On 09/12/2022 09:54, Alexander Stein wrote: > Hello Krzysztof, > > thanks for the fast feedback. > > Am Freitag, 9. Dezember 2022, 09:39:49 CET schrieb Krzysztof Kozlowski: >> On 09/12/2022 09:33, Alexander Stein wrote: >>> It takes some time until the enable GPIO has settled when turning on. >>> This delay is platform specific and may be caused by e.g. voltage >>> shifts, capacitors etc. >>> >>> Signed-off-by: Alexander Stein <alexander.stein@xxxxxxxxxxxxxxx> >>> --- >>> >>> .../devicetree/bindings/display/bridge/ti,sn65dsi83.yaml | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git >>> a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi83.yaml >>> b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi83.yaml >>> index 48a97bb3e2e0d..3f50d497cf8ac 100644 >>> --- a/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi83.yaml >>> +++ b/Documentation/devicetree/bindings/display/bridge/ti,sn65dsi83.yaml >>> >>> @@ -32,6 +32,10 @@ properties: >>> maxItems: 1 >>> description: GPIO specifier for bridge_en pin (active high). >>> >>> + ti,enable-delay-us: >>> + default: 10000 >>> + description: Enable time delay for enable-gpios >> >> Aren't you now mixing two separate delays? One for entire block on (I >> would assume mostly fixed delay) and one depending on regulators >> (regulator-ramp-delay, regulator-enable-ramp-delay). Maybe you miss the >> second delays in your power supply? If so, the first one might be fixed >> and hard-coded in the driver? > > Apparently there are two different delays: reset time (t_reset) of 10ms as > specified by datasheet. This is already ensured by a following delay after > requesting enable_gpio as low and switching the GPIO to low in disable path. > > When enabling this GPIO it takes some time until it is valid on the chip, this > is what this series is about. It's highly platform specific. > > Unfortunately this is completely unrelated to the vcc-supply regulator. This > one has to be enabled before the enable GPIO can be enabled. So there is no > regulator-ramp-delay. Your driver does one after another - regulator followed immediately by gpio - so this as well can be a delay from regulator (maybe not ramp but enable delay). Best regards, Krzysztof
