Re: [PATCH v5 05/46] pwm: introduce the pwm_args concept

Boris Brezillon
2016-04-12T13:06:27Z

On Tue, 12 Apr 2016 13:39:12 +0200
Thierry Reding <thierry.reding@gmail.com> wrote:

> On Wed, Mar 30, 2016 at 10:03:28PM +0200, Boris Brezillon wrote:
> > Currently the PWM core mixes the current PWM state with the per-platform
> > reference config (specified through the PWM lookup table, DT definition or
> > directly hardcoded in PWM drivers).
> >
> > Create a pwm_args struct to store this reference config, so that PWM users
> > can differentiate the current config from the reference one.
> >
> > Patch all places where pwm->args should be initialized. We keep the
> > pwm_set_polarity/period() calls until all PWM users are patched to
> > use pwm_args instead of pwm_get_period/polarity().
>
> Perhaps a helper would be useful? Something like:
>
> static inline void
> pwm_apply_args(struct pwm_device *pwm, const struct pwm_args *args)
> {
> pwm_set_duty_cycle(pwm, args->duty_cycle);
> pwm_set_period(pwm, args->period);
> }
>
> ? That would make it slightly easier to get rid of it again after all
> clients have been converted.
>
> With the exception of pwm-clps711x all of these args are set at of_xlate
> time (for DT) or from the lookup table in pwm_get() (for non-DT), so it
> might even be possible to move this call to the core, so that removal of
> it will be a one-liner.

Okay, I think I misunderstood your suggestion. I thought you wanted
this helper to set the reference config, but you actually want to apply
a new state based on the PWM reference values.

Except that pwm_args does not contain all the required information to
apply a full config (args->duty_cycle and args->enable do not exist).

This being said, in my v6 I moved the content of
pwm_regulator_adjust_pwm_config() (patch 27) into a generic helper
(pwm_adjust_config()). This helper is doing pretty much what you're
suggesting here (but again, I'm not sure I correctly understood your
suggestion :-/).

--
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering