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[PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B

Luca Weiss posted 4 patches 11 months, 3 weeks ago
There is a newer version of this series
[PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Luca Weiss 11 months, 3 weeks ago 
Himax HX83112B is a display driver IC used to drive LCD DSI panels.
Describe it and the Fairphone 3 panel from DJN using it.

Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
---
 .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
@@ -0,0 +1,75 @@
+# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Himax HX83112B-based DSI display panels
+
+maintainers:
+  - Luca Weiss <luca@lucaweiss.eu>
+
+description:
+  The Himax HX83112B is a generic DSI Panel IC used to control
+  LCD panels.
+
+allOf:
+  - $ref: panel-common.yaml#
+
+properties:
+  compatible:
+    contains:
+      const: djn,fairphone-fp3-panel
+
+  reg:
+    maxItems: 1
+
+  iovcc-supply:
+    description: I/O voltage rail
+
+  vsn-supply:
+    description: Positive source voltage rail
+
+  vsp-supply:
+    description: Negative source voltage rail
+
+  port: true
+
+required:
+  - compatible
+  - reg
+  - reset-gpios
+  - iovcc-supply
+  - vsn-supply
+  - vsp-supply
+  - port
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    dsi {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        panel@0 {
+            compatible = "djn,fairphone-fp3-panel";
+            reg = <0>;
+
+            reset-gpios = <&tlmm 61 GPIO_ACTIVE_LOW>;
+
+            iovcc-supply = <&pm8953_l6>;
+            vsn-supply = <&pmi632_lcdb_ncp>;
+            vsp-supply = <&pmi632_lcdb_ldo>;
+
+            port {
+                panel_in_0: endpoint {
+                    remote-endpoint = <&dsi0_out>;
+                };
+            };
+        };
+    };
+
+...

-- 
2.48.1
Re: [PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Dmitry Baryshkov 11 months, 3 weeks ago 
On Sat, Feb 22, 2025 at 06:58:05PM +0100, Luca Weiss wrote:
> Himax HX83112B is a display driver IC used to drive LCD DSI panels.
> Describe it and the Fairphone 3 panel from DJN using it.
> 
> Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
> ---
>  .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
>  1 file changed, 75 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
> @@ -0,0 +1,75 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Himax HX83112B-based DSI display panels
> +
> +maintainers:
> +  - Luca Weiss <luca@lucaweiss.eu>
> +
> +description:
> +  The Himax HX83112B is a generic DSI Panel IC used to control
> +  LCD panels.
> +
> +allOf:
> +  - $ref: panel-common.yaml#
> +
> +properties:
> +  compatible:
> +    contains:
> +      const: djn,fairphone-fp3-panel

Would you know a better name or ID for a panel?

> +
> +  reg:
> +    maxItems: 1
> +
> +  iovcc-supply:
> +    description: I/O voltage rail
> +
> +  vsn-supply:
> +    description: Positive source voltage rail
> +
> +  vsp-supply:
> +    description: Negative source voltage rail
> +
> +  port: true
> +
> +required:
> +  - compatible
> +  - reg
> +  - reset-gpios
> +  - iovcc-supply
> +  - vsn-supply
> +  - vsp-supply
> +  - port
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/gpio/gpio.h>
> +
> +    dsi {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        panel@0 {
> +            compatible = "djn,fairphone-fp3-panel";
> +            reg = <0>;
> +
> +            reset-gpios = <&tlmm 61 GPIO_ACTIVE_LOW>;
> +
> +            iovcc-supply = <&pm8953_l6>;
> +            vsn-supply = <&pmi632_lcdb_ncp>;
> +            vsp-supply = <&pmi632_lcdb_ldo>;
> +
> +            port {
> +                panel_in_0: endpoint {
> +                    remote-endpoint = <&dsi0_out>;
> +                };
> +            };
> +        };
> +    };
> +
> +...
> 
> -- 
> 2.48.1
> 

