Re: [PATCH v3 5/6] pwm: fsl-ftm: Don't update the state for the caller of pwm_apply_state()

[Doug Anderson <dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>]

Hi,

On Mon, Sep 2, 2019 at 7:27 AM Uwe Kleine-König
<u.kleine-koenig@pengutronix.de> wrote:
>
> On Fri, Aug 30, 2019 at 10:39:16AM -0700, Doug Anderson wrote:
> > Hi,
> >
> > On Sat, Aug 24, 2019 at 8:37 AM Uwe Kleine-König <uwe@kleine-koenig.org> wrote:
> > >
> > > The pwm-fsl-ftm driver is one of only three PWM drivers which updates
> > > the state for the caller of pwm_apply_state(). This might have
> > > surprising results if the caller reuses the values expecting them to
> > > still represent the same state.
> > >
> > > Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
> > > ---
> > >  drivers/pwm/pwm-fsl-ftm.c | 4 ----
> > >  1 file changed, 4 deletions(-)
> >
> > Presumably this patch could break something since the pwm-fsl-ftm
> > driver doesn't appear to implement the get_state() function.  ...or
> > did I miss it?
>
> I don't expect breakage. We have more than 50 pwm drivers and only three
> of them made use of adapting the passed state. So unless you do
> something special with the PWM (i.e. more than backlight, LED or fan
> control) I don't think a consumer might care. But it might well be that
> I miss something so feel free to prove me wrong.

I don't have this hardware so I can't prove you wrong.  ...but
presumably someone added the code to return the state on purpose?

Maybe you could implement get_state() for this driver in your series?

-Doug

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