Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
Hi,
On 18-05-2021 01:51, Doug Anderson wrote:
Hi,
On Tue, May 11, 2021 at 4:17 PM Doug Anderson
wrote:
Hi,
On Tue, May 11, 2021 at 11:12 AM wrote:
>
> On 01-05-2021 03:08, Doug Anderson wrote:
> > Hi,
> >
> > On Fri, Apr 30, 2021 at 8:10 AM wrote:
> >>
> >> On 30-04-2021 02:33, Doug Anderson wrote:
> >> > Hi,
> >> >
> >> > On Thu, Apr 29, 2021 at 11:04 AM Rob Herring wrote:
> >> >>
> >> >> On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
> >> >> > Add bindings for DisplayPort aux backlight driver.
> >> >> >
> >> >> > Changes in v2:
> >> >> > - New
> >> >> >
> >> >> > Signed-off-by: Rajeev Nandan
> >> >> > ---
> >> >> > .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
++
> >> >> > 1 file changed, 49 insertions(+)
> >> >> > create mode 100644
Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> >
> >> >> > diff --git
a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> > new file mode 100644
> >> >> > index ..0fa8bf0
> >> >> > --- /dev/null
> >> >> > +++
b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> > @@ -0,0 +1,49 @@
> >> >> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> >> > +%YAML 1.2
> >> >> > +---
> >> >> > +$id:
http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
> >> >> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> >> > +
> >> >> > +title: DisplayPort aux backlight driver bindings
> >> >> > +
> >> >> > +maintainers:
> >> >> > + - Rajeev Nandan
> >> >> > +
> >> >> > +description:
> >> >> > + Backlight driver to control the brightness over DisplayPort aux
channel.
> >> >> > +
> >> >> > +allOf:
> >> >> > + - $ref: common.yaml#
> >> >> > +
> >> >> > +properties:
> >> >> > + compatible:
> >> >> > +const: dp-aux-backlight
> >> >> > +
> >> >> > + ddc-i2c-bus:
> >> >> > +$ref: /schemas/types.yaml#/definitions/phandle
> >> >> > +description:
> >> >> > + A phandle to the system I2C controller connected to the DDC
bus used
> >> >> > + for the DisplayPort AUX channel.
> >> >> > +
> >> >> > + enable-gpios:
> >> >> > +maxItems: 1
> >> >> > +description: GPIO specifier for backlight enable pin.
> >> >> > +
> >> >> > + max-brightness: true
> >> >> > +
> >> >> > +required:
> >> >> > + - compatible
> >> >> > + - ddc-i2c-bus
> >> >> > +
> >> >> > +additionalProperties: false
> >> >> > +
> >> >> > +examples:
> >> >> > + - |
> >> >> > +backlight {
> >> >> > +compatible = "dp-aux-backlight";
> >> >> > +ddc-i2c-bus = <&sn65dsi86_bridge>;
> >> >> > +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
> >> >>
> >> >> So the DDC bus is connected to a backlight and also a panel? This
> >> >> binding is not reflecting the h/w, but rather what you want for some
> >> >> driver.
> >> >>
> >> >> There's only one thing here and that's an eDP panel which supports
> >> >> backlight control via DP aux channel. You can figure all that out from
> >> >> the panel's compatible and/or reading the EDID.
> >> >>
> >> >> You might also be interested in this thread:
> >> >>
> >> >> https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
> >> >
> >> > I think Rajeev needs to rework everything anyway as per:
> >> >
> >> > https://lore.kernel.org/r/87zgxl5qar@intel.com
> >> >
> >> > ...but you're right that it makes sense not to model the backlight as
> >> > a separate node in the device tree. The panel driver can handle
> >> > setting up the backlight.
> >> >
> >> > -Doug
> >>
> >> It was not a good idea to create a separate backlight driver and use
> >> ddc-i2c-bus to get access to DP aux. I am working to move the code
> >> to the panel driver and to utilize the new DRM helper functions
> >> (drm_edp_backlight_*) Lyude has added [1].
> >>
> >> To use these helper functions, the panel driver should have access to
> >> the
> >> "struct drm_dp_aux *". The simple-panel has a "ddc-i2c-bus" property
> >> to give the panel access to the DDC bus and is currently being used to
> >> get the EDID from the panel. Can I use the same ddc bus i2c_adapter to
> >> get
> >> the "struct drm_dp_aux *"?
> >>
> >> As per the suggestion [2], I get the "struct drm_dp_aux *" from the
> >> i2c_adapter of ddc bus (maybe I didn't understand the suggestion
> >> correctly),
> >> and, it turned out, the way I have implemented is not the right way
> >> [3].
> >> So, I am afraid to use the same method in the panel driver.
