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SubjectRE: [PATCH] PWM: Add support for configuring polarity of PWM
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On Mon, Jul 23, 2012 at 18:38:25, Thierry Reding wrote:
> On Mon, Jul 23, 2012 at 12:51:11PM +0000, Philip, Avinash wrote:
> > On Mon, Jul 23, 2012 at 14:00:32, Thierry Reding wrote:
> > > On Wed, Jul 18, 2012 at 06:24:13PM +0530, Philip, Avinash wrote:
> [...]
> > > > +
> > > > + if (test_bit(PWMF_ENABLED, &pwm->flags)) {
> > > > + dev_err(pwm->chip->dev,
> > > > + "Polarity configuration Failed!, PWM device enabled\n");
> > > > + return -EBUSY;
> > > > + }
> > >
> > > Maybe something like: "polarity cannot be configured while PWM device is
> > > enabled"?
> >
> > Ok I will update.
> >
> > > Though I'm not sure the error message is all that useful. I'd
> > > expect the user driver to handle -EBUSY specially.
> >
> > On EBUSY, client driver has to rework on it. Nothing to be done from
> > framework
>
> Exactly, so I think that if an error is displayed because the PWM has
> been enabled, then that client (== user) driver should output an error
> message, not the framework. Also, it really shouldn't happen because it
> clearly is a driver problem that needs to be fixed.

Ok. I will remove.

>
> > > > /*
> > > > * pwm_enable - start a PWM output toggling
> > > > */
> > > > @@ -37,6 +47,7 @@ struct pwm_chip;
> > > > enum {
> > > > PWMF_REQUESTED = 1 << 0,
> > > > PWMF_ENABLED = 1 << 1,
> > > > + PWMF_POLARITY_INVERSE = 1 << 2,
> > >
> > > This should be named PWMF_POLARITY_INVERSED for consistency.
> >
> > Ok I will correct it.
> >
> > > I'm not sure that we really need this flag, though. It isn't used anywhere. But
> > > maybe you have a use-case in mind?
> >
> > It can be used to find the polarity of the PWM at runtime.
>
> Yes, but is there any use-case where this information would be required?

It's been added as a feature enhancement. May be it can ignore?


Thanks
Avinash

>
> Thierry
>



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