cmd_err);
+
+master_out:
+	if (i2c_bus->mode == DMA_MODE) {
+		kfree(i2c_bus->master_safe_buf);
+	    i2c_bus->master_safe_buf = NULL;
+	}
+
+	return ret;
+}
+
+static void ast2600_i2c_init(struct ast2600_i2c_bus *i2c_bus)
+{
+	struct platform_device *pdev = to_platform_device(i2c_bus->dev);
+	u32 fun_ctrl = AST2600_I2CC_BUS_AUTO_RELEASE | AST2600_I2CC_MASTER_EN;
+
+	/* I2C Reset */
+	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	if (of_property_read_bool(pdev->dev.of_node, "multi-master"))
+		i2c_bus->multi_master = true;
+	else
+		fun_ctrl |= AST2600_I2CC_MULTI_MASTER_DIS;
+
+	/* Enable Master Mode */
+	writel(fun_ctrl, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+	/* disable slave address */
+	writel(0, i2c_bus->reg_base + AST2600_I2CS_ADDR_CTRL);
+
+	/* Set AC Timing */
+	writel(ast2600_select_i2c_clock(i2c_bus), i2c_bus->reg_base + AST2600_I2CC_AC_TIMING);
+
+	/* Clear Interrupt */
+	writel(GENMASK(27, 0), i2c_bus->reg_base + AST2600_I2CM_ISR);
+
+#ifdef CONFIG_I2C_SLAVE
+	/* for memory buffer initial */
+	if (i2c_bus->mode == DMA_MODE) {
+		i2c_bus->slave_dma_buf =
+			dmam_alloc_coherent(i2c_bus->dev, I2C_SLAVE_MSG_BUF_SIZE,
+					    &i2c_bus->slave_dma_addr, GFP_KERNEL);
+		if (!i2c_bus->slave_dma_buf)
+			return;
+	}
+
+	writel(GENMASK(27, 0), i2c_bus->reg_base + AST2600_I2CS_ISR);
+
+	if (i2c_bus->mode == BYTE_MODE) {
+		writel(GENMASK(15, 0), i2c_bus->reg_base + AST2600_I2CS_IER);
+	} else {
+		/* Set interrupt generation of I2C slave controller */
+		writel(AST2600_I2CS_PKT_DONE, i2c_bus->reg_base + AST2600_I2CS_IER);
+	}
+#endif
+}
+
+#ifdef CONFIG_I2C_SLAVE
+static int ast2600_i2c_reg_slave(struct i2c_client *client)
+{
+	struct ast2600_i2c_bus *i2c_bus = i2c_get_adapdata(client->adapter);
+	u32 cmd = SLAVE_TRIGGER_CMD;
+
+	if (i2c_bus->slave)
+		return -EINVAL;
+
+	dev_dbg(i2c_bus->dev, "slave addr %x\n", client->addr);
+
+	writel(0, i2c_bus->reg_base + AST2600_I2CS_ADDR_CTRL);
+	writel(AST2600_I2CC_SLAVE_EN | readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL),
+	       i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+
+	/* trigger rx buffer */
+	if (i2c_bus->mode == DMA_MODE) {
+		cmd |= AST2600_I2CS_RX_DMA_EN;
+		writel(i2c_bus->slave_dma_addr, i2c_bus->reg_base + AST2600_I2CS_RX_DMA);
+		writel(i2c_bus->slave_dma_addr, i2c_bus->reg_base + AST2600_I2CS_TX_DMA);
+		writel(AST2600_I2CS_SET_RX_DMA_LEN(I2C_SLAVE_MSG_BUF_SIZE),
+		       i2c_bus->reg_base + AST2600_I2CS_DMA_LEN);
+	} else if (i2c_bus->mode == BUFF_MODE) {
+		cmd = SLAVE_TRIGGER_CMD;
+	} else {
+		cmd &= ~AST2600_I2CS_PKT_MODE_EN;
+	}
+
+	writel(cmd, i2c_bus->reg_base + AST2600_I2CS_CMD_STS);
+	i2c_bus->slave = client;
+	/* Set slave addr. */
+	writel(client->addr | AST2600_I2CS_ADDR1_ENABLE,
+	       i2c_bus->reg_base + AST2600_I2CS_ADDR_CTRL);
+
+	return 0;
+}
+
+static int ast2600_i2c_unreg_slave(struct i2c_client *slave)