> >>
> >>
> >> [1] https://lore.kernel.org/dri-devel/871rb5bcf9@intel.com/
> >> [2] https://www.spinics.net/lists/dri-devel/msg295429.html
> >> [3]
> >>
https://lore.kernel.org/dri-devel/2021042616.4lc3ekxjugjr3...@maple.lan/
> >
> > So it's definitely up to maintainers, not me. ...but I guess I would
> > have expected something like a new property called "ddc-aux-bus". Then
> > you'd have to create
Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
Hi,
On Tue, May 11, 2021 at 4:17 PM Doug Anderson wrote:
>
> Hi,
>
> On Tue, May 11, 2021 at 11:12 AM wrote:
> >
> > On 01-05-2021 03:08, Doug Anderson wrote:
> > > Hi,
> > >
> > > On Fri, Apr 30, 2021 at 8:10 AM wrote:
> > >>
> > >> On 30-04-2021 02:33, Doug Anderson wrote:
> > >> > Hi,
> > >> >
> > >> > On Thu, Apr 29, 2021 at 11:04 AM Rob Herring wrote:
> > >> >>
> > >> >> On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
> > >> >> > Add bindings for DisplayPort aux backlight driver.
> > >> >> >
> > >> >> > Changes in v2:
> > >> >> > - New
> > >> >> >
> > >> >> > Signed-off-by: Rajeev Nandan
> > >> >> > ---
> > >> >> > .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
> > >> >> > ++
> > >> >> > 1 file changed, 49 insertions(+)
> > >> >> > create mode 100644
> > >> >> > Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> > >> >> >
> > >> >> > diff --git
> > >> >> > a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> > >> >> >
> > >> >> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> > >> >> > new file mode 100644
> > >> >> > index ..0fa8bf0
> > >> >> > --- /dev/null
> > >> >> > +++
> > >> >> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> > >> >> > @@ -0,0 +1,49 @@
> > >> >> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > >> >> > +%YAML 1.2
> > >> >> > +---
> > >> >> > +$id:
> > >> >> > http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
> > >> >> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > >> >> > +
> > >> >> > +title: DisplayPort aux backlight driver bindings
> > >> >> > +
> > >> >> > +maintainers:
> > >> >> > + - Rajeev Nandan
> > >> >> > +
> > >> >> > +description:
> > >> >> > + Backlight driver to control the brightness over DisplayPort aux
> > >> >> > channel.
> > >> >> > +
> > >> >> > +allOf:
> > >> >> > + - $ref: common.yaml#
> > >> >> > +
> > >> >> > +properties:
> > >> >> > + compatible:
> > >> >> > +const: dp-aux-backlight
> > >> >> > +
> > >> >> > + ddc-i2c-bus:
> > >> >> > +$ref: /schemas/types.yaml#/definitions/phandle
> > >> >> > +description:
> > >> >> > + A phandle to the system I2C controller connected to the DDC
> > >> >> > bus used
> > >> >> > + for the DisplayPort AUX channel.
> > >> >> > +
> > >> >> > + enable-gpios:
> > >> >> > +maxItems: 1
> > >> >> > +description: GPIO specifier for backlight enable pin.
> > >> >> > +
> > >> >> > + max-brightness: true
> > >> >> > +
> > >> >> > +required:
> > >> >> > + - compatible
> > >> >> > + - ddc-i2c-bus
> > >> >> > +
> > >> >> > +additionalProperties: false
> > >> >> > +
> > >> >> > +examples:
> > >> >> > + - |
> > >> >> > +backlight {
> > >> >> > +compatible = "dp-aux-backlight";
> > >> >> > +ddc-i2c-bus = <&sn65dsi86_bridge>;
> > >> >> > +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
> > >> >>
> > >> >> So the DDC bus is connected to a backlight and also a panel? This
> > >> >> binding is not reflecting the h/w, but rather what you want for some
> > >> >> driver.
> > >> >>
> > >> >> There's only one thing here and that's an eDP panel which supports
> > >> >> backlight control via DP aux channel. You can figure all that out from
> > >> >> the panel's compatible and/or reading the EDID.
> > >> >>
> > >> >> You might also be interested in this thread:
> > >> >>
> > >> >> https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
> > >> >
> > >> > I think Rajeev needs to rework everything anyway as per:
> > >> >
> > >> > https://lore.kernel.org/r/87zgxl5qar@intel.com
> > >> >
> > >> > ...but you're right that it makes sense not to model the backlight as
> > >> > a separate node in the device tree. The panel driver can handle
> > >> > setting up the backlight.
> > >> >
> > >> > -Doug
> > >>
> > >> It was not a good idea to create a separate backlight driver and use
> > >> ddc-i2c-bus to get access to DP aux. I am working to move the code
> > >> to the panel driver and to utilize the new DRM helper functions
> > >> (drm_edp_backlight_*) Lyude has added [1].
