[v4,1/3] i2c: Add Qualcomm CCI I2C driver

Message ID 1583515184-9636-1-git-send-email-loic.poulain@linaro.org
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  • [v4,1/3] i2c: Add Qualcomm CCI I2C driver
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Commit Message

Loic Poulain March 6, 2020, 5:19 p.m.
This commit adds I2C bus support for the Camera Control Interface
(CCI) I2C controller found on the Qualcomm SoC processors. This I2C
controller supports two masters and they are registered to the core.

CCI versions supported in the driver are MSM8916 and MSM8996.

This is a rework of the patch posted by Vinod:
https://patchwork.kernel.org/patch/10569961/

With additional fixes + most of the comments addressed.

Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
Tested-by: Robert Foss <robert.foss@linaro.org>
---
  v2: Remove clock rates config from driver (done via assigned clock)
     Added CCI timeout recovery from Ricardo's patch:
        https://www.spinics.net/lists/linux-i2c/msg36973.html
 v3: add sdm845 support
     rework cci_init function
 v4: fix checkpatch issue (double semi-colon)

 drivers/i2c/busses/Kconfig        |  10 +
 drivers/i2c/busses/Makefile       |   1 +
 drivers/i2c/busses/i2c-qcom-cci.c | 787 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 798 insertions(+)
 create mode 100644 drivers/i2c/busses/i2c-qcom-cci.c

Comments

Bjorn Andersson March 7, 2020, 2:05 a.m. | #1
On Fri 06 Mar 09:19 PST 2020, Loic Poulain wrote:

> This commit adds I2C bus support for the Camera Control Interface
> (CCI) I2C controller found on the Qualcomm SoC processors. This I2C
> controller supports two masters and they are registered to the core.
> 
> CCI versions supported in the driver are MSM8916 and MSM8996.

+SDM845

> 
> This is a rework of the patch posted by Vinod:
> https://patchwork.kernel.org/patch/10569961/
> 
> With additional fixes + most of the comments addressed.
> 
> Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
> Signed-off-by: Vinod Koul <vkoul@kernel.org>
> Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> Tested-by: Robert Foss <robert.foss@linaro.org>
> ---
>   v2: Remove clock rates config from driver (done via assigned clock)
>      Added CCI timeout recovery from Ricardo's patch:
>         https://www.spinics.net/lists/linux-i2c/msg36973.html
>  v3: add sdm845 support
>      rework cci_init function
>  v4: fix checkpatch issue (double semi-colon)
> 
>  drivers/i2c/busses/Kconfig        |  10 +
>  drivers/i2c/busses/Makefile       |   1 +
>  drivers/i2c/busses/i2c-qcom-cci.c | 787 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 798 insertions(+)
>  create mode 100644 drivers/i2c/busses/i2c-qcom-cci.c
> 
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 6a0aa76..807a052 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -894,6 +894,16 @@ config I2C_QCOM_GENI
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called i2c-qcom-geni.
>  
> +config I2C_QCOM_CCI

Please move this above GENI, to keep sort order.

> +	tristate "Qualcomm Camera Control Interface"
> +	depends on ARCH_QCOM || COMPILE_TEST
> +	help
> +	  If you say yes to this option, support will be included for the
> +	  built-in camera control interface on the Qualcomm SoCs.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called i2c-qcom-cci.
> +
>  config I2C_QUP
>  	tristate "Qualcomm QUP based I2C controller"
>  	depends on ARCH_QCOM
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index 3ab8aeb..9028b77 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -92,6 +92,7 @@ obj-$(CONFIG_I2C_PUV3)		+= i2c-puv3.o
>  obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
>  obj-$(CONFIG_I2C_PXA_PCI)	+= i2c-pxa-pci.o
>  obj-$(CONFIG_I2C_QCOM_GENI)	+= i2c-qcom-geni.o
> +obj-$(CONFIG_I2C_QCOM_CCI)	+= i2c-qcom-cci.o

Sort order.

>  obj-$(CONFIG_I2C_QUP)		+= i2c-qup.o
>  obj-$(CONFIG_I2C_RIIC)		+= i2c-riic.o
>  obj-$(CONFIG_I2C_RK3X)		+= i2c-rk3x.o
> diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
[..]
> +/* Max number of resources + 1 for a NULL terminator */
> +#define CCI_RES_MAX	6
> +
> +

Extra newline?

> +#define CCI_I2C_SET_PARAM	1
> +#define CCI_I2C_REPORT		8
> +#define CCI_I2C_WRITE		9
> +#define CCI_I2C_READ		10
[..]
> +static int cci_i2c_read(struct cci *cci, u16 master,
> +			u16 addr, u8 *buf, u16 len)
> +{
> +	u32 val, words_read, words_exp;
> +	u8 queue = QUEUE_1;
> +	int i, index = 0, ret;
> +	bool first = true;
> +
> +	/*
> +	 * Call validate queue to make sure queue is empty before starting.
> +	 * This is to avoid overflow / underflow of queue.
> +	 */
> +	ret = cci_validate_queue(cci, master, queue);
> +	if (ret < 0)
> +		return ret;
> +
> +	val = CCI_I2C_SET_PARAM | (addr & 0x7f) << 4;
> +	writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
> +
> +	val = CCI_I2C_READ | len << 4;
> +	writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
> +
> +	ret = cci_run_queue(cci, master, queue);
> +	if (ret < 0)
> +		return ret;
> +
> +	words_read = readl(cci->base + CCI_I2C_Mm_READ_BUF_LEVEL(master));
> +	words_exp = len / 4 + 1;
> +	if (words_read != words_exp) {
> +		dev_err(cci->dev, "words read = %d, words expected = %d\n",
> +			words_read, words_exp);
> +		return -EIO;
> +	}
> +
> +	do {
> +		val = readl(cci->base + CCI_I2C_Mm_READ_DATA(master));
> +
> +		for (i = 0; i < 4 && index < len; i++) {
> +			if (first) {

So lower 8 bits of the first word read should always be discarded? Do we
know why? Can we have a comment describing this behavior?

> +				first = false;
> +				continue;
> +			}
> +			buf[index++] = (val >> (i * 8)) & 0xff;
> +		}
> +	} while (--words_read);
> +
> +	return 0;
> +}
[..]
> +static int cci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
> +{
> +	struct cci_master *cci_master = i2c_get_adapdata(adap);
> +	struct cci *cci = cci_master->cci;
> +	int i, ret;
> +
> +	ret = pm_runtime_get_sync(cci->dev);
> +	if (ret < 0)
> +		goto err;
> +
> +	for (i = 0; i < num; i++) {
> +		if (msgs[i].flags & I2C_M_RD)
> +			ret = cci_i2c_read(cci, cci_master->master,
> +					   msgs[i].addr, msgs[i].buf,
> +					   msgs[i].len);
> +		else
> +			ret = cci_i2c_write(cci, cci_master->master,
> +					    msgs[i].addr, msgs[i].buf,
> +					    msgs[i].len);
> +
> +		if (ret < 0) {

Most cases this can happen has already printed a more specific error
message, so perhaps better to ensure that all paths has specific error
messages (if that's not already the case) and simply break here if ret <
0?

