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

[Dmitry Baryshkov]

On Thu, Sep 12, 2024 at 04:11:58PM GMT, Bryan O'Donoghue wrote:
> On 12/09/2024 13:44, Vladimir Zapolskiy wrote:
> > > 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.
> 
> There is a Power Grid Analysis document which specifies these rails @ the
> SoC level and assumes you've used the Qcom PMIC to power, moreover the PGA
> re-uses the same regulator over and over again.
> 
> You _could_ provide that power from your own PMIC which provides the same
> voltage range as the Qcom PMIC you haven't used. Even if you did provide
> that from your own PMIC you'd have to provide _separate_ rails for the
> various CSIPHYs before it would be required to have a per PHY rail
> requirement on this SoC.
> 
> Are people really powering these SoCs with their own PMICs ?
> No probably not.

Yes, they are.

-- 
With best wishes
Dmitry