Re: [PATCH v2 1/2] media: dt-bindings: i2c: add Himax HM1246 image sensor

[Matthias Fend <matthias.fend@emfend.at>]

Hi Sakari,

Thanks for you feedback!

Am 05.09.2025 um 11:59 schrieb Sakari Ailus:
> Hi Matthias,
> 
> Thanks for the set.
> 
> On Mon, May 26, 2025 at 08:59:27AM +0200, Matthias Fend wrote:
>> Add YAML device tree binding for Himax HM1246 image sensor.
>>
>> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
>> Signed-off-by: Matthias Fend <matthias.fend@emfend.at>
>> ---
>>   .../bindings/media/i2c/himax,hm1246.yaml           | 111 +++++++++++++++++++++
>>   1 file changed, 111 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/media/i2c/himax,hm1246.yaml b/Documentation/devicetree/bindings/media/i2c/himax,hm1246.yaml
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..8a67de7e3ffcaa9f1acfe443b1e36fffb79dbacf
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/media/i2c/himax,hm1246.yaml
>> @@ -0,0 +1,111 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +# Copyright 2025 Matthias Fend <matthias.fend@emfend.at>
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/media/i2c/himax,hm1246.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Himax HM1246-AWD 1/3.7-Inch megapixel SoC image sensor
>> +
>> +maintainers:
>> +  - Matthias Fend <matthias.fend@emfend.at>
>> +
>> +description:
>> +  The Himax HM1246-AWD is a 1/3.7-Inch CMOS image sensor SoC with an active
>> +  array size of 1296 x 976. It is programmable through an I2C interface and
>> +  connected via parallel bus.
>> +
>> +allOf:
>> +  - $ref: /schemas/media/video-interface-devices.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    const: himax,hm1246
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  clocks:
>> +    description: Input reference clock (6 - 27 MHz)
>> +    maxItems: 1
>> +
>> +  reset-gpios:
>> +    description: Active low XSHUTDOWN pin
>> +    maxItems: 1
>> +
>> +  avdd-supply:
>> +    description: Power for analog circuit (3.0 - 3.6 V)
>> +
>> +  iovdd-supply:
>> +    description: Power for I/O circuit (1.7 - 3.6 V)
>> +
>> +  dvdd-supply:
>> +    description: Power for digital circuit (1.5 / 1.8 V)
>> +
>> +  port:
>> +    $ref: /schemas/graph.yaml#/$defs/port-base
>> +    additionalProperties: false
>> +    description: Parallel video output port
>> +
>> +    properties:
>> +      endpoint:
>> +        $ref: /schemas/media/video-interfaces.yaml#
>> +        unevaluatedProperties: false
>> +
>> +        properties:
>> +          bus-type:
>> +            const: 5
> 
> Does the device also support e.g. Bt.656? If not, you can drop this.

It is always a parallel interface. Okay, will remove it.
> 
> If the rest of the parallel interface parameter properties aren't
> mandatory, what are their default values?

The defaults are:
hsync-active: 1 (high)
vsync-active: 1 (high)
pclk-sample: 0 (falling)

Should I add the default values? The properties section of the endpoint 
would then look like this:

properties:
   hsync-active:
     default: 1

   vsync-active:
     default: 1

   pclk-sample:
     default: 0

> 
>> +
>> +        required:
>> +          - bus-type

Then I should probably remove that too?

>> +
>> +    required:
>> +      - endpoint
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - clocks
>> +  - avdd-supply
>> +  - iovdd-supply
>> +  - dvdd-supply
>> +  - port
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/gpio/gpio.h>
>> +    #include <dt-bindings/media/video-interfaces.h>
>> +
>> +    i2c {
>> +        #address-cells = <1>;
>> +        #size-cells = <0>;
>> +
>> +        sensor@24 {
>> +            compatible =  "himax,hm1246";
>> +            reg = <0x24>;
>> +
>> +            clocks = <&hm1246_clk>;
>> +
>> +            reset-gpios = <&gpio0 0 GPIO_ACTIVE_LOW>;
>> +
>> +            avdd-supply = <&hm1246_avdd>;
>> +            iovdd-supply = <&hm1246_iovdd>;
>> +            dvdd-supply = <&hm1246_dvdd>;
>> +
>> +            orientation = <2>;
> 
> It'd be nice to add macros for these in
> include/dt-bindings/media/video-interfaces.h .

True. However, since this is not specific to this sensor, I think it's 
something for a separate series.
Should I omit these properties in this example?

Thanks
  ~Matthias

> 
>> +            rotation = <0>;
>> +
>> +            port {
>> +                endpoint {
>> +                    remote-endpoint = <&isp_par_in>;
>> +                    bus-type = <MEDIA_BUS_TYPE_PARALLEL>;
>> +                    bus-width = <10>;
>> +                    hsync-active = <1>; /* active high */
>> +                    vsync-active = <1>; /* active high */
>> +                    pclk-sample = <1>; /* sample on rising edge */
>> +                };
>> +            };
>> +        };
>> +    };
>>
>