Message-ID: <90e0c4ac-1636-4936-ba40-2f7693bc6b32@nxp.com>
Date: Mon, 14 Oct 2024 13:33:44 +0800
From: Liu Ying <victor.liu@....com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
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Subject: Re: [PATCH v2 5/9] dt-bindings: display: bridge: Add ITE IT6263 LVDS
 to HDMI converter

On 10/14/2024, Dmitry Baryshkov wrote:
> On Sat, Oct 12, 2024 at 05:14:13PM +0800, Liu Ying wrote:
>> On 10/12/2024, Dmitry Baryshkov wrote:
>>> On Sat, Oct 12, 2024 at 03:35:39PM +0800, Liu Ying wrote:
>>>> Document ITE IT6263 LVDS to HDMI converter.
>>>>
>>>> Product link:
>>>> https://www.ite.com.tw/en/product/cate1/IT6263
>>>>
>>>> Signed-off-by: Liu Ying <victor.liu@....com>
>>>> ---
>>>> v2:
>>>> * Document number of LVDS link data lanes.  (Biju)
>>>> * Simplify ports property by dropping "oneOf".  (Rob)
>>>>
>>>>  .../bindings/display/bridge/ite,it6263.yaml   | 276 ++++++++++++++++++
>>>>  1 file changed, 276 insertions(+)
>>>>  create mode 100644 Documentation/devicetree/bindings/display/bridge/ite,it6263.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/display/bridge/ite,it6263.yaml b/Documentation/devicetree/bindings/display/bridge/ite,it6263.yaml
>>>> new file mode 100644
>>>> index 000000000000..bc2bbec07623
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/display/bridge/ite,it6263.yaml
>>>> @@ -0,0 +1,276 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: http://devicetree.org/schemas/display/bridge/ite,it6263.yaml#
>>>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>>>> +
>>>> +title: ITE IT6263 LVDS to HDMI converter
>>>> +
>>>> +maintainers:
>>>> +  - Liu Ying <victor.liu@....com>
>>>> +
>>>> +description: |
>>>> +  The IT6263 is a high-performance single-chip De-SSC(De-Spread Spectrum) LVDS
>>>> +  to HDMI converter.  Combined with LVDS receiver and HDMI 1.4a transmitter,
>>>> +  the IT6263 supports LVDS input and HDMI 1.4 output by conversion function.
>>>> +  The built-in LVDS receiver can support single-link and dual-link LVDS inputs,
>>>> +  and the built-in HDMI transmitter is fully compliant with HDMI 1.4a/3D, HDCP
>>>> +  1.2 and backward compatible with DVI 1.0 specification.
>>>> +
>>>> +  The IT6263 also encodes and transmits up to 8 channels of I2S digital audio,
>>>> +  with sampling rate up to 192KHz and sample size up to 24 bits. In addition,
>>>> +  an S/PDIF input port takes in compressed audio of up to 192KHz frame rate.
>>>> +
>>>> +  The newly supported High-Bit Rate(HBR) audio by HDMI specifications v1.3 is
>>>> +  provided by the IT6263 in two interfaces: the four I2S input ports or the
>>>> +  S/PDIF input port.  With both interfaces the highest possible HBR frame rate
>>>> +  is supported at up to 768KHz.
>>>> +
>>>> +properties:
>>>
>>> No LVDS data-mapping support?
>>
>> It is enough to document number of LVDS link data lanes
>> because OS should be able to determine the data-mapping
>> by looking at the number and the data-mapping capability
>> of the other side of the LVDS link. 
> 
> From what I can see, data-mapping is specified on the consumer sink side
> of the LVDS link. This means it should go to the bridge's device node.

Then, I won't define data-lanes, because data-mapping implies it,
e.g., jeida-24 implies data lanes 0/1/2/3, see lvds-data-mapping.yaml.

Please let me know which one you prefer.

