Re: [PATCH] hwmon: gpio-fan: fix set_rpm() return value

[Guenter Roeck]

On Sun, Feb 01, 2026 at 09:35:06PM +0100, Gabor Juhos wrote:
> The set_rpm function is used as a 'store' callback of a device attribute,
> and as such it should return with the number of bytes consumed. However
> since commit 0d01110e6356 ("hwmon: (gpio-fan) Add regulator support"),
> the function returns with zero on success.
> 
> Due to this, the function gets called again and again whenever the user
> tries to change the FAN speed by writing the desired RPM value into the
> 'fan1_target' sysfs attribute.
> 
> The broken behaviour can be reproduced easily. For example, the following
> command never returns unless it gets terminated:
> 
>   $ echo 500 > /sys/class/hwmon/hwmon1/fan1_target
>   ^C
>   $
> 
> Change the code to return with the same value as the 'count' parameter
> on success to indicate that all bytes from the input buffer are consumed.
> The function behaved the same way prior to the offending change.
> 
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 0d01110e6356 ("hwmon: (gpio-fan) Add regulator support")
> Signed-off-by: Gabor Juhos <j4g8y7@xxxxxxxxx>

Applied.

Thanks,
Guenter