[RFC PATCH] sdhci: arasan: Add runtime PM support

[RFC PATCH] sdhci: arasan: Add runtime PM support

[naranimanish]

From: Manish Narani <mnarani@xilinx.com>

This patch adds runtime PM support in Arasan SD driver.

Signed-off-by: Manish Narani <mnarani@xilinx.com>
---
 drivers/mmc/host/sdhci-of-arasan.c | 83 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 81 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
index c33a5f7..47196b5 100644
--- a/drivers/mmc/host/sdhci-of-arasan.c
+++ b/drivers/mmc/host/sdhci-of-arasan.c
@@ -23,6 +23,7 @@
 #include <linux/mfd/syscon.h>
 #include <linux/module.h>
 #include <linux/of_device.h>
+#include <linux/pm_runtime.h>
 #include <linux/phy/phy.h>
 #include <linux/regmap.h>
 #include <linux/of.h>
@@ -349,6 +350,75 @@ static const struct sdhci_pltfm_data sdhci_arasan_cqe_pdata = {
 			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
 };
 
+#ifdef CONFIG_PM
+/**
+ * sdhci_arasan_runtime_suspend - Suspend method for the driver
+ * @dev:	Address of the device structure
+ * Returns 0 on success and error value on error
+ *
+ * Put the device in a low power state.
+ */
+static int sdhci_arasan_runtime_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	int ret;
+
+	ret = sdhci_runtime_suspend_host(host);
+	if (ret)
+		return ret;
+
+	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
+		mmc_retune_needed(host->mmc);
+
+	clk_disable(pltfm_host->clk);
+	clk_disable(sdhci_arasan->clk_ahb);
+
+	return 0;
+}
+
+/**
+ * sdhci_arasan_runtime_resume - Resume method for the driver
+ * @dev:	Address of the device structure
+ * Returns 0 on success and error value on error
+ *
+ * Resume operation after suspend
+ */
+static int sdhci_arasan_runtime_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
+	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
+	int ret;
+
+	ret = clk_enable(sdhci_arasan->clk_ahb);
+	if (ret) {
+		dev_err(dev, "Cannot enable AHB clock.\n");
+		return ret;
+	}
+
+	ret = clk_enable(pltfm_host->clk);
+	if (ret) {
+		dev_err(dev, "Cannot enable SD clock.\n");
+		return ret;
+	}
+
+	ret = sdhci_runtime_resume_host(host);
+	if (ret)
+		goto out;
+
+	return 0;
+out:
+	clk_disable(pltfm_host->clk);
+	clk_disable(sdhci_arasan->clk_ahb);
+
+	return ret;
+}
+#endif /* ! CONFIG_PM */
+
 #ifdef CONFIG_PM_SLEEP
 /**
  * sdhci_arasan_suspend - Suspend method for the driver
@@ -443,8 +513,11 @@ static int sdhci_arasan_resume(struct device *dev)
 }
 #endif /* ! CONFIG_PM_SLEEP */
 
-static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops, sdhci_arasan_suspend,
-			 sdhci_arasan_resume);
+static const struct dev_pm_ops sdhci_arasan_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(sdhci_arasan_suspend, sdhci_arasan_resume)
+	SET_RUNTIME_PM_OPS(sdhci_arasan_runtime_suspend,
+			   sdhci_arasan_runtime_resume, NULL)
+};
 
 static const struct of_device_id sdhci_arasan_of_match[] = {
 	/* SoC-specific compatible strings w/ soc_ctl_map */
@@ -806,6 +879,12 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_add_host;
 
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
+	pm_runtime_mark_last_busy(&pdev->dev);
+	pm_runtime_use_autosuspend(&pdev->dev);
+
 	return 0;
 
 err_add_host:
-- 
2.7.4

Re: [RFC PATCH] sdhci: arasan: Add runtime PM support

[Shawn Lin]

