linux-kernel - Re: [PATCH] ARM: dts: allwinner: orangepi-zero: Enable audio codec

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Message-ID: <aA9fa4Ynt3Vq2Xsh@probook>
Date: Mon, 28 Apr 2025 10:58:51 +0000
From: J. Neuschäfer <j.ne@...teo.net>
To: Chen-Yu Tsai <wens@...e.org>
Cc: J. Neuschäfer <j.ne@...teo.net>,
	Rob Herring <robh@...nel.org>,
	Krzysztof Kozlowski <krzk+dt@...nel.org>,
	Conor Dooley <conor+dt@...nel.org>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Samuel Holland <samuel@...lland.org>, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ARM: dts: allwinner: orangepi-zero: Enable audio codec

On Mon, Apr 28, 2025 at 04:37:31PM +0800, Chen-Yu Tsai wrote:
> On Mon, Apr 28, 2025 at 3:26 PM J. Neuschäfer <j.ne@...teo.net> wrote:
> >
> > On Sun, Apr 27, 2025 at 01:28:58PM +0800, Chen-Yu Tsai wrote:
> > > On Fri, Apr 18, 2025 at 7:32 AM J. Neuschäfer via B4 Relay
> > > <devnull+j.ne.posteo.net@...nel.org> wrote:
> > > >
> > > > From: "J. Neuschäfer" <j.ne@...teo.net>
> > > >
> > > > Line out playback and microphone capture work, after enabling the
> > > > corresponding ALSA controls. Tested with the Orange Pi Zero interface
> > > > board, which is a (mostly) passive adapter from the 13-pin header to
> > > > standard connectors (2x USB A, 1x Audio/Video output, 1x built-in
> > > > microphone).
> > > >
> > > >   https://orangepi.com/index.php?route=product/product&product_id=871
> > >
> > > What about the USB ports?
> >
> > Good point, I could test these. I have not mentioned them because they
> > are not related to audio.
> >
> > > In any case, we don't enable peripherals on "headers" by default. That's
> > > up to the end user. The description for the whole adapter board could be
> > > an overlay that users can then apply directly.
> >
> > For features such as pinmuxed UARTs (already present and disabled in the
> > dts), I fully agree, because they could as well be used as GPIO, and
> > that's for the user to decide.
> >
> > For the audio pins, there's nothing else one can do with them, as far as
> > I understand it. It is possible to use at the least the Line Out pins
> > with very minimal setup, e.g. just connecting the pins to headphones or
> > something else.
> 
> Sure, but you are also adding the routing information, which could be
> different if someone designs a different adapter board. One could
> include GPIOs and I2C from the 26-pin header, and make a headset
> adapter (mic on the TRRS instead of tv-out) with a headphone amp
> and headset detection IC.

Ah, that's a fair point that I didn't consider.

> It's easily overridable, and I suppose providing the basic use-case
> that one can directly use via the pins does have value. Instead of
> doing a lot of editing, the user can just toggle the status via
> the bootloader.

Sounds good!

> 
> > I'll clarify the following points in a comment in the next version:
> >
> >  - The audio signals are exposed on the 1x13 header described in
> >    https://linux-sunxi.org/Xunlong_Orange_Pi_Zero
> >
> >  - The pins can't be used for anything else according to section
> >    3.1. Pin Characteristics of the Allwinner H3 Datasheet.
> >
> > Although I would prefer to enable the audio pins by default (because
> > they are present on the Orange Pi Zero board), I would also be ok with
> > adding them as status = "disabled", as is the case with uart1 and uart2.
> > Please let me know your opinion.
> 
> I think it's better to have them disabled by default. We don't want to
> confuse users that don't have the adapter board, who might end up looking
> at their audio mixer and wondering where the line out is.

Fair enough, that makes sense.

> If they have the adapter, or they are explicitly using wires to hook up
> things, then they can toggle the status. If they have something else,
> then they load whatever overlay that matches their hardware.



Thank you for your review and explanations!

Best regards,
J. Neuschäfer