[v4,1/2] i2c: davinci: Add PM Runtime Support

Message ID 20170911201145.31257-2-fcooper@ti.com
State New
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Series
  • i2c: davinci: Add PM Runtime Support needed by 66AK2G
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Commit Message

Franklin S Cooper Jr Sept. 11, 2017, 8:11 p.m.
66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
unlike other Keystone 2 SoCs and OMAPL138. Therefore, pm_runtime
is required to insure the power domain used by the specific I2C instance is
properly turned on along with its functional clock.

Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
---
Version 4 changes:
Fix wording on error message
Fix additional error path

Version 3 changes:
Remove several statements that set clk to NULL
Fix error path

 drivers/i2c/busses/i2c-davinci.c | 67 +++++++++++++++++++++++++++++++++-------
 1 file changed, 55 insertions(+), 12 deletions(-)

Comments

Baolin Wang Sept. 12, 2017, 1:58 a.m. | #1
Hi,

On 12 September 2017 at 04:11, Franklin S Cooper Jr <fcooper@ti.com> wrote:
> 66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
> unlike other Keystone 2 SoCs and OMAPL138. Therefore, pm_runtime
> is required to insure the power domain used by the specific I2C instance is
> properly turned on along with its functional clock.
>
> Signed-off-by: Franklin S Cooper Jr <fcooper@ti.com>
> ---
> Version 4 changes:
> Fix wording on error message
> Fix additional error path
>
> Version 3 changes:
> Remove several statements that set clk to NULL
> Fix error path
>
>  drivers/i2c/busses/i2c-davinci.c | 67 +++++++++++++++++++++++++++++++++-------
>  1 file changed, 55 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
> index b8c4353..a2d9f7c 100644
> --- a/drivers/i2c/busses/i2c-davinci.c
> +++ b/drivers/i2c/busses/i2c-davinci.c
> @@ -36,6 +36,7 @@
>  #include <linux/gpio.h>
>  #include <linux/of_device.h>
>  #include <linux/platform_data/i2c-davinci.h>
> +#include <linux/pm_runtime.h>
>
>  /* ----- global defines ----------------------------------------------- */
>
> @@ -122,6 +123,9 @@
>  /* set the SDA GPIO low */
>  #define DAVINCI_I2C_DCLR_PDCLR1        BIT(1)
>
> +/* timeout for pm runtime autosuspend */
> +#define DAVINCI_I2C_PM_TIMEOUT 1000    /* ms */
> +
>  struct davinci_i2c_dev {
>         struct device           *dev;
>         void __iomem            *base;
> @@ -541,10 +545,17 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>
>         dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
>
> +       ret = pm_runtime_get_sync(dev->dev);
> +       if (ret < 0) {
> +               dev_err(dev->dev, "Failed to runtime_get device: %d\n", ret);
> +               pm_runtime_put_noidle(dev->dev);
> +               return ret;
> +       }
> +
>         ret = i2c_davinci_wait_bus_not_busy(dev);
>         if (ret < 0) {
>                 dev_warn(dev->dev, "timeout waiting for bus ready\n");
> -               return ret;
> +               goto out;
>         }
>
>         for (i = 0; i < num; i++) {
> @@ -552,14 +563,19 @@ i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
>                 dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
>                         ret);
>                 if (ret < 0)
> -                       return ret;
> +                       goto out;
>         }
>
> +       ret = num;
>  #ifdef CONFIG_CPU_FREQ
>         complete(&dev->xfr_complete);
>  #endif
>
> -       return num;
> +out:
> +       pm_runtime_mark_last_busy(dev->dev);
> +       pm_runtime_put_autosuspend(dev->dev);
> +
> +       return ret;
>  }
>
>  static u32 i2c_davinci_func(struct i2c_adapter *adap)
> @@ -599,6 +615,9 @@ static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
>         int count = 0;
>         u16 w;
>
> +       if (pm_runtime_suspended(dev->dev))
> +               return IRQ_NONE;
> +
>         while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
>                 dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
>                 if (count++ == 100) {
> @@ -802,13 +821,24 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>         dev->clk = devm_clk_get(&pdev->dev, NULL);
>         if (IS_ERR(dev->clk))
>                 return PTR_ERR(dev->clk);
> -       clk_prepare_enable(dev->clk);

You removed clk enable here, I think it can not work if we did not
open CONFIG_PM macro. I think you should keep clk enable here, and set
rpm active by pm_runtime_set_active() before issuing
pm_runtime_enable().