+{
+	struct ast2600_i2c_bus *i2c_bus = i2c_get_adapdata(slave->adapter);
+
+	/* Turn off slave mode. */
+	writel(~AST2600_I2CC_SLAVE_EN & readl(i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL),
+	       i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+	writel(readl(i2c_bus->reg_base + AST2600_I2CS_ADDR_CTRL) & ~AST2600_I2CS_ADDR1_MASK,
+	       i2c_bus->reg_base + AST2600_I2CS_ADDR_CTRL);
+
+	i2c_bus->slave = NULL;
+
+	return 0;
+}
+#endif
+
+static u32 ast2600_i2c_functionality(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
+}
+
+static const struct i2c_algorithm i2c_ast2600_algorithm = {
+	.master_xfer = ast2600_i2c_master_xfer,
+#if IS_ENABLED(CONFIG_I2C_SLAVE)
+	.reg_slave = ast2600_i2c_reg_slave,
+	.unreg_slave = ast2600_i2c_unreg_slave,
+#endif
+	.functionality = ast2600_i2c_functionality,
+};
+
+static const struct of_device_id ast2600_i2c_bus_of_table[] = {
+	{
+		.compatible = "aspeed,ast2600-i2cv2",
+	},
+	{}
+};
+MODULE_DEVICE_TABLE(of, ast2600_i2c_bus_of_table);
+
+static int ast2600_i2c_probe(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct device *dev = &pdev->dev;
+	struct ast2600_i2c_bus *i2c_bus;
+	struct resource *res;
+	u32 global_ctrl;
+	int ret = 0;
+
+	i2c_bus = devm_kzalloc(dev, sizeof(*i2c_bus), GFP_KERNEL);
+	if (!i2c_bus)
+		return -ENOMEM;
+
+	i2c_bus->reg_base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(i2c_bus->reg_base))
+		return PTR_ERR(i2c_bus->reg_base);
+
+	i2c_bus->rst = devm_reset_control_get_shared(dev, NULL);
+	if (IS_ERR(i2c_bus->rst))
+		return dev_err_probe(dev, PTR_ERR(i2c_bus->rst), "Missing reset ctrl\n");
+
+	reset_control_deassert(i2c_bus->rst);
+
+	i2c_bus->global_regs = syscon_regmap_lookup_by_phandle(np, "aspeed,global-regs");
+	if (IS_ERR(i2c_bus->global_regs))
+		return PTR_ERR(i2c_bus->global_regs);
+
+	regmap_read(i2c_bus->global_regs, AST2600_I2CG_CTRL, &global_ctrl);
+	if ((global_ctrl & AST2600_GLOBAL_INIT) != AST2600_GLOBAL_INIT) {
+		regmap_write(i2c_bus->global_regs, AST2600_I2CG_CTRL, AST2600_GLOBAL_INIT);
+		regmap_write(i2c_bus->global_regs, AST2600_I2CG_CLK_DIV_CTRL, I2CCG_DIV_CTRL);
+	}
+
+	i2c_bus->slave_operate = 0;
+	i2c_bus->dev = dev;
+	i2c_bus->mode = BUFF_MODE;
+
+	if (device_property_read_bool(&pdev->dev, "aspeed,enable-dma"))
+		i2c_bus->mode = DMA_MODE;
+
+	if (i2c_bus->mode == BUFF_MODE) {
+		i2c_bus->buf_base = devm_platform_ioremap_resource(pdev, 1);
+		if (!IS_ERR_OR_NULL(i2c_bus->buf_base))
+			i2c_bus->buf_size = resource_size(res) / 2;
+		else
+			i2c_bus->mode = BYTE_MODE;
+	}
+
+	/*
+	 * i2c timeout counter: use base clk4 1Mhz,
+	 * per unit: 1/(1000/4096) = 4096us
+	 */
+	ret = of_property_read_u32(dev->of_node,
+				   "i2c-scl-clk-low-timeout-us",
+				   &i2c_bus->timeout);
+	if (!ret)
+		i2c_bus->timeout /= 4096;
+
+	init_completion(&i2c_bus->cmd_complete);
+
+	i2c_bus->irq = platform_get_irq(pdev, 0);