-- 
With best wishes
Dmitry
Re: [PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Luca Weiss 11 months, 2 weeks ago 
On 23-02-2025 7:25 p.m., Dmitry Baryshkov wrote:
> On Sat, Feb 22, 2025 at 06:58:05PM +0100, Luca Weiss wrote:
>> Himax HX83112B is a display driver IC used to drive LCD DSI panels.
>> Describe it and the Fairphone 3 panel from DJN using it.
>>
>> Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
>> ---
>>   .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
>>   1 file changed, 75 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
>> @@ -0,0 +1,75 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Himax HX83112B-based DSI display panels
>> +
>> +maintainers:
>> +  - Luca Weiss <luca@lucaweiss.eu>
>> +
>> +description:
>> +  The Himax HX83112B is a generic DSI Panel IC used to control
>> +  LCD panels.
>> +
>> +allOf:
>> +  - $ref: panel-common.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    contains:
>> +      const: djn,fairphone-fp3-panel
> 
> Would you know a better name or ID for a panel?

Initially no, as mentioned on the cover letter.

But I dug a bit more in some other documents and found this number now: 
"98-03057-6598B-I"

This also somewhat matches the format of the Fairphone 4 panel from DJN: 
("djn,9a-3r063-1102b").

So I'll change the compatible to "djn,98-03057-6598b-i" in the next 
revision.

Regards
Luca

> 
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  iovcc-supply:
>> +    description: I/O voltage rail
>> +
>> +  vsn-supply:
>> +    description: Positive source voltage rail
>> +
>> +  vsp-supply:
>> +    description: Negative source voltage rail
>> +
>> +  port: true
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - reset-gpios
>> +  - iovcc-supply
>> +  - vsn-supply
>> +  - vsp-supply
>> +  - port
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/gpio/gpio.h>
>> +
>> +    dsi {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        panel@0 {
>> +            compatible = "djn,fairphone-fp3-panel";
>> +            reg = <0>;
>> +
>> +            reset-gpios = <&tlmm 61 GPIO_ACTIVE_LOW>;
>> +
>> +            iovcc-supply = <&pm8953_l6>;
>> +            vsn-supply = <&pmi632_lcdb_ncp>;
>> +            vsp-supply = <&pmi632_lcdb_ldo>;
>> +
>> +            port {
>> +                panel_in_0: endpoint {
>> +                    remote-endpoint = <&dsi0_out>;
>> +                };
>> +            };
>> +        };
>> +    };
>> +
>> +...
>>
>> -- 
>> 2.48.1
>>
>
Re: [PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Dmitry Baryshkov 11 months, 2 weeks ago 
On Mon, Feb 24, 2025 at 09:40:23PM +0100, Luca Weiss wrote:
> On 23-02-2025 7:25 p.m., Dmitry Baryshkov wrote:
> > On Sat, Feb 22, 2025 at 06:58:05PM +0100, Luca Weiss wrote:
> > > Himax HX83112B is a display driver IC used to drive LCD DSI panels.
> > > Describe it and the Fairphone 3 panel from DJN using it.
> > > 
> > > Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
> > > ---
> > >   .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
> > >   1 file changed, 75 insertions(+)
> > > 
> > > diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
> > > new file mode 100644
> > > index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
> > > --- /dev/null
> > > +++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
> > > @@ -0,0 +1,75 @@
> > > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > > +%YAML 1.2
> > > +---
> > > +$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Himax HX83112B-based DSI display panels
> > > +
> > > +maintainers:
> > > +  - Luca Weiss <luca@lucaweiss.eu>
> > > +
> > > +description:
> > > +  The Himax HX83112B is a generic DSI Panel IC used to control
> > > +  LCD panels.
> > > +
> > > +allOf:
> > > +  - $ref: panel-common.yaml#
> > > +
> > > +properties:
> > > +  compatible:
> > > +    contains:
> > > +      const: djn,fairphone-fp3-panel
> > 
> > Would you know a better name or ID for a panel?
> 
> Initially no, as mentioned on the cover letter.
> 
> But I dug a bit more in some other documents and found this number now:
> "98-03057-6598B-I"
> 
> This also somewhat matches the format of the Fairphone 4 panel from DJN:
> ("djn,9a-3r063-1102b").
> 
> So I'll change the compatible to "djn,98-03057-6598b-i" in the next
> revision.

