Re: [PATCH v2] pwm: Add support for configuring the PWM polarity

From: Thierry Reding
Date: Thu Aug 09 2012 - 01:47:08 EST


On Tue, Jul 24, 2012 at 07:35:32PM +0530, Philip, Avinash wrote:
> Some hardware supports inverting the polarity of the PWM signal. This
> commit adds support to the PWM framework to allow users of the PWM API
> to configure the polarity. Note that in order to reduce complexity,
> changing the polarity of a PWM signal is only allowed while the PWM is
> disabled.
>
> A practical example where this can prove useful is to simulate inversion
> of the duty cycle. While inversion of polarity and duty cycle are not
> exactly the same, the differences for most use-cases are negligible.
>
> Signed-off-by: Philip, Avinash <avinashphilip@xxxxxx>
> ---
> changes in V2:
> - Updates commit message
> - Provides proper comments
> - Removes usage of polarity variable.
> - Removes encoding of polarity in flags
>
> Configuring polarity to be done with PWM device disabled, if not failure
> reported.
>
> If PWM device is enabled while configuring polarity, disabling and
> re_enabling make it complex. Whoever uses this API has to taken care of
> the basic rules.
>
> Discussions related to this can found at
> http://www.spinics.net/lists/kernel/msg1372110.html
>
> :100644 100644 ecb7690... f0a1db3... M drivers/pwm/core.c
> :100644 100644 21d076c... 354764c... M include/linux/pwm.h
> drivers/pwm/core.c | 22 ++++++++++++++++++++++
> include/linux/pwm.h | 23 +++++++++++++++++++++++
> 2 files changed, 45 insertions(+), 0 deletions(-)

Applied, thanks.

Thierry

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