+	if (i2c_bus->irq < 0)
+		return i2c_bus->irq;
+
+	platform_set_drvdata(pdev, i2c_bus);
+
+	i2c_bus->clk = devm_clk_get(i2c_bus->dev, NULL);
+	if (IS_ERR(i2c_bus->clk))
+		return dev_err_probe(i2c_bus->dev, PTR_ERR(i2c_bus->clk), "Can't get clock\n");
+
+	i2c_bus->apb_clk = clk_get_rate(i2c_bus->clk);
+
+	ret = device_property_read_u32(&pdev->dev, "clock-frequency", &i2c_bus->bus_frequency);
+	if (ret < 0) {
+		dev_warn(dev, "Could not read clock-frequency property\n");
+		i2c_bus->bus_frequency = I2C_MAX_STANDARD_MODE_FREQ;
+	}
+
+	/* Initialize the I2C adapter */
+	i2c_bus->adap.owner = THIS_MODULE;
+	i2c_bus->adap.algo = &i2c_ast2600_algorithm;
+	i2c_bus->adap.retries = 0;
+	i2c_bus->adap.dev.parent = i2c_bus->dev;
+	device_set_node(&i2c_bus->adap.dev, dev_fwnode(dev));
+	i2c_bus->adap.algo_data = i2c_bus;
+	strscpy(i2c_bus->adap.name, pdev->name, sizeof(i2c_bus->adap.name));
+	i2c_set_adapdata(&i2c_bus->adap, i2c_bus);
+
+	ast2600_i2c_init(i2c_bus);
+
+	ret = devm_request_irq(dev, i2c_bus->irq, ast2600_i2c_bus_irq, 0,
+			       dev_name(dev), i2c_bus);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Unable to request irq %d\n", i2c_bus->irq);
+
+	if (of_property_read_bool(dev->of_node, "smbus-alert")) {
+		i2c_bus->alert_enable = true;
+		i2c_bus->ara = i2c_new_smbus_alert_device(&i2c_bus->adap, &i2c_bus->alert_data);
+		if (!i2c_bus->ara)
+			dev_warn(dev, "Failed to register ARA client\n");
+
+		writel(AST2600_I2CM_PKT_DONE | AST2600_I2CM_BUS_RECOVER | AST2600_I2CM_SMBUS_ALT,
+		       i2c_bus->reg_base + AST2600_I2CM_IER);
+	} else {
+		i2c_bus->alert_enable = false;
+		/* Set interrupt generation of I2C master controller */
+		writel(AST2600_I2CM_PKT_DONE | AST2600_I2CM_BUS_RECOVER,
+		       i2c_bus->reg_base + AST2600_I2CM_IER);
+	}
+
+	ret = devm_i2c_add_adapter(dev, &i2c_bus->adap);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int ast2600_i2c_remove(struct platform_device *pdev)
+{
+	struct ast2600_i2c_bus *i2c_bus = platform_get_drvdata(pdev);
+
+	/* Disable everything. */
+	writel(0, i2c_bus->reg_base + AST2600_I2CC_FUN_CTRL);
+	writel(0, i2c_bus->reg_base + AST2600_I2CM_IER);
+
+	i2c_del_adapter(&i2c_bus->adap);
+	devm_free_irq(&pdev->dev, i2c_bus->irq, i2c_bus);
+
+#ifdef CONFIG_I2C_SLAVE
+	/* for memory buffer initial */
+	if (i2c_bus->mode == DMA_MODE)
+		dmam_free_coherent(i2c_bus->dev, I2C_SLAVE_MSG_BUF_SIZE,
+				   i2c_bus->slave_dma_buf, i2c_bus->slave_dma_addr);
+#endif
+
+	return 0;
+}
+
+static struct platform_driver ast2600_i2c_bus_driver = {
+	.probe = ast2600_i2c_probe,
+	.remove = ast2600_i2c_remove,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.of_match_table = ast2600_i2c_bus_of_table,
+	},
+};
+module_platform_driver(ast2600_i2c_bus_driver);
+
+MODULE_AUTHOR("Ryan Chen <ryan_chen@aspeedtech.com>");
+MODULE_DESCRIPTION("ASPEED AST2600 I2C Controller Driver");
+MODULE_LICENSE("GPL");