linux-kernel - Re: [PATCH 06/13] iio: buffer: add hardware triggered buffer support

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: <CAMknhBHs32nHH8o-m3ByFfiKGAY=U7is18LMM2tGhH-v4v+8EQ@mail.gmail.com>
Date: Fri, 12 Jan 2024 09:42:12 -0600
From: David Lechner <dlechner@...libre.com>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>
Cc: Mark Brown <broonie@...nel.org>, Jonathan Cameron <jic23@...nel.org>, 
	Rob Herring <robh+dt@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Michael Hennerich <michael.hennerich@...log.com>, Nuno Sá <nuno.sa@...log.com>, 
	Frank Rowand <frowand.list@...il.com>, Thierry Reding <thierry.reding@...il.com>, 
	Uwe Kleine-König <u.kleine-koenig@...gutronix.de>, 
	Jonathan Corbet <corbet@....net>, linux-spi@...r.kernel.org, linux-iio@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-doc@...r.kernel.org, 
	linux-pwm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 06/13] iio: buffer: add hardware triggered buffer support

On Fri, Jan 12, 2024 at 6:37 AM Jonathan Cameron
<Jonathan.Cameron@...wei.com> wrote:
>
> On Wed, 10 Jan 2024 13:49:47 -0600
> David Lechner <dlechner@...libre.com> wrote:
>
> > This adds a new mode INDIO_HW_BUFFER_TRIGGERED to the IIO subsystem.
> >
> > This mode is essentially the hardware version of INDIO_BUFFER_TRIGGERED
> > where the trigger has the semantics of INDIO_HARDWARE_TRIGGERED and the
> > buffer has the semantics of INDIO_BUFFER_HARDWARE.
> >
> > So basically INDIO_HW_BUFFER_TRIGGERED is the same as
> > INDIO_BUFFER_HARDWARE except that it also enables the trigger when the
> > buffer is enabled.
>
> If the trigger isn't routeable to multiple devices we normally don't
> make it visible at all.
>
> I'm not yet understanding what a trigger actually means in this case.
> Why do you need it to be userspace configurable?
>
> J
>

It looks like this question was answered in another thread (we need to
configure the sampling frequency from userspace). But there you
mentioned that adding a trigger for that seemed overkill. So you would
you suggest to add the sampling_frequency sysfs attribute to the
iio:deviceX instead and just forget about the trigger part? It seems a
bit odd to me to have an attribute that may or may not be there
depending other hardware external to the ADC chip. But if that is a
normal acceptable thing to do, then it does seem like the simpler
thing to do.