>Quoting Sankeerth Billakanti (2022-05-05 11:02:36) >> >> >> >> Quoting Douglas Anderson (2022-04-25 14:06:42) >> >> >> >> 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. > >Do your internal power grid documents indicate what these supplies are >powering? The question is if these supplies power any of the logic inside the >eDP controller or if they only supply power to the analog circuits in the eDP >phy. If it's the eDP phy only then the regulator usage in the eDP driver should >be removed. I would suspect this is the case because the controller is >probably all digital logic and runs at the typical 1.8V that the rest of the SoC >uses. Similarly, these are voltage references which sound like a PLL reference >voltage. > >Please clarify this further. > For the DP driver using the usb-dp combo phy, there were cases where the usb driver was turning off the phy and pll regulators whenever usb-dp concurrent mode need not be supported. This caused phy and pll to be powered down causing aux transaction failures and display blankouts. >From then on, it became a practice for the controller driver to vote for the phy and pll regulators also. >> >> So, as a practice, we put the same name in the DT files. Hence, >> >> Reviewed-by: Sankeerth Billakanti <quic_sbillaka@xxxxxxxxxxx> >>
