[PATCH v2] hwmon: (pwm-fan) stop fan on shutdown

[PATCH v2] hwmon: (pwm-fan) stop fan on shutdown

[Akinobu Mita]

The pwm-fan driver stops the fan in suspend but leaves the fan on in
shutdown.  It seems strange to leave the fan on in shutdown because there
is no use case in my mind and the gpio-fan driver on the other hand stops
in shutdown.

This change turns off the fan in shutdown.  If anyone complains then we'll
add an optional property to switch the behavior.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Kamil Debski <kamil@wypas.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
* v2
- remove optional property and just turn off the fan in shutdown

 drivers/hwmon/pwm-fan.c | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 42ffd2e..30b7b3e 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -390,8 +390,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
 	return 0;
 }
 
-#ifdef CONFIG_PM_SLEEP
-static int pwm_fan_suspend(struct device *dev)
+static int pwm_fan_disable(struct device *dev)
 {
 	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
 	struct pwm_args args;
@@ -418,6 +417,17 @@ static int pwm_fan_suspend(struct device *dev)
 	return 0;
 }
 
+static void pwm_fan_shutdown(struct platform_device *pdev)
+{
+	pwm_fan_disable(&pdev->dev);
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int pwm_fan_suspend(struct device *dev)
+{
+	return pwm_fan_disable(dev);
+}
+
 static int pwm_fan_resume(struct device *dev)
 {
 	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
@@ -455,6 +465,7 @@ MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
 
 static struct platform_driver pwm_fan_driver = {
 	.probe		= pwm_fan_probe,
+	.shutdown	= pwm_fan_shutdown,
 	.driver	= {
 		.name		= "pwm-fan",
 		.pm		= &pwm_fan_pm,
-- 
2.7.4

Re: [PATCH v2] hwmon: (pwm-fan) stop fan on shutdown

[Guenter Roeck]

On Tue, Jan 21, 2020 at 12:32:24AM +0900, Akinobu Mita wrote:
> The pwm-fan driver stops the fan in suspend but leaves the fan on in
> shutdown.  It seems strange to leave the fan on in shutdown because there
> is no use case in my mind and the gpio-fan driver on the other hand stops
> in shutdown.
> 
> This change turns off the fan in shutdown.  If anyone complains then we'll
> add an optional property to switch the behavior.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Kamil Debski <kamil@wypas.org>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Thierry Reding <thierry.reding@gmail.com>
> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

Applied.

Thanks,
Guenter

> ---
> * v2
> - remove optional property and just turn off the fan in shutdown
> 
>  drivers/hwmon/pwm-fan.c | 15 +++++++++++++--
>  1 file changed, 13 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> index 42ffd2e..30b7b3e 100644
> --- a/drivers/hwmon/pwm-fan.c
> +++ b/drivers/hwmon/pwm-fan.c
> @@ -390,8 +390,7 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  	return 0;
>  }
>  
> -#ifdef CONFIG_PM_SLEEP
> -static int pwm_fan_suspend(struct device *dev)
> +static int pwm_fan_disable(struct device *dev)
>  {
>  	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
>  	struct pwm_args args;
> @@ -418,6 +417,17 @@ static int pwm_fan_suspend(struct device *dev)
>  	return 0;
>  }
>  
> +static void pwm_fan_shutdown(struct platform_device *pdev)
> +{
> +	pwm_fan_disable(&pdev->dev);
> +}
> +
> +#ifdef CONFIG_PM_SLEEP
> +static int pwm_fan_suspend(struct device *dev)
> +{
> +	return pwm_fan_disable(dev);
> +}
> +
>  static int pwm_fan_resume(struct device *dev)
>  {
>  	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
> @@ -455,6 +465,7 @@ MODULE_DEVICE_TABLE(of, of_pwm_fan_match);
>  
>  static struct platform_driver pwm_fan_driver = {
>  	.probe		= pwm_fan_probe,
> +	.shutdown	= pwm_fan_shutdown,
>  	.driver	= {
>  		.name		= "pwm-fan",
>  		.pm		= &pwm_fan_pm,

Re: [PATCH v2] hwmon: (pwm-fan) stop fan on shutdown

[Billy Tsai]

Hi Akinobu,

Can you add optional properties to switch the behavior?
For the use case below, the pwm fan should not stop when the device is
shutdown by the system reboot. Our platform is BMC that will use a PWM-FAN
driver to control the fan on the managed host. In our case, we do not want
to stop the fan when the BMC is reboot, which may cause the temperature of
the managed host not to be lowered.