> > >>
> > >> To use these helper functions, the panel driver should have access to
> > >> the
> > >> "struct drm_dp_aux *". The simple-panel has a "ddc-i2c-bus" property
> > >> to give the panel access to the DDC bus and is currently being used to
> > >> get the EDID from the panel. Can I use the same ddc bus i2c_adapter to
> > >> get
> > >> the "struct drm_dp_aux *"?
> > >>
> > >> As per the suggestion [2], I get the "struct drm_dp_aux *" from the
> > >> i2c_adapter of ddc bus (maybe I didn't understand the suggestion
> > >> correctly),
> > >> and, it turned out, the way I have implemented is not the right way
> > >> [3].
> > >> So, I am afraid to use the same method in the panel driver.
> > >>
> > >>
> > >> [1] https://lore.kernel.org/dri-devel/871rb5bcf9@intel.com/
> > >> [2] https://www.spinics.
Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
Hi,
On Tue, May 11, 2021 at 11:12 AM wrote:
>
> On 01-05-2021 03:08, Doug Anderson wrote:
> > Hi,
> >
> > On Fri, Apr 30, 2021 at 8:10 AM wrote:
> >>
> >> On 30-04-2021 02:33, Doug Anderson wrote:
> >> > Hi,
> >> >
> >> > On Thu, Apr 29, 2021 at 11:04 AM Rob Herring wrote:
> >> >>
> >> >> On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
> >> >> > Add bindings for DisplayPort aux backlight driver.
> >> >> >
> >> >> > Changes in v2:
> >> >> > - New
> >> >> >
> >> >> > Signed-off-by: Rajeev Nandan
> >> >> > ---
> >> >> > .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
> >> >> > ++
> >> >> > 1 file changed, 49 insertions(+)
> >> >> > create mode 100644
> >> >> > Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> >
> >> >> > diff --git
> >> >> > a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> >
> >> >> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> > new file mode 100644
> >> >> > index ..0fa8bf0
> >> >> > --- /dev/null
> >> >> > +++
> >> >> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> > @@ -0,0 +1,49 @@
> >> >> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> >> > +%YAML 1.2
> >> >> > +---
> >> >> > +$id:
> >> >> > http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
> >> >> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> >> > +
> >> >> > +title: DisplayPort aux backlight driver bindings
> >> >> > +
> >> >> > +maintainers:
> >> >> > + - Rajeev Nandan
> >> >> > +
> >> >> > +description:
> >> >> > + Backlight driver to control the brightness over DisplayPort aux
> >> >> > channel.
> >> >> > +
> >> >> > +allOf:
> >> >> > + - $ref: common.yaml#
> >> >> > +
> >> >> > +properties:
> >> >> > + compatible:
> >> >> > +const: dp-aux-backlight
> >> >> > +
> >> >> > + ddc-i2c-bus:
> >> >> > +$ref: /schemas/types.yaml#/definitions/phandle
> >> >> > +description:
> >> >> > + A phandle to the system I2C controller connected to the DDC
> >> >> > bus used
> >> >> > + for the DisplayPort AUX channel.
> >> >> > +
> >> >> > + enable-gpios:
> >> >> > +maxItems: 1
> >> >> > +description: GPIO specifier for backlight enable pin.
> >> >> > +
> >> >> > + max-brightness: true
> >> >> > +
> >> >> > +required:
> >> >> > + - compatible
> >> >> > + - ddc-i2c-bus
> >> >> > +
> >> >> > +additionalProperties: false
> >> >> > +
> >> >> > +examples:
> >> >> > + - |
> >> >> > +backlight {
> >> >> > +compatible = "dp-aux-backlight";
> >> >> > +ddc-i2c-bus = <&sn65dsi86_bridge>;
> >> >> > +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
> >> >>
> >> >> So the DDC bus is connected to a backlight and also a panel? This
> >> >> binding is not reflecting the h/w, but rather what you want for some
> >> >> driver.
> >> >>
> >> >> There's only one thing here and that's an eDP panel which supports
> >> >> backlight control via DP aux channel. You can figure all that out from
> >> >> the panel's compatible and/or reading the EDID.
> >> >>
> >> >> You might also be interested in this thread:
> >> >>
> >> >> https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
> >> >
> >> > I think Rajeev needs to rework everything anyway as per:
> >> >
> >> > https://lore.kernel.org/r/87zgxl5qar@intel.com
> >> >
> >> > ...but you're right that it makes sense not to model the backlight as
> >> > a separate node in the device tree. The panel driver can handle
> >> > setting up the backlight.
> >> >
> >> > -Doug
> >>
> >> It was not a good idea to create a separate backlight driver and use
> >> ddc-i2c-bus to get access to DP aux. I am working to move the code
> >> to the panel driver and to utilize the new DRM helper functions
> >> (drm_edp_backlight_*) Lyude has added [1].
> >>
> >> To use these helper functions, the panel driver should have access to
> >> the
> >> "struct drm_dp_aux *". The simple-panel has a "ddc-i2c-bus" property
> >> to give the panel access to the DDC bus and is currently being used to
> >> get the EDID from the panel. Can I use the same ddc bus i2c_adapter to
> >> get
> >> the "struct drm_dp_aux *"?
