[v3,1/2] i2c: davinci: Add PM Runtime Support

Message ID 20170908175448.3367-2-fcooper@ti.com
State Superseded
Headers show
Series
  • ARM: dts: keystone-k2g: Add I2C support for 66AK2G
Related show

Commit Message

Franklin S Cooper Jr Sept. 8, 2017, 5:54 p.m.
66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
like 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 3 changes:
Remove several statements that set clk to NULL
Fix error path

 drivers/i2c/busses/i2c-davinci.c | 64 +++++++++++++++++++++++++++++++++-------
 1 file changed, 53 insertions(+), 11 deletions(-)

Comments

Sekhar Nori Sept. 11, 2017, 11:29 a.m. | #1
On Friday 08 September 2017 11:24 PM, Franklin S Cooper Jr wrote:
> 66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
> like other Keystone 2 SoCs and OMAPL138. Therefore, pm_runtime

unlike ?

> 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 3 changes:
> Remove several statements that set clk to NULL
> Fix error path
> 
>  drivers/i2c/busses/i2c-davinci.c | 64 +++++++++++++++++++++++++++++++++-------
>  1 file changed, 53 insertions(+), 11 deletions(-)

> @@ -802,12 +821,22 @@ 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);
> +		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);
>  		goto err_unuse_clocks;

You end up doing a pm_runtime_put_sync() on failure here, instead of
pm_runtime_put_noidle() like rest of the patch.

May be handle this failure here instead of relying on the goto path.

>  	}
>  
> @@ -849,27 +878,40 @@ 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;
>  }

Thanks,
Sekhar
Franklin S Cooper Jr Sept. 11, 2017, 8:07 p.m. | #2
On 09/11/2017 06:29 AM, Sekhar Nori wrote:
> On Friday 08 September 2017 11:24 PM, Franklin S Cooper Jr wrote:
>> 66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
>> like other Keystone 2 SoCs and OMAPL138. Therefore, pm_runtime
> 
> unlike ?
> 
>> 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 3 changes:
>> Remove several statements that set clk to NULL
>> Fix error path
>>
>>  drivers/i2c/busses/i2c-davinci.c | 64 +++++++++++++++++++++++++++++++++-------
>>  1 file changed, 53 insertions(+), 11 deletions(-)
> 
>> @@ -802,12 +821,22 @@ 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);
>> +		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);
>>  		goto err_unuse_clocks;
> 
> You end up doing a pm_runtime_put_sync() on failure here, instead of
> pm_runtime_put_noidle() like rest of the patch.
> 
> May be handle this failure here instead of relying on the goto path.

Ok
> 
>>  	}
>>  
>> @@ -849,27 +878,40 @@ 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;
>>  }
> 
> Thanks,
> Sekhar
>
Grygorii Strashko Sept. 11, 2017, 8:11 p.m. | #3
On 09/11/2017 03:07 PM, Franklin S Cooper Jr wrote:
> 
> 
> On 09/11/2017 06:29 AM, Sekhar Nori wrote:
>> On Friday 08 September 2017 11:24 PM, Franklin S Cooper Jr wrote:
>>> 66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
>>> like other Keystone 2 SoCs and OMAPL138. Therefore, pm_runtime
>>
>> unlike ?
>>
>>> 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 3 changes:
>>> Remove several statements that set clk to NULL
>>> Fix error path
>>>
>>>   drivers/i2c/busses/i2c-davinci.c | 64 +++++++++++++++++++++++++++++++++-------
>>>   1 file changed, 53 insertions(+), 11 deletions(-)
>>
>>> @@ -802,12 +821,22 @@ 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);
>>> +		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);
>>>   		goto err_unuse_clocks;
>>
>> You end up doing a pm_runtime_put_sync() on failure here, instead of
>> pm_runtime_put_noidle() like rest of the patch.
>>
>> May be handle this failure here instead of relying on the goto path.
> 
> Ok

I think, it's not necessary - pm_runtime_put_sync() can be used in this case
 (and used the same way in many other drivers).
In case, of failure in this place - pm_runtime_put_sync() will just decrement usage counter.


>>
>>>   	}
>>>   
>>> @@ -849,27 +878,40 @@ 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;
>>>   }
>>
>> Thanks,
>> Sekhar
>>
Sekhar Nori Sept. 12, 2017, 8:25 a.m. | #4
On Tuesday 12 September 2017 01:41 AM, Grygorii Strashko wrote:
> 
> 
> On 09/11/2017 03:07 PM, Franklin S Cooper Jr wrote:
>>
>>
>> On 09/11/2017 06:29 AM, Sekhar Nori wrote:
>>> On Friday 08 September 2017 11:24 PM, Franklin S Cooper Jr wrote:
>>>> 66AK2G has I2C instances that are not apart of the ALWAYS_ON power domain
>>>> like other Keystone 2 SoCs and OMAPL138. Therefore, pm_runtime
>>>
>>> unlike ?
>>>
>>>> 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 3 changes:
>>>> Remove several statements that set clk to NULL
>>>> Fix error path
>>>>
>>>>   drivers/i2c/busses/i2c-davinci.c | 64 +++++++++++++++++++++++++++++++++-------
>>>>   1 file changed, 53 insertions(+), 11 deletions(-)
>>>
>>>> @@ -802,12 +821,22 @@ 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);
>>>> +		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);
>>>>   		goto err_unuse_clocks;
>>>
>>> You end up doing a pm_runtime_put_sync() on failure here, instead of
>>> pm_runtime_put_noidle() like rest of the patch.
>>>
>>> May be handle this failure here instead of relying on the goto path.
>>
>> Ok
> 
> I think, it's not necessary - pm_runtime_put_sync() can be used in this case
>  (and used the same way in many other drivers).
> In case, of failure in this place - pm_runtime_put_sync() will just decrement usage counter.

Can you please explain why this is the case? At least on DA850, I see
the runtime_idle callback invoked from rpm_idle() if
pm_runtime_put_sync() is used in the failure path.

Thanks
Sekhar

Patch

diff --git a/drivers/i2c/busses/i2c-davinci.c b/drivers/i2c/busses/i2c-davinci.c
index b8c4353..57612cb 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) {
@@ -802,12 +821,22 @@  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);
+		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);
 		goto err_unuse_clocks;
 	}
 
@@ -849,27 +878,40 @@  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 +922,6 @@  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 +930,6 @@  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 +939,8 @@  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)