[PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Akinobu Mita]

This adds an optional property "retain-state-shutdown" as requested by
Billy Tsai.

Billy said:
 "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."

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Billy Tsai <billy_tsai@aspeedtech.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 drivers/hwmon/pwm-fan.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
index 17518b4cab1b..1ea0d0562c28 100644
--- a/drivers/hwmon/pwm-fan.c
+++ b/drivers/hwmon/pwm-fan.c
@@ -38,6 +38,7 @@ struct pwm_fan_ctx {
 	struct pwm_fan_tach *tachs;
 	ktime_t sample_start;
 	struct timer_list rpm_timer;
+	bool retain_state_shutdown;
 
 	unsigned int pwm_value;
 	unsigned int pwm_fan_state;
@@ -312,6 +313,9 @@ static int pwm_fan_probe(struct platform_device *pdev)
 
 	mutex_init(&ctx->lock);
 
+	ctx->retain_state_shutdown =
+		of_property_read_bool(dev->of_node, "retain-state-shutdown");
+
 	ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
 	if (IS_ERR(ctx->pwm))
 		return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
@@ -492,7 +496,10 @@ static int pwm_fan_disable(struct device *dev)
 
 static void pwm_fan_shutdown(struct platform_device *pdev)
 {
-	pwm_fan_disable(&pdev->dev);
+	struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
+
+	if (!ctx->retain_state_shutdown)
+		pwm_fan_disable(&pdev->dev);
 }
 
 #ifdef CONFIG_PM_SLEEP
-- 
2.25.1

[PATCH 2/2] dt-bindings: hwmon: (pwm-fan) add retain-state-shutdown property

[Akinobu Mita]

Document new retain-state-shutdown property.

Cc: Rob Herring <robh+dt@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Billy Tsai <billy_tsai@aspeedtech.com>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
---
 Documentation/devicetree/bindings/hwmon/pwm-fan.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
index 4509e688623a..c1b2c3ff7ba8 100644
--- a/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
+++ b/Documentation/devicetree/bindings/hwmon/pwm-fan.txt
@@ -19,6 +19,8 @@ Optional properties:
 			  interrupts per revolution). The value must be
 			  greater than zero.
 
+- retain-state-shutdown: Retain the state of the PWM on shutdown.
+
 Example:
 	fan0: pwm-fan {
 		compatible = "pwm-fan";
-- 
2.25.1

Re: [PATCH 2/2] dt-bindings: hwmon: (pwm-fan) add retain-state-shutdown property

[Krzysztof Kozlowski]

On 23/09/2021 04:34, Akinobu Mita wrote:
> Document new retain-state-shutdown property.
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Billy Tsai <billy_tsai@aspeedtech.com>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

You develop on some very old kernel, please don't and rather use mainline.

<form letter>
Please use scripts/get_maintainers.pl to get a list of necessary people
and lists to CC. It might happen, that command when run on an older
kernel, gives you outdated entries. Therefore please be sure you base
your patches on recent Linux kernel.

Tools like b4 or scripts/get_maintainer.pl provide you proper list of
people, so fix your workflow. Tools might also fail if you work on some
ancient tree (don't, instead use mainline) or work on fork of kernel
(don't, instead use mainline). Just use b4 and everything should be
fine, although remember about `b4 prep --auto-to-cc` if you added new
patches to the patchset.

You missed at least devicetree list (maybe more), so this won't be
tested by automated tooling. Performing review on untested code might be
a waste of time.

Please kindly resend and include all necessary To/Cc entries.
</form letter>

Best regards,
Krzysztof

Re: [PATCH 2/2] dt-bindings: hwmon: (pwm-fan) add retain-state-shutdown property

[Krzysztof Kozlowski]

On 25/10/2024 10:28, Krzysztof Kozlowski wrote:
> On 23/09/2021 04:34, Akinobu Mita wrote:
>> Document new retain-state-shutdown property.
>>
>> Cc: Rob Herring <robh+dt@kernel.org>
>> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
>> Cc: Guenter Roeck <linux@roeck-us.net>
>> Cc: Billy Tsai <billy_tsai@aspeedtech.com>
>> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> 
> You develop on some very old kernel, please don't and rather use mainline.

And I need to start checking dates of messages which lei brings to me.

Sorry for the noise, although missing cc to DT is still valid argument.

Best regards,
Krzysztof

Re: [PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Guenter Roeck]

On Thu, Sep 23, 2021 at 11:34:47AM +0900, Akinobu Mita wrote:
> This adds an optional property "retain-state-shutdown" as requested by
> Billy Tsai.
> 
> Billy said:
>  "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."
> 
> Cc: Rob Herring <robh+dt@kernel.org>
> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: Billy Tsai <billy_tsai@aspeedtech.com>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

For my reference (waiting for DT property approval):

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

Guenter

> ---
>  drivers/hwmon/pwm-fan.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
> index 17518b4cab1b..1ea0d0562c28 100644
> --- a/drivers/hwmon/pwm-fan.c
> +++ b/drivers/hwmon/pwm-fan.c
> @@ -38,6 +38,7 @@ struct pwm_fan_ctx {
>  	struct pwm_fan_tach *tachs;
>  	ktime_t sample_start;
>  	struct timer_list rpm_timer;
> +	bool retain_state_shutdown;
>  
>  	unsigned int pwm_value;
>  	unsigned int pwm_fan_state;
> @@ -312,6 +313,9 @@ static int pwm_fan_probe(struct platform_device *pdev)
>  
>  	mutex_init(&ctx->lock);
>  
> +	ctx->retain_state_shutdown =
> +		of_property_read_bool(dev->of_node, "retain-state-shutdown");
> +
>  	ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
>  	if (IS_ERR(ctx->pwm))
>  		return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
> @@ -492,7 +496,10 @@ static int pwm_fan_disable(struct device *dev)
>  
>  static void pwm_fan_shutdown(struct platform_device *pdev)
>  {
> -	pwm_fan_disable(&pdev->dev);
> +	struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
> +
> +	if (!ctx->retain_state_shutdown)
> +		pwm_fan_disable(&pdev->dev);
>  }
>  
>  #ifdef CONFIG_PM_SLEEP

