diff mbox series

[v2,2/2] rtc: Add ASPEED RTC driver

Message ID 20190325133159.10653-3-joel@jms.id.au
State Superseded
Headers show
Series rtc: Add ASPEED RTC driver | expand

Commit Message

Joel Stanley March 25, 2019, 1:31 p.m. UTC
Read and writes the time to the non-battery backed RTC in the ASPEED BMC
system on chip families.

Signed-off-by: Joel Stanley <joel@jms.id.au>

---
v2: Address review from Alexandre
 - Use devm_rtc_allocate_device
 - Fill in range_min
 - Direcly fill in tm struct
 - Return EINVAL when RTC is not enabled

v1: https://lore.kernel.org/linux-arm-kernel/20181003133155.27494-2-joel@jms.id.au/
Signed-off-by: Joel Stanley <joel@jms.id.au>

---
 drivers/rtc/Kconfig      |  10 +++
 drivers/rtc/Makefile     |   1 +
 drivers/rtc/rtc-aspeed.c | 152 +++++++++++++++++++++++++++++++++++++++
 3 files changed, 163 insertions(+)
 create mode 100644 drivers/rtc/rtc-aspeed.c

-- 
2.20.1

Comments

Alexandre Belloni March 25, 2019, 2:59 p.m. UTC | #1
Hi,

This seems mostly good to me.

On 26/03/2019 00:01:59+1030, Joel Stanley wrote:
> +	dev_dbg(dev, "%s: %4d-%02d-%02d %02d:%02d:%02d\n", __func__,

> +			1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,

> +			tm->tm_hour, tm->tm_min, tm->tm_sec);

> +


We now have %ptR, could you use that?

> +	rtc->rtc_dev->ops = &aspeed_rtc_ops;

> +	rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900;

> +	rtc->rtc_dev->range_max = 38814989399LL; /* 3199-12-31 23:59:59 */

> +


I'm curious how many RTC have been properly designed, could you run
rtc-range?

https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/rtc-tools.git/tree/rtc-range.c

Thanks!

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
Joel Stanley March 25, 2019, 3:28 p.m. UTC | #2
On Mon, 25 Mar 2019 at 14:59, Alexandre Belloni
<alexandre.belloni@bootlin.com> wrote:
>

> Hi,

>

> This seems mostly good to me.

>

> On 26/03/2019 00:01:59+1030, Joel Stanley wrote:

> > +     dev_dbg(dev, "%s: %4d-%02d-%02d %02d:%02d:%02d\n", __func__,

> > +                     1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,

> > +                     tm->tm_hour, tm->tm_min, tm->tm_sec);

> > +

>

> We now have %ptR, could you use that?


I tried this:

  dev_dbg(dev, "%s: %ptR", __func__, tm);

Yes, that appears to do the job. Can you make the change when applying?

>

> > +     rtc->rtc_dev->ops = &aspeed_rtc_ops;

> > +     rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900;

> > +     rtc->rtc_dev->range_max = 38814989399LL; /* 3199-12-31 23:59:59 */

> > +

>

> I'm curious how many RTC have been properly designed, could you run

> rtc-range?

>

> https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/rtc-tools.git/tree/rtc-range.c


It appears to pass the test:

Testing 2000-02-28 23:59:59.
OK

Testing 2038-01-19 03:14:07.
OK

Testing 2069-12-31 23:59:59.
OK

Testing 2099-12-31 23:59:59.
OK

Testing 2100-02-28 23:59:59.
OK

Testing 2106-02-07 06:28:15.
OK

Testing 2262-04-11 23:47:16.
OK

The qemu model I have for the device failed though. A good test! Are
you going to put it in the kernel tree?

Cheers,

Joel
Alexandre Belloni March 25, 2019, 3:43 p.m. UTC | #3
On 25/03/2019 15:28:26+0000, Joel Stanley wrote:
> On Mon, 25 Mar 2019 at 14:59, Alexandre Belloni

> <alexandre.belloni@bootlin.com> wrote:

> > On 26/03/2019 00:01:59+1030, Joel Stanley wrote:

> > > +     dev_dbg(dev, "%s: %4d-%02d-%02d %02d:%02d:%02d\n", __func__,

> > > +                     1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,

> > > +                     tm->tm_hour, tm->tm_min, tm->tm_sec);

> > > +

> >

> > We now have %ptR, could you use that?

> 

> I tried this:

> 

>   dev_dbg(dev, "%s: %ptR", __func__, tm);

> 

> Yes, that appears to do the job. Can you make the change when applying?

> 


Ok, I'll do that.

> >

> > > +     rtc->rtc_dev->ops = &aspeed_rtc_ops;

> > > +     rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900;

> > > +     rtc->rtc_dev->range_max = 38814989399LL; /* 3199-12-31 23:59:59 */

> > > +

> >

> > I'm curious how many RTC have been properly designed, could you run

> > rtc-range?

