Hello, On Wednesday, 19 December 2018 11:57:32 EET Peter Rosin wrote: > On 2018-12-19 10:12, Andrzej Hajda wrote: > > On 19.12.2018 00:19, Peter Rosin wrote: > >> Add optional property to specify a power-down GPIO. > >> The pwdn-gpios name is already in use by the thine,thc63lvdm83d > >> binding, so go with that. > >> > >> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx> > >> --- > >> > >> Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt | > >> 3 +++ > >> 1 file changed, 3 insertions(+) > >> > >> diff --git > >> a/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt > >> b/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt > >> index f9e7dd666f58..47941d39f92f 100644 > >> --- > >> a/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt > >> +++ > >> b/Documentation/devicetree/bindings/display/bridge/lvds-transmitter.txt > >> @@ -31,6 +31,9 @@ Required properties: > >> device-specific version corresponding to the device first > >> followed by the generic version. > >> > >> +Optional properties: > >> +- pwdn-gpios: Power-down control GPIO > >> + > > > > Since naming is not enforced by any datasheet I would propose something > > more popular with less twisted logic. Maybe: > > > > - enable-gpios: ... (active high). > > That was my original thought too, but the driver implementing the > lvds-encoder bindings also handles the mentioned thine,thc63lvdm83d > lvds encoder, and that binding has the "pwdn" naming. So, for driver > implementation simplicity I went with what was already there, thus > allowing adding support for both bindings with one implementation > (in patch 3/3). > > Adding code just to handle multiple names for the same thing does > not sounds too appealing. I'm afraid I think we shouldn't add pwdn-gpios support to the lvds encoder DT bindings. The reason is that control GPIOs (and regulators) come with device- specific semantics. If we add pwdn-gpios now, we'll then add reset-gpios, and power supplies, and all of a sudden we'll end up having to encode sequencing of GPIOs and power supplies in DT. That path has been tried in the past, with no good results. I would instead create device-specific bindings, like done for thine,thc63lvdm83d. It's fine to then add support for the pwdn-gpios property in the lvds-encoder driver, as long as the meaning of the property comes from specific DT bindings, not from the generic ones. -- Regards, Laurent Pinchart