On 2018/3/29 13:48, naranimanish@gmail.com wrote:
> From: Manish Narani <mnarani@xilinx.com>
> 
> This patch adds runtime PM support in Arasan SD driver.
> 
> Signed-off-by: Manish Narani <mnarani@xilinx.com>
> ---
>   drivers/mmc/host/sdhci-of-arasan.c | 83 +++++++++++++++++++++++++++++++++++++-
>   1 file changed, 81 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index c33a5f7..47196b5 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -23,6 +23,7 @@
>   #include <linux/mfd/syscon.h>
>   #include <linux/module.h>
>   #include <linux/of_device.h>
> +#include <linux/pm_runtime.h>
>   #include <linux/phy/phy.h>
>   #include <linux/regmap.h>
>   #include <linux/of.h>
> @@ -349,6 +350,75 @@ static const struct sdhci_pltfm_data sdhci_arasan_cqe_pdata = {
>   			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
>   };
>   
> +#ifdef CONFIG_PM
> +/**
> + * sdhci_arasan_runtime_suspend - Suspend method for the driver
> + * @dev:	Address of the device structure
> + * Returns 0 on success and error value on error
> + *
> + * Put the device in a low power state.
> + */
> +static int sdhci_arasan_runtime_suspend(struct device *dev)
> +{

Would you help take care of cqhci_suspend?

> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct sdhci_host *host = platform_get_drvdata(pdev);
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
> +	int ret;
> +
> +	ret = sdhci_runtime_suspend_host(host);
> +	if (ret)
> +		return ret;
> +
> +	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
> +		mmc_retune_needed(host->mmc);
> +
> +	clk_disable(pltfm_host->clk);
> +	clk_disable(sdhci_arasan->clk_ahb);
> +
> +	return 0;
> +}
> +
> +/**
> + * sdhci_arasan_runtime_resume - Resume method for the driver
> + * @dev:	Address of the device structure
> + * Returns 0 on success and error value on error
> + *
> + * Resume operation after suspend
> + */
> +static int sdhci_arasan_runtime_resume(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct sdhci_host *host = platform_get_drvdata(pdev);
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
> +	int ret;
> +

Ditto, for cqhci_resume.

> +	ret = clk_enable(sdhci_arasan->clk_ahb);
> +	if (ret) {
> +		dev_err(dev, "Cannot enable AHB clock.\n");
> +		return ret;
> +	}
> +
> +	ret = clk_enable(pltfm_host->clk);
> +	if (ret) {
> +		dev_err(dev, "Cannot enable SD clock.\n");
> +		return ret;
> +	}
> +
> +	ret = sdhci_runtime_resume_host(host);
> +	if (ret)
> +		goto out;
> +
> +	return 0;
> +out:
> +	clk_disable(pltfm_host->clk);
> +	clk_disable(sdhci_arasan->clk_ahb);
> +
> +	return ret;
> +}
> +#endif /* ! CONFIG_PM */
> +
>   #ifdef CONFIG_PM_SLEEP
>   /**
>    * sdhci_arasan_suspend - Suspend method for the driver
> @@ -443,8 +513,11 @@ static int sdhci_arasan_resume(struct device *dev)
>   }
>   #endif /* ! CONFIG_PM_SLEEP */
>   
> -static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops, sdhci_arasan_suspend,
> -			 sdhci_arasan_resume);
> +static const struct dev_pm_ops sdhci_arasan_dev_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(sdhci_arasan_suspend, sdhci_arasan_resume)
> +	SET_RUNTIME_PM_OPS(sdhci_arasan_runtime_suspend,
> +			   sdhci_arasan_runtime_resume, NULL)
> +};
>   
>   static const struct of_device_id sdhci_arasan_of_match[] = {
>   	/* SoC-specific compatible strings w/ soc_ctl_map */
> @@ -806,6 +879,12 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>   	if (ret)
>   		goto err_add_host;
>   
> +	pm_runtime_set_active(&pdev->dev);
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
> +	pm_runtime_mark_last_busy(&pdev->dev);
> +	pm_runtime_use_autosuspend(&pdev->dev);
> +
>   	return 0;
>   
>   err_add_host:
> 

RE: [RFC PATCH] sdhci: arasan: Add runtime PM support

[Manish Narani]