> 
>>
>>>
>>>> +  compatible:
>>>> +    const: ite,it6263
>>>> +
>>>> +  reg:
>>>> +    maxItems: 1
>>>> +
>>>> +  clocks:
>>>> +    maxItems: 1
>>>> +    description: audio master clock
>>>> +
>>>> +  clock-names:
>>>> +    const: mclk
>>>> +
>>>> +  reset-gpios:
>>>> +    maxItems: 1
>>>> +
>>>> +  ivdd-supply:
>>>> +    description: 1.8V digital logic power
>>>> +
>>>> +  ovdd-supply:
>>>> +    description: 3.3V I/O pin power
>>>> +
>>>> +  txavcc18-supply:
>>>> +    description: 1.8V HDMI analog frontend power
>>>> +
>>>> +  txavcc33-supply:
>>>> +    description: 3.3V HDMI analog frontend power
>>>> +
>>>> +  pvcc1-supply:
>>>> +    description: 1.8V HDMI frontend core PLL power
>>>> +
>>>> +  pvcc2-supply:
>>>> +    description: 1.8V HDMI frontend filter PLL power
>>>> +
>>>> +  avcc-supply:
>>>> +    description: 3.3V LVDS frontend power
>>>> +
>>>> +  anvdd-supply:
>>>> +    description: 1.8V LVDS frontend analog power
>>>> +
>>>> +  apvdd-supply:
>>>> +    description: 1.8V LVDS frontend PLL power
>>>> +
>>>> +  "#sound-dai-cells":
>>>> +    const: 0
>>>> +
>>>> +  ite,lvds-link-num-data-lanes:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint8
>>>> +    enum: [3, 4, 5]
>>>> +    description: number of data lanes per LVDS link
>>>
>>> Please use data-lanes property inside the OF graph.
>>
>> In both port@0 and port@1?
> 
> Yes

I'm assuming if data-mapping is defined, then no need to
define data-lanes.

> 
>>
>>>
>>>> +
>>>> +  ite,i2s-audio-fifo-sources:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint32-array
>>>> +    minItems: 1
>>>> +    maxItems: 4
>>>> +    items:
>>>> +      enum: [0, 1, 2, 3]
>>>> +    description:
>>>> +      Each array element indicates the pin number of an I2S serial data input
>>>> +      line which is connected to an audio FIFO, from audio FIFO0 to FIFO3.
>>>
>>> What does that mean from the board point of view? Routed audio links for
>>> the multichannel audio?
>>
>> Yes, also for single channel audio.
>>
>>>
>>>> +
>>>> +  ite,rl-channel-swap-audio-sources:
>>>> +    $ref: /schemas/types.yaml#/definitions/uint32-array
>>>> +    minItems: 1
>>>> +    maxItems: 4
>>>> +    uniqueItems: true
>>>> +    items:
>>>> +      enum: [0, 1, 2, 3]
>>>> +    description:
>>>> +      Each array element indicates an audio source whose right channel and left
>>>> +      channel are swapped by this converter. For I2S, the element is the pin
>>>> +      number of an I2S serial data input line. For S/PDIF, the element is always
>>>> +      0.
>>>
>>> Why?
>>
>> Because this converter has the capability to swap right channel
>> and left channel and S/PDIF always uses audio source0. 
>>
>>>
>>>> +
>>>> +  ports:
>>>> +    $ref: /schemas/graph.yaml#/properties/ports
>>>> +
>>>> +    properties:
>>>> +      port@0:
>>>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>>>> +        unevaluatedProperties: false
>>>> +        description:
>>>> +          The first LVDS input link.
>>>> +          In dual-link LVDS mode, this link works together with the second LVDS
>>>> +          input link, and one link receives odd pixels while the other receives
>>>> +          even pixels. Specify the pixels with one of the dual-lvds-odd-pixels
>>>> +          and dual-lvds-even-pixels properties when and only when dual-link LVDS
>>>> +          mode is used.
>>>> +
>>>> +        properties:
>>>> +          dual-lvds-odd-pixels:
>>>> +            type: boolean
>>>> +            description: the first sink port for odd pixels
>>>> +
>>>> +          dual-lvds-even-pixels:
>>>> +            type: boolean
>>>> +            description: the first sink port for even pixels
>>>> +
>>>> +      port@1:
>>>> +        $ref: /schemas/graph.yaml#/$defs/port-base
>>>> +        unevaluatedProperties: false
>>>> +        description: the second LVDS input link
>>>> +
>>>> +        properties:
>>>> +          dual-lvds-even-pixels:
>>>> +            type: boolean
>>>> +            description: the second sink port for even pixels
>>>> +
>>>> +          dual-lvds-odd-pixels:
>>>> +            type: boolean
>>>> +            description: the second sink port for odd pixels
>>>> +
>>>> +        oneOf:
>>>> +          - required: [dual-lvds-even-pixels]
>>>> +          - required: [dual-lvds-odd-pixels]
>>>
>>> This still allows one to specify that both ports provide odd pixels. Is
>>> that expected? Also why do you need two properties which specify the
>>> same option.
>>
>> No, that is not expected. Description for port@0 already mentions
>> one link receives odd pixels while the other receives even pixels.
> 
> That's not expected, but permitted by the bindings.

