linux-kernel - Re: [PATCH v2 2/2] gpio: add gpio-line-mux driver

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: <db36ee25-8a1e-f95c-4ac9-867379a1a5e3@axentia.se>
Date: Tue, 28 Oct 2025 11:09:04 +0100
From: Peter Rosin <peda@...ntia.se>
To: Thomas Richard <thomas.richard@...tlin.com>,
 Jonas Jelonek <jelonek.jonas@...il.com>,
 Linus Walleij <linus.walleij@...aro.org>, Bartosz Golaszewski
 <brgl@...ev.pl>, Rob Herring <robh@...nel.org>,
 Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley
 <conor+dt@...nel.org>, Geert Uytterhoeven <geert+renesas@...der.be>
Cc: linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/2] gpio: add gpio-line-mux driver

Hi!

2025-10-28 at 10:45, Thomas Richard wrote:
> On 10/27/25 12:17 AM, Jonas Jelonek wrote:
>> +	ret = mux_control_select(glm->mux, glm->gpio_mux_states[offset]);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	ret = gpiod_get_raw_value_cansleep(glm->shared_gpio);
> 
> Why ignoring ACTIVE_LOW status ?
> And cansleep depends on your shared_gpio line, maybe it is not the case.
> 
>> +	mux_control_deselect(glm->mux);

*snip*

>> +	glm->gc.can_sleep = true;
> 
> depends on your shared_gpio line.

Does it? In this case, the gpio will always need to be able to
sleep, since mux_control_select() may sleep. Or, what am I
missing?

>                                   Use gpiod_cansleep() like in the
> gpio-aggregator driver to know if your shared_gpio can sleep.

Cheers,
Peter