Thanks!

> 
> Regards
> Luca
> 
> > 
> > > +
> > > +  reg:
> > > +    maxItems: 1
> > > +
> > > +  iovcc-supply:
> > > +    description: I/O voltage rail
> > > +
> > > +  vsn-supply:
> > > +    description: Positive source voltage rail
> > > +
> > > +  vsp-supply:
> > > +    description: Negative source voltage rail
> > > +
> > > +  port: true
> > > +
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +  - reset-gpios
> > > +  - iovcc-supply
> > > +  - vsn-supply
> > > +  - vsp-supply
> > > +  - port
> > > +
> > > +unevaluatedProperties: false
> > > +
> > > +examples:
> > > +  - |
> > > +    #include <dt-bindings/gpio/gpio.h>
> > > +
> > > +    dsi {
> > > +        #address-cells = <1>;
> > > +        #size-cells = <0>;
> > > +
> > > +        panel@0 {
> > > +            compatible = "djn,fairphone-fp3-panel";
> > > +            reg = <0>;
> > > +
> > > +            reset-gpios = <&tlmm 61 GPIO_ACTIVE_LOW>;
> > > +
> > > +            iovcc-supply = <&pm8953_l6>;
> > > +            vsn-supply = <&pmi632_lcdb_ncp>;
> > > +            vsp-supply = <&pmi632_lcdb_ldo>;
> > > +
> > > +            port {
> > > +                panel_in_0: endpoint {
> > > +                    remote-endpoint = <&dsi0_out>;
> > > +                };
> > > +            };
> > > +        };
> > > +    };
> > > +
> > > +...
> > > 
> > > -- 
> > > 2.48.1
> > > 
> > 
> 

-- 
With best wishes
Dmitry
Re: [PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Krzysztof Kozlowski 11 months, 3 weeks ago 
On Sat, Feb 22, 2025 at 06:58:05PM +0100, Luca Weiss wrote:
> Himax HX83112B is a display driver IC used to drive LCD DSI panels.
> Describe it and the Fairphone 3 panel from DJN using it.
> 
> Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
> ---
>  .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
>  1 file changed, 75 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
> @@ -0,0 +1,75 @@
> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Himax HX83112B-based DSI display panels
> +
> +maintainers:
> +  - Luca Weiss <luca@lucaweiss.eu>
> +
> +description:
> +  The Himax HX83112B is a generic DSI Panel IC used to control
> +  LCD panels.
> +
> +allOf:
> +  - $ref: panel-common.yaml#
> +
> +properties:
> +  compatible:
> +    contains:
> +      const: djn,fairphone-fp3-panel

Why no himax,hx83112b fallback?

Best regards,
Krzysztof
Re: [PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Luca Weiss 11 months, 3 weeks ago 
Hi Krzysztof,

On 23-02-2025 12:54 p.m., Krzysztof Kozlowski wrote:
> On Sat, Feb 22, 2025 at 06:58:05PM +0100, Luca Weiss wrote:
>> Himax HX83112B is a display driver IC used to drive LCD DSI panels.
>> Describe it and the Fairphone 3 panel from DJN using it.
>>
>> Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
>> ---
>>   .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
>>   1 file changed, 75 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
>> @@ -0,0 +1,75 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Himax HX83112B-based DSI display panels
>> +
>> +maintainers:
>> +  - Luca Weiss <luca@lucaweiss.eu>
>> +
>> +description:
>> +  The Himax HX83112B is a generic DSI Panel IC used to control
>> +  LCD panels.
>> +
>> +allOf:
>> +  - $ref: panel-common.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    contains:
>> +      const: djn,fairphone-fp3-panel
> 
> Why no himax,hx83112b fallback?

While this is the driver IC for this panel, I don't think there's any 
"generic" init sequence that can successfully configure this panel, so 
generic hx83112b driver could work I'd say.