It is not permitted by port@1. If "dual-lvds-odd-pixels;" is added
to port@1 in the dual-link LVDS example, the below warning will be
generated by dt_binding_check.

Documentation/devicetree/bindings/display/bridge/ite,it6263.example.dtb: hdmi@4c: ports:port@1: {'reg': [[1]], 'dual-lvds-even-pixels': True, 'dual-lvds-odd-pixels': True, 'endpoint': {'remote-endpoint': [[4294967295]]}} is valid under each of {'required': ['dual-lvds-odd-pixels']}, {'required': ['dual-lvds-even-pixels']}
	from schema $id: http://devicetree.org/schemas/display/bridge/ite,it6263.yaml#

However, the binding for port@0 does allow DT writers to specify
both even and odd pixels. I raised similar concerns in v1 discussion.
According to Rob's comment in #devicetree IRC, the ports property
is simplified to this form and more description for port@0 is added
to tell when to specify the even/odd pixels.  If you know any better
way to indicate the constraints, please shout.

> 
>>
>> Two options are supported for dual-link LVDS, not the same option:
>> 1) LVDS link1(port@0) gets odd pixels
>>    and
>>    LVDS link2(port@1) gets even pixels.
>>
>> 2) LVDS link1(port@0) gets even pixels
>>    and
>>    LVDS link2(port@1) gets odd pixels.
>> That's the reason why each port needs two properties to define
>> odd/even pixels.
>>
>>>
>>> My suggestion would be to add a single root-level property which
>>> specifies which port provides even pixel data.
>>
>> That won't work.  The LVDS source side expects the ports of
>> the sink side specify dual-lvds-{odd,even}-pixels properties.
> 
> I didn't notice that these properties are already defined.
> 
> As these properties are common between several schema files, please
> extract them to a common schema file (like lvds.yaml).

I'm not sure how to do that. Is it obvious?
Please shed some light. 

Only two panel schema files are defining even/odd pixels now -
advantech,idk-2121wr.yaml and panel-simple-lvds-dual-ports.yaml.
Maybe, extract them later when more schema files(especially for
bridges) try to define the same?  I'd like to keep a low profile
for now.

