[v3] Introduce STM32 LVDS driver

[PATCH v3 1/6] dt-bindings: display: add dt-bindings for STM32 LVDS device

Posted by Raphael Gallais-Pou 1 year, 11 months ago

Add "st,stm32mp25-lvds" compatible.

Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
---
Depends on: "dt-bindings: stm32: add clocks and reset binding for
	    stm32mp25 platform" by Gabriel Fernandez

Changes in v3:
	- Clarify commit dependency
	- Fix includes in the example
	- Fix YAML
	- Add "clock-cells" description
	- s/regroups/is composed of/
	- Changed compatible to show SoC specificity

Changes in v2:
	- Switch compatible and clock-cells related areas
	- Remove faulty #include in the example.
	- Add entry in MAINTAINERS
---
 .../bindings/display/st,stm32-lvds.yaml       | 119 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 120 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/display/st,stm32-lvds.yaml

diff --git a/Documentation/devicetree/bindings/display/st,stm32-lvds.yaml b/Documentation/devicetree/bindings/display/st,stm32-lvds.yaml
new file mode 100644
index 000000000000..a6383858cd2c
--- /dev/null
+++ b/Documentation/devicetree/bindings/display/st,stm32-lvds.yaml
@@ -0,0 +1,119 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/display/st,stm32-lvds.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: STMicroelectronics STM32 LVDS Display Interface Transmitter
+
+maintainers:
+  - Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
+  - Yannick Fertre <yannick.fertre@foss.st.com>
+
+description: |
+  The STMicroelectronics STM32 LVDS Display Interface Transmitter handles the
+  LVDS protocol: it maps the pixels received from the upstream Pixel-DMA (LTDC)
+  onto the LVDS PHY.
+
+  It is composed of three sub blocks:
+    - LVDS host: handles the LVDS protocol (FPD / OpenLDI) and maps its input
+      pixels onto the data lanes of the PHY
+    - LVDS PHY: parallelize the data and drives the LVDS data lanes
+    - LVDS wrapper: handles top-level settings
+
+  The LVDS controller driver supports the following high-level features:
+    - FDP-Link-I and OpenLDI (v0.95) protocols
+    - Single-Link or Dual-Link operation
+    - Single-Display or Double-Display (with the same content duplicated on both)
+    - Flexible Bit-Mapping, including JEIDA and VESA
+    - RGB888 or RGB666 output
+    - Synchronous design, with one input pixel per clock cycle
+
+properties:
+  compatible:
+    const: st,stm32mp25-lvds
+
+  "#clock-cells":
+    const: 0
+    description:
+      Provides the internal LVDS PHY clock to the framework.
+
+  reg:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: APB peripheral clock
+      - description: Reference clock for the internal PLL
+
+  clock-names:
+    items:
+      - const: pclk
+      - const: ref
+
+  resets:
+    maxItems: 1
+
+  ports:
+    $ref: /schemas/graph.yaml#/properties/ports
+
+    properties:
+      port@0:
+        $ref: /schemas/graph.yaml#/properties/port
+        description:
+          LVDS input port node, connected to the LTDC RGB output port.
+
+      port@1:
+        $ref: /schemas/graph.yaml#/properties/port
+        description:
+          LVDS output port node, connected to a panel or bridge input port.
+
+    required:
+      - port@0
+      - port@1
+
+required:
+  - compatible
+  - "#clock-cells"
+  - reg
+  - clocks
+  - clock-names
+  - resets
+  - ports
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
+    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
+
+    lvds: lvds@48060000 {
+        compatible = "st,stm32-lvds";
+        reg = <0x48060000 0x2000>;
+        #clock-cells = <0>;
+        clocks = <&rcc CK_BUS_LVDS>, <&rcc CK_KER_LVDSPHY>;
+        clock-names = "pclk", "ref";
+        resets = <&rcc LVDS_R>;
+
+        ports {
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            port@0 {
+                reg = <0>;
+                lvds_in: endpoint {
+                   remote-endpoint = <&ltdc_ep1_out>;
+                };
+            };
+
+            port@1 {
+                reg = <1>;
+                lvds_out0: endpoint {
+                   remote-endpoint = <&lvds_panel_in>;
+                };
+            };
+        };
+    };
+
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 9d959a6881f7..0b6ec5347195 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7193,6 +7193,7 @@ L:	dri-devel@lists.freedesktop.org
 S:	Maintained
 T:	git git://anongit.freedesktop.org/drm/drm-misc
 F:	Documentation/devicetree/bindings/display/st,stm32-ltdc.yaml
+F:	Documentation/devicetree/bindings/display/st,stm32-lvds.yaml
 F:	drivers/gpu/drm/stm
 
