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] [day] [month] [year] [list]
Date:   Sat, 28 Jan 2023 14:43:23 +0100
From:   Francesco Dolcini <francesco@...cini.it>
To:     Mark Brown <broonie@...nel.org>
CC:     linux-kernel@...r.kernel.org, Liam Girdwood <lgirdwood@...il.com>
Subject: Re: fixed-regulator with enable from another regulator

Il 28 gennaio 2023 14:16:00 CET, Mark Brown <broonie@...nel.org> ha scritto:
>On Fri, Jan 27, 2023 at 10:33:14PM +0100, Francesco Dolcini wrote:
>
>> I am trying to figure out if it is possible with the current
>> regulator-fixed or with any other solution already implemented in Linux
>> to have a regulator enabled from another one.
>
>Not really.  You can model the regulators as sharing the same
>enable if there's a GPIO enable for the parent regulator,
>otherwise it'd need some framework work.

Thanks, I'll propose a patch if needed.

>> I am still not 100% sure if describing this specific hardware connection
>> would be required on my system, maybe I can just ignore all of that.
>
>It seems like a fairly strange hardware design TBH.

Just to shred some light on this weird request, I am not the one who did the design, but there is a reason.

There is one device that requires 3 different voltages, one of those come from a dedicated output of a PMIC, the other 2 from dedicated LDOs.

Having the enable of the 2 LDO on the PMIC output allows to control the power of the device without additional GPIOs usage (that were not available, for instance, while the PMIC can enable/disable the output from I2C).

(not that is relevant for this discussion, but this is of course fine for the power sequencing of this specific device).

Francesco


Hello Mark,

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