> >>
> >> As per the suggestion [2], I get the "struct drm_dp_aux *" from the
> >> i2c_adapter of ddc bus (maybe I didn't understand the suggestion
> >> correctly),
> >> and, it turned out, the way I have implemented is not the right way
> >> [3].
> >> So, I am afraid to use the same method in the panel driver.
> >>
> >>
> >> [1] https://lore.kernel.org/dri-devel/871rb5bcf9@intel.com/
> >> [2] https://www.spinics.net/lists/dri-devel/msg295429.html
> >> [3]
> >> https://lore.kernel.org/dri-devel/2021042616.4lc3ekxjugjr3...@maple.lan/
> >
> > So it's definitely up to maintainers, not me. ...but I guess I would
> > have expected something like a new property called "ddc-aux-bus". Then
> > you'd have to create a new API call called
Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
Hi Rajeevny,
On Tue, May 11, 2021 at 11:41:57PM +0530, rajee...@codeaurora.org wrote:
> On 01-05-2021 03:08, Doug Anderson wrote:
> > On Fri, Apr 30, 2021 at 8:10 AM wrote:
> >> On 30-04-2021 02:33, Doug Anderson wrote:
> >> > On Thu, Apr 29, 2021 at 11:04 AM Rob Herring wrote:
> >> >> On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
> >> >> > Add bindings for DisplayPort aux backlight driver.
> >> >> >
> >> >> > Changes in v2:
> >> >> > - New
> >> >> >
> >> >> > Signed-off-by: Rajeev Nandan
> >> >> > ---
> >> >> > .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
> >> >> > ++
> >> >> > 1 file changed, 49 insertions(+)
> >> >> > create mode 100644
> >> >> > Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> >
> >> >> > diff --git
> >> >> > a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> >
> >> >> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> > new file mode 100644
> >> >> > index ..0fa8bf0
> >> >> > --- /dev/null
> >> >> > +++
> >> >> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >> > @@ -0,0 +1,49 @@
> >> >> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> >> > +%YAML 1.2
> >> >> > +---
> >> >> > +$id:
> >> >> > http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
> >> >> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> >> > +
> >> >> > +title: DisplayPort aux backlight driver bindings
> >> >> > +
> >> >> > +maintainers:
> >> >> > + - Rajeev Nandan
> >> >> > +
> >> >> > +description:
> >> >> > + Backlight driver to control the brightness over DisplayPort aux
> >> >> > channel.
> >> >> > +
> >> >> > +allOf:
> >> >> > + - $ref: common.yaml#
> >> >> > +
> >> >> > +properties:
> >> >> > + compatible:
> >> >> > +const: dp-aux-backlight
> >> >> > +
> >> >> > + ddc-i2c-bus:
> >> >> > +$ref: /schemas/types.yaml#/definitions/phandle
> >> >> > +description:
> >> >> > + A phandle to the system I2C controller connected to the DDC
> >> >> > bus used
> >> >> > + for the DisplayPort AUX channel.
> >> >> > +
> >> >> > + enable-gpios:
> >> >> > +maxItems: 1
> >> >> > +description: GPIO specifier for backlight enable pin.
> >> >> > +
> >> >> > + max-brightness: true
> >> >> > +
> >> >> > +required:
> >> >> > + - compatible
> >> >> > + - ddc-i2c-bus
> >> >> > +
> >> >> > +additionalProperties: false
> >> >> > +
> >> >> > +examples:
> >> >> > + - |
> >> >> > +backlight {
> >> >> > +compatible = "dp-aux-backlight";
> >> >> > +ddc-i2c-bus = <&sn65dsi86_bridge>;
> >> >> > +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
> >> >>
> >> >> So the DDC bus is connected to a backlight and also a panel? This
> >> >> binding is not reflecting the h/w, but rather what you want for some
> >> >> driver.
> >> >>
> >> >> There's only one thing here and that's an eDP panel which supports
> >> >> backlight control via DP aux channel. You can figure all that out from
> >> >> the panel's compatible and/or reading the EDID.
> >> >>
> >> >> You might also be interested in this thread:
> >> >>
> >> >> https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
> >> >
> >> > I think Rajeev needs to rework everything anyway as per:
> >> >
> >> > https://lore.kernel.org/r/87zgxl5qar@intel.com
> >> >
> >> > ...but you're right that it makes sense not to model the backlight as
> >> > a separate node in the device tree. The panel driver can handle
> >> > setting up the backlight.
> >>
> >> It was not a good idea to create a separate backlight driver and use
> >> ddc-i2c-bus to get access to DP aux. I am working to move the code
> >> to the panel driver and to utilize the new DRM helper functions
> >> (drm_edp_backlight_*) Lyude has added [1].
