Re: Re: [RESEND PATCH v6 5/6] arm64: tegra: Audio graph header for Tegra210

From: Thierry Reding <thierry.reding@gmail.com>
To: Sameer Pujar <spujar@nvidia.com>
Cc: broonie@kernel.org, robh+dt@kernel.org, jonathanh@nvidia.com,
	kuninori.morimoto.gx@renesas.com, alsa-devel@alsa-project.org,
	devicetree@vger.kernel.org, linux-tegra@vger.kernel.org,
	linux-kernel@vger.kernel.org, sharadg@nvidia.com
Subject: Re: Re: [RESEND PATCH v6 5/6] arm64: tegra: Audio graph header for Tegra210
Date: Tue, 19 Jan 2021 18:57:31 +0100	[thread overview]
Message-ID: <YAcdi7ARk0imXafQ@ulmo> (raw)
In-Reply-To: <b83eb795-328e-acc5-4555-7befd919a136@nvidia.com>

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On Tue, Jan 19, 2021 at 11:09:32PM +0530, Sameer Pujar wrote:
> 
> 
> On 1/19/2021 10:45 PM, Thierry Reding wrote:
> > On Tue, Jan 19, 2021 at 02:58:15PM +0530, Sameer Pujar wrote:
> > > Expose a header which describes DT bindings required to use audio-graph
> > > based sound card. All Tegra210 based platforms can include this header
> > > and add platform specific information. Currently, from SoC point of view,
> > > all links are exposed for ADMAIF, AHUB, I2S and DMIC components.
> > > 
> > > Signed-off-by: Sameer Pujar <spujar@nvidia.com>
> > > Reviewed-by: Jon Hunter <jonathanh@nvidia.com>
> > > ---
> > >   .../boot/dts/nvidia/tegra210-audio-graph.dtsi      | 153 +++++++++++++++++++++
> > >   1 file changed, 153 insertions(+)
> > >   create mode 100644 arch/arm64/boot/dts/nvidia/tegra210-audio-graph.dtsi
> > I prefer keeping everything in tegra210.dtsi, but I can do that merge
> > when I apply, after the DT bindings have been acked, so no need to
> > resend just because of that.
> 
> I think this may be fine for Tegra210 based boards. But for Tegra186 and
> Tegra194, whenever we add support for it, can rely on a common audio-graph
> dtsi because there is no change w.r.t APE. This can help us to avoid
> duplication of the bindings. This most likely applies to future chips as
> well (where Tegra186 audio-graph bindings can be considered as base) when
> there is no significant change in APE.

Maybe. Although that argument is somewhat extreme because we already
have some of that same duplication throughout the other .dtsi files. By
the same argument we could save a bit of duplication by having something
like tegra-gpio.dtsi and including that in all the SoC .dtsi files and
only update the compatible string, because that's the only significant
change.

Duplication isn't a big problem for DTS files because the data is meant
to be stable anyway. So once it is in place and doesn't have to change,
it really doesn't matter if it comes from an include or it's duplicated.

Thierry

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