>
>         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>         dev->base = devm_ioremap_resource(&pdev->dev, mem);
>         if (IS_ERR(dev->base)) {
> -               r = PTR_ERR(dev->base);
> -               goto err_unuse_clocks;
> +               return PTR_ERR(dev->base);
> +       }
> +
> +       pm_runtime_set_autosuspend_delay(dev->dev,
> +                                        DAVINCI_I2C_PM_TIMEOUT);
> +       pm_runtime_use_autosuspend(dev->dev);
> +
> +       pm_runtime_enable(dev->dev);
> +
> +       r = pm_runtime_get_sync(dev->dev);
> +       if (r < 0) {
> +               dev_err(dev->dev, "failed to runtime_get device: %d\n", r);
> +               pm_runtime_put_noidle(dev->dev);
> +               return r;
>         }
>
>         i2c_davinci_init(dev);
> @@ -849,27 +879,40 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>         if (r)
>                 goto err_unuse_clocks;
>
> +       pm_runtime_mark_last_busy(dev->dev);
> +       pm_runtime_put_autosuspend(dev->dev);
> +
>         return 0;
>
>  err_unuse_clocks:
> -       clk_disable_unprepare(dev->clk);
> -       dev->clk = NULL;
> +       pm_runtime_dont_use_autosuspend(dev->dev);
> +       pm_runtime_put_sync(dev->dev);
> +       pm_runtime_disable(dev->dev);
> +
>         return r;
>  }
>
>  static int davinci_i2c_remove(struct platform_device *pdev)
>  {
>         struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
> +       int ret;
>
>         i2c_davinci_cpufreq_deregister(dev);
>
>         i2c_del_adapter(&dev->adapter);
>
> -       clk_disable_unprepare(dev->clk);
> -       dev->clk = NULL;
> +       ret = pm_runtime_get_sync(&pdev->dev);
> +       if (ret < 0) {
> +               pm_runtime_put_noidle(&pdev->dev);
> +               return ret;
> +       }
>
>         davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
>
> +       pm_runtime_dont_use_autosuspend(dev->dev);
> +       pm_runtime_put_sync(dev->dev);
> +       pm_runtime_disable(dev->dev);
> +
>         return 0;
>  }
>
> @@ -880,7 +923,6 @@ static int davinci_i2c_suspend(struct device *dev)
>
>         /* put I2C into reset */
>         davinci_i2c_reset_ctrl(i2c_dev, 0);
> -       clk_disable_unprepare(i2c_dev->clk);
>
>         return 0;
>  }
> @@ -889,7 +931,6 @@ static int davinci_i2c_resume(struct device *dev)
>  {
>         struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev);
>
> -       clk_prepare_enable(i2c_dev->clk);
>         /* take I2C out of reset */
>         davinci_i2c_reset_ctrl(i2c_dev, 1);
>
> @@ -899,6 +940,8 @@ static int davinci_i2c_resume(struct device *dev)
>  static const struct dev_pm_ops davinci_i2c_pm = {
>         .suspend        = davinci_i2c_suspend,
>         .resume         = davinci_i2c_resume,
> +       SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
> +                                     pm_runtime_force_resume)
>  };
>
>  #define davinci_i2c_pm_ops (&davinci_i2c_pm)
> --
> 2.9.4.dirty
>
Sekhar Nori Sept. 12, 2017, 8:48 a.m. | #2
On Tuesday 12 September 2017 07:28 AM, Baolin Wang wrote:
>> @@ -802,13 +821,24 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>>         dev->clk = devm_clk_get(&pdev->dev, NULL);
>>         if (IS_ERR(dev->clk))
>>                 return PTR_ERR(dev->clk);
>> -       clk_prepare_enable(dev->clk);

> You removed clk enable here, I think it can not work if we did not
> open CONFIG_PM macro. I think you should keep clk enable here, and set

What do you mean by "open CONFIG_PM macro" ?

> rpm active by pm_runtime_set_active() before issuing
> pm_runtime_enable().

Can you explain why you want to do this instead of relying on
pm_runtime_get_sync() to enable clock?