> >>
> >> To use these helper functions, the panel driver should have access to the
> >> "struct drm_dp_aux *". The simple-panel has a "ddc-i2c-bus" property
> >> to give the panel access to the DDC bus and is currently being used to
> >> get the EDID from the panel. Can I use the same ddc bus i2c_adapter to get
> >> the "struct drm_dp_aux *"?
> >>
> >> As per the suggestion [2], I get the "struct drm_dp_aux *" from the
> >> i2c_adapter of ddc bus (maybe I didn't understand the suggestion
> >> correctly),
> >> and, it turned out, the way I have implemented is not the right way [3].
> >> So, I am afraid to use the same method in the panel driver.
> >>
> >>
> >> [1] https://lore.kernel.org/dri-devel/871rb5bcf9@intel.com/
> >> [2] https://www.spinics.net/lists/dri-devel/msg295429.html
> >> [3]
> >> https://lore.kernel.org/dri-devel/2021042616.4lc3ekxjugjr3...@maple.lan/
> >
> > So it's definitely up to maintainers, not me. ...but I guess I would
> > have expected something like a new property called "ddc-aux-bus". Then
> > you'd have to create a new API call called something like
> > "of_find_ddc
Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
On 01-05-2021 03:08, Doug Anderson wrote:
Hi,
On Fri, Apr 30, 2021 at 8:10 AM wrote:
On 30-04-2021 02:33, Doug Anderson wrote:
> Hi,
>
> On Thu, Apr 29, 2021 at 11:04 AM Rob Herring wrote:
>>
>> On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
>> > Add bindings for DisplayPort aux backlight driver.
>> >
>> > Changes in v2:
>> > - New
>> >
>> > Signed-off-by: Rajeev Nandan
>> > ---
>> > .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
++
>> > 1 file changed, 49 insertions(+)
>> > create mode 100644
Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
>> >
>> > diff --git
a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
>> > new file mode 100644
>> > index ..0fa8bf0
>> > --- /dev/null
>> > +++
b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
>> > @@ -0,0 +1,49 @@
>> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> > +%YAML 1.2
>> > +---
>> > +$id: http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
>> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> > +
>> > +title: DisplayPort aux backlight driver bindings
>> > +
>> > +maintainers:
>> > + - Rajeev Nandan
>> > +
>> > +description:
>> > + Backlight driver to control the brightness over DisplayPort aux channel.
>> > +
>> > +allOf:
>> > + - $ref: common.yaml#
>> > +
>> > +properties:
>> > + compatible:
>> > +const: dp-aux-backlight
>> > +
>> > + ddc-i2c-bus:
>> > +$ref: /schemas/types.yaml#/definitions/phandle
>> > +description:
>> > + A phandle to the system I2C controller connected to the DDC bus used
>> > + for the DisplayPort AUX channel.
>> > +
>> > + enable-gpios:
>> > +maxItems: 1
>> > +description: GPIO specifier for backlight enable pin.
>> > +
>> > + max-brightness: true
>> > +
>> > +required:
>> > + - compatible
>> > + - ddc-i2c-bus
>> > +
>> > +additionalProperties: false
>> > +
>> > +examples:
>> > + - |
>> > +backlight {
>> > +compatible = "dp-aux-backlight";
>> > +ddc-i2c-bus = <&sn65dsi86_bridge>;
>> > +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
>>
>> So the DDC bus is connected to a backlight and also a panel? This
>> binding is not reflecting the h/w, but rather what you want for some
>> driver.
>>
>> There's only one thing here and that's an eDP panel which supports
>> backlight control via DP aux channel. You can figure all that out from
>> the panel's compatible and/or reading the EDID.
>>
>> You might also be interested in this thread:
>>
>> https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
>
> I think Rajeev needs to rework everything anyway as per:
>
> https://lore.kernel.org/r/87zgxl5qar@intel.com
>
> ...but you're right that it makes sense not to model the backlight as
> a separate node in the device tree. The panel driver can handle
> setting up the backlight.
>
> -Doug
It was not a good idea to create a separate backlight driver and use
ddc-i2c-bus to get access to DP aux. I am working to move the code
to the panel driver and to utilize the new DRM helper functions
(drm_edp_backlight_*) Lyude has added [1].
To use these helper functions, the panel driver should have access to
the
"struct drm_dp_aux *". The simple-panel has a "ddc-i2c-bus" property
to give the panel access to the DDC bus and is currently being used to
get the EDID from the panel. Can I use the same ddc bus i2c_adapter to
get
the "struct drm_dp_aux *"?
As per the suggestion [2], I get the "struct drm_dp_aux *" from the
i2c_adapter of ddc bus (maybe I didn't understand the suggestion
correctly),
and, it turned out, the way I have implemented is not the right way
[3].
So, I am afraid to use the same method in the panel driver.
