Hi Bryan,
On 9/12/24 18:11, 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.
Should we add the support for it anyway ?
Maybe.
To have a set of regulators is a matter of proper IC/IP description, actually
here I see very little option for a divergence or disagreement.
So to reiterate:
1. csiphyX-vdda-phy-supply
csiphyX-vdda-pll-supply
In the dts and yaml
=> The names should be generic from the perspective of the driver
As for me I don't care about the particular names, somebody else can care.
2. camss.c::csiphy_res_sm8550
[0].regulators = { "csiphy0-vdda-phy-supply",
"csiphy0-vdda-pll-supply" }
...
[N].regulators = { "csiphyN-vdda-phy-supply",
"csiphyN-vdda-pll-supply" }
=> The regulators for the PHY should be defined in the
PHY resources description
This is obvious.
3. Required not optional in the yaml
=> You can't use the PHY without its regulators
No, the supplies shall be optional, since it's absolutely possible to have
such a board, where supplies are merely not connected to the SoC.
Hence there shall be no requirement to describe any non-present supplies,
which is a legit case, if there is no connection and usage of the
correspondent non-supplied PHY.
--
Best wishes,
Vladimir
