[PATCH 1/2] dt-bindings: hwmon: Add optional regulator support to pwm-fan

[PATCH 1/2] dt-bindings: hwmon: Add optional regulator support to pwm-fan

[Stefan Wahren]

This adds an optional regulator support (e.g. switchable supply) to the
pwm fan binding.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
---
 Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
index c6d5332..49ca5d8 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
@@ -6,6 +6,9 @@ Required properties:
 - cooling-levels      : PWM duty cycle values in a range from 0 to 255
 			which correspond to thermal cooling states
 
+Optional properties:
+- fan-supply    : phandle to the regulator that provides power to the fan
+
 Example:
 	fan0: pwm-fan {
 		compatible = "pwm-fan";
-- 
2.7.4

[PATCH 2/2] hwmon: pwm-fan: Add optional regulator support

[Stefan Wahren]

This adds optional regulator support to the pwm-fan driver. This is
necessary for pwm fans which are powered by a switchable supply.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
---
 drivers/hwmon/pwm-fan.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 2c94482..9e0591e 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -23,6 +23,7 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/pwm.h>
+#include <linux/regulator/consumer.h>
 #include <linux/sysfs.h>
 #include <linux/thermal.h>
 
@@ -31,6 +32,7 @@
 struct pwm_fan_ctx {
 	struct mutex lock;
 	struct pwm_device *pwm;
+	struct regulator *reg_en;
 	unsigned int pwm_value;
 	unsigned int pwm_fan_state;
 	unsigned int pwm_fan_max_state;
@@ -244,6 +246,23 @@ static int pwm_fan_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ctx->reg_en = devm_regulator_get_optional(&pdev->dev, "fan");
+	if (!IS_ERR(ctx->reg_en)) {
+		ret = regulator_enable(ctx->reg_en);
+		if (ret)
+			dev_err(&pdev->dev,
+				"Failed to enable fan supply: %d\n", ret);
+	} else {
+		switch (PTR_ERR(ctx->reg_en)) {
+		case -ENODEV:
+		case -ENOSYS:
+			ctx->reg_en = NULL;
+			break;
+		default:
+			return PTR_ERR(ctx->reg_en);
+		}
+	}
+
 	hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan",
 						       ctx, pwm_fan_groups);
 	if (IS_ERR(hwmon)) {
@@ -287,6 +306,10 @@ static int pwm_fan_remove(struct platform_device *pdev)
 	thermal_cooling_device_unregister(ctx->cdev);
 	if (ctx->pwm_value)
 		pwm_disable(ctx->pwm);
+
+	if (ctx->reg_en)
+		regulator_disable(ctx->reg_en);
+
 	return 0;
 }
 
@@ -299,6 +322,12 @@ static int pwm_fan_suspend(struct device *dev)
 
 	pwm_get_args(ctx->pwm, &args);
 
+	if (ctx->reg_en) {
+		ret = regulator_disable(ctx->reg_en);
+		if (ret)
+			dev_err(dev, "Failed to disable fan supply: %d\n", ret);
+	}
+
 	if (ctx->pwm_value) {
 		ret = pwm_config(ctx->pwm, 0, args.period);
 		if (ret < 0)
@@ -317,6 +346,12 @@ static int pwm_fan_resume(struct device *dev)
 	unsigned long duty;
 	int ret;
 
+	if (ctx->reg_en) {
+		ret = regulator_enable(ctx->reg_en);
+		if (ret)
+			dev_err(dev, "Failed to enable fan supply: %d\n", ret);
+	}
+
 	if (ctx->pwm_value == 0)
 		return 0;
 
-- 
2.7.4

Re: [PATCH 2/2] hwmon: pwm-fan: Add optional regulator support

[Guenter Roeck]

On Tue, Jan 29, 2019 at 06:07:11PM +0100, Stefan Wahren wrote:
> This adds optional regulator support to the pwm-fan driver. This is
> necessary for pwm fans which are powered by a switchable supply.
> 
> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
> ---
>  drivers/hwmon/pwm-fan.c | 35 +++++++++++++++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> index 2c94482..9e0591e 100644
> --- a/drivers/hwmon/pwm-fan.c
> +++ b/drivers/hwmon/pwm-fan.c
> @@ -23,6 +23,7 @@
>  #include <linux/of.h>
>  #include <linux/platform_device.h>
>  #include <linux/pwm.h>
> +#include <linux/regulator/consumer.h>
>  #include <linux/sysfs.h>
>  #include <linux/thermal.h>
>  
> @@ -31,6 +32,7 @@
>  struct pwm_fan_ctx {
>  	struct mutex lock;
>  	struct pwm_device *pwm;
> +	struct regulator *reg_en;
>  	unsigned int pwm_value;
>  	unsigned int pwm_fan_state;
>  	unsigned int pwm_fan_max_state;
> @@ -244,6 +246,23 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> +	ctx->reg_en = devm_regulator_get_optional(&pdev->dev, "fan");
> +	if (!IS_ERR(ctx->reg_en)) {

It is customary to handle the error case first.

