On 2021/10/11, 10:34 PM, "Guenter Roeck" <groeck7@xxxxxxxxx on behalf of linux@xxxxxxxxxxxx> 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@xxxxxxxxxx>
> > Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
> > Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> > Cc: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
> > Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
> For my reference (waiting for DT property approval):
> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> Guenter
Reviewed-by: Billy Tsai <billy_tsai@xxxxxxxxxxxxxx>
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
