Re: [PATCH v5 3/5] arm64: dts: ti: k3-j784s4: Add WIZ and SERDES PHY nodes

On 14/07/23 00:28, Nishanth Menon wrote:

On 13:31-20230713, Andrew Davis wrote:

quoted

On 7/13/23 1:21 PM, Nishanth Menon wrote:

quoted

On 21:01-20230713, Jayesh Choudhary wrote:

quoted

On 12/07/23 19:48, Nishanth Menon wrote:

quoted

On 15:47-20230710, Jayesh Choudhary wrote:

quoted

From: Siddharth Vadapalli <s-vadapalli@ti.com>

J784S4 SoC has 4 Serdes instances along with their respective WIZ
instances. Add device-tree nodes for them and disable them by default.

Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
[j-choudhary@ti.com: fix serdes_wiz clock order]
Signed-off-by: Jayesh Choudhary <redacted>
---

NAK. This patch introduces the following dtbs_check warning.
arch/arm64/boot/dts/ti/k3-am69-sk.dtb: serdes-refclk: 'clock-frequency' is a required property

Sorry for this. This property was added in the final board file.
I will fix it in the next revision.
I will add '0' as clock-property in the main file similar to j721e[1]
which will be overridden in the board file with required value to get
rid of this warning.

That would follow what renesas (r8a774a1.dtsi) and imx
(imx8dxl-ss-conn.dtsi) seem to be doing as well. Just make sure to add
documentation to the property to indicate expectation. Unless someone
has objections to this approach.

Would it work better to disable these nodes, only enabling them in the
board files when a real clock-frequency can be provided?

My initial reaction would be to move the whole external reference clock
node to the board file since that is where it is provided, but seems
that would cause more churn in serdes_wiz* nodes than we would want..

I would prefer that as well, but I have'nt gone around looking for
similar examples on other SoCs (Jayesh, can you check?). One other
approach (alipine and few other places) has been for the bootloader to
update the property set in dtb as 0, which is not needed in this case
to the best of what I see.. just hoping we use a technique that most
board folks are familiar with across SoCs.

I can see the clock nodes in board files for some vendors. But like
Andrew said, that would cause issues with serdes_wiz node in the
main.dtsi.

So I think it would be better to keep the external clock node in main
dtsi itself. I will add comments to the property to indicate that this
value will be over-written in board dts.
Posting v6 to address these comments and others on the series.

Thanks,
Jayesh

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