linux-kernel - Re: [PATCH 0/2] pwm: axi-pwmgen: always enable FORCE

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Message-ID: <9e10ec246ec03eab2833c27aae4d64e2ab2231b9.camel@gmail.com>
Date: Fri, 11 Oct 2024 12:14:28 +0200
From: Nuno Sá <noname.nuno@...il.com>
To: Uwe Kleine-König <u.kleine-koenig@...libre.com>
Cc: David Lechner <dlechner@...libre.com>, Michael Hennerich	
 <michael.hennerich@...log.com>, Nuno Sá
 <nuno.sa@...log.com>,  Trevor Gamblin <tgamblin@...libre.com>,
 linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 0/2] pwm: axi-pwmgen: always enable FORCE_ALIGN

On Fri, 2024-10-11 at 11:51 +0200, Uwe Kleine-König wrote:
> On Thu, Oct 10, 2024 at 10:33:20AM +0200, Nuno Sá wrote:
> > On Wed, 2024-10-09 at 16:11 -0500, David Lechner wrote:
> > > When using the axi-pwmgen as a trigger for ADCs, we've found that the
> > > default behavior of the PWMGEN IP block is not ideal. The default
> > > behavior is to wait for the period of all PWM outputs to run out before
> > > applying any new settings. But there isn't a way to block until this
> > > happens (and even if there was, it could take a long time). So the
> > > pwm apply function returns before the new settings are actually applied.
> > > 
> > > This makes certain use cases impossible. For example, to use the PWM
> > > like a GPIO to create a single pulse on and off to trigger a single ADC
> > > conversion.
> > > 
> > > The AXI PWMGEN has a FORCE_ALIGN configuration option that changes the
> > > behavior so that any new output settings (period, duty cycle, etc.) are
> > > applied immediately. This can cause glitches in the output, but makes
> > > the PWM actually useable for most applications.
> > > 
> > > Also, there was a naming conflict with register names, so there is a
> > > preliminary cleanup patch to sort that out.
> > > 
> > > ---
> > 
> > Reviewed-by: Nuno Sa <nuno.sa@...log.com>
> 
> b4 diagnoses for that:
> NOTE: some trailers ignored due to from/email mismatches:
>     ! Trailer: Reviewed-by: Nuno Sa <nuno.sa@...log.com>
>      Msg From: Nuno Sá <noname.nuno@...il.com>
> 
> I fixed that manually now, but would be nice if you'd care for matching
> addresses in the future.
> 
> 

Arghh,

Completely forgot... As i said in the first time, I'm doing this all the time
and never got a complain about it. I'll try to remember for pwm to reply from my
work email client (which I want to avoid for mailing lists as you might guess
the client I'm speaking about).

- Nuno Sá