Re: [PATCH v9 07/17] pwm: lpss: Remove suspend/resume handlers

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On Thu, Sep 03, 2020 at 12:51:04PM +0200, Hans de Goede wrote:
> PWM controller drivers should not restore the PWM state on resume. The
> convention is that PWM consumers do this by calling pwm_apply_state(),
> so that it can be done at the exact moment when the consumer needs
> the state to be stored, avoiding e.g. backlight flickering.
> 
> The only in kernel consumers of the pwm-lpss code, the i915 driver
> and the pwm-class sysfs interface code both correctly restore the
> state on resume, so there is no need to do this in the pwm-lpss code.
> 
> More-over the removed resume handler is buggy, since it blindly
> restores the ctrl-register contents without setting the update
> bit, which is necessary to get the controller to actually use/apply
> the restored base-unit and on-time-div values.
> 
> Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
> ---
>  drivers/pwm/pwm-lpss-platform.c |  1 -
>  drivers/pwm/pwm-lpss.c          | 24 ------------------------
>  drivers/pwm/pwm-lpss.h          |  3 ---
>  3 files changed, 28 deletions(-)

Nice!

Acked-by: Thierry Reding <thierry.reding@xxxxxxxxx>

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