Re: [PATCH 1/2] dt-bindings: phy: qcom,sc8280xp-qmp-pcie-phy: Add vdda-refgen supply for Glymur

[Dmitry Baryshkov]

On Mon, Mar 02, 2026 at 02:21:24AM -0800, Qiang Yu wrote:
> On Fri, Feb 13, 2026 at 07:47:36PM +0200, Dmitry Baryshkov wrote:
> > On Wed, Feb 11, 2026 at 07:32:23PM -0800, Qiang Yu wrote:
> > > On Mon, Feb 09, 2026 at 09:06:23AM +0100, Krzysztof Kozlowski wrote:
> > > > On Sun, Feb 08, 2026 at 08:49:39PM -0800, Qiang Yu wrote:
> > > > > The PCIe QMP PHYs on Glymur require stable reference voltage provided by
> > > > > refgen. The refgen itself requires two separate power supplies:
> > > > > vdda-refgen0p9 and vdda-refgen1p2.
> > > > > 
> > > > > Since there is no dedicated driver for REFGEN, add vdda-refgen0p9-supply
> > > > 
> > > > How does the driver matter for the bindings? If I add dedicated driver
> > > > for refgen, then I change the bindings?
> > > 
> > > Yeah, I know that dt-bindings should describe hardware, not software. But
> > > what I meant to say is that the refgen is different from qref which is
> > > controlled via TCSR registers and its LDOs are requested to vote in
> > > tcsrcc driver. The refgen doesn't required register setting and it doesn't
> > > have dedicated driver, so we vote its LDOs in phy driver. I will avoid
> > > this statement in next version.
> > 
> > I must admit, I could not find references to the refgen in any of Glymur
> > PCIe-related HPGs.
> > 
> > > 
> > > > 
> > > > There is qcom,sc8280xp-refgen-regulator so why there cannot be
> > > > qcom,x1e-refgen-regulator?
> > > 
> > > I think we can and it seems better because the refgen for pcie phy also
> > > supplies reference voltage to other modules like usb. But I checked the
> > > qcom-refgen-regulator.c, it contains some register settings and there is
> > > no LDOs voting. I'm not sure what does those register do, maybe Konrad
> > > can provide some backgroud.
> > 
> > Those regs provide voting for refgen, because on those platforms DSI
> > block doesn't have a hardware vote for refgen.
> 
> Hi Konrad, Dmitry
> 
> I tried to model the reference voltage as a fixed regulator but the fixed
> regulator driver only supports a single vin-supply. However, the refgen
> block requires two separate power supplies (1.2V and 0.9V LDOs).

On which platform? Does it require those power supplies only on GLymur
or on all relevant platforms?

> Would it be appropriate to modify the qcom-refgen-regulator.c driver to
> handle LDO voting for both the 1.2V and 0.9V supplies? In the regulator's
> enable/disable callbacks, we could vote for and unvote these two LDOs
> instead of performing register operations.

Depending on the answer on the previous question either we should fix
all refgens to use proper power supplies, or you should add separate,
Glymur-specific one (especially if you don't need to program it. Do
you?).

But, let's first sort out regulators for older platforms. Please inquiry
internally.

> > > But on Glymur, we only need to vote LDOs. So
> > > what if we use a fixed regulator in the device tree to represent refgen?
> > > We could set refgen0p9 and refgen1p2 as its input supplies, then the PCIe
> > > PHY would just need one refgen supply reference.
> > > 
> > > > > and vdda-refgen1p2-supply properties to the PCIe PHY dt-bindings. Use
> > > > > conditional schema to restrict these properties to only Glymur PCIe QMP
> > > > > PHYs.
> > > > 
> > > > Best regards,
> > > > Krzysztof
> > > > 
> > 
> > -- 
> > With best wishes
> > Dmitry

-- 
With best wishes
Dmitry