Thanks,
Sekhar
Baolin Wang Sept. 12, 2017, 9:14 a.m. | #3
Hi,

On 12 September 2017 at 16:48, Sekhar Nori <nsekhar@ti.com> wrote:
> On Tuesday 12 September 2017 07:28 AM, Baolin Wang wrote:
>>> @@ -802,13 +821,24 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>>>         dev->clk = devm_clk_get(&pdev->dev, NULL);
>>>         if (IS_ERR(dev->clk))
>>>                 return PTR_ERR(dev->clk);
>>> -       clk_prepare_enable(dev->clk);
>
>> You removed clk enable here, I think it can not work if we did not
>> open CONFIG_PM macro. I think you should keep clk enable here, and set
>
> What do you mean by "open CONFIG_PM macro" ?

If you did not open CONFIG_PM macro, then the pm_runtime_xxx() will be
dummy functions, but now the i2c driver can not work since you did not
enable clock, right?

>
>> rpm active by pm_runtime_set_active() before issuing
>> pm_runtime_enable().
>
> Can you explain why you want to do this instead of relying on
> pm_runtime_get_sync() to enable clock?

What I mean is you should compatible whether CONFIG_PM is enabled or not.
Sekhar Nori Sept. 12, 2017, 9:22 a.m. | #4
On Tuesday 12 September 2017 02:44 PM, Baolin Wang wrote:
> Hi,
> 
> On 12 September 2017 at 16:48, Sekhar Nori <nsekhar@ti.com> wrote:
>> On Tuesday 12 September 2017 07:28 AM, Baolin Wang wrote:
>>>> @@ -802,13 +821,24 @@ static int davinci_i2c_probe(struct platform_device *pdev)
>>>>         dev->clk = devm_clk_get(&pdev->dev, NULL);
>>>>         if (IS_ERR(dev->clk))
>>>>                 return PTR_ERR(dev->clk);
>>>> -       clk_prepare_enable(dev->clk);
>>
>>> You removed clk enable here, I think it can not work if we did not
>>> open CONFIG_PM macro. I think you should keep clk enable here, and set
>>
>> What do you mean by "open CONFIG_PM macro" ?
> 
> If you did not open CONFIG_PM macro, then the pm_runtime_xxx() will be
> dummy functions, but now the i2c driver can not work since you did not
> enable clock, right?

Ah, okay. I am not sure thats a concern on platforms on which this
driver is used. Without PM runtime support, most likely the platforms
will not boot and multiple drivers will fail.

Thanks,
Sekhar

Patch

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index b8c4353..a2d9f7c 100644
--- a/drivers/i2c/busses/i2c-davinci.c
+++ b/drivers/i2c/busses/i2c-davinci.c
@@ -36,6 +36,7 @@ 
 #include <linux/gpio.h>
 #include <linux/of_device.h>
 #include <linux/platform_data/i2c-davinci.h>
+#include <linux/pm_runtime.h>
 
 /* ----- global defines ----------------------------------------------- */
 
@@ -122,6 +123,9 @@ 
 /* set the SDA GPIO low */
 #define DAVINCI_I2C_DCLR_PDCLR1	BIT(1)
 
+/* timeout for pm runtime autosuspend */
+#define DAVINCI_I2C_PM_TIMEOUT	1000	/* ms */
+
 struct davinci_i2c_dev {
 	struct device           *dev;
 	void __iomem		*base;
@@ -541,10 +545,17 @@  i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 
 	dev_dbg(dev->dev, "%s: msgs: %d\n", __func__, num);
 
+	ret = pm_runtime_get_sync(dev->dev);
+	if (ret < 0) {
+		dev_err(dev->dev, "Failed to runtime_get device: %d\n", ret);
+		pm_runtime_put_noidle(dev->dev);
+		return ret;
+	}
+
 	ret = i2c_davinci_wait_bus_not_busy(dev);
 	if (ret < 0) {
 		dev_warn(dev->dev, "timeout waiting for bus ready\n");
-		return ret;
+		goto out;
 	}
 
 	for (i = 0; i < num; i++) {
@@ -552,14 +563,19 @@  i2c_davinci_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 		dev_dbg(dev->dev, "%s [%d/%d] ret: %d\n", __func__, i + 1, num,
 			ret);
 		if (ret < 0)
-			return ret;
+			goto out;
 	}
 
