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

[Boris Brezillon <boris.brezillon@collabora.com>]

Hi,

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.
> 
> >                                 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.

Works for me. Thanks for chiming in Liviu.

Regards,

Boris