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Message-ID: <c22ff1c6-704f-affc-93a7-e2080c58c53d@ideasonboard.com>
Date:   Tue, 13 Dec 2022 16:06:11 +0200
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Subject: Re: [PATCH v5 4/8] dt-bindings: media: add bindings for TI DS90UB953
Content-Language: en-US
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     linux-media@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Wolfram Sang <wsa@kernel.org>,
        Luca Ceresoli <luca.ceresoli@bootlin.com>,
        Andy Shevchenko <andriy.shevchenko@intel.com>,
        Matti Vaittinen <Matti.Vaittinen@fi.rohmeurope.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Peter Rosin <peda@axentia.se>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Mark Brown <broonie@kernel.org>,
        Sakari Ailus <sakari.ailus@linux.intel.com>,
        Michael Tretter <m.tretter@pengutronix.de>,
        Shawn Tu <shawnx.tu@intel.com>,
        Hans Verkuil <hverkuil@xs4all.nl>,
        Mike Pagano <mpagano@gentoo.org>,
        =?UTF-8?Q?Krzysztof_Ha=c5=82asa?= <khalasa@piap.pl>,
        Marek Vasut <marex@denx.de>
References: <20221208104006.316606-1-tomi.valkeinen@ideasonboard.com>
 <20221208104006.316606-5-tomi.valkeinen@ideasonboard.com>
 <Y5YUoEWmHsUT8zgf@pendragon.ideasonboard.com>
From:   Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
In-Reply-To: <Y5YUoEWmHsUT8zgf@pendragon.ideasonboard.com>
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On 11/12/2022 19:34, Laurent Pinchart wrote:
> Hi Tomi,
> 
> Thank you for the patch.
> 
> On Thu, Dec 08, 2022 at 12:40:02PM +0200, Tomi Valkeinen wrote:
>> Add DT bindings for TI DS90UB953 FPDLink-3 Serializer.
>>
>> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> ---
>>   .../bindings/media/i2c/ti,ds90ub953.yaml      | 112 ++++++++++++++++++
>>   1 file changed, 112 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml b/Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml
>> new file mode 100644
>> index 000000000000..fd7d25d93e2c
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/media/i2c/ti,ds90ub953.yaml
>> @@ -0,0 +1,112 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/media/i2c/ti,ds90ub953.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Texas Instruments DS90UB953 FPD-Link 3 Serializer
>> +
>> +maintainers:
>> +  - Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
>> +
>> +description:
>> +  The TI DS90UB953 is an FPD-Link 3 video serializer for MIPI CSI-2.
>> +
>> +properties:
>> +  compatible:
>> +    enum:
>> +      - ti,ds90ub953-q1
>> +      - ti,ds90ub971-q1
>> +
>> +  '#gpio-cells':
>> +    const: 2
> 
> I would add a description here, to tell what the cells correspond to. In
> particular, the first cell selects the GPIO_* pin number, it would be
> nice to document that its value should be in the range [0, 3].
> 
> Same comment for patch 3/8 (DS90UB913 bindings). There you could also
> mention that GPO2 and the output clock are mutually exclusive.

Yep. I have added this for ub913:
       First cell is the GPO pin number, second cell is the flags. The 
GPO pin
       number must be in range of [0, 3]. Note that GPOs 2 and 3 are not
       available in external oscillator mode.

and this for ub953:
       First cell is the GPIO pin number, second cell is the flags. The 
GPIO pin
       number must be in range of [0, 3].

>> +
>> +  gpio-controller: true
>> +
> 
> No need for clocks and clock-names for the reference input clock ? Or is
> this because you support sync mode only for now ?

Right, I don't have the clock on my hw, but it's probably better to add 
it to the binding already.

>> +  '#clock-cells':
>> +    const: 0
>> +
>> +  ports:
>> +    $ref: /schemas/graph.yaml#/properties/ports
>> +
>> +    properties:
>> +      port@0:
>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>> +        unevaluatedProperties: false
>> +        description: CSI-2 input port
>> +
>> +        properties:
>> +          endpoint:
>> +            $ref: /schemas/media/video-interfaces.yaml#
>> +            unevaluatedProperties: false
> 
> Should the data-lanes property be required for the CSI-2 input ?

Yes.

>> +
>> +      port@1:
>> +        $ref: /schemas/graph.yaml#/properties/port
>> +        unevaluatedProperties: false
>> +        description: FPD-Link 3 output port
>> +
>> +  i2c:
>> +    $ref: /schemas/i2c/i2c-controller.yaml#
>> +    unevaluatedProperties: false
>> +
>> +required:
>> +  - compatible
>> +  - '#gpio-cells'
>> +  - gpio-controller
>> +  - '#clock-cells'
>> +  - ports
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/gpio/gpio.h>
>> +
>> +    serializer {
>> +      compatible = "ti,ds90ub953-q1";
>> +
>> +      gpio-controller;
>> +      #gpio-cells = <2>;
>> +
>> +      #clock-cells = <0>;
>> +
>> +      ports {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        port@0 {
>> +          reg = <0>;
>> +          ub953_in: endpoint {
>> +            clock-lanes = <0>;
>> +            data-lanes = <1 2 3 4>;
>> +            remote-endpoint = <&sensor_out>;
>> +          };
>> +        };
>> +
>> +        port@1 {
>> +          reg = <1>;
>> +          endpoint {
>> +            remote-endpoint = <&deser_fpd_in>;
>> +          };
>> +        };
>> +      };
>> +
>> +      i2c {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        sensor@1a {
>> +          compatible = "sony,imx274";
>> +          reg = <0x1a>;
>> +
>> +          reset-gpios = <&serializer 0 GPIO_ACTIVE_LOW>;
> 
> Maybe add
> 
>            clocks = <&serializer>;
> 	  clock-names = "inck";
> 
> to showcase the clock connection ?

Yes, that's a good idea.

  Tomi