[1] https://lore.kernel.org/dri-devel/871rb5bcf9@intel.com/
[2] https://www.spinics.net/lists/dri-devel/msg295429.html
[3]
https://lore.kernel.org/dri-devel/2021042616.4lc3ekxjugjr3...@maple.lan/
So it's definitely up to maintainers, not me. ...but I guess I would
have expected something like a new property called "ddc-aux-bus". Then
you'd have to create a new API call called something like
"of_find_ddc_aux_adapter_by_node()" that would allow you to find it.
To implement the first suggestion, I can think of the following way
to get the "struct drm_dp_aux" in the panel_simple_probe function:
- Create a new panel-simple DT property "ddc-aux-bus", a phandle to the
platform device that implements the AUX channel.
- Create a global list of drm_dp_aux in drm_dp_helper.c. Initialize list
head
in drm_dp_aux_init(), add the drm_dp_aux onto the list in
drm_dp_aux_register().
Similarly, remove the drm_dp_aux from list in drm_dp_aux_unregister().
- Create a new function of_drm_find_dp_aux_by_node() to get the expected
drm_dp_aux from this global list.
Please let me know your views on this implementation.
Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
Hi,
On Fri, Apr 30, 2021 at 8:10 AM wrote:
>
> On 30-04-2021 02:33, Doug Anderson wrote:
> > Hi,
> >
> > On Thu, Apr 29, 2021 at 11:04 AM Rob Herring wrote:
> >>
> >> On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
> >> > Add bindings for DisplayPort aux backlight driver.
> >> >
> >> > Changes in v2:
> >> > - New
> >> >
> >> > Signed-off-by: Rajeev Nandan
> >> > ---
> >> > .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
> >> > ++
> >> > 1 file changed, 49 insertions(+)
> >> > create mode 100644
> >> > Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> >
> >> > diff --git
> >> > a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> > new file mode 100644
> >> > index ..0fa8bf0
> >> > --- /dev/null
> >> > +++
> >> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >> > @@ -0,0 +1,49 @@
> >> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >> > +%YAML 1.2
> >> > +---
> >> > +$id: http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
> >> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> >> > +
> >> > +title: DisplayPort aux backlight driver bindings
> >> > +
> >> > +maintainers:
> >> > + - Rajeev Nandan
> >> > +
> >> > +description:
> >> > + Backlight driver to control the brightness over DisplayPort aux
> >> > channel.
> >> > +
> >> > +allOf:
> >> > + - $ref: common.yaml#
> >> > +
> >> > +properties:
> >> > + compatible:
> >> > +const: dp-aux-backlight
> >> > +
> >> > + ddc-i2c-bus:
> >> > +$ref: /schemas/types.yaml#/definitions/phandle
> >> > +description:
> >> > + A phandle to the system I2C controller connected to the DDC bus
> >> > used
> >> > + for the DisplayPort AUX channel.
> >> > +
> >> > + enable-gpios:
> >> > +maxItems: 1
> >> > +description: GPIO specifier for backlight enable pin.
> >> > +
> >> > + max-brightness: true
> >> > +
> >> > +required:
> >> > + - compatible
> >> > + - ddc-i2c-bus
> >> > +
> >> > +additionalProperties: false
> >> > +
> >> > +examples:
> >> > + - |
> >> > +backlight {
> >> > +compatible = "dp-aux-backlight";
> >> > +ddc-i2c-bus = <&sn65dsi86_bridge>;
> >> > +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
> >>
> >> So the DDC bus is connected to a backlight and also a panel? This
> >> binding is not reflecting the h/w, but rather what you want for some
> >> driver.
> >>
> >> There's only one thing here and that's an eDP panel which supports
> >> backlight control via DP aux channel. You can figure all that out from
> >> the panel's compatible and/or reading the EDID.
> >>
> >> You might also be interested in this thread:
> >>
> >> https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
> >
> > I think Rajeev needs to rework everything anyway as per:
> >
> > https://lore.kernel.org/r/87zgxl5qar@intel.com
> >
> > ...but you're right that it makes sense not to model the backlight as
> > a separate node in the device tree. The panel driver can handle
> > setting up the backlight.
> >
> > -Doug
>
> It was not a good idea to create a separate backlight driver and use
> ddc-i2c-bus to get access to DP aux. I am working to move the code
> to the panel driver and to utilize the new DRM helper functions
> (drm_edp_backlight_*) Lyude has added [1].
>
> To use these helper functions, the panel driver should have access to
> the
> "struct drm_dp_aux *". The simple-panel has a "ddc-i2c-bus" property
> to give the panel access to the DDC bus and is currently being used to
> get the EDID from the panel. Can I use the same ddc bus i2c_adapter to
> get
> the "struct drm_dp_aux *"?
>
> As per the suggestion [2], I get the "struct drm_dp_aux *" from the
> i2c_adapter of ddc bus (maybe I didn't understand the suggestion
> correctly),
> and, it turned out, the way I have implemented is not the right way [3].