Hi Shawn,

> -----Original Message-----
> From: Shawn Lin [mailto:shawn.lin@rock-chips.com]
> Sent: Thursday, March 29, 2018 12:57 PM
> To: naranimanish@gmail.com
> Cc: adrian.hunter@intel.com; michal.simek@xilinx.com;
> ulf.hansson@linaro.org; linux-mmc@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org; shawn.lin@rock-
> chips.com; Manish Narani <MNARANI@xilinx.com>
> Subject: Re: [RFC PATCH] sdhci: arasan: Add runtime PM support
> 
> On 2018/3/29 13:48, naranimanish@gmail.com wrote:
> > From: Manish Narani <mnarani@xilinx.com>
> >
> > This patch adds runtime PM support in Arasan SD driver.
> >
> > Signed-off-by: Manish Narani <mnarani@xilinx.com>
> > ---
> >   drivers/mmc/host/sdhci-of-arasan.c | 83
> +++++++++++++++++++++++++++++++++++++-
> >   1 file changed, 81 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/mmc/host/sdhci-of-arasan.c
> > b/drivers/mmc/host/sdhci-of-arasan.c
> > index c33a5f7..47196b5 100644
> > --- a/drivers/mmc/host/sdhci-of-arasan.c
> > +++ b/drivers/mmc/host/sdhci-of-arasan.c
> > @@ -23,6 +23,7 @@
> >   #include <linux/mfd/syscon.h>
> >   #include <linux/module.h>
> >   #include <linux/of_device.h>
> > +#include <linux/pm_runtime.h>
> >   #include <linux/phy/phy.h>
> >   #include <linux/regmap.h>
> >   #include <linux/of.h>
> > @@ -349,6 +350,75 @@ static const struct sdhci_pltfm_data
> sdhci_arasan_cqe_pdata = {
> >   			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
> >   };
> >
> > +#ifdef CONFIG_PM
> > +/**
> > + * sdhci_arasan_runtime_suspend - Suspend method for the driver
> > + * @dev:	Address of the device structure
> > + * Returns 0 on success and error value on error
> > + *
> > + * Put the device in a low power state.
> > + */
> > +static int sdhci_arasan_runtime_suspend(struct device *dev) {
> 
> Would you help take care of cqhci_suspend?
Yes, sure. Will take care of this in next version of patch.

> 
> > +	struct platform_device *pdev = to_platform_device(dev);
> > +	struct sdhci_host *host = platform_get_drvdata(pdev);
> > +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> > +	struct sdhci_arasan_data *sdhci_arasan =
> sdhci_pltfm_priv(pltfm_host);
> > +	int ret;
> > +
> > +	ret = sdhci_runtime_suspend_host(host);
> > +	if (ret)
> > +		return ret;
> > +
> > +	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
> > +		mmc_retune_needed(host->mmc);
> > +
> > +	clk_disable(pltfm_host->clk);
> > +	clk_disable(sdhci_arasan->clk_ahb);
> > +
> > +	return 0;
> > +}
> > +
> > +/**
> > + * sdhci_arasan_runtime_resume - Resume method for the driver
> > + * @dev:	Address of the device structure
> > + * Returns 0 on success and error value on error
> > + *
> > + * Resume operation after suspend
> > + */
> > +static int sdhci_arasan_runtime_resume(struct device *dev) {
> > +	struct platform_device *pdev = to_platform_device(dev);
> > +	struct sdhci_host *host = platform_get_drvdata(pdev);
> > +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> > +	struct sdhci_arasan_data *sdhci_arasan =
> sdhci_pltfm_priv(pltfm_host);
> > +	int ret;
> > +
> 
> Ditto, for cqhci_resume.
Yes, okay.

