Re: [PATCH v1] pwm: add sysfs interface

From: Thierry Reding
Date: Mon Apr 08 2013 - 07:35:15 EST


On Mon, Apr 08, 2013 at 01:15:37PM +0200, Lars Poeschel wrote:
[...]
> You mean change only while a PWM is disabled ?Ok, as said above, I need to be
> able to change at least the duty cycle while the PWM is running without
> having gaps. But prohibiting changes of the period could be done with
> returning -EBUSY.

Okay, that sounds acceptable. duty-cycle should be the only value that
can be changed while a PWM is enabled. Obviously it should still return
-EINVAL if the duty-cycle is larger than the period, but the PWM core
will take care of that automatically.

By the way, would you mind elaborating a bit on the various use-cases
that you have? I'm interested in what people use the PWM subsystem for
and you seem to be the only one currently using it from userspace. I'm
hoping I can get a better understanding of what the PWM subsystem nedes
to provide if I know what people use it for.

Thierry

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