Re: [PATCH 07/13] dt-bindings: media: camss: Add qcom,sm8550-camss binding

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Hi Bryan.

On 9/12/24 14:41, Bryan O'Donoghue wrote:
On 12/09/2024 09:22, Vladimir Zapolskiy wrote:
+
+  vdda-phy-supply:
+    description:
+      Phandle to a regulator supply to PHY core block.
+
+  vdda-pll-supply:
+    description:
+      Phandle to 1.2V regulator supply to PHY refclk pll block.
+

Here the supplies should be split into ones, which are specific to CSI
blocks,
and I believe they shall be set as optional.

In principle I agree with that, each CSIPHY should have its own vdda-phy
and vdda-pll regulator specified.

In practice though I don't believe its necessary, below.

The proposed names are:

vdda-phy-01-supply
vdda-pll-01-supply
vdda-phy-23-supply
vdda-pll-23-supply
vdda-phy-46-supply
vdda-pll-46-supply
vdda-phy-57-supply
vdda-pll-57-supply

In principle, you're right, we need to expand the name set here.

I understand that what I ask is much more clumsy, and it could be seen
even as
unneeded, however it'll be the right set of properties to describe the
CAMSS IP
in this respect
I think the following naming would be better as it matches the
power-grid naming in the docs.

csiphyX-vdda-phy-supply
csiphyX-vdda-pll-supply

I have no opinion about the names, any reason for name selection is
good for me.

=>

// voltage domain = vdd_a_csi_01_09 = regulator l1e
csiphy0-vdda-phy-supply = <&vreg_l1e_0p9>;

// voltage domain = vdd_a_csi_01_1p2 = regulator l3e
csiphy0-vdda-pll-supply = <&vreg_l3e_1p2>;

//
csiphy1-vdda-phy-supply = <&vreg_l1e_0p9>;
csiphy1-vdda-pll-supply = <&vreg_l3e_1p2>;

Where X indicates the CSIPHY number.

So in fact, in practice we don't need to differentiate these entries.

Checking x1e80100 ...

Checking some particular board, right?

csiphy0

vdda-phy-supply = <&vreg_l2c_0p9>;
vdda-pll-supply = <&vreg_l1c_1p2>;

This is also the case for csiphy 1/2/4

So, I _don't_ believe this is work we need to do, since its the same
regulator for each PHY.

This is board specific, and even if the separation is not needed on the boards
you have just checked, still it may be needed on some boards, which are not yet
checked/not yet known.

It's needed to make the best predictions about all possible usage of hardware,
fortunately it's easy in this particular case, and it's trivial to correct it now
than on some day later on.

--
Best wishes,
Vladimir




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