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

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <4f5hkbgx4rk7je4jhkady6jd7275zkx3jxqi4k6d4evrwk4x24@s6vw7s72zzbw>
Date: Fri, 11 Oct 2024 11:53:40 +0200
From: Uwe Kleine-König <u.kleine-koenig@...libre.com>
To: David Lechner <dlechner@...libre.com>
Cc: 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

Hello David,

On Wed, Oct 09, 2024 at 04:11:48PM -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.

Applied with Nuno's review-tag.

Thanks
Uwe

Download attachment "signature.asc" of type "application/pgp-signature" (485 bytes)