> +			dev_err(cci->dev, "cci i2c xfer error %d", ret);
> +			break;
> +		}
> +	}
> +
> +	if (!ret)
> +		ret = num;
> +
> +err:
> +	pm_runtime_mark_last_busy(cci->dev);
> +	pm_runtime_put_autosuspend(cci->dev);
> +
> +	return ret;
> +}
> +
> +static u32 cci_func(struct i2c_adapter *adap)
> +{
> +	return I2C_FUNC_I2C;
> +}
> +
> +static const struct i2c_algorithm cci_algo = {
> +	.master_xfer	= cci_xfer,
> +	.functionality	= cci_func,
> +};
> +
> +static int cci_enable_clocks(struct cci *cci)
> +{
> +	int ret;
> +
> +	ret = clk_bulk_prepare_enable(cci->nclocks, cci->clocks);
> +	if (ret < 0)
> +		dev_err(cci->dev, "Bulk clock prepare failed: %d\n", ret);

If clk_bulk_prepare_enable() return an error it already printed an
error, which includes the name of the clock that failed to enable. So
you can do:

	return clk_bulk_prepare_enable(...);

instead.

> +
> +	return ret;
> +}
> +
> +static void cci_disable_clocks(struct cci *cci)
> +{
> +	clk_bulk_disable_unprepare(cci->nclocks, cci->clocks);
> +}
> +
> +#ifdef CONFIG_PM

Instead of the #ifdef, use __maybe_unused on these functions.

> +static int cci_suspend_runtime(struct device *dev)

I.e:

static int __maybe_unused cci_suspend_runtime(...)

> +{
> +	struct cci *cci = dev_get_drvdata(dev);
> +
> +	dev_dbg(dev, "Supend invoked\n");
> +	cci_disable_clocks(cci);
> +	return 0;
> +}
> +
> +static int cci_resume_runtime(struct device *dev)
> +{
> +	struct cci *cci = dev_get_drvdata(dev);
> +	int ret;
> +
> +	dev_dbg(dev, "Resume invoked\n");
> +	ret = cci_enable_clocks(cci);
> +	if (ret)
> +		return ret;
> +
> +	cci_init(cci);
> +	return 0;
> +}
> +#endif
> +
> +#ifdef CONFIG_PM_SLEEP

As above.

> +static int cci_suspend(struct device *dev)
> +{
> +	if (!pm_runtime_suspended(dev))
> +		return cci_suspend_runtime(dev);
> +
> +	return 0;
> +}
> +
> +static int cci_resume(struct device *dev)
> +{
> +	cci_resume_runtime(dev);
> +	pm_runtime_mark_last_busy(dev);
> +	pm_request_autosuspend(dev);
> +
> +	return 0;
> +}
> +#endif
> +
> +static const struct dev_pm_ops qcom_cci_pm = {
> +	SET_SYSTEM_SLEEP_PM_OPS(cci_suspend, cci_resume)
> +	SET_RUNTIME_PM_OPS(cci_suspend_runtime, cci_resume_runtime, NULL)
> +};
> +
> +static int cci_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *of_node = NULL;

No need to initialize of_node.

> +	unsigned long cci_clk_rate = 0;
> +	struct resource *r;
> +	struct cci *cci;
> +	int ret = 0, i;

No need to zero-initialize ret.

> +	u32 val;
> +
> +	cci = devm_kzalloc(dev, sizeof(*cci), GFP_KERNEL);
> +	if (!cci)
> +		return -ENOMEM;
> +
> +	cci->dev = dev;
> +	platform_set_drvdata(pdev, cci);
> +	cci->data = device_get_match_data(&pdev->dev);

s/&pdev->dev/dev/ for consistency.

> +	if (!cci->data) {
> +		dev_err(&pdev->dev, "Driver data is null, abort\n");
> +		return -EIO;
> +	}
> +
> +	for (i = 0; i < cci->data->num_masters; i++) {
> +		cci->master[i].adap.quirks = &cci->data->quirks;
> +		cci->master[i].adap.algo = &cci_algo;
> +		cci->master[i].adap.dev.parent = cci->dev;

s/cci->dev/dev/ for consistency.

> +		cci->master[i].master = i;
> +		cci->master[i].cci = cci;
> +
> +		i2c_set_adapdata(&cci->master[i].adap, &cci->master[i]);
> +		snprintf(cci->master[i].adap.name,
> +			 sizeof(cci->master[i].adap.name),
> +			 "Qualcomm Camera Control Interface: %d", i);
> +
> +		/* find the child node for i2c-bus as we are on cci node */
> +		of_node = of_get_next_available_child(dev->of_node, of_node);
> +		if (!of_node) {
> +			dev_err(dev, "Missing i2c-bus@%d child node\n", i);
> +			return -EINVAL;
> +		}
> +		cci->master[i].adap.dev.of_node = of_node;

Won't this break if the two masters are provided in reverse order in the
DT?

> +
> +		cci->master[i].mode = I2C_MODE_STANDARD;
> +		ret = of_property_read_u32(of_node, "clock-frequency", &val);
> +		if (!ret) {
> +			if (val == 400000)
> +				cci->master[i].mode = I2C_MODE_FAST;
> +			else if (val == 1000000)
> +				cci->master[i].mode = I2C_MODE_FAST_PLUS;
> +		}
> +
> +		init_completion(&cci->master[i].irq_complete);
> +	}
> +
> +	/* Memory */
> +
> +	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	cci->base = devm_ioremap_resource(dev, r);
> +	if (IS_ERR(cci->base))
> +		return PTR_ERR(cci->base);
> +
> +	/* Interrupt */
> +
> +	ret = platform_get_irq(pdev, 0);
> +	if (ret < 0) {
> +		dev_err(dev, "missing IRQ: %d\n", ret);
> +		return ret;
> +	}
> +	cci->irq = ret;
> +
> +	ret = devm_request_irq(dev, cci->irq, cci_isr,
> +			       IRQF_TRIGGER_RISING, dev_name(dev), cci);

Wouldn't it be better to request the irq after the clocks are enabled?
Presumably it won't fire here, but if it does then the isr might access
unclocked registers?

At least you shouldn't have to temporarily disable the irqs until later
in the probe?


Also, please rely on irq flags from DT and leave the flags as 0.

