Re: [RFC 0/6] Proposal for a Generic PWM Device API

[Bill Gatliff <bgat@billgatliff.com>]

Mike Frysinger wrote:
> On Wed, Oct 8, 2008 at 12:43, Bill Gatliff wrote:
>> This series proposes a "generic PWM" driver API.
> 
> seems that the API is solely geared to handle PWM as an output signal.

True.  The peripherals I'm currently targeting are output-only devices, and the
API reflects that.

>  what about input ?

Well, the SAM9263 has timer/counters that could be used to measure PWM period
and duty cycle.  But they are a different peripheral entirely.  I haven't done
an exhaustive survey, but I'm not aware of any PWM-generating hardware that is
simultaneously PWM-measuring hardware as well.  Seems like they are either one
or the other.

Are you proposing that the API accommodate both input and output devices?

> all the utility config functions lack "set" in their name.  it's a
> little confusing as to whether the function is a get or set at first
> glance.  rather than expecting drivers to poke directly into the
> structure, a set of "get" functions would work better (even if they're
> simply #define's that poke into the structure) and line up better with
> how the GPIO framework operates.

Good point.

Originally, I was thinking along the lines of a set-and-forget use case.  Do you
use "get" functionality much when generating PWM signals in your applications?


b.g.
-- 
Bill Gatliff
bgat@billgatliff.com