Thanks,
Manish

> 
> > +	ret = clk_enable(sdhci_arasan->clk_ahb);
> > +	if (ret) {
> > +		dev_err(dev, "Cannot enable AHB clock.\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = clk_enable(pltfm_host->clk);
> > +	if (ret) {
> > +		dev_err(dev, "Cannot enable SD clock.\n");
> > +		return ret;
> > +	}
> > +
> > +	ret = sdhci_runtime_resume_host(host);
> > +	if (ret)
> > +		goto out;
> > +
> > +	return 0;
> > +out:
> > +	clk_disable(pltfm_host->clk);
> > +	clk_disable(sdhci_arasan->clk_ahb);
> > +
> > +	return ret;
> > +}
> > +#endif /* ! CONFIG_PM */
> > +
> >   #ifdef CONFIG_PM_SLEEP
> >   /**
> >    * sdhci_arasan_suspend - Suspend method for the driver @@ -443,8
> > +513,11 @@ static int sdhci_arasan_resume(struct device *dev)
> >   }
> >   #endif /* ! CONFIG_PM_SLEEP */
> >
> > -static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops,
> sdhci_arasan_suspend,
> > -			 sdhci_arasan_resume);
> > +static const struct dev_pm_ops sdhci_arasan_dev_pm_ops = {
> > +	SET_SYSTEM_SLEEP_PM_OPS(sdhci_arasan_suspend,
> sdhci_arasan_resume)
> > +	SET_RUNTIME_PM_OPS(sdhci_arasan_runtime_suspend,
> > +			   sdhci_arasan_runtime_resume, NULL) };
> >
> >   static const struct of_device_id sdhci_arasan_of_match[] = {
> >   	/* SoC-specific compatible strings w/ soc_ctl_map */ @@ -806,6
> > +879,12 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
> >   	if (ret)
> >   		goto err_add_host;
> >
> > +	pm_runtime_set_active(&pdev->dev);
> > +	pm_runtime_enable(&pdev->dev);
> > +	pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
> > +	pm_runtime_mark_last_busy(&pdev->dev);
> > +	pm_runtime_use_autosuspend(&pdev->dev);
> > +
> >   	return 0;
> >
> >   err_add_host:
> >

Re: [RFC PATCH] sdhci: arasan: Add runtime PM support

[Adrian Hunter]

On 29/03/18 08:48, naranimanish@gmail.com wrote:
> From: Manish Narani <mnarani@xilinx.com>
> 
> This patch adds runtime PM support in Arasan SD driver.
> 
> Signed-off-by: Manish Narani <mnarani@xilinx.com>

Just a couple of comments about style.

> ---
>  drivers/mmc/host/sdhci-of-arasan.c | 83 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 81 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
> index c33a5f7..47196b5 100644
> --- a/drivers/mmc/host/sdhci-of-arasan.c
> +++ b/drivers/mmc/host/sdhci-of-arasan.c
> @@ -23,6 +23,7 @@
>  #include <linux/mfd/syscon.h>
>  #include <linux/module.h>
>  #include <linux/of_device.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/phy/phy.h>
>  #include <linux/regmap.h>
>  #include <linux/of.h>
> @@ -349,6 +350,75 @@ static const struct sdhci_pltfm_data sdhci_arasan_cqe_pdata = {
>  			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
>  };
>  
> +#ifdef CONFIG_PM
> +/**
> + * sdhci_arasan_runtime_suspend - Suspend method for the driver
> + * @dev:	Address of the device structure
> + * Returns 0 on success and error value on error
> + *
> + * Put the device in a low power state.
> + */

Kernel style is not to put kerneldoc on callback functions.

> +static int sdhci_arasan_runtime_suspend(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct sdhci_host *host = platform_get_drvdata(pdev);
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
> +	int ret;
> +
> +	ret = sdhci_runtime_suspend_host(host);
> +	if (ret)
> +		return ret;
> +
> +	if (host->tuning_mode != SDHCI_TUNING_MODE_3)
> +		mmc_retune_needed(host->mmc);
> +
> +	clk_disable(pltfm_host->clk);
> +	clk_disable(sdhci_arasan->clk_ahb);
> +
> +	return 0;
> +}
> +
> +/**
> + * sdhci_arasan_runtime_resume - Resume method for the driver
> + * @dev:	Address of the device structure
> + * Returns 0 on success and error value on error
> + *
> + * Resume operation after suspend
> + */

Kernel style is not to put kerneldoc on callback functions.