> +	if (ret < 0) {
> +		dev_err(dev, "request_irq failed, ret: %d\n", ret);
> +		return ret;
> +	}
> +
> +	disable_irq(cci->irq);
> +
> +	/* Clocks */
> +
> +	ret = devm_clk_bulk_get_all(dev, &cci->clocks);
> +	if (ret < 1) {
> +		dev_err(dev, "failed to get clocks %d\n", ret);
> +		return ret;
> +	}
> +	cci->nclocks = ret;
> +
> +	/* Retrieve CCI clock rate */
> +	for (i = 0; i < cci->nclocks; i++) {
> +		if (!strncmp(cci->clocks[i].id, "cci", 4)) {

Isn't this just a strcmp()?

> +			cci_clk_rate = clk_get_rate(cci->clocks[i].clk);
> +			break;
> +		}
> +	}
> +
> +	if (cci_clk_rate != cci->data->cci_clk_rate) {
> +		/* cci clock set by the bootloader or via assigned clock rate
> +		 * in DT.
> +		 */
> +		dev_warn(dev, "Found %lu cci clk rate while %lu was expected\n",
> +			 cci_clk_rate, cci->data->cci_clk_rate);
> +	}
> +
> +	ret = cci_enable_clocks(cci);
> +	if (ret < 0)
> +		return ret;
> +
> +	val = readl_relaxed(cci->base + CCI_HW_VERSION);

Skip the "_relaxed" part.

> +	dev_info(dev, "%s: CCI HW version = 0x%08x", __func__, val);

I think the __func__ here is unnecessary, and perhaps make this a
dev_dbg() instead?

Regards,
Bjorn
> +
> +	enable_irq(cci->irq);
> +
> +	ret = cci_reset(cci);
> +	if (ret < 0)
> +		goto error;
> +
> +	ret = cci_init(cci);
> +	if (ret < 0)
> +		goto error;
> +
> +	for (i = 0; i < cci->data->num_masters; i++) {
> +		ret = i2c_add_adapter(&cci->master[i].adap);
> +		if (ret < 0)
> +			goto error_i2c;
> +	}
> +
> +	pm_runtime_set_autosuspend_delay(dev, MSEC_PER_SEC);
> +	pm_runtime_use_autosuspend(dev);
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +
> +	return 0;
> +
> +error_i2c:
> +	for (; i >= 0; i--)
> +		i2c_del_adapter(&cci->master[i].adap);
> +error:
> +	disable_irq(cci->irq);
> +	cci_disable_clocks(cci);
> +
> +	return ret;
> +}
> +
Loic Poulain March 9, 2020, 3:25 p.m. | #2
Hi Bjorn,

On Sat, 7 Mar 2020 at 03:05, Bjorn Andersson <bjorn.andersson@linaro.org> wrote:
>
> On Fri 06 Mar 09:19 PST 2020, Loic Poulain wrote:
>
> > This commit adds I2C bus support for the Camera Control Interface
> > (CCI) I2C controller found on the Qualcomm SoC processors. This I2C
> > controller supports two masters and they are registered to the core.
> >
> > CCI versions supported in the driver are MSM8916 and MSM8996.
>
> +SDM845
>
> >
> > This is a rework of the patch posted by Vinod:
> > https://patchwork.kernel.org/patch/10569961/
> >
> > With additional fixes + most of the comments addressed.
> >
> > Signed-off-by: Todor Tomov <todor.tomov@linaro.org>
> > Signed-off-by: Vinod Koul <vkoul@kernel.org>
> > Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> > Tested-by: Robert Foss <robert.foss@linaro.org>
> > ---
> >   v2: Remove clock rates config from driver (done via assigned clock)
> >      Added CCI timeout recovery from Ricardo's patch:
> >         https://www.spinics.net/lists/linux-i2c/msg36973.html
> >  v3: add sdm845 support
> >      rework cci_init function
> >  v4: fix checkpatch issue (double semi-colon)
> >
> >  drivers/i2c/busses/Kconfig        |  10 +
> >  drivers/i2c/busses/Makefile       |   1 +
> >  drivers/i2c/busses/i2c-qcom-cci.c | 787 ++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 798 insertions(+)
> >  create mode 100644 drivers/i2c/busses/i2c-qcom-cci.c
> >
> > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> > index 6a0aa76..807a052 100644
> > --- a/drivers/i2c/busses/Kconfig
> > +++ b/drivers/i2c/busses/Kconfig
> > @@ -894,6 +894,16 @@ config I2C_QCOM_GENI
> >         This driver can also be built as a module.  If so, the module
> >         will be called i2c-qcom-geni.
> >
> > +config I2C_QCOM_CCI
>
> Please move this above GENI, to keep sort order.

ack

>
> > +     tristate "Qualcomm Camera Control Interface"
> > +     depends on ARCH_QCOM || COMPILE_TEST
> > +     help
> > +       If you say yes to this option, support will be included for the
> > +       built-in camera control interface on the Qualcomm SoCs.
> > +
> > +       This driver can also be built as a module.  If so, the module
> > +       will be called i2c-qcom-cci.
> > +
> >  config I2C_QUP
> >       tristate "Qualcomm QUP based I2C controller"
> >       depends on ARCH_QCOM
> > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> > index 3ab8aeb..9028b77 100644
> > --- a/drivers/i2c/busses/Makefile
> > +++ b/drivers/i2c/busses/Makefile
> > @@ -92,6 +92,7 @@ obj-$(CONFIG_I2C_PUV3)              += i2c-puv3.o
> >  obj-$(CONFIG_I2C_PXA)                += i2c-pxa.o
> >  obj-$(CONFIG_I2C_PXA_PCI)    += i2c-pxa-pci.o
> >  obj-$(CONFIG_I2C_QCOM_GENI)  += i2c-qcom-geni.o
> > +obj-$(CONFIG_I2C_QCOM_CCI)   += i2c-qcom-cci.o
>
> Sort order.