 DRM DRIVERS FOR TI KEYSTONE
-- 
2.25.1

Re: [PATCH v3 1/6] dt-bindings: display: add dt-bindings for STM32 LVDS device

Posted by Rob Herring 1 year, 11 months ago

On Mon, Jan 15, 2024 at 02:20:04PM +0100, Raphael Gallais-Pou wrote:
> Add "st,stm32mp25-lvds" compatible.
> 
> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
> ---
> Depends on: "dt-bindings: stm32: add clocks and reset binding for
> 	    stm32mp25 platform" by Gabriel Fernandez
> 
> Changes in v3:
> 	- Clarify commit dependency
> 	- Fix includes in the example
> 	- Fix YAML
> 	- Add "clock-cells" description
> 	- s/regroups/is composed of/
> 	- Changed compatible to show SoC specificity
> 
> Changes in v2:
> 	- Switch compatible and clock-cells related areas
> 	- Remove faulty #include in the example.
> 	- Add entry in MAINTAINERS
> ---
>  .../bindings/display/st,stm32-lvds.yaml       | 119 ++++++++++++++++++

Filename matching compatible.

> +properties:
> +  compatible:
> +    const: st,stm32mp25-lvds


> +examples:
> +  - |
> +    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
> +    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
> +
> +    lvds: lvds@48060000 {
> +        compatible = "st,stm32-lvds";

Wrong compatible.

Re: [PATCH v3 1/6] dt-bindings: display: add dt-bindings for STM32 LVDS device

Posted by Raphael Gallais-Pou 1 year, 11 months ago

On 1/15/24 16:46, Rob Herring wrote:
> On Mon, Jan 15, 2024 at 02:20:04PM +0100, Raphael Gallais-Pou wrote:
>> Add "st,stm32mp25-lvds" compatible.
>>
>> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
>> ---
>> Depends on: "dt-bindings: stm32: add clocks and reset binding for
>> 	    stm32mp25 platform" by Gabriel Fernandez
>>
>> Changes in v3:
>> 	- Clarify commit dependency
>> 	- Fix includes in the example
>> 	- Fix YAML
>> 	- Add "clock-cells" description
>> 	- s/regroups/is composed of/
>> 	- Changed compatible to show SoC specificity
>>
>> Changes in v2:
>> 	- Switch compatible and clock-cells related areas
>> 	- Remove faulty #include in the example.
>> 	- Add entry in MAINTAINERS
>> ---
>>  .../bindings/display/st,stm32-lvds.yaml       | 119 ++++++++++++++++++
> Filename matching compatible.

Hi Rob,


I was unsure about this.

The driver will eventually support several SoCs with different compatibles,
wouldn't this be more confusing ?

I also wanted to keep the similarity with the "st,stm32-<ip>.yaml" name for the
DRM STM drivers. Would that be possible ?


Regards,

Raphaël



>
>> +properties:
>> +  compatible:
>> +    const: st,stm32mp25-lvds
>
>> +examples:
>> +  - |
>> +    #include <dt-bindings/clock/st,stm32mp25-rcc.h>
>> +    #include <dt-bindings/reset/st,stm32mp25-rcc.h>
>> +
>> +    lvds: lvds@48060000 {
>> +        compatible = "st,stm32-lvds";
> Wrong compatible.

Re: [PATCH v3 1/6] dt-bindings: display: add dt-bindings for STM32 LVDS device

Posted by Krzysztof Kozlowski 1 year, 11 months ago

On 15/01/2024 17:51, Raphael Gallais-Pou wrote:
> 
> On 1/15/24 16:46, Rob Herring wrote:
>> On Mon, Jan 15, 2024 at 02:20:04PM +0100, Raphael Gallais-Pou wrote:
>>> Add "st,stm32mp25-lvds" compatible.
>>>

A nit, subject: drop second/last, redundant "dt-bindings for". The
"dt-bindings" prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v6.7-rc8/source/Documentation/devicetree/bindings/submitting-patches.rst#L18

>>> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
>>> ---
>>> Depends on: "dt-bindings: stm32: add clocks and reset binding for
>>> 	    stm32mp25 platform" by Gabriel Fernandez
>>>
>>> Changes in v3:
>>> 	- Clarify commit dependency
>>> 	- Fix includes in the example
>>> 	- Fix YAML
>>> 	- Add "clock-cells" description
>>> 	- s/regroups/is composed of/
>>> 	- Changed compatible to show SoC specificity
>>>
>>> Changes in v2:
>>> 	- Switch compatible and clock-cells related areas
>>> 	- Remove faulty #include in the example.
>>> 	- Add entry in MAINTAINERS
>>> ---
>>>  .../bindings/display/st,stm32-lvds.yaml       | 119 ++++++++++++++++++
>> Filename matching compatible.
> 
> Hi Rob,
> 
> 
> I was unsure about this.
> 
> The driver will eventually support several SoCs with different compatibles,
> wouldn't this be more confusing ?

No. "Eventually" might never happen.

> I also wanted to keep the similarity with the "st,stm32-<ip>.yaml" name for the
> DRM STM drivers. Would that be possible ?

But why? The consistency we want is the filename matching compatible,
not matching other filenames. If you have here multiple devices,
document them *now*.

> 
> 
> Regards,
> 
> Raphaël

I hope you did not ignore rest of the comments... We expect some sort of
"ack/ok/I'll fix/whatever" message and you wrote nothing further.

