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

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Message-ID: <zm6uc43aidfouc5wj4outd2cqribbzqnbp76my7ntcflbn6drb@sc7nwgho6x2c>
Date: Fri, 11 Oct 2024 11:51:56 +0200
From: Uwe Kleine-König <u.kleine-koenig@...libre.com>
To: Nuno Sá <noname.nuno@...il.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 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.

Best regards
Uwe

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