ack

>
> >  obj-$(CONFIG_I2C_QUP)                += i2c-qup.o
> >  obj-$(CONFIG_I2C_RIIC)               += i2c-riic.o
> >  obj-$(CONFIG_I2C_RK3X)               += i2c-rk3x.o
> > diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
> [..]
> > +/* Max number of resources + 1 for a NULL terminator */
> > +#define CCI_RES_MAX  6
> > +
> > +
>
> Extra newline?
>
> > +#define CCI_I2C_SET_PARAM    1
> > +#define CCI_I2C_REPORT               8
> > +#define CCI_I2C_WRITE                9
> > +#define CCI_I2C_READ         10
> [..]
> > +static int cci_i2c_read(struct cci *cci, u16 master,
> > +                     u16 addr, u8 *buf, u16 len)
> > +{
> > +     u32 val, words_read, words_exp;
> > +     u8 queue = QUEUE_1;
> > +     int i, index = 0, ret;
> > +     bool first = true;
> > +
> > +     /*
> > +      * Call validate queue to make sure queue is empty before starting.
> > +      * This is to avoid overflow / underflow of queue.
> > +      */
> > +     ret = cci_validate_queue(cci, master, queue);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     val = CCI_I2C_SET_PARAM | (addr & 0x7f) << 4;
> > +     writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
> > +
> > +     val = CCI_I2C_READ | len << 4;
> > +     writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
> > +
> > +     ret = cci_run_queue(cci, master, queue);
> > +     if (ret < 0)
> > +             return ret;
> > +
> > +     words_read = readl(cci->base + CCI_I2C_Mm_READ_BUF_LEVEL(master));
> > +     words_exp = len / 4 + 1;
> > +     if (words_read != words_exp) {
> > +             dev_err(cci->dev, "words read = %d, words expected = %d\n",
> > +                     words_read, words_exp);
> > +             return -EIO;
> > +     }
> > +
> > +     do {
> > +             val = readl(cci->base + CCI_I2C_Mm_READ_DATA(master));
> > +
> > +             for (i = 0; i < 4 && index < len; i++) {
> > +                     if (first) {
>
> So lower 8 bits of the first word read should always be discarded? Do we
> know why? Can we have a comment describing this behavior?

Yes, the first byte contains the SID (slave ID), I'll add a comment.


> > +             cci->master[i].master = i;
> > +             cci->master[i].cci = cci;
> > +
> > +             i2c_set_adapdata(&cci->master[i].adap, &cci->master[i]);
> > +             snprintf(cci->master[i].adap.name,
> > +                      sizeof(cci->master[i].adap.name),
> > +                      "Qualcomm Camera Control Interface: %d", i);
> > +
> > +             /* find the child node for i2c-bus as we are on cci node */
> > +             of_node = of_get_next_available_child(dev->of_node, of_node);
> > +             if (!of_node) {
> > +                     dev_err(dev, "Missing i2c-bus@%d child node\n", i);
> > +                     return -EINVAL;
> > +             }
> > +             cci->master[i].adap.dev.of_node = of_node;
>
> Won't this break if the two masters are provided in reverse order in the
> DT?

Indeed, I'm going to rework that.

> > +     /* Interrupt */
> > +
> > +     ret = platform_get_irq(pdev, 0);
> > +     if (ret < 0) {
> > +             dev_err(dev, "missing IRQ: %d\n", ret);
> > +             return ret;
> > +     }
> > +     cci->irq = ret;
> > +
> > +     ret = devm_request_irq(dev, cci->irq, cci_isr,
> > +                            IRQF_TRIGGER_RISING, dev_name(dev), cci);
>
> Wouldn't it be better to request the irq after the clocks are enabled?
> Presumably it won't fire here, but if it does then the isr might access
> unclocked registers?
>
> At least you shouldn't have to temporarily disable the irqs until later
> in the probe?

Yes we can move the request at a later time in the probe.

Regards,
Loic

Patch

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 6a0aa76..807a052 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -894,6 +894,16 @@  config I2C_QCOM_GENI
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-qcom-geni.
 
