linux-kernel - Re: [PATCH 6/7] ARM: dts: Add dts for Raspberry Pi 4 + Cirrus Logic Lochnagar2

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: <72eb1414-0657-fd62-e0c7-fc5f53d6aa6c@opensource.cirrus.com>
Date:   Fri, 16 Oct 2020 10:01:46 +0100
From:   Richard Fitzgerald <rf@...nsource.cirrus.com>
To:     Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
        <broonie@...nel.org>, <robh+dt@...nel.org>
CC:     <devicetree@...r.kernel.org>, <alsa-devel@...a-project.org>,
        <patches@...nsource.cirrus.com>, <linux-kernel@...r.kernel.org>,
        <linux-rpi-kernel@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH 6/7] ARM: dts: Add dts for Raspberry Pi 4 + Cirrus Logic
 Lochnagar2


On 15/10/2020 16:12, Nicolas Saenz Julienne wrote:
> On Thu, 2020-10-15 at 12:14 +0100, Richard Fitzgerald wrote:
>>> Sadly I don't think creating a new device tree is a good solution here. If we
>>> were to do so for every RPi hat/usage it'd become unmanageable very fast. There
>>> is a way to maintain this in the open nonetheless. I suggest you build a DT
>>> overlay and submit it to https://github.com/raspberrypi/linux, see
>>> 'arch/arm/boot/dts/overlays.' The Raspberry Pi engineers have a kernel branch
>>
>> We want something in mainline so that it can be used by people
>> developing on mainline and taken as a starting point for configuring
>> the codecs for other host platforms. The RPi is a convenient platform to
>> use as the base because it is widely available and low-cost.
> 
> If what you want to convey is the proper way of configuring your specific
> device the way to go is writing a devicetree binding. See

If we have a working configuration it is unreasonable not to make this
available for people who want to use it or examine it. A working example
can be more helpful than a ton of documentation.

It's also worth noting that setting up a working sound system involves
configuring multiple drivers (for example you also need a properly
configured ASoC machine driver at least) crossing multiple driver
bindings. So a complete working example is valuable to see how
it fits together.

> Documentation/devicetree. It's even possible to validate a given devicetree
> against the bindings (given they are written in yaml format).
> 

Validating only checks syntax and bounds. It doesn't prove that it will
work.

> Regards,
> Nicolas
>