> +static int sdhci_arasan_runtime_resume(struct device *dev)
> +{
> +	struct platform_device *pdev = to_platform_device(dev);
> +	struct sdhci_host *host = platform_get_drvdata(pdev);
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_arasan_data *sdhci_arasan = sdhci_pltfm_priv(pltfm_host);
> +	int ret;
> +
> +	ret = clk_enable(sdhci_arasan->clk_ahb);
> +	if (ret) {
> +		dev_err(dev, "Cannot enable AHB clock.\n");
> +		return ret;
> +	}
> +
> +	ret = clk_enable(pltfm_host->clk);
> +	if (ret) {
> +		dev_err(dev, "Cannot enable SD clock.\n");
> +		return ret;
> +	}
> +
> +	ret = sdhci_runtime_resume_host(host);
> +	if (ret)
> +		goto out;
> +
> +	return 0;
> +out:
> +	clk_disable(pltfm_host->clk);
> +	clk_disable(sdhci_arasan->clk_ahb);
> +
> +	return ret;
> +}
> +#endif /* ! CONFIG_PM */
> +
>  #ifdef CONFIG_PM_SLEEP
>  /**
>   * sdhci_arasan_suspend - Suspend method for the driver
> @@ -443,8 +513,11 @@ static int sdhci_arasan_resume(struct device *dev)
>  }
>  #endif /* ! CONFIG_PM_SLEEP */
>  
> -static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops, sdhci_arasan_suspend,
> -			 sdhci_arasan_resume);
> +static const struct dev_pm_ops sdhci_arasan_dev_pm_ops = {
> +	SET_SYSTEM_SLEEP_PM_OPS(sdhci_arasan_suspend, sdhci_arasan_resume)
> +	SET_RUNTIME_PM_OPS(sdhci_arasan_runtime_suspend,
> +			   sdhci_arasan_runtime_resume, NULL)
> +};
>  
>  static const struct of_device_id sdhci_arasan_of_match[] = {
>  	/* SoC-specific compatible strings w/ soc_ctl_map */
> @@ -806,6 +879,12 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err_add_host;
>  
> +	pm_runtime_set_active(&pdev->dev);
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_set_autosuspend_delay(&pdev->dev, 2000);
> +	pm_runtime_mark_last_busy(&pdev->dev);
> +	pm_runtime_use_autosuspend(&pdev->dev);
> +
>  	return 0;
>  
>  err_add_host:
> 

Re: [RFC PATCH] sdhci: arasan: Add runtime PM support

[Michal Simek]

Hi Adrian,

On 10.4.2018 13:42, Adrian Hunter wrote:
> On 29/03/18 08:48, naranimanish@gmail.com wrote:
>> From: Manish Narani <mnarani@xilinx.com>
>>
>> This patch adds runtime PM support in Arasan SD driver.
>>
>> Signed-off-by: Manish Narani <mnarani@xilinx.com>
> 
> Just a couple of comments about style.
> 
>> ---
>>  drivers/mmc/host/sdhci-of-arasan.c | 83 +++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 81 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
>> index c33a5f7..47196b5 100644
>> --- a/drivers/mmc/host/sdhci-of-arasan.c
>> +++ b/drivers/mmc/host/sdhci-of-arasan.c
>> @@ -23,6 +23,7 @@
>>  #include <linux/mfd/syscon.h>
>>  #include <linux/module.h>
>>  #include <linux/of_device.h>
>> +#include <linux/pm_runtime.h>
>>  #include <linux/phy/phy.h>
>>  #include <linux/regmap.h>
>>  #include <linux/of.h>
>> @@ -349,6 +350,75 @@ static const struct sdhci_pltfm_data sdhci_arasan_cqe_pdata = {
>>  			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
>>  };
>>  
>> +#ifdef CONFIG_PM
>> +/**
>> + * sdhci_arasan_runtime_suspend - Suspend method for the driver
>> + * @dev:	Address of the device structure
>> + * Returns 0 on success and error value on error
>> + *
>> + * Put the device in a low power state.
>> + */
> 
> Kernel style is not to put kerneldoc on callback functions.

I have never read that there are some sort of list of functions which
shouldn't be covered by kernel-doc.
What's the problem with using kerneldoc format here? Maybe I am not
getting your comments.

Thanks,
Michal

Re: [RFC PATCH] sdhci: arasan: Add runtime PM support

[Adrian Hunter]