> So, I am afraid to use the same method in the panel driver.
>
>
> [1] https://lore.kernel.org/dri-devel/871rb5bcf9@intel.com/
> [2] https://www.spinics.net/lists/dri-devel/msg295429.html
> [3]
> https://lore.kernel.org/dri-devel/2021042616.4lc3ekxjugjr3...@maple.lan/
So it's definitely up to maintainers, not me. ...but I guess I would
have expected something like a new property called "ddc-aux-bus". Then
you'd have to create a new API call called something like
"of_find_ddc_aux_adapter_by_node()" that would allow you to find it.
I guess an alternate way to solve this (I'm not totally sure whether
it's better or worse) would be to add a function that would walk up
the chain of parent bridges and ask them for a pointer to the aux bus.
I definitely haven't thought it all the way through, but I'd imagine
something like drm_bridge_chain_get_ddc_aux(). This is _probably_
better than adding the "ddc-aux-bus" property but it assumes that the
aux bus is prov
Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
On 30-04-2021 02:33, Doug Anderson wrote:
Hi,
On Thu, Apr 29, 2021 at 11:04 AM Rob Herring wrote:
On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
> Add bindings for DisplayPort aux backlight driver.
>
> Changes in v2:
> - New
>
> Signed-off-by: Rajeev Nandan
> ---
> .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
++
> 1 file changed, 49 insertions(+)
> create mode 100644
Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
>
> diff --git
a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> new file mode 100644
> index ..0fa8bf0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> @@ -0,0 +1,49 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: DisplayPort aux backlight driver bindings
> +
> +maintainers:
> + - Rajeev Nandan
> +
> +description:
> + Backlight driver to control the brightness over DisplayPort aux channel.
> +
> +allOf:
> + - $ref: common.yaml#
> +
> +properties:
> + compatible:
> +const: dp-aux-backlight
> +
> + ddc-i2c-bus:
> +$ref: /schemas/types.yaml#/definitions/phandle
> +description:
> + A phandle to the system I2C controller connected to the DDC bus used
> + for the DisplayPort AUX channel.
> +
> + enable-gpios:
> +maxItems: 1
> +description: GPIO specifier for backlight enable pin.
> +
> + max-brightness: true
> +
> +required:
> + - compatible
> + - ddc-i2c-bus
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> +backlight {
> +compatible = "dp-aux-backlight";
> +ddc-i2c-bus = <&sn65dsi86_bridge>;
> +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
So the DDC bus is connected to a backlight and also a panel? This
binding is not reflecting the h/w, but rather what you want for some
driver.
There's only one thing here and that's an eDP panel which supports
backlight control via DP aux channel. You can figure all that out from
the panel's compatible and/or reading the EDID.
You might also be interested in this thread:
https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
I think Rajeev needs to rework everything anyway as per:
https://lore.kernel.org/r/87zgxl5qar@intel.com
...but you're right that it makes sense not to model the backlight as
a separate node in the device tree. The panel driver can handle
setting up the backlight.
-Doug
It was not a good idea to create a separate backlight driver and use
ddc-i2c-bus to get access to DP aux. I am working to move the code
to the panel driver and to utilize the new DRM helper functions
(drm_edp_backlight_*) Lyude has added [1].
To use these helper functions, the panel driver should have access to
the
"struct drm_dp_aux *". The simple-panel has a "ddc-i2c-bus" property
to give the panel access to the DDC bus and is currently being used to
get the EDID from the panel. Can I use the same ddc bus i2c_adapter to
get
the "struct drm_dp_aux *"?
As per the suggestion [2], I get the "struct drm_dp_aux *" from the
i2c_adapter of ddc bus (maybe I didn't understand the suggestion
correctly),
and, it turned out, the way I have implemented is not the right way [3].
So, I am afraid to use the same method in the panel driver.
[1] https://lore.kernel.org/dri-devel/871rb5bcf9@intel.com/
[2] https://www.spinics.net/lists/dri-devel/msg295429.html
[3]
https://lore.kernel.org/dri-devel/2021042616.4lc3ekxjugjr3...@maple.lan/
Thanks,
Rajeev
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Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
Hi,
On Thu, Apr 29, 2021 at 11:04 AM Rob Herring wrote:
>
> On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
> > Add bindings for DisplayPort aux backlight driver.
> >
> > Changes in v2:
> > - New
> >
> > Signed-off-by: Rajeev Nandan
> > ---
> > .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
> > ++
> > 1 file changed, 49 insertions(+)
> > create mode 100644
> > Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> >
> > diff --git
> > a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> > b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> > new file mode 100644
> > index ..0fa8bf0
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> > @@ -0,0 +1,49 @@
> > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: DisplayPort aux backlight driver bindings
> > +
> > +maintainers:
> > + - Rajeev Nandan
> > +
> > +description:
> > + Backlight driver to control the brightness over DisplayPort aux channel.
