Re: [PATCH 2/3] dt-bindings: display: bridge: lvds-transmitter: add pwdn-gpios
On 2018-12-19 12:38, Laurent Pinchart wrote: > 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 --- 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. Right, I'll fork out the bindings for the texas chips. v2 coming up. Cheers, Peter
Re: [PATCH 2/3] dt-bindings: display: bridge: lvds-transmitter: add pwdn-gpios
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 > >> --- > >> > >> 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
Re: [PATCH 2/3] dt-bindings: display: bridge: lvds-transmitter: add pwdn-gpios
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 >> --- >> 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. Cheers, Peter
Re: [PATCH 2/3] dt-bindings: display: bridge: lvds-transmitter: add pwdn-gpios
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 > --- > 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). Regards Andrzej > Required nodes: > > This device has two video ports. Their connections are modeled using the OF