> +		ret = regulator_enable(ctx->reg_en);
> +		if (ret)
> +			dev_err(&pdev->dev,
> +				"Failed to enable fan supply: %d\n", ret);
> +	} else {
> +		switch (PTR_ERR(ctx->reg_en)) {
> +		case -ENODEV:
> +		case -ENOSYS:

Does devm_regulator_get_optional() ever return -ENOSYS ?
I glanced through other calls to devm_regulator_get_optional(),
but I don't see that check anywhere.

> +			ctx->reg_en = NULL;
> +			break;
> +		default:
> +			return PTR_ERR(ctx->reg_en);
> +		}

This is inconsistent. Provided regulators which fail to enable are
accepted, albeit with an error message, while unexpected errors from
devm_regulator_get_optional() result in a bailout. Please be consistent.

> +	}
> +
>  	hwmon = devm_hwmon_device_register_with_groups(&pdev->dev, "pwmfan",
>  						       ctx, pwm_fan_groups);
>  	if (IS_ERR(hwmon)) {
> @@ -287,6 +306,10 @@ static int pwm_fan_remove(struct platform_device *pdev)
>  	thermal_cooling_device_unregister(ctx->cdev);
>  	if (ctx->pwm_value)
>  		pwm_disable(ctx->pwm);
> +
> +	if (ctx->reg_en)
> +		regulator_disable(ctx->reg_en);

As written, this is also called after regulator_enable() failed.
Same below.

> +
>  	return 0;
>  }
>  
> @@ -299,6 +322,12 @@ static int pwm_fan_suspend(struct device *dev)
>  
>  	pwm_get_args(ctx->pwm, &args);
>  
> +	if (ctx->reg_en) {
> +		ret = regulator_disable(ctx->reg_en);
> +		if (ret)
> +			dev_err(dev, "Failed to disable fan supply: %d\n", ret);
> +	}
> +
>  	if (ctx->pwm_value) {
>  		ret = pwm_config(ctx->pwm, 0, args.period);
>  		if (ret < 0)
> @@ -317,6 +346,12 @@ static int pwm_fan_resume(struct device *dev)
>  	unsigned long duty;
>  	int ret;
>  
> +	if (ctx->reg_en) {
> +		ret = regulator_enable(ctx->reg_en);
> +		if (ret)
> +			dev_err(dev, "Failed to enable fan supply: %d\n", ret);
> +	}
> +
>  	if (ctx->pwm_value == 0)
>  		return 0;
>  

Re: [PATCH 2/2] hwmon: pwm-fan: Add optional regulator support

[Stefan Wahren]

Hi Guenter,

Am 31.01.19 um 18:56 schrieb Guenter Roeck:
> On Tue, Jan 29, 2019 at 06:07:11PM +0100, Stefan Wahren wrote:
>> This adds optional regulator support to the pwm-fan driver. This is
>> necessary for pwm fans which are powered by a switchable supply.
>>
>> Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
>> ---
>>  drivers/hwmon/pwm-fan.c | 35 +++++++++++++++++++++++++++++++++++
>>  1 file changed, 35 insertions(+)
>>
>> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
>> index 2c94482..9e0591e 100644
>> --- a/drivers/hwmon/pwm-fan.c
>> +++ b/drivers/hwmon/pwm-fan.c
>> @@ -23,6 +23,7 @@
>>  #include <linux/of.h>
>>  #include <linux/platform_device.h>
>>  #include <linux/pwm.h>
>> +#include <linux/regulator/consumer.h>
>>  #include <linux/sysfs.h>
>>  #include <linux/thermal.h>
>>  
>> @@ -31,6 +32,7 @@
>>  struct pwm_fan_ctx {
>>  	struct mutex lock;
>>  	struct pwm_device *pwm;
>> +	struct regulator *reg_en;
>>  	unsigned int pwm_value;
>>  	unsigned int pwm_fan_state;
>>  	unsigned int pwm_fan_max_state;
>> @@ -244,6 +246,23 @@ static int pwm_fan_probe(struct platform_device *pdev)
>>  		return ret;
>>  	}
>>  
>> +	ctx->reg_en = devm_regulator_get_optional(&pdev->dev, "fan");
>> +	if (!IS_ERR(ctx->reg_en)) {
> It is customary to handle the error case first.
>
>> +		ret = regulator_enable(ctx->reg_en);
>> +		if (ret)
>> +			dev_err(&pdev->dev,
>> +				"Failed to enable fan supply: %d\n", ret);
>> +	} else {
>> +		switch (PTR_ERR(ctx->reg_en)) {
>> +		case -ENODEV:
>> +		case -ENOSYS:
> Does devm_regulator_get_optional() ever return -ENOSYS ?
> I glanced through other calls to devm_regulator_get_optional(),
> but I don't see that check anywhere.

sorry, i mixed this up with. In case CONFIG_REGULATOR=n we are getting
-ENODEV.

Thanks Stefan