+config I2C_QCOM_CCI
+	tristate "Qualcomm Camera Control Interface"
+	depends on ARCH_QCOM || COMPILE_TEST
+	help
+	  If you say yes to this option, support will be included for the
+	  built-in camera control interface on the Qualcomm SoCs.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-qcom-cci.
+
 config I2C_QUP
 	tristate "Qualcomm QUP based I2C controller"
 	depends on ARCH_QCOM
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 3ab8aeb..9028b77 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -92,6 +92,7 @@  obj-$(CONFIG_I2C_PUV3)		+= i2c-puv3.o
 obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_PXA_PCI)	+= i2c-pxa-pci.o
 obj-$(CONFIG_I2C_QCOM_GENI)	+= i2c-qcom-geni.o
+obj-$(CONFIG_I2C_QCOM_CCI)	+= i2c-qcom-cci.o
 obj-$(CONFIG_I2C_QUP)		+= i2c-qup.o
 obj-$(CONFIG_I2C_RIIC)		+= i2c-riic.o
 obj-$(CONFIG_I2C_RK3X)		+= i2c-rk3x.o
diff --git a/drivers/i2c/busses/i2c-qcom-cci.c b/drivers/i2c/busses/i2c-qcom-cci.c
new file mode 100644
index 0000000..10c8ac8
--- /dev/null
+++ b/drivers/i2c/busses/i2c-qcom-cci.c
@@ -0,0 +1,787 @@ 
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2012-2016, The Linux Foundation. All rights reserved.
+// Copyright (c) 2017-19 Linaro Limited.
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/i2c.h>
+#include <linux/io.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+
+#define CCI_HW_VERSION				0x0
+#define CCI_RESET_CMD				0x004
+#define CCI_RESET_CMD_MASK			0x0f73f3f7
+#define CCI_RESET_CMD_M0_MASK			0x000003f1
+#define CCI_RESET_CMD_M1_MASK			0x0003f001
+#define CCI_QUEUE_START				0x008
+#define CCI_HALT_REQ				0x034
+#define CCI_HALT_REQ_I2C_M0_Q0Q1		BIT(0)
+#define CCI_HALT_REQ_I2C_M1_Q0Q1		BIT(1)
+
+#define CCI_I2C_Mm_SCL_CTL(m)			(0x100 + 0x100 * (m))
+#define CCI_I2C_Mm_SDA_CTL_0(m)			(0x104 + 0x100 * (m))
+#define CCI_I2C_Mm_SDA_CTL_1(m)			(0x108 + 0x100 * (m))
+#define CCI_I2C_Mm_SDA_CTL_2(m)			(0x10c + 0x100 * (m))
+#define CCI_I2C_Mm_MISC_CTL(m)			(0x110 + 0x100 * (m))
+
+#define CCI_I2C_Mm_READ_DATA(m)			(0x118 + 0x100 * (m))
+#define CCI_I2C_Mm_READ_BUF_LEVEL(m)		(0x11c + 0x100 * (m))
+#define CCI_I2C_Mm_Qn_EXEC_WORD_CNT(m, n)	(0x300 + 0x200 * (m) + 0x100 * (n))
+#define CCI_I2C_Mm_Qn_CUR_WORD_CNT(m, n)	(0x304 + 0x200 * (m) + 0x100 * (n))
+#define CCI_I2C_Mm_Qn_CUR_CMD(m, n)		(0x308 + 0x200 * (m) + 0x100 * (n))
+#define CCI_I2C_Mm_Qn_REPORT_STATUS(m, n)	(0x30c + 0x200 * (m) + 0x100 * (n))
+#define CCI_I2C_Mm_Qn_LOAD_DATA(m, n)		(0x310 + 0x200 * (m) + 0x100 * (n))
+
+#define CCI_IRQ_GLOBAL_CLEAR_CMD		0xc00
+#define CCI_IRQ_MASK_0				0xc04
+#define CCI_IRQ_MASK_0_I2C_M0_RD_DONE		BIT(0)
+#define CCI_IRQ_MASK_0_I2C_M0_Q0_REPORT		BIT(4)
+#define CCI_IRQ_MASK_0_I2C_M0_Q1_REPORT		BIT(8)
+#define CCI_IRQ_MASK_0_I2C_M1_RD_DONE		BIT(12)
+#define CCI_IRQ_MASK_0_I2C_M1_Q0_REPORT		BIT(16)
+#define CCI_IRQ_MASK_0_I2C_M1_Q1_REPORT		BIT(20)
+#define CCI_IRQ_MASK_0_RST_DONE_ACK		BIT(24)
+#define CCI_IRQ_MASK_0_I2C_M0_Q0Q1_HALT_ACK	BIT(25)
+#define CCI_IRQ_MASK_0_I2C_M1_Q0Q1_HALT_ACK	BIT(26)
+#define CCI_IRQ_MASK_0_I2C_M0_ERROR		0x18000ee6
+#define CCI_IRQ_MASK_0_I2C_M1_ERROR		0x60ee6000
+#define CCI_IRQ_CLEAR_0				0xc08
+#define CCI_IRQ_STATUS_0			0xc0c
+#define CCI_IRQ_STATUS_0_I2C_M0_RD_DONE		BIT(0)
+#define CCI_IRQ_STATUS_0_I2C_M0_Q0_REPORT	BIT(4)
+#define CCI_IRQ_STATUS_0_I2C_M0_Q1_REPORT	BIT(8)
+#define CCI_IRQ_STATUS_0_I2C_M1_RD_DONE		BIT(12)
+#define CCI_IRQ_STATUS_0_I2C_M1_Q0_REPORT	BIT(16)
+#define CCI_IRQ_STATUS_0_I2C_M1_Q1_REPORT	BIT(20)
+#define CCI_IRQ_STATUS_0_RST_DONE_ACK		BIT(24)
+#define CCI_IRQ_STATUS_0_I2C_M0_Q0Q1_HALT_ACK	BIT(25)
+#define CCI_IRQ_STATUS_0_I2C_M1_Q0Q1_HALT_ACK	BIT(26)
+#define CCI_IRQ_STATUS_0_I2C_M0_ERROR		0x18000ee6
+#define CCI_IRQ_STATUS_0_I2C_M1_ERROR		0x60ee6000
+
+#define CCI_TIMEOUT	(msecs_to_jiffies(100))
+#define NUM_MASTERS	2
+#define NUM_QUEUES	2
+
+/* Max number of resources + 1 for a NULL terminator */
+#define CCI_RES_MAX	6
+
+
+#define CCI_I2C_SET_PARAM	1
+#define CCI_I2C_REPORT		8
+#define CCI_I2C_WRITE		9
+#define CCI_I2C_READ		10
+
+#define CCI_I2C_REPORT_IRQ_EN	BIT(8)
+
+enum {
+	I2C_MODE_STANDARD,
+	I2C_MODE_FAST,
+	I2C_MODE_FAST_PLUS,
+};
+
+enum cci_i2c_queue_t {
+	QUEUE_0,
+	QUEUE_1
+};
+
+struct hw_params {
+	u16 thigh; /* HIGH period of the SCL clock in clock ticks */
+	u16 tlow; /* LOW period of the SCL clock */
+	u16 tsu_sto; /* set-up time for STOP condition */
+	u16 tsu_sta; /* set-up time for a repeated START condition */
+	u16 thd_dat; /* data hold time */
+	u16 thd_sta; /* hold time (repeated) START condition */
+	u16 tbuf; /* bus free time between a STOP and START condition */
+	u8 scl_stretch_en;
+	u16 trdhld;
+	u16 tsp; /* pulse width of spikes suppressed by the input filter */
+};
+
+struct cci;
+
+struct cci_master {
+	struct i2c_adapter adap;
+	u16 master;
+	u8 mode;
+	int status;
+	struct completion irq_complete;
+	struct cci *cci;
+};
+
+struct cci_data {
+	unsigned int num_masters;
+	struct i2c_adapter_quirks quirks;
+	u16 queue_size[NUM_QUEUES];
+	unsigned long cci_clk_rate;
+	struct hw_params params[3];
+};
+
+struct cci {
+	struct device *dev;
+	void __iomem *base;
+	unsigned int irq;
+	const struct cci_data *data;
+	struct clk_bulk_data *clocks;