> >

> > https://git.kernel.org/pub/scm/linux/kernel/git/abelloni/rtc-tools.git/tree/rtc-range.c

> 

> It appears to pass the test:

> 

> Testing 2000-02-28 23:59:59.

> OK

> 

> Testing 2038-01-19 03:14:07.

> OK

> 

> Testing 2069-12-31 23:59:59.

> OK

> 

> Testing 2099-12-31 23:59:59.

> OK

> 

> Testing 2100-02-28 23:59:59.

> OK

> 

> Testing 2106-02-07 06:28:15.

> OK

> 

> Testing 2262-04-11 23:47:16.

> OK

> 

> The qemu model I have for the device failed though. A good test! Are

> you going to put it in the kernel tree?

> 


I was planning to add more dates to test and detect when the range is
properly reported by the rtc (right now, it reports a failure) before
doing so.

-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
Alexandre Belloni March 25, 2019, 4:10 p.m. UTC | #4
On 25/03/2019 15:28:26+0000, Joel Stanley wrote:
> On Mon, 25 Mar 2019 at 14:59, Alexandre Belloni

> <alexandre.belloni@bootlin.com> wrote:

> >

> > Hi,

> >

> > This seems mostly good to me.

> >

> > On 26/03/2019 00:01:59+1030, Joel Stanley wrote:

> > > +     dev_dbg(dev, "%s: %4d-%02d-%02d %02d:%02d:%02d\n", __func__,

> > > +                     1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,

> > > +                     tm->tm_hour, tm->tm_min, tm->tm_sec);

> > > +

> >

> > We now have %ptR, could you use that?

> 

> I tried this:

> 

>   dev_dbg(dev, "%s: %ptR", __func__, tm);

> 

> Yes, that appears to do the job. Can you make the change when applying?

> 


While doing that change, I relaized that the whole locking is probably
unnecessary as all the rtc_ops are called with the rtc lock taken. If
you are not planning to add alarm support, the lock can be removed.


-- 
Alexandre Belloni, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
Joel Stanley March 27, 2019, 1 a.m. UTC | #5
On Mon, 25 Mar 2019 at 16:10, Alexandre Belloni
<alexandre.belloni@bootlin.com> wrote:> >
> While doing that change, I relaized that the whole locking is probably

> unnecessary as all the rtc_ops are called with the rtc lock taken. If

> you are not planning to add alarm support, the lock can be removed.


I had a stab at alarm support, but the select() tests in rtctest.c
were failing. I will submit a v3 without the locking so we can get
that out of the way, and defer adding alarm support for now.

Cheers,

Joel
diff mbox series

Patch

diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig
index dc0d66e80038..2d0482bc468b 100644
--- a/drivers/rtc/Kconfig
+++ b/drivers/rtc/Kconfig
@@ -1841,6 +1841,16 @@  config RTC_DRV_RTD119X
 	  If you say yes here, you get support for the RTD1295 SoC
 	  Real Time Clock.
 
+config RTC_DRV_ASPEED
+	tristate "Aspeed RTC"
+	depends on ARCH_ASPEED || COMPILE_TEST
+	help
+	  If you say yes here you get support for the ASPEED AST2400 and
+	  AST2500 SoC real time clocks.
+
+	  This driver can also be built as a module, if so, the module
+	  will be called "rtc-aspeed".
+
 comment "HID Sensor RTC drivers"
 
