Re: [PATCH v2 1/1] drm/tyr: make SRAM supply optional like panthor

["Onur Özkan" <work@onurozkan.dev>]

Hi Liviu,

Thank you for reviewing this.

On Fri, 13 Feb 2026 12:15:47 +0000
Liviu Dudau <Liviu.Dudau@arm.com> wrote:

> On Thu, Feb 12, 2026 at 09:30:10PM +0300, Onur Özkan wrote:
> > On Thu, 12 Feb 2026 14:51:34 +0100
> > Boris Brezillon <boris.brezillon@collabora.com> wrote:
> > 
> > > On Thu, 12 Feb 2026 13:13:31 +0000
> > > Mark Brown <broonie@kernel.org> wrote:
> > > 
> > > > On Thu, Feb 12, 2026 at 01:46:01PM +0100, Boris Brezillon wrote:
> > > > > Mark Brown <broonie@kernel.org> wrote:  
> > > > 
> > > > > > The panthor driver is buggy here and should be fixed, the
> > > > > > driver should treat the supply as mandatory and let the
> > > > > > system integration work out how it's actually made
> > > > > > available.  
> > > > 
> > > > > > Trying to open code this just breaks the error handling.  
> > > > 
> > > > > Maybe, but the thing is, the DT bindings have been accepted
> > > > > already, and it's not something we can easily change. What we
> > > > > can do is make this sram-supply mandatory for new
> > > > > compatibles, but we can't force it on older/existing SoCs
> > > > > without breaking backward-DT compat.  
> > > > 
> > > > In practice you can because we do sub in a dummy regulator for
> > > > missing supplies, it produces a warning but works fine.  If we
> > > > didn't do this it'd be basically impossible to add regulator
> > > > support to anything at any point after the original merge which
> > > > is clearly not reasonable.
> > > 
> > > Okay, I guess we need to fix panthor then...
> > > 
> > 
> > That + updating the log to something like "sram-supply is missing in
> > the DT" would be quite better I think. It would make the issue more
> > obvious and convey that the DT file is expected to configure that
> > field explicitly. With the current log message, not many people will
> > understand the problem at a glance.
> > 
> > As for the bug I described in this patch, we can proceed with the
> > alternative solution (updating the DT file) that I mentioned in the
> > Zulip thread (the link is included in the patch). Which is this
> > simple diff:
> > 
> > diff --git a/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5.dtsi
> > b/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5.dtsi
> > index dafad29f9854..a30339fd2c10 100644
> > --- a/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5.dtsi
> > +++ b/arch/arm64/boot/dts/rockchip/rk3588s-orangepi-5.dtsi
> > @@ -177,6 +177,7 @@ &gmac1_rgmii_clk
> > 
> >  &gpu {
> >         mali-supply = <&vdd_gpu_s0>;
> > +       sram-supply = <&vdd_gpu_mem_s0>;
> >         status = "okay";
> >  };
> > 
> > @@ -537,7 +538,7 @@ rk806_dvs3_null: dvs3-null-pins {
> >                 };
> > 
> >                 regulators {
> > -                       vdd_gpu_s0: dcdc-reg1 {
> > +                       vdd_gpu_s0: vdd_gpu_mem_s0: dcdc-reg1 {
> 
> You don't need to define a new label, using the same supply for
> mali-supply and sram-supply should be fine.
>

That also works but I never seen that usage (sram-supply =
<&vdd_gpu_s0>) anywhere in the tree and I wanted to follow the
current standard.
 
> >                                 regulator-name = "vdd_gpu_s0";
> >                                 regulator-boot-on;
> >                                 regulator-min-microvolt = <550000>;
> > 
> > Note that this only fixes the issue for the Orange Pi 5. If we want
> > to go further, the same approach should be applied to many other
> > boards as well. I can generate a list of the DT files (using a
> > simple Python script) that need this update over the weekend.
> 
> Yes, please, but bias the script towards using the same regulator as
> mali-supply.
> 
> > 
> > If we want to go even further and fix all DT files to properly
> > include sram-supply we could also enforce that DT files do not omit
> > sram-supply in the future. I am not sure this is strictly necessary
> > but it also doesn't seem consistent to leave things as they are.
> > Right now, some DT files include sram-supply even when there is no
> > separate SRAM rail, while others do not. As a result, some boards
> > will continue to print that annoying log message.
> > 
> > It's not very clear which approach is best.
> 
> I'm in favor of the proposal here, where we make sram-supply
> mandatory for non-"mt8196-mali" SoCs and we patch the DTs to add the
> sram-supply for those.
> 

Cool! 

Regards,
Onur

> Best regards,
> Liviu
> 
>