+	int nclocks;
+	struct cci_master master[NUM_MASTERS];
+};
+
+static irqreturn_t cci_isr(int irq, void *dev)
+{
+	struct cci *cci = dev;
+	u32 val, reset = 0;
+	int ret = IRQ_NONE;
+
+	val = readl(cci->base + CCI_IRQ_STATUS_0);
+	writel(val, cci->base + CCI_IRQ_CLEAR_0);
+	writel(0x1, cci->base + CCI_IRQ_GLOBAL_CLEAR_CMD);
+
+	if (val & CCI_IRQ_STATUS_0_RST_DONE_ACK) {
+		complete(&cci->master[0].irq_complete);
+		if (cci->master[1].master)
+			complete(&cci->master[1].irq_complete);
+		ret = IRQ_HANDLED;
+	}
+
+	if (val & CCI_IRQ_STATUS_0_I2C_M0_RD_DONE ||
+			val & CCI_IRQ_STATUS_0_I2C_M0_Q0_REPORT ||
+			val & CCI_IRQ_STATUS_0_I2C_M0_Q1_REPORT) {
+		cci->master[0].status = 0;
+		complete(&cci->master[0].irq_complete);
+		ret = IRQ_HANDLED;
+	}
+
+	if (val & CCI_IRQ_STATUS_0_I2C_M1_RD_DONE ||
+			val & CCI_IRQ_STATUS_0_I2C_M1_Q0_REPORT ||
+			val & CCI_IRQ_STATUS_0_I2C_M1_Q1_REPORT) {
+		cci->master[1].status = 0;
+		complete(&cci->master[1].irq_complete);
+		ret = IRQ_HANDLED;
+	}
+
+	if (unlikely(val & CCI_IRQ_STATUS_0_I2C_M0_Q0Q1_HALT_ACK)) {
+		reset = CCI_RESET_CMD_M0_MASK;
+		ret = IRQ_HANDLED;
+	}
+
+	if (unlikely(val & CCI_IRQ_STATUS_0_I2C_M1_Q0Q1_HALT_ACK)) {
+		reset = CCI_RESET_CMD_M1_MASK;
+		ret = IRQ_HANDLED;
+	}
+
+	if (unlikely(reset))
+		writel(reset, cci->base + CCI_RESET_CMD);
+
+	if (unlikely(val & CCI_IRQ_STATUS_0_I2C_M0_ERROR)) {
+		dev_err_ratelimited(cci->dev, "Master 0 error 0x%08x\n", val);
+		cci->master[0].status = -EIO;
+		writel(CCI_HALT_REQ_I2C_M0_Q0Q1, cci->base + CCI_HALT_REQ);
+		ret = IRQ_HANDLED;
+	}
+
+	if (unlikely(val & CCI_IRQ_STATUS_0_I2C_M1_ERROR)) {
+		dev_err_ratelimited(cci->dev, "Master 1 error 0x%08x\n", val);
+		cci->master[1].status = -EIO;
+		writel(CCI_HALT_REQ_I2C_M1_Q0Q1, cci->base + CCI_HALT_REQ);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
+static int cci_halt(struct cci *cci, u8 master_num)
+{
+	struct cci_master *master;
+	u32 val;
+
+	if (master_num > 1) {
+		dev_err(cci->dev, "Unsupported master idx (%u)\n", master_num);
+		return -EINVAL;
+	}
+
+	val = BIT(master_num);
+	master = &cci->master[master_num];
+
+	reinit_completion(&master->irq_complete);
+	writel(val, cci->base + CCI_HALT_REQ);
+
+	if (!wait_for_completion_timeout(&master->irq_complete, CCI_TIMEOUT)) {
+		dev_err(cci->dev, "CCI halt timeout\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int cci_reset(struct cci *cci)
+{
+	/*
+	 * we reset the whole controller, here and for implicity use
+	 * master[0].xxx for waiting on it.
+	 */
+	reinit_completion(&cci->master[0].irq_complete);
+	writel(CCI_RESET_CMD_MASK, cci->base + CCI_RESET_CMD);
+
+	if (!wait_for_completion_timeout(&cci->master[0].irq_complete,
+					 CCI_TIMEOUT)) {
+		dev_err(cci->dev, "CCI reset timeout\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int cci_init(struct cci *cci)
+{
+	u32 val = CCI_IRQ_MASK_0_I2C_M0_RD_DONE |
+			CCI_IRQ_MASK_0_I2C_M0_Q0_REPORT |
+			CCI_IRQ_MASK_0_I2C_M0_Q1_REPORT |
+			CCI_IRQ_MASK_0_I2C_M1_RD_DONE |
+			CCI_IRQ_MASK_0_I2C_M1_Q0_REPORT |
+			CCI_IRQ_MASK_0_I2C_M1_Q1_REPORT |
+			CCI_IRQ_MASK_0_RST_DONE_ACK |
+			CCI_IRQ_MASK_0_I2C_M0_Q0Q1_HALT_ACK |
+			CCI_IRQ_MASK_0_I2C_M1_Q0Q1_HALT_ACK |
+			CCI_IRQ_MASK_0_I2C_M0_ERROR |
+			CCI_IRQ_MASK_0_I2C_M1_ERROR;
+	int i;
+
+	writel(val, cci->base + CCI_IRQ_MASK_0);
+
+	for (i = 0; i < cci->data->num_masters; i++) {
+		int mode = cci->master[i].mode;
+		const struct hw_params *hw = &cci->data->params[mode];
+
+		val = hw->thigh << 16 | hw->tlow;
+		writel(val, cci->base + CCI_I2C_Mm_SCL_CTL(i));
+
+		val = hw->tsu_sto << 16 | hw->tsu_sta;
+		writel(val, cci->base + CCI_I2C_Mm_SDA_CTL_0(i));
+
+		val = hw->thd_dat << 16 | hw->thd_sta;
+		writel(val, cci->base + CCI_I2C_Mm_SDA_CTL_1(i));
+
+		val = hw->tbuf;
+		writel(val, cci->base + CCI_I2C_Mm_SDA_CTL_2(i));
+
+		val = hw->scl_stretch_en << 8 | hw->trdhld << 4 | hw->tsp;
+		writel(val, cci->base + CCI_I2C_Mm_MISC_CTL(i));
+	}
+
+	return 0;
+}
+
+static int cci_run_queue(struct cci *cci, u8 master, u8 queue)
+{
+	u32 val;
+	int ret;
+
+	val = readl(cci->base + CCI_I2C_Mm_Qn_CUR_WORD_CNT(master, queue));
+	writel(val, cci->base + CCI_I2C_Mm_Qn_EXEC_WORD_CNT(master, queue));
+
+	reinit_completion(&cci->master[master].irq_complete);
+	val = BIT(master * 2 + queue);
+	writel(val, cci->base + CCI_QUEUE_START);
+
+	if (!wait_for_completion_timeout(&cci->master[master].irq_complete,
+					 CCI_TIMEOUT)) {
+		dev_err(cci->dev, "master %d queue %d timeout\n",
+			master, queue);
+		cci_reset(cci);
+		cci_init(cci);
+		return -ETIMEDOUT;
+	}
+
+	ret = cci->master[master].status;
+	if (ret < 0)
+		dev_err(cci->dev, "master %d queue %d error %d\n",
+			master, queue, ret);
+
+	return ret;
+}
+
+static int cci_validate_queue(struct cci *cci, u8 master, u8 queue)
+{
+	u32 val;
+
+	val = readl(cci->base + CCI_I2C_Mm_Qn_CUR_WORD_CNT(master, queue));
+	if (val == cci->data->queue_size[queue])
+		return -EINVAL;
+
+	if (!val)
+		return 0;
+
+	val = CCI_I2C_REPORT | CCI_I2C_REPORT_IRQ_EN;
+	writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
+
+	return cci_run_queue(cci, master, queue);
+}
+
+static int cci_i2c_read(struct cci *cci, u16 master,
