Hi Doug,
Quoting Douglas Anderson (2022-04-25 14:06:42)
We're supposed to list the supplies in the dt bindings but there are none in the DP controller bindings. Looking at the Linux driver and existing device trees, we can see that two supplies are expected:
- vdda-0p9-supply
- vdda-1p2-supply
Let's list them both in the bindings. Note that the datasheet for sc7280 doesn't describe these supplies very verbosely. For the 0p9 supply, for instance, it says "Power for eDP 0.9 V circuits". This this is obvious from the property name, we don't bother cluttering the bindings with a description.
Signed-off-by: Douglas Anderson dianders@chromium.org
.../devicetree/bindings/display/msm/dp-controller.yaml | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml b/Documentation/devicetree/bindings/display/msm/dp-controller.yaml index cd05cfd76536..dba31108db51 100644
a/Documentation/devicetree/bindings/display/msm/dp-controller.yaml +++ b/Documentation/devicetree/bindings/display/msm/dp-controller.ya +++ ml @@ -76,6 +76,9 @@ properties: "#sound-dai-cells": const: 0
- vdda-0p9-supply: true
- vdda-1p2-supply: true
- ports: $ref: /schemas/graph.yaml#/properties/ports properties:
@@ -137,6 +140,9 @@ examples:
power-domains = <&rpmhpd SC7180_CX>;
vdda-0p9-supply = <&vdda_usb_ss_dp_core>;Having 'a' in 'vdda' typically means 'analog' for 'analog' circuits, so I'd expect this to only matter for the phy that contains the analog circuitry. It would be great to remove the regulator code from drivers/gpu/drm/msm/dp/dp_power.c and move the regulator_set_load() call to the phy driver if possible. Hopefully qcom folks can help clarify here.
Interesting. Oddly enough, the sc7280 datasheet doesn't list the "_A". It calls these "VDD_VREF_0P9" and "VDD_VREF_1P2". However, on the schematic in front of me someone labeled these pins on the sc7280 with the "A". ...and the driver looks for a supply with the "a". :-/
It would be good to get clarification from someone with better information.
-Doug
Our internal power grid documents list the regulators as VDD_A_*_1P2 and VDD_A_*_0P9 for all the platforms.
So, as a practice, we put the same name in the DT files. Hence,
Reviewed-by: Sankeerth Billakanti quic_sbillaka@quicinc.com
Thank you, Sankeerth