linux-kernel - Re: [PATCH v1] arm64: dts: ti: k3-am62p: Enable AUDIO

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Message-ID: <20250228135324.jy3qumbg4rg2kdih@factsheet>
Date: Fri, 28 Feb 2025 07:53:24 -0600
From: Nishanth Menon <nm@...com>
To: Francesco Dolcini <francesco@...cini.it>
CC: Jayesh Choudhary <j-choudhary@...com>,
        Vignesh Raghavendra
	<vigneshr@...com>,
        Tero Kristo <kristo@...nel.org>, Rob Herring
	<robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
	<conor+dt@...nel.org>,
        Francesco Dolcini <francesco.dolcini@...adex.com>,
        <linux-arm-kernel@...ts.infradead.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1] arm64: dts: ti: k3-am62p: Enable AUDIO_REFCLKx

On 13:43-20250228, Francesco Dolcini wrote:
> On Fri, Feb 07, 2025 at 09:33:01AM +0100, Francesco Dolcini wrote:
> > On Thu, Feb 06, 2025 at 07:42:39PM -0600, Nishanth Menon wrote:
> > > On 16:39-20250206, Francesco Dolcini wrote:
> > > > From: Francesco Dolcini <francesco.dolcini@...adex.com>
> > > > 
> > > > On AM62P-based SoCs the AUDIO_REFCLKx clocks can be used as an input to
> > > > external peripherals when configured through CTRL_MMR, so add the
> > > > clock nodes.
> > > > 
> > > > Link: http://downloads.ti.com/tisci/esd/latest/5_soc_doc/am62px/clocks.html
> > > > Signed-off-by: Francesco Dolcini <francesco.dolcini@...adex.com>
> > > > ---
> > > >  arch/arm64/boot/dts/ti/k3-am62p-main.dtsi | 20 ++++++++++++++++++++
> > > >  1 file changed, 20 insertions(+)
> > > > 
> > > > diff --git a/arch/arm64/boot/dts/ti/k3-am62p-main.dtsi b/arch/arm64/boot/dts/ti/k3-am62p-main.dtsi
> > > > index 420c77c8e9e5..4b47b0774330 100644
> > > > --- a/arch/arm64/boot/dts/ti/k3-am62p-main.dtsi
> > > > +++ b/arch/arm64/boot/dts/ti/k3-am62p-main.dtsi
> > > > @@ -42,6 +42,26 @@ &inta_main_dmss {
> > > >  	ti,interrupt-ranges = <5 69 35>;
> > > >  };
> > > >  
> > > > +&main_conf {
> > > 
> > > 	Why not add it to main_conf section it self in the file?
> > 
> > The reason is that main_conf is defined in k3-am62p-j722s-common-main.dtsi,
> > that is shared between am62p and j722s.
> > 
> > On j722s the audio refclk is added in k3-j722s-main.dtsi the same way as I did
> > here, so I cannot move this to k3-am62p-j722s-common-main.dtsi without updating
> > also k3-j722s-main.dtsi.
> > 
> > I looked into the differences of j722s and am62p, and from my understanding,
> > from the audio refclk point of view, they are identical (same IP, same reg, same
> > clocks and same IDs), so this should naturally be moved to
> > k3-am62p-j722s-common-main.dtsi as you are suggesting.
> > 
> > ... however, for some reason I am not aware of, on k3-j722s-main.dtsi a different
> > parent clock is used, and I cannot understand the reason. The actual parent clocks
> > in this patch are just the same we already have everywhere apart on j722s. I tried
> > to look at the history of this and it seems that on the TI downstream kernel branch
> > this is defined in the board dts file (!) and this confused me even more.
> > 
> > So, not wanting to break stuff I was not able to understand I came up with this
> > proposal.
> > 
> > An alternative could be to override the "unexpected" clocks from
> > k3-j722s-main.dtsi to the board dts file, and have the "standard" clocks, as
> > proposed in this patch and already used on all the other AM62 variants, in
> > k3-am62p-j722s-common-main.dtsi.
> > 
> > +Jayesh that is the author of this specific change in k3-j722s-main.dtsi.
> 
> Jayesh, Nishanth, any comment on this?
> 
> Should I proceed with this last option ?
> 
>    An alternative could be to override the "unexpected" clocks from
>    k3-j722s-main.dtsi to the board dts file, and have the "standard" clocks, as
>    proposed in this patch and already used on all the other AM62 variants, in
>    k3-am62p-j722s-common-main.dtsi.
> 

no, with your explanation it is clear that your patch matches with the
strategy we are using currently.

-- 
Regards,
Nishanth Menon
Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D