Regards
Luca

> 
> Best regards,
> Krzysztof
>
Re: [PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Krzysztof Kozlowski 11 months, 2 weeks ago 
On 23/02/2025 16:29, Luca Weiss wrote:
> Hi Krzysztof,
> 
> On 23-02-2025 12:54 p.m., Krzysztof Kozlowski wrote:
>> On Sat, Feb 22, 2025 at 06:58:05PM +0100, Luca Weiss wrote:
>>> Himax HX83112B is a display driver IC used to drive LCD DSI panels.
>>> Describe it and the Fairphone 3 panel from DJN using it.
>>>
>>> Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
>>> ---
>>>   .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
>>>   1 file changed, 75 insertions(+)
>>>
>>> diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
>>> new file mode 100644
>>> index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
>>> @@ -0,0 +1,75 @@
>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>> +%YAML 1.2
>>> +---
>>> +$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>> +
>>> +title: Himax HX83112B-based DSI display panels
>>> +
>>> +maintainers:
>>> +  - Luca Weiss <luca@lucaweiss.eu>
>>> +
>>> +description:
>>> +  The Himax HX83112B is a generic DSI Panel IC used to control
>>> +  LCD panels.
>>> +
>>> +allOf:
>>> +  - $ref: panel-common.yaml#
>>> +
>>> +properties:
>>> +  compatible:
>>> +    contains:
>>> +      const: djn,fairphone-fp3-panel
>>
>> Why no himax,hx83112b fallback?
> 
> While this is the driver IC for this panel, I don't think there's any 
> "generic" init sequence that can successfully configure this panel, so 
> generic hx83112b driver could work I'd say.


Hm, indeed usually this would mean no need for unusable fallback alone,
but still drivers could use it for some common pieces of code. I imagine
there could be a piece of init sequence which is generic. Or some piece
of attributes.
We already have examples of both approaches for panels - with generic
fallback (himax,hx83102) and without (himax,hx83112a).

@Rob
what is your generic advice? Which of above (himax,hx83102 vs
himax,hx83112a) should be used, if the fallback compatible cannot be
used alone?

Best regards,
Krzysztof
Re: [PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Luca Weiss 10 months, 2 weeks ago 
Hi all,

On 2/24/25 9:16 AM, Krzysztof Kozlowski wrote:
> On 23/02/2025 16:29, Luca Weiss wrote:
>> Hi Krzysztof,
>>
>> On 23-02-2025 12:54 p.m., Krzysztof Kozlowski wrote:
>>> On Sat, Feb 22, 2025 at 06:58:05PM +0100, Luca Weiss wrote:
>>>> Himax HX83112B is a display driver IC used to drive LCD DSI panels.
>>>> Describe it and the Fairphone 3 panel from DJN using it.
>>>>
>>>> Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
>>>> ---
>>>>    .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
>>>>    1 file changed, 75 insertions(+)
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
>>>> new file mode 100644
>>>> index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
>>>> @@ -0,0 +1,75 @@
>>>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: Himax HX83112B-based DSI display panels
>>>> +
>>>> +maintainers:
>>>> +  - Luca Weiss <luca@lucaweiss.eu>
>>>> +
>>>> +description:
>>>> +  The Himax HX83112B is a generic DSI Panel IC used to control
>>>> +  LCD panels.
>>>> +
>>>> +allOf:
>>>> +  - $ref: panel-common.yaml#
>>>> +
>>>> +properties:
>>>> +  compatible:
>>>> +    contains:
>>>> +      const: djn,fairphone-fp3-panel
>>>
>>> Why no himax,hx83112b fallback?
>>
>> While this is the driver IC for this panel, I don't think there's any
>> "generic" init sequence that can successfully configure this panel, so
>> generic hx83112b driver could work I'd say.
> 
> 
> Hm, indeed usually this would mean no need for unusable fallback alone,
> but still drivers could use it for some common pieces of code. I imagine
> there could be a piece of init sequence which is generic. Or some piece
> of attributes.
> We already have examples of both approaches for panels - with generic
> fallback (himax,hx83102) and without (himax,hx83112a).
> 
> @Rob
> what is your generic advice? Which of above (himax,hx83102 vs
> himax,hx83112a) should be used, if the fallback compatible cannot be
> used alone?

