Re: [RFC] add pwmlib support

From: Lars-Peter Clausen
Date: Sat Jan 29 2011 - 15:52:56 EST

On 01/28/2011 01:21 PM, Sascha Hauer wrote:
> Hi all,
> While implementing just another pwm driver I thought it's time to implement
> generic pwm support. The following series adds drivers/pwm/pwmlib.c and
> a i.MX23/28 pwm driver which serves as a usage example for pwmlib. The
> code is inspired by gpiolib support and tested using the backlight pwm
> driver by Eric Miao.
> Currently the pwm_request, pwm_add, pwm_remove and pwm_free operations are
> protected with a single mutex wherea the pwm_enable, pwm_disable and
> pwm_config operations are unlocked. It is assumed that the owners of the
> pwm handle the serialization of the pwm accesses. This may not be enough, so
> i'd like to discuss the locking (and type of locking) here.
> I Cced the people working with PWMs in the kernel in the hope that they can
> give input on what's missing / wrong in this implementation
> Sascha


There have been two other proposals for a generic PWM api during the last year.
You might want to take a look at them.

I've added Bill Gatliff and Arun Murthy to Cc.

- Lars
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