linux-kernel - Re: [PATCH 0/1] auxdisplay: Add I2C gpio expander example

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: <CANiq72nTkw_6-5u4V8c9ZSGxjCSTZ1cM26xtJjZHrgJKCxcQ0w@mail.gmail.com>
Date:   Wed, 6 Jan 2021 13:12:28 +0100
From:   Miguel Ojeda <miguel.ojeda.sandonis@...il.com>
To:     Ralf Schlatterbeck <rsc@...tux.com>
Cc:     linux-kernel <linux-kernel@...r.kernel.org>,
        Willy Tarreau <w@....eu>, Lars Poeschel <poeschel@...onage.de>,
        Linus Walleij <linus.walleij@...aro.org>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        devicetree@...r.kernel.org
Subject: Re: [PATCH 0/1] auxdisplay: Add I2C gpio expander example

On Wed, Jan 6, 2021 at 12:37 PM Ralf Schlatterbeck <rsc@...tux.com> wrote:
>
> The Hitachi HD44780 is often used together with a PCF8574 based I2C
> I/O expander. It was non-obvious to me that the existing parallel
> connected version of the auxdisplay driver can already handle this
> configuration with appropriate device tree magic. This patch documents
> the necessary incantations in an example.
>
> That this is not only non-obvious to me is documented by at least two
> I2C kernel implementations for the display out there.
>
> Thanks to Geert Uytterhoeven for pointing out how this is done.
> Thanks to Miguel Ojeda for extensively commenting on my previous patch.

You're welcome!

A couple tips:
  - Normally, you will want to use scripts/get_maintainer.pl to know
to whom send a given change. In this case, I am Cc'ing Rob, Geert and
the devicetree mailing list which were missing.
  - Also, for single patches, typically you would want to send the
patch without a cover letter. If you want to put comments that
shouldn't go into the commit, you can write them just below the "---"
line.

Thank you for contributing to the kernel and welcome!

Cheers,
Miguel