I believe this thread is still pending of a resolution, based on the 
model number I've found, I made the compatible "djn,98-03057-6598b-i" 
for v2, but it's still a question whether himax,hx83112b should be part 
of the compatible.

Regards
Luca

> 
> Best regards,
> Krzysztof
Re: [PATCH 2/4] dt-bindings: display: panel: Add Himax HX83112B
Posted by Dmitry Baryshkov 10 months, 2 weeks ago 
On Sat, Mar 29, 2025 at 02:54:27PM +0100, Luca Weiss wrote:
> Hi all,
> 
> On 2/24/25 9:16 AM, Krzysztof Kozlowski wrote:
> > On 23/02/2025 16:29, Luca Weiss wrote:
> > > Hi Krzysztof,
> > > 
> > > On 23-02-2025 12:54 p.m., Krzysztof Kozlowski wrote:
> > > > On Sat, Feb 22, 2025 at 06:58:05PM +0100, Luca Weiss wrote:
> > > > > Himax HX83112B is a display driver IC used to drive LCD DSI panels.
> > > > > Describe it and the Fairphone 3 panel from DJN using it.
> > > > > 
> > > > > Signed-off-by: Luca Weiss <luca@lucaweiss.eu>
> > > > > ---
> > > > >    .../bindings/display/panel/himax,hx83112b.yaml     | 75 ++++++++++++++++++++++
> > > > >    1 file changed, 75 insertions(+)
> > > > > 
> > > > > diff --git a/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
> > > > > new file mode 100644
> > > > > index 0000000000000000000000000000000000000000..e6bd4b33d40be98e479d84617aea6d2af0df70e4
> > > > > --- /dev/null
> > > > > +++ b/Documentation/devicetree/bindings/display/panel/himax,hx83112b.yaml
> > > > > @@ -0,0 +1,75 @@
> > > > > +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
> > > > > +%YAML 1.2
> > > > > +---
> > > > > +$id: http://devicetree.org/schemas/display/panel/himax,hx83112b.yaml#
> > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > +
> > > > > +title: Himax HX83112B-based DSI display panels
> > > > > +
> > > > > +maintainers:
> > > > > +  - Luca Weiss <luca@lucaweiss.eu>
> > > > > +
> > > > > +description:
> > > > > +  The Himax HX83112B is a generic DSI Panel IC used to control
> > > > > +  LCD panels.
> > > > > +
> > > > > +allOf:
> > > > > +  - $ref: panel-common.yaml#
> > > > > +
> > > > > +properties:
> > > > > +  compatible:
> > > > > +    contains:
> > > > > +      const: djn,fairphone-fp3-panel
> > > > 
> > > > Why no himax,hx83112b fallback?
> > > 
> > > While this is the driver IC for this panel, I don't think there's any
> > > "generic" init sequence that can successfully configure this panel, so
> > > generic hx83112b driver could work I'd say.
> > 
> > 
> > Hm, indeed usually this would mean no need for unusable fallback alone,
> > but still drivers could use it for some common pieces of code. I imagine
> > there could be a piece of init sequence which is generic. Or some piece
> > of attributes.
> > We already have examples of both approaches for panels - with generic
> > fallback (himax,hx83102) and without (himax,hx83112a).
> > 
> > @Rob
> > what is your generic advice? Which of above (himax,hx83102 vs
> > himax,hx83112a) should be used, if the fallback compatible cannot be
> > used alone?
> 
> I believe this thread is still pending of a resolution, based on the model
> number I've found, I made the compatible "djn,98-03057-6598b-i" for v2, but
> it's still a question whether himax,hx83112b should be part of the
> compatible.

My 2c (note, not a DT maintainer or anything): no, the IC driver doesn't
fully define panel programming, so it should not be used as a fallback
compat.

-- 
With best wishes
Dmitry

Patchew 2.1-devel-b67e4c2

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