Hi Fei, On Tue, Apr 18, 2023 at 08:49:51PM +0800, Fei Shao wrote: > We observed that on Chromebook device Steelix, if Goodix GT7375P > touchscreen is powered in suspend (because, for example, it connects to > an always-on regulator) and with the reset GPIO asserted, it will > introduce about 14mW power leakage. > > This property is used to indicate that the touchscreen is powered in > suspend. If it's set, the driver will stop asserting the reset GPIO in > power-down, and it will do it in power-up instead to ensure that the > state is always reset after resuming. > > Signed-off-by: Fei Shao <fshao@xxxxxxxxxxxx> > --- This is an interesting problem; were you able to root-cause why the silicon exhibits this behavior? Simply asserting reset should not cause it to draw additional power, let alone 14 mW. This almost sounds like a back-powering problem during suspend. If this is truly expected behavior, is it sufficient to use the always_on constraint of the relevant regulator(s) to make this decision as opposed to introducing a new property? > > Documentation/devicetree/bindings/input/goodix,gt7375p.yaml | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml b/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml > index ce18d7dadae2..942acb286d77 100644 > --- a/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml > +++ b/Documentation/devicetree/bindings/input/goodix,gt7375p.yaml > @@ -43,6 +43,12 @@ properties: > itself as long as it allows the main board to make signals compatible > with what the touchscreen is expecting for its IO rails. > > + powered-in-suspend: > + description: > + This indicates that the touchscreen is powered in suspend, so the driver > + will not assert the reset GPIO in power-down to prevent power leakage. > + type: boolean > + > required: > - compatible > - reg > -- > 2.40.0.634.g4ca3ef3211-goog > Kind regards, Jeff LaBundy