+	ret = num;
 #ifdef CONFIG_CPU_FREQ
 	complete(&dev->xfr_complete);
 #endif
 
-	return num;
+out:
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+
+	return ret;
 }
 
 static u32 i2c_davinci_func(struct i2c_adapter *adap)
@@ -599,6 +615,9 @@  static irqreturn_t i2c_davinci_isr(int this_irq, void *dev_id)
 	int count = 0;
 	u16 w;
 
+	if (pm_runtime_suspended(dev->dev))
+		return IRQ_NONE;
+
 	while ((stat = davinci_i2c_read_reg(dev, DAVINCI_I2C_IVR_REG))) {
 		dev_dbg(dev->dev, "%s: stat=0x%x\n", __func__, stat);
 		if (count++ == 100) {
@@ -802,13 +821,24 @@  static int davinci_i2c_probe(struct platform_device *pdev)
 	dev->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(dev->clk))
 		return PTR_ERR(dev->clk);
-	clk_prepare_enable(dev->clk);
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	dev->base = devm_ioremap_resource(&pdev->dev, mem);
 	if (IS_ERR(dev->base)) {
-		r = PTR_ERR(dev->base);
-		goto err_unuse_clocks;
+		return PTR_ERR(dev->base);
+	}
+
+	pm_runtime_set_autosuspend_delay(dev->dev,
+					 DAVINCI_I2C_PM_TIMEOUT);
+	pm_runtime_use_autosuspend(dev->dev);
+
+	pm_runtime_enable(dev->dev);
+
+	r = pm_runtime_get_sync(dev->dev);
+	if (r < 0) {
+		dev_err(dev->dev, "failed to runtime_get device: %d\n", r);
+		pm_runtime_put_noidle(dev->dev);
+		return r;
 	}
 
 	i2c_davinci_init(dev);
@@ -849,27 +879,40 @@  static int davinci_i2c_probe(struct platform_device *pdev)
 	if (r)
 		goto err_unuse_clocks;
 
+	pm_runtime_mark_last_busy(dev->dev);
+	pm_runtime_put_autosuspend(dev->dev);
+
 	return 0;
 
 err_unuse_clocks:
-	clk_disable_unprepare(dev->clk);
-	dev->clk = NULL;
+	pm_runtime_dont_use_autosuspend(dev->dev);
+	pm_runtime_put_sync(dev->dev);
+	pm_runtime_disable(dev->dev);
+
 	return r;
 }
 
 static int davinci_i2c_remove(struct platform_device *pdev)
 {
 	struct davinci_i2c_dev *dev = platform_get_drvdata(pdev);
+	int ret;
 
 	i2c_davinci_cpufreq_deregister(dev);
 
 	i2c_del_adapter(&dev->adapter);
 
-	clk_disable_unprepare(dev->clk);
-	dev->clk = NULL;
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0) {
+		pm_runtime_put_noidle(&pdev->dev);
+		return ret;
+	}
 
 	davinci_i2c_write_reg(dev, DAVINCI_I2C_MDR_REG, 0);
 
+	pm_runtime_dont_use_autosuspend(dev->dev);
+	pm_runtime_put_sync(dev->dev);
+	pm_runtime_disable(dev->dev);
+
 	return 0;
 }
 
@@ -880,7 +923,6 @@  static int davinci_i2c_suspend(struct device *dev)
 
 	/* put I2C into reset */
 	davinci_i2c_reset_ctrl(i2c_dev, 0);
-	clk_disable_unprepare(i2c_dev->clk);
 
 	return 0;
 }
@@ -889,7 +931,6 @@  static int davinci_i2c_resume(struct device *dev)
 {
 	struct davinci_i2c_dev *i2c_dev = dev_get_drvdata(dev);
 
-	clk_prepare_enable(i2c_dev->clk);
 	/* take I2C out of reset */
 	davinci_i2c_reset_ctrl(i2c_dev, 1);
 
@@ -899,6 +940,8 @@  static int davinci_i2c_resume(struct device *dev)
 static const struct dev_pm_ops davinci_i2c_pm = {
 	.suspend        = davinci_i2c_suspend,
 	.resume         = davinci_i2c_resume,
+	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
+				      pm_runtime_force_resume)
 };
 
 #define davinci_i2c_pm_ops (&davinci_i2c_pm)