Re: [PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Billy Tsai]

On 2021/10/11, 10:34 PM, "Guenter Roeck" <groeck7@gmail.com on behalf of linux@roeck-us.net> wrote:

    On Thu, Sep 23, 2021 at 11:34:47AM +0900, Akinobu Mita wrote:
    > > This adds an optional property "retain-state-shutdown" as requested by
    > > Billy Tsai.
    > > 
    > > Billy said:
    > >  "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."
    > > 
    > > Cc: Rob Herring <robh+dt@kernel.org>
    > > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
    > > Cc: Guenter Roeck <linux@roeck-us.net>
    > > Cc: Billy Tsai <billy_tsai@aspeedtech.com>
    > > Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>

    > For my reference (waiting for DT property approval):

    > Reviewed-by: Guenter Roeck <linux@roeck-us.net>
 
    > Guenter

Reviewed-by: Billy Tsai <billy_tsai@aspeedtech.com>

Billy

    > > ---
    > >  drivers/hwmon/pwm-fan.c | 9 ++++++++-
    > >  1 file changed, 8 insertions(+), 1 deletion(-)
    > > 
    > > diff --git a/drivers/hwmon/pwm-fan.c b/drivers/hwmon/pwm-fan.c
    > > index 17518b4cab1b..1ea0d0562c28 100644
    > > --- a/drivers/hwmon/pwm-fan.c
    > > +++ b/drivers/hwmon/pwm-fan.c
    > > @@ -38,6 +38,7 @@ struct pwm_fan_ctx {
    > >  	struct pwm_fan_tach *tachs;
    > >  	ktime_t sample_start;
    > >  	struct timer_list rpm_timer;
    > > +	bool retain_state_shutdown;
    > >  
    > >  	unsigned int pwm_value;
    > >  	unsigned int pwm_fan_state;
    > > @@ -312,6 +313,9 @@ static int pwm_fan_probe(struct platform_device *pdev)
    > >  
    > >  	mutex_init(&ctx->lock);
    > >  
    > > +	ctx->retain_state_shutdown =
    > > +		of_property_read_bool(dev->of_node, "retain-state-shutdown");
    > > +
    > >  	ctx->pwm = devm_of_pwm_get(dev, dev->of_node, NULL);
    > >  	if (IS_ERR(ctx->pwm))
    > >  		return dev_err_probe(dev, PTR_ERR(ctx->pwm), "Could not get PWM\n");
    > > @@ -492,7 +496,10 @@ static int pwm_fan_disable(struct device *dev)
    > >  
    > >  static void pwm_fan_shutdown(struct platform_device *pdev)
    > >  {
    > > -	pwm_fan_disable(&pdev->dev);
    > > +	struct pwm_fan_ctx *ctx = platform_get_drvdata(pdev);
    > > +
    > > +	if (!ctx->retain_state_shutdown)
    > > +		pwm_fan_disable(&pdev->dev);
    > >  }
    > >  
    > >  #ifdef CONFIG_PM_SLEEP

Re: [PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Billy Tsai]

Hi All,

I found that these patches have been rejected. 
Is there any other reason why it can't be merged into the mainline?

Thanks

Re: [PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Rob Herring]

On Wed, Oct 23, 2024 at 1:08 AM Billy Tsai <billy_tsai@aspeedtech.com> wrote:
>
> Hi All,
>
> I found that these patches have been rejected.

Where did that happen?

> Is there any other reason why it can't be merged into the mainline?

I don't see any replies on the binding. Perhaps that's because it
wasn't sent to the DT list and it doesn't get reviewed if not. In any
case, lots has changed in 3 years such as we have a fan binding now.

Rob

Re: [PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Guenter Roeck]

On 10/23/24 08:24, Rob Herring wrote:
> On Wed, Oct 23, 2024 at 1:08 AM Billy Tsai <billy_tsai@aspeedtech.com> wrote:
>>
>> Hi All,
>>
>> I found that these patches have been rejected.
> 
> Where did that happen?
> 

https://patchwork.kernel.org/project/linux-hwmon/patch/20210923023448.4190-1-akinobu.mita@gmail.com/

It has been a long time, but from the available history I guess I marked
it as rejected because the DT patch was never approved. That is just a
guess, though; I really don't remember.

Guenter

>> Is there any other reason why it can't be merged into the mainline?
> 
> I don't see any replies on the binding. Perhaps that's because it
> wasn't sent to the DT list and it doesn't get reviewed if not. In any
> case, lots has changed in 3 years such as we have a fan binding now.
> 
> Rob

Re: [PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Akinobu Mita]

Hi Billy,

I have updated and resubmitted these patches. I don't have the hardware to test
at the moment, so is it possible for you to test it?

Re: [PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Guenter Roeck]

On 10/26/24 01:08, Akinobu Mita wrote:
> Hi Billy,
> 
> I have updated and resubmitted these patches. I don't have the hardware to test
> at the moment, so is it possible for you to test it?


You did not provide a change log. I do not review patch resubmissions
without change log.

Guenter

Re: [PATCH 1/2] hwmon: (pwm-fan) add option to leave fan on shutdown

[Billy Tsai]

> I have updated and resubmitted these patches. I don't have the hardware to test
> at the moment, so is it possible for you to test it?

Okay, I will try the v2 patch and add the Tested-by.

Thanks