Best regards,
Krzysztof

Re: [PATCH v3 1/6] dt-bindings: display: add dt-bindings for STM32 LVDS device

Posted by Raphael Gallais-Pou 1 year, 11 months ago

On 1/16/24 08:42, Krzysztof Kozlowski wrote:
> On 15/01/2024 17:51, Raphael Gallais-Pou wrote:
>> On 1/15/24 16:46, Rob Herring wrote:
>>> On Mon, Jan 15, 2024 at 02:20:04PM +0100, Raphael Gallais-Pou wrote:
>>>> Add "st,stm32mp25-lvds" compatible.
>>>>
> A nit, subject: drop second/last, redundant "dt-bindings for". The
> "dt-bindings" prefix is already stating that these are bindings.
> See also:
> https://elixir.bootlin.com/linux/v6.7-rc8/source/Documentation/devicetree/bindings/submitting-patches.rst#L18
>
>>>> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
>>>> ---
>>>> Depends on: "dt-bindings: stm32: add clocks and reset binding for
>>>> 	    stm32mp25 platform" by Gabriel Fernandez
>>>>
>>>> Changes in v3:
>>>> 	- Clarify commit dependency
>>>> 	- Fix includes in the example
>>>> 	- Fix YAML
>>>> 	- Add "clock-cells" description
>>>> 	- s/regroups/is composed of/
>>>> 	- Changed compatible to show SoC specificity
>>>>
>>>> Changes in v2:
>>>> 	- Switch compatible and clock-cells related areas
>>>> 	- Remove faulty #include in the example.
>>>> 	- Add entry in MAINTAINERS
>>>> ---
>>>>  .../bindings/display/st,stm32-lvds.yaml       | 119 ++++++++++++++++++
>>> Filename matching compatible.
>> Hi Rob,
>>
>>
>> I was unsure about this.
>>
>> The driver will eventually support several SoCs with different compatibles,
>> wouldn't this be more confusing ?
> No. "Eventually" might never happen.
>
>> I also wanted to keep the similarity with the "st,stm32-<ip>.yaml" name for the
>> DRM STM drivers. Would that be possible ?
> But why? The consistency we want is the filename matching compatible,
> not matching other filenames. If you have here multiple devices,
> document them *now*.


Hi Krzysztof,

|There is no multiple devices, so I will stick to the "st,stm32mp25-lvds"
pattern for now.|

>
>>
>> Regards,
>>
>> Raphaël
> I hope you did not ignore rest of the comments... We expect some sort of
> "ack/ok/I'll fix/whatever" message and you wrote nothing further.

Although I did not acknowledged what has been said previously, I always take
into account every comment on my patches.  I understand that it can lead to some confusion.  So rest assured that I did not
ignore Rob's and Dmitry's review.


Regards,

Raphaël

>
> Best regards,
> Krzysztof
>

Re: [PATCH v3 1/6] dt-bindings: display: add dt-bindings for STM32 LVDS device

Posted by Rob Herring 1 year, 11 months ago

On Mon, 15 Jan 2024 14:20:04 +0100, Raphael Gallais-Pou wrote:
> Add "st,stm32mp25-lvds" compatible.
> 
> Signed-off-by: Raphael Gallais-Pou <raphael.gallais-pou@foss.st.com>
> ---
> Depends on: "dt-bindings: stm32: add clocks and reset binding for
> 	    stm32mp25 platform" by Gabriel Fernandez
> 
> Changes in v3:
> 	- Clarify commit dependency
> 	- Fix includes in the example
> 	- Fix YAML
> 	- Add "clock-cells" description
> 	- s/regroups/is composed of/
> 	- Changed compatible to show SoC specificity
> 
> Changes in v2:
> 	- Switch compatible and clock-cells related areas
> 	- Remove faulty #include in the example.
> 	- Add entry in MAINTAINERS
> ---
>  .../bindings/display/st,stm32-lvds.yaml       | 119 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 120 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/display/st,stm32-lvds.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:
Documentation/devicetree/bindings/display/st,stm32-lvds.example.dts:18:18: fatal error: dt-bindings/clock/st,stm32mp25-rcc.h: No such file or directory
   18 |         #include <dt-bindings/clock/st,stm32mp25-rcc.h>
      |                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
compilation terminated.
make[2]: *** [scripts/Makefile.lib:419: Documentation/devicetree/bindings/display/st,stm32-lvds.example.dtb] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [/builds/robherring/dt-review-ci/linux/Makefile:1424: dt_binding_check] Error 2
make: *** [Makefile:234: __sub-make] Error 2

doc reference errors (make refcheckdocs):

See https://patchwork.ozlabs.org/project/devicetree-bindings/patch/20240115132009.101718-2-raphael.gallais-pou@foss.st.com

The base for the series is generally the latest rc1. A different dependency
should be noted in *this* patch.

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 after running the above command yourself. Note
that DT_SCHEMA_FILES can be set to your schema file to speed up checking
your schema. However, it must be unset to test all examples with your schema.