> > +
> > +allOf:
> > + - $ref: common.yaml#
> > +
> > +properties:
> > + compatible:
> > +const: dp-aux-backlight
> > +
> > + ddc-i2c-bus:
> > +$ref: /schemas/types.yaml#/definitions/phandle
> > +description:
> > + A phandle to the system I2C controller connected to the DDC bus used
> > + for the DisplayPort AUX channel.
> > +
> > + enable-gpios:
> > +maxItems: 1
> > +description: GPIO specifier for backlight enable pin.
> > +
> > + max-brightness: true
> > +
> > +required:
> > + - compatible
> > + - ddc-i2c-bus
> > +
> > +additionalProperties: false
> > +
> > +examples:
> > + - |
> > +backlight {
> > +compatible = "dp-aux-backlight";
> > +ddc-i2c-bus = <&sn65dsi86_bridge>;
> > +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
>
> So the DDC bus is connected to a backlight and also a panel? This
> binding is not reflecting the h/w, but rather what you want for some
> driver.
>
> There's only one thing here and that's an eDP panel which supports
> backlight control via DP aux channel. You can figure all that out from
> the panel's compatible and/or reading the EDID.
>
> You might also be interested in this thread:
>
> https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
I think Rajeev needs to rework everything anyway as per:
https://lore.kernel.org/r/87zgxl5qar@intel.com
...but you're right that it makes sense not to model the backlight as
a separate node in the device tree. The panel driver can handle
setting up the backlight.
-Doug
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Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
On Mon, Apr 26, 2021 at 11:29:15AM +0530, Rajeev Nandan wrote:
> Add bindings for DisplayPort aux backlight driver.
>
> Changes in v2:
> - New
>
> Signed-off-by: Rajeev Nandan
> ---
> .../bindings/leds/backlight/dp-aux-backlight.yaml | 49
> ++
> 1 file changed, 49 insertions(+)
> create mode 100644
> Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
>
> diff --git
> a/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> new file mode 100644
> index ..0fa8bf0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml
> @@ -0,0 +1,49 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/leds/backlight/dp-aux-backlight.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: DisplayPort aux backlight driver bindings
> +
> +maintainers:
> + - Rajeev Nandan
> +
> +description:
> + Backlight driver to control the brightness over DisplayPort aux channel.
> +
> +allOf:
> + - $ref: common.yaml#
> +
> +properties:
> + compatible:
> +const: dp-aux-backlight
> +
> + ddc-i2c-bus:
> +$ref: /schemas/types.yaml#/definitions/phandle
> +description:
> + A phandle to the system I2C controller connected to the DDC bus used
> + for the DisplayPort AUX channel.
> +
> + enable-gpios:
> +maxItems: 1
> +description: GPIO specifier for backlight enable pin.
> +
> + max-brightness: true
> +
> +required:
> + - compatible
> + - ddc-i2c-bus
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> +backlight {
> +compatible = "dp-aux-backlight";
> +ddc-i2c-bus = <&sn65dsi86_bridge>;
> +enable-gpios = <&tlmm 12 GPIO_ACTIVE_HIGH>;
So the DDC bus is connected to a backlight and also a panel? This
binding is not reflecting the h/w, but rather what you want for some
driver.
There's only one thing here and that's an eDP panel which supports
backlight control via DP aux channel. You can figure all that out from
the panel's compatible and/or reading the EDID.
You might also be interested in this thread:
https://lore.kernel.org/lkml/yiksdtjcihgnv...@orome.fritz.box/
Rob
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Re: [v3 1/2] dt-bindings: backlight: add DisplayPort aux backlight
On Mon, 26 Apr 2021 11:29:15 +0530, Rajeev Nandan wrote: > Add bindings for DisplayPort aux backlight driver. > > Changes in v2: > - New > > Signed-off-by: Rajeev Nandan > --- > .../bindings/leds/backlight/dp-aux-backlight.yaml | 49 > ++ > 1 file changed, 49 insertions(+) > create mode 100644 > Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.yaml > My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check' on your patch (DT_CHECKER_FLAGS is new in v5.13): yamllint warnings/errors: dtschema/dtc warnings/errors: Error: Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.example.dts:22.38-39 syntax error FATAL ERROR: Unable to parse input tree make[1]: *** [scripts/Makefile.lib:377: Documentation/devicetree/bindings/leds/backlight/dp-aux-backlight.example.dt.yaml] Error 1 make[1]: *** Waiting for unfinished jobs make: *** [Makefile:1414: dt_binding_check] Error 2 See https://patchwork.ozlabs.org/patch/1470203 This check can fail if there are any dependencies. The base for a patch series is generally the most recent rc1. If you already ran 'make dt_binding_check' and didn't see the above error(s), then make sure 'yamllint' is installed and dt-schema is up to date: pip3 install dtschema --upgrade Please check and re-submit. ___ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
