Re: [PATCH v5 36/46] input: misc: max77693: switch to the atomic API

Boris Brezillon
2016-03-31T18:57:26Z

On Thu, 31 Mar 2016 10:48:01 -0700
Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote:

> Hi Boris,
>
> On Wed, Mar 30, 2016 at 10:03:59PM +0200, Boris Brezillon wrote:
> > pwm_config/enable/disable() have been deprecated and should be replaced
> > by pwm_apply_state().
> >
> > Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
> > ---
> > drivers/input/misc/max77693-haptic.c | 23 +++++++++++++++++------
> > 1 file changed, 17 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/input/misc/max77693-haptic.c b/drivers/input/misc/max77693-haptic.c
> > index cf6aac0..aef7dc4 100644
> > --- a/drivers/input/misc/max77693-haptic.c
> > +++ b/drivers/input/misc/max77693-haptic.c
> > @@ -70,13 +70,16 @@ struct max77693_haptic {
> >
> > static int max77693_haptic_set_duty_cycle(struct max77693_haptic *haptic)
> > {
> > + struct pwm_state pstate;
> > struct pwm_args pargs = { };
> > - int delta;
> > int error;
> >
> > pwm_get_args(haptic->pwm_dev, &pargs);
> > - delta = (pargs.period + haptic->pwm_duty) / 2;
> > - error = pwm_config(haptic->pwm_dev, delta, pargs.period);
> > + pwm_get_state(haptic->pwm_dev, &pstate);
> > +
> > + pstate.period = pargs.period;
> > + pstate.duty_cycle = (pargs.period + haptic->pwm_duty) / 2;
> > + error = pwm_apply_state(haptic->pwm_dev, &pstate);
>
> This does not make sense with regard to the atomic API. If you look in
> max77693_haptic_play_work(), right after calling
> max77693_haptic_set_duty_cycle() we either try to enable or disable the
> pwm. When switching to this new API we should combine both actions.

True. I'll address that, unless Thierry is fine keeping the non-atomic
API, in which case I'll just drop patches 32 to 46.

>
> > if (error) {
> > dev_err(haptic->dev, "failed to configure pwm: %d\n", error);
> > return error;
> > @@ -161,12 +164,16 @@ static int max77693_haptic_lowsys(struct max77693_haptic *haptic, bool enable)
> >
> > static void max77693_haptic_enable(struct max77693_haptic *haptic)
> > {
> > + struct pwm_state pstate;
> > int error;
> >
> > if (haptic->enabled)
> > return;
> >
> > - error = pwm_enable(haptic->pwm_dev);
> > + pwm_get_state(haptic->pwm_dev, &pstate);
> > + pstate.enabled = true;
> > +
> > + error = pwm_apply_state(haptic->pwm_dev, &pstate);
>
> As I mentioned I'd rather we did not deprecate pwm_enable() and
> pwm_disable() (and maybe others), as it forces us to add unnecessary
> boilerplate code to the drivers.
>
> > if (error) {
> > dev_err(haptic->dev,
> > "failed to enable haptic pwm device: %d\n", error);
> > @@ -188,11 +195,13 @@ static void max77693_haptic_enable(struct max77693_haptic *haptic)
> > err_enable_config:
> > max77693_haptic_lowsys(haptic, false);
> > err_enable_lowsys:
> > - pwm_disable(haptic->pwm_dev);
> > + pstate.enabled = false;
> > + pwm_apply_state(haptic->pwm_dev, &pstate);
> > }
> >
> > static void max77693_haptic_disable(struct max77693_haptic *haptic)
> > {
> > + struct pwm_state pstate;
> > int error;
> >
> > if (!haptic->enabled)
> > @@ -206,7 +215,9 @@ static void max77693_haptic_disable(struct max77693_haptic *haptic)
> > if (error)
> > goto err_disable_lowsys;
> >
> > - pwm_disable(haptic->pwm_dev);
> > + pwm_get_state(haptic->pwm_dev, &pstate);
> > + pstate.enabled = false;
> > + pwm_apply_state(haptic->pwm_dev, &pstate);
>
> Same here.
>
> > haptic->enabled = false;
> >
> > return;
> > --
> > 2.5.0
> >
>
> Thanks.
>

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