+			u16 addr, u8 *buf, u16 len)
+{
+	u32 val, words_read, words_exp;
+	u8 queue = QUEUE_1;
+	int i, index = 0, ret;
+	bool first = true;
+
+	/*
+	 * Call validate queue to make sure queue is empty before starting.
+	 * This is to avoid overflow / underflow of queue.
+	 */
+	ret = cci_validate_queue(cci, master, queue);
+	if (ret < 0)
+		return ret;
+
+	val = CCI_I2C_SET_PARAM | (addr & 0x7f) << 4;
+	writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
+
+	val = CCI_I2C_READ | len << 4;
+	writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
+
+	ret = cci_run_queue(cci, master, queue);
+	if (ret < 0)
+		return ret;
+
+	words_read = readl(cci->base + CCI_I2C_Mm_READ_BUF_LEVEL(master));
+	words_exp = len / 4 + 1;
+	if (words_read != words_exp) {
+		dev_err(cci->dev, "words read = %d, words expected = %d\n",
+			words_read, words_exp);
+		return -EIO;
+	}
+
+	do {
+		val = readl(cci->base + CCI_I2C_Mm_READ_DATA(master));
+
+		for (i = 0; i < 4 && index < len; i++) {
+			if (first) {
+				first = false;
+				continue;
+			}
+			buf[index++] = (val >> (i * 8)) & 0xff;
+		}
+	} while (--words_read);
+
+	return 0;
+}
+
+static int cci_i2c_write(struct cci *cci, u16 master,
+			 u16 addr, u8 *buf, u16 len)
+{
+	u8 queue = QUEUE_0;
+	u8 load[12] = { 0 };
+	int i = 0, j, ret;
+	u32 val;
+
+	/*
+	 * Call validate queue to make sure queue is empty before starting.
+	 * This is to avoid overflow / underflow of queue.
+	 */
+	ret = cci_validate_queue(cci, master, queue);
+	if (ret < 0)
+		return ret;
+
+	val = CCI_I2C_SET_PARAM | (addr & 0x7f) << 4;
+	writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
+
+	load[i++] = CCI_I2C_WRITE | len << 4;
+
+	for (j = 0; j < len; j++)
+		load[i++] = buf[j];
+
+	for (j = 0; j < i; j += 4) {
+		val = load[j];
+		val |= load[j + 1] << 8;
+		val |= load[j + 2] << 16;
+		val |= load[j + 3] << 24;
+		writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
+	}
+
+	val = CCI_I2C_REPORT | CCI_I2C_REPORT_IRQ_EN;
+	writel(val, cci->base + CCI_I2C_Mm_Qn_LOAD_DATA(master, queue));
+
+	return cci_run_queue(cci, master, queue);
+}
+
+static int cci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
+{
+	struct cci_master *cci_master = i2c_get_adapdata(adap);
+	struct cci *cci = cci_master->cci;
+	int i, ret;
+
+	ret = pm_runtime_get_sync(cci->dev);
+	if (ret < 0)
+		goto err;
+
+	for (i = 0; i < num; i++) {
+		if (msgs[i].flags & I2C_M_RD)
+			ret = cci_i2c_read(cci, cci_master->master,
+					   msgs[i].addr, msgs[i].buf,
+					   msgs[i].len);
+		else
+			ret = cci_i2c_write(cci, cci_master->master,
+					    msgs[i].addr, msgs[i].buf,
+					    msgs[i].len);
+
+		if (ret < 0) {
+			dev_err(cci->dev, "cci i2c xfer error %d", ret);
+			break;
+		}
+	}
+
+	if (!ret)
+		ret = num;
+
+err:
+	pm_runtime_mark_last_busy(cci->dev);
+	pm_runtime_put_autosuspend(cci->dev);
+
+	return ret;
+}
+
+static u32 cci_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C;
+}
+
+static const struct i2c_algorithm cci_algo = {
+	.master_xfer	= cci_xfer,
+	.functionality	= cci_func,
+};
+
+static int cci_enable_clocks(struct cci *cci)
+{
+	int ret;
+
+	ret = clk_bulk_prepare_enable(cci->nclocks, cci->clocks);
+	if (ret < 0)
+		dev_err(cci->dev, "Bulk clock prepare failed: %d\n", ret);
+
+	return ret;
+}
+
+static void cci_disable_clocks(struct cci *cci)
+{
+	clk_bulk_disable_unprepare(cci->nclocks, cci->clocks);
+}
+
+#ifdef CONFIG_PM
+static int cci_suspend_runtime(struct device *dev)
+{
+	struct cci *cci = dev_get_drvdata(dev);
+
+	dev_dbg(dev, "Supend invoked\n");
+	cci_disable_clocks(cci);
+	return 0;
+}
+
+static int cci_resume_runtime(struct device *dev)
+{
+	struct cci *cci = dev_get_drvdata(dev);
+	int ret;
+
+	dev_dbg(dev, "Resume invoked\n");
+	ret = cci_enable_clocks(cci);
+	if (ret)
+		return ret;
+
+	cci_init(cci);
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_PM_SLEEP
+static int cci_suspend(struct device *dev)
+{
+	if (!pm_runtime_suspended(dev))
+		return cci_suspend_runtime(dev);
+
+	return 0;
+}
+
+static int cci_resume(struct device *dev)
+{
+	cci_resume_runtime(dev);
+	pm_runtime_mark_last_busy(dev);
+	pm_request_autosuspend(dev);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops qcom_cci_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(cci_suspend, cci_resume)
+	SET_RUNTIME_PM_OPS(cci_suspend_runtime, cci_resume_runtime, NULL)
+};
+
+static int cci_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct device_node *of_node = NULL;
+	unsigned long cci_clk_rate = 0;
+	struct resource *r;
+	struct cci *cci;
+	int ret = 0, i;
+	u32 val;
+
+	cci = devm_kzalloc(dev, sizeof(*cci), GFP_KERNEL);
+	if (!cci)
+		return -ENOMEM;
+
+	cci->dev = dev;
+	platform_set_drvdata(pdev, cci);
+	cci->data = device_get_match_data(&pdev->dev);
+	if (!cci->data) {
+		dev_err(&pdev->dev, "Driver data is null, abort\n");
+		return -EIO;
+	}
+
+	for (i = 0; i < cci->data->num_masters; i++) {
+		cci->master[i].adap.quirks = &cci->data->quirks;
+		cci->master[i].adap.algo = &cci_algo;
+		cci->master[i].adap.dev.parent = cci->dev;
+		cci->master[i].master = i;
+		cci->master[i].cci = cci;
+
+		i2c_set_adapdata(&cci->master[i].adap, &cci->master[i]);
+		snprintf(cci->master[i].adap.name,
+			 sizeof(cci->master[i].adap.name),
+			 "Qualcomm Camera Control Interface: %d", i);
+
+		/* find the child node for i2c-bus as we are on cci node */
+		of_node = of_get_next_available_child(dev->of_node, of_node);
+		if (!of_node) {
+			dev_err(dev, "Missing i2c-bus@%d child node\n", i);
+			return -EINVAL;
+		}
+		cci->master[i].adap.dev.of_node = of_node;
+
+		cci->master[i].mode = I2C_MODE_STANDARD;
+		ret = of_property_read_u32(of_node, "clock-frequency", &val);
+		if (!ret) {
+			if (val == 400000)
+				cci->master[i].mode = I2C_MODE_FAST;
+			else if (val == 1000000)
+				cci->master[i].mode = I2C_MODE_FAST_PLUS;
+		}
+
+		init_completion(&cci->master[i].irq_complete);
+	}
+
+	/* Memory */
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	cci->base = devm_ioremap_resource(dev, r);
+	if (IS_ERR(cci->base))
+		return PTR_ERR(cci->base);
+
+	/* Interrupt */
+
+	ret = platform_get_irq(pdev, 0);
+	if (ret < 0) {
+		dev_err(dev, "missing IRQ: %d\n", ret);
+		return ret;
+	}
+	cci->irq = ret;
+
+	ret = devm_request_irq(dev, cci->irq, cci_isr,
+			       IRQF_TRIGGER_RISING, dev_name(dev), cci);
+	if (ret < 0) {
+		dev_err(dev, "request_irq failed, ret: %d\n", ret);
+		return ret;
+	}
+
+	disable_irq(cci->irq);
+
+	/* Clocks */
+
+	ret = devm_clk_bulk_get_all(dev, &cci->clocks);
+	if (ret < 1) {
+		dev_err(dev, "failed to get clocks %d\n", ret);
+		return ret;
+	}
+	cci->nclocks = ret;
+
+	/* Retrieve CCI clock rate */
+	for (i = 0; i < cci->nclocks; i++) {
+		if (!strncmp(cci->clocks[i].id, "cci", 4)) {
+			cci_clk_rate = clk_get_rate(cci->clocks[i].clk);
+			break;
+		}
+	}
+
+	if (cci_clk_rate != cci->data->cci_clk_rate) {
+		/* cci clock set by the bootloader or via assigned clock rate
+		 * in DT.
+		 */
+		dev_warn(dev, "Found %lu cci clk rate while %lu was expected\n",
+			 cci_clk_rate, cci->data->cci_clk_rate);
+	}
+
+	ret = cci_enable_clocks(cci);
+	if (ret < 0)
+		return ret;
+
+	val = readl_relaxed(cci->base + CCI_HW_VERSION);
+	dev_info(dev, "%s: CCI HW version = 0x%08x", __func__, val);
+
+	enable_irq(cci->irq);
+
+	ret = cci_reset(cci);
+	if (ret < 0)
+		goto error;
+
+	ret = cci_init(cci);
+	if (ret < 0)
+		goto error;
+
+	for (i = 0; i < cci->data->num_masters; i++) {
+		ret = i2c_add_adapter(&cci->master[i].adap);
+		if (ret < 0)
+			goto error_i2c;
+	}
+
+	pm_runtime_set_autosuspend_delay(dev, MSEC_PER_SEC);
+	pm_runtime_use_autosuspend(dev);
+	pm_runtime_set_active(dev);
+	pm_runtime_enable(dev);
+
+	return 0;
+
+error_i2c:
+	for (; i >= 0; i--)
+		i2c_del_adapter(&cci->master[i].adap);
+error:
+	disable_irq(cci->irq);
+	cci_disable_clocks(cci);
+
+	return ret;
+}
+
+static int cci_remove(struct platform_device *pdev)
+{
+	struct cci *cci = platform_get_drvdata(pdev);
+	int i;
+
+	for (i = 0; i < cci->data->num_masters; i++) {
+		i2c_del_adapter(&cci->master[i].adap);
+		cci_halt(cci, i);
+	}
+
+	disable_irq(cci->irq);
+	pm_runtime_disable(&pdev->dev);
+	pm_runtime_set_suspended(&pdev->dev);
+
+	return 0;
+}
+
+static const struct cci_data cci_v1_data = {
+	.num_masters = 1,
+	.queue_size = { 64, 16 },
+	.quirks = {
+		.max_write_len = 10,
+		.max_read_len = 12,
+	},
+	.cci_clk_rate =  19200000,
+	.params[I2C_MODE_STANDARD] = {
+		.thigh = 78,
+		.tlow = 114,
+		.tsu_sto = 28,
+		.tsu_sta = 28,
+		.thd_dat = 10,
+		.thd_sta = 77,
+		.tbuf = 118,
+		.scl_stretch_en = 0,
+		.trdhld = 6,
+		.tsp = 1
+	},
+	.params[I2C_MODE_FAST] = {
+		.thigh = 20,
+		.tlow = 28,
+		.tsu_sto = 21,
+		.tsu_sta = 21,
+		.thd_dat = 13,
+		.thd_sta = 18,
+		.tbuf = 32,
+		.scl_stretch_en = 0,
+		.trdhld = 6,
+		.tsp = 3
+	},
+};
+
+static const struct cci_data cci_v2_data = {
+	.num_masters = 2,
+	.queue_size = { 64, 16 },
+	.quirks = {
+		.max_write_len = 11,
+		.max_read_len = 12,
+	},
+	.cci_clk_rate =  37500000,
+	.params[I2C_MODE_STANDARD] = {
+		.thigh = 201,
+		.tlow = 174,
+		.tsu_sto = 204,
+		.tsu_sta = 231,
+		.thd_dat = 22,
+		.thd_sta = 162,
+		.tbuf = 227,
+		.scl_stretch_en = 0,
+		.trdhld = 6,
+		.tsp = 3
+	},
+	.params[I2C_MODE_FAST] = {
+		.thigh = 38,
+		.tlow = 56,
+		.tsu_sto = 40,
+		.tsu_sta = 40,
+		.thd_dat = 22,
+		.thd_sta = 35,
+		.tbuf = 62,
+		.scl_stretch_en = 0,
+		.trdhld = 6,
+		.tsp = 3
+	},
+	.params[I2C_MODE_FAST_PLUS] = {
+		.thigh = 16,
+		.tlow = 22,
+		.tsu_sto = 17,
+		.tsu_sta = 18,
+		.thd_dat = 16,
+		.thd_sta = 15,
+		.tbuf = 24,
+		.scl_stretch_en = 0,
+		.trdhld = 3,
+		.tsp = 3
+	},
+};
+
+static const struct of_device_id cci_dt_match[] = {
+	{ .compatible = "qcom,msm8916-cci", .data = &cci_v1_data},
+	{ .compatible = "qcom,msm8996-cci", .data = &cci_v2_data},
+	{ .compatible = "qcom,sdm845-cci", .data = &cci_v2_data},
+	{}
+};
+MODULE_DEVICE_TABLE(of, cci_dt_match);
+
+static struct platform_driver qcom_cci_driver = {
+	.probe  = cci_probe,
+	.remove = cci_remove,
+	.driver = {
+		.name = "i2c-qcom-cci",
+		.of_match_table = cci_dt_match,
+		.pm = &qcom_cci_pm,
+	},
+};
+
+module_platform_driver(qcom_cci_driver);
+
+MODULE_DESCRIPTION("Qualcomm Camera Control Interface driver");
+MODULE_AUTHOR("Todor Tomov <todor.tomov@linaro.org>");
+MODULE_AUTHOR("Loic Poulain <loic.poulain@linaro.org>");
+MODULE_LICENSE("GPL v2");