On 10/04/18 15:06, Michal Simek wrote:
> Hi Adrian,
> 
> On 10.4.2018 13:42, Adrian Hunter wrote:
>> On 29/03/18 08:48, naranimanish@gmail.com wrote:
>>> From: Manish Narani <mnarani@xilinx.com>
>>>
>>> This patch adds runtime PM support in Arasan SD driver.
>>>
>>> Signed-off-by: Manish Narani <mnarani@xilinx.com>
>>
>> Just a couple of comments about style.
>>
>>> ---
>>>  drivers/mmc/host/sdhci-of-arasan.c | 83 +++++++++++++++++++++++++++++++++++++-
>>>  1 file changed, 81 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
>>> index c33a5f7..47196b5 100644
>>> --- a/drivers/mmc/host/sdhci-of-arasan.c
>>> +++ b/drivers/mmc/host/sdhci-of-arasan.c
>>> @@ -23,6 +23,7 @@
>>>  #include <linux/mfd/syscon.h>
>>>  #include <linux/module.h>
>>>  #include <linux/of_device.h>
>>> +#include <linux/pm_runtime.h>
>>>  #include <linux/phy/phy.h>
>>>  #include <linux/regmap.h>
>>>  #include <linux/of.h>
>>> @@ -349,6 +350,75 @@ static const struct sdhci_pltfm_data sdhci_arasan_cqe_pdata = {
>>>  			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
>>>  };
>>>  
>>> +#ifdef CONFIG_PM
>>> +/**
>>> + * sdhci_arasan_runtime_suspend - Suspend method for the driver
>>> + * @dev:	Address of the device structure
>>> + * Returns 0 on success and error value on error
>>> + *
>>> + * Put the device in a low power state.
>>> + */
>>
>> Kernel style is not to put kerneldoc on callback functions.
> 
> I have never read that there are some sort of list of functions which
> shouldn't be covered by kernel-doc.
> What's the problem with using kerneldoc format here? Maybe I am not
> getting your comments.

It is not a list of functions.  It is any implementation of a well-known
callback. i.e. we already know what ->runtime_suspend() is for, so we don't
need untold numbers of drivers describing it in comments.

Re: [RFC PATCH] sdhci: arasan: Add runtime PM support

[Michal Simek]

On 10.4.2018 14:17, Adrian Hunter wrote:
> On 10/04/18 15:06, Michal Simek wrote:
>> Hi Adrian,
>>
>> On 10.4.2018 13:42, Adrian Hunter wrote:
>>> On 29/03/18 08:48, naranimanish@gmail.com wrote:
>>>> From: Manish Narani <mnarani@xilinx.com>
>>>>
>>>> This patch adds runtime PM support in Arasan SD driver.
>>>>
>>>> Signed-off-by: Manish Narani <mnarani@xilinx.com>
>>>
>>> Just a couple of comments about style.
>>>
>>>> ---
>>>>  drivers/mmc/host/sdhci-of-arasan.c | 83 +++++++++++++++++++++++++++++++++++++-
>>>>  1 file changed, 81 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
>>>> index c33a5f7..47196b5 100644
>>>> --- a/drivers/mmc/host/sdhci-of-arasan.c
>>>> +++ b/drivers/mmc/host/sdhci-of-arasan.c
>>>> @@ -23,6 +23,7 @@
>>>>  #include <linux/mfd/syscon.h>
>>>>  #include <linux/module.h>
>>>>  #include <linux/of_device.h>
>>>> +#include <linux/pm_runtime.h>
>>>>  #include <linux/phy/phy.h>
>>>>  #include <linux/regmap.h>
>>>>  #include <linux/of.h>
>>>> @@ -349,6 +350,75 @@ static const struct sdhci_pltfm_data sdhci_arasan_cqe_pdata = {
>>>>  			SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
>>>>  };
>>>>  
>>>> +#ifdef CONFIG_PM
>>>> +/**
>>>> + * sdhci_arasan_runtime_suspend - Suspend method for the driver
>>>> + * @dev:	Address of the device structure
>>>> + * Returns 0 on success and error value on error
>>>> + *
>>>> + * Put the device in a low power state.
>>>> + */
>>>
>>> Kernel style is not to put kerneldoc on callback functions.
>>
>> I have never read that there are some sort of list of functions which
>> shouldn't be covered by kernel-doc.
>> What's the problem with using kerneldoc format here? Maybe I am not
>> getting your comments.
> 
> It is not a list of functions.  It is any implementation of a well-known
> callback. i.e. we already know what ->runtime_suspend() is for, so we don't
> need untold numbers of drivers describing it in comments.
> 

Personally in general I can't see any issue with it especially for
people who has no idea how these callbacks are working but I understand
your concern here especially when there is anything specific written in
connection to this device.

Thanks,
Michal