On Thu, 9 Jun 2022 at 00:02, Stephen Boyd swboyd@chromium.org wrote:
Quoting Dmitry Baryshkov (2022-06-08 05:07:18)
DB820c makes use of core-vcc-supply and core-vdda-supply, however the driver code doesn't support these regulators. Enable them for HDMI on 8996 platform.
The 'vdda-supply' name makes me think this is another scenario where the phy isn't powering on the analog supply when it should be and so the controller driver is doing it instead. Is that the case here?
Good question. There are different HDMI pins on 8996, with slight disagreement between the schematics and the datasheet. vcca_hdmi/vdd_hdmi1: 0.925V, Power for HDMI circuits – low voltage vdda_hdmi/vdd_hdmi2: 1.8V, Power for HDMI circuits – high voltage vdda_hdmi_pll/vdd_pll3, 1.8V, Power for PLL circuits
I'm not sure which are required for the PHY and which are required for the core HDMI. However I'd note that we have a generic tendency of duplicating pins between the HDMI and the PHY devices. Compare this with 8064, where core-vdda-supply is also used both by the hdmi-tx and hdmi-phy devices. I think we unify 8x74/84 with 8996 and allow powering up the HDMI correctly even if it results in duplication between the -phy and -tx parts.