 config RTC_DRV_HID_SENSOR_TIME
diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile
index fe3962496685..9d997faa2c26 100644
--- a/drivers/rtc/Makefile
+++ b/drivers/rtc/Makefile
@@ -34,6 +34,7 @@  obj-$(CONFIG_RTC_DRV_AC100)	+= rtc-ac100.o
 obj-$(CONFIG_RTC_DRV_ARMADA38X)	+= rtc-armada38x.o
 obj-$(CONFIG_RTC_DRV_AS3722)	+= rtc-as3722.o
 obj-$(CONFIG_RTC_DRV_ASM9260)	+= rtc-asm9260.o
+obj-$(CONFIG_RTC_DRV_ASPEED)	+= rtc-aspeed.o
 obj-$(CONFIG_RTC_DRV_AT91RM9200)+= rtc-at91rm9200.o
 obj-$(CONFIG_RTC_DRV_AT91SAM9)	+= rtc-at91sam9.o
 obj-$(CONFIG_RTC_DRV_AU1XXX)	+= rtc-au1xxx.o
diff --git a/drivers/rtc/rtc-aspeed.c b/drivers/rtc/rtc-aspeed.c
new file mode 100644
index 000000000000..9ddb3121b30d
--- /dev/null
+++ b/drivers/rtc/rtc-aspeed.c
@@ -0,0 +1,152 @@ 
+// SPDX-License-Identifier: GPL-2.0+
+// Copyright 2015 IBM Corp.
+
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/rtc.h>
+#include <linux/io.h>
+
+struct aspeed_rtc {
+	struct rtc_device	*rtc_dev;
+	void __iomem		*base;
+	spinlock_t		lock;
+};
+
+#define RTC_TIME	0x00
+#define RTC_YEAR	0x04
+#define RTC_CTRL	0x10
+
+#define RTC_UNLOCK	BIT(1)
+#define RTC_ENABLE	BIT(0)
+
+static int aspeed_rtc_read_time(struct device *dev, struct rtc_time *tm)
+{
+	struct aspeed_rtc *rtc = dev_get_drvdata(dev);
+	unsigned int cent, year;
+	unsigned long flags;
+	u32 reg1, reg2;
+
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	if (!(readl(rtc->base + RTC_CTRL) & RTC_ENABLE)) {
+		spin_unlock_irqrestore(&rtc->lock, flags);
+		dev_dbg(dev, "%s failing as rtc disabled\n", __func__);
+		return -EINVAL;
+	}
+
+	do {
+		reg2 = readl(rtc->base + RTC_YEAR);
+		reg1 = readl(rtc->base + RTC_TIME);
+	} while (reg2 != readl(rtc->base + RTC_YEAR));
+
+	tm->tm_mday = (reg1 >> 24) & 0x1f;
+	tm->tm_hour = (reg1 >> 16) & 0x1f;
+	tm->tm_min = (reg1 >> 8) & 0x3f;
+	tm->tm_sec = (reg1 >> 0) & 0x3f;
+
+	cent = (reg2 >> 16) & 0x1f;
+	year = (reg2 >> 8) & 0x7f;
+	tm->tm_mon = ((reg2 >>  0) & 0x0f) - 1;
+	tm->tm_year = year + (cent * 100) - 1900;
+
+	dev_dbg(dev, "%s: %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
+			1900 + tm->tm_year, tm->tm_mon + 1, tm->tm_mday,
+			tm->tm_hour, tm->tm_min, tm->tm_sec);
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+	return 0;
+}
+
+static int aspeed_rtc_set_time(struct device *dev, struct rtc_time *tm)
+{
+	struct aspeed_rtc *rtc = dev_get_drvdata(dev);
+	unsigned long flags;
+	u32 reg1, reg2, ctrl;
+	int year, cent;
+
+	cent = (tm->tm_year + 1900) / 100;
+	year = tm->tm_year % 100;
+
+	reg1 = (tm->tm_mday << 24) | (tm->tm_hour << 16) | (tm->tm_min << 8) |
+		tm->tm_sec;
+
+	reg2 = ((cent & 0x1f) << 16) | ((year & 0x7f) << 8) |
+		((tm->tm_mon + 1) & 0xf);
+
+	spin_lock_irqsave(&rtc->lock, flags);
+
+	ctrl = readl(rtc->base + RTC_CTRL);
+	writel(ctrl | RTC_UNLOCK, rtc->base + RTC_CTRL);
+
+	writel(reg1, rtc->base + RTC_TIME);
+	writel(reg2, rtc->base + RTC_YEAR);
+
+	/* Re-lock and ensure enable is set now that a time is programmed */
+	writel(ctrl | RTC_ENABLE, rtc->base + RTC_CTRL);
+
+	spin_unlock_irqrestore(&rtc->lock, flags);
+
+	return 0;
+}
+
+static const struct rtc_class_ops aspeed_rtc_ops = {
+	.read_time = aspeed_rtc_read_time,
+	.set_time = aspeed_rtc_set_time,
+};
+
+static int aspeed_rtc_probe(struct platform_device *pdev)
+{
+	struct aspeed_rtc *rtc;
+	struct resource *res;
+	int ret;
+
+	rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL);
+	if (!rtc)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	rtc->base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(rtc->base))
+		return PTR_ERR(rtc->base);
+
+	rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc->rtc_dev))
+		return PTR_ERR(rtc->rtc_dev);
+
+	platform_set_drvdata(pdev, rtc);
+
+	rtc->rtc_dev->ops = &aspeed_rtc_ops;
+	rtc->rtc_dev->range_min = RTC_TIMESTAMP_BEGIN_1900;
+	rtc->rtc_dev->range_max = 38814989399LL; /* 3199-12-31 23:59:59 */
+
+	ret = rtc_register_device(rtc->rtc_dev);
+	if (ret)
+		return ret;
+
+	spin_lock_init(&rtc->lock);
+
+	return 0;
+}
+
+static const struct of_device_id aspeed_rtc_match[] = {
+	{ .compatible = "aspeed,ast2400-rtc", },
+	{ .compatible = "aspeed,ast2500-rtc", },
+	{ .compatible = "aspeed,ast2600-rtc", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, aspeed_rtc_match);
+
+static struct platform_driver aspeed_rtc_driver = {
+	.driver = {
+		.name = "aspeed-rtc",
+		.of_match_table = of_match_ptr(aspeed_rtc_match),
+	},
+};
+
+module_platform_driver_probe(aspeed_rtc_driver, aspeed_rtc_probe);
+
+MODULE_DESCRIPTION("ASPEED RTC driver");
+MODULE_AUTHOR("Joel Stanley <joel@jms.id.au>");
+MODULE_LICENSE("GPL");