> 
>>
>>>
>>>> +
>>>> +      port@2:
>>>> +        $ref: /schemas/graph.yaml#/properties/port
>>>> +        description: video port for the HDMI output
>>>> +
>>>> +      port@3:
>>>> +        $ref: /schemas/graph.yaml#/properties/port
>>>> +        description: sound input port
>>>> +
>>>> +    required:
>>>> +      - port@0
>>>> +      - port@2
>>>> +
>>>> +required:
>>>> +  - compatible
>>>> +  - reg
>>>> +  - ivdd-supply
>>>> +  - ovdd-supply
>>>> +  - txavcc18-supply
>>>> +  - txavcc33-supply
>>>> +  - pvcc1-supply
>>>> +  - pvcc2-supply
>>>> +  - avcc-supply
>>>> +  - anvdd-supply
>>>> +  - apvdd-supply
>>>> +  - ite,lvds-link-num-data-lanes
>>>> +  - ports
>>>> +
>>>> +additionalProperties: false
>>>> +
>>>> +examples:
>>>> +  - |
>>>> +    /* single-link LVDS input */
>>>> +    #include <dt-bindings/gpio/gpio.h>
>>>> +
>>>> +    i2c {
>>>> +        #address-cells = <1>;
>>>> +        #size-cells = <0>;
>>>> +
>>>> +        hdmi@4c {
>>>> +            compatible = "ite,it6263";
>>>> +            reg = <0x4c>;
>>>> +            reset-gpios = <&gpio1 10 GPIO_ACTIVE_LOW>;
>>>> +            ivdd-supply = <&reg_buck5>;
>>>> +            ovdd-supply = <&reg_vext_3v3>;
>>>> +            txavcc18-supply = <&reg_buck5>;
>>>> +            txavcc33-supply = <&reg_vext_3v3>;
>>>> +            pvcc1-supply = <&reg_buck5>;
>>>> +            pvcc2-supply = <&reg_buck5>;
>>>> +            avcc-supply = <&reg_vext_3v3>;
>>>> +            anvdd-supply = <&reg_buck5>;
>>>> +            apvdd-supply = <&reg_buck5>;
>>>> +            ite,lvds-link-num-data-lanes = /bits/ 8 <4>;
>>>> +
>>>> +            ports {
>>>> +                #address-cells = <1>;
>>>> +                #size-cells = <0>;
>>>> +
>>>> +                port@0 {
>>>> +                    reg = <0>;
>>>> +
>>>> +                    it6263_lvds_link1: endpoint {
>>>> +                        remote-endpoint = <&ldb_lvds_ch0>;
>>>> +                    };
>>>> +                };
>>>> +
>>>> +                port@2 {
>>>> +                    reg = <2>;
>>>> +
>>>> +                    it6263_out: endpoint {
>>>> +                        remote-endpoint = <&hdmi_in>;
>>>> +                    };
>>>> +                };
>>>> +            };
>>>> +        };
>>>> +    };
>>>> +
>>>> +  - |
>>>> +    /* dual-link LVDS input */
>>>> +    #include <dt-bindings/gpio/gpio.h>
>>>> +
>>>> +    i2c {
>>>> +        #address-cells = <1>;
>>>> +        #size-cells = <0>;
>>>> +
>>>> +        hdmi@4c {
>>>> +            compatible = "ite,it6263";
>>>> +            reg = <0x4c>;
>>>> +            reset-gpios = <&gpio1 10 GPIO_ACTIVE_LOW>;
>>>> +            ivdd-supply = <&reg_buck5>;
>>>> +            ovdd-supply = <&reg_vext_3v3>;
>>>> +            txavcc18-supply = <&reg_buck5>;
>>>> +            txavcc33-supply = <&reg_vext_3v3>;
>>>> +            pvcc1-supply = <&reg_buck5>;
>>>> +            pvcc2-supply = <&reg_buck5>;
>>>> +            avcc-supply = <&reg_vext_3v3>;
>>>> +            anvdd-supply = <&reg_buck5>;
>>>> +            apvdd-supply = <&reg_buck5>;
>>>> +            ite,lvds-link-num-data-lanes = /bits/ 8 <4>;
>>>> +
>>>> +            ports {
>>>> +                #address-cells = <1>;
>>>> +                #size-cells = <0>;
>>>> +
>>>> +                port@0 {
>>>> +                    reg = <0>;
>>>> +                    dual-lvds-odd-pixels;
>>>> +
>>>> +                    it6263_lvds_link1_dual: endpoint {
>>>> +                        remote-endpoint = <&ldb_lvds_ch0>;
>>>> +                    };
>>>> +                };
>>>> +
>>>> +                port@1 {
>>>> +                    reg = <1>;
>>>> +                    dual-lvds-even-pixels;
>>>> +
>>>> +                    it6263_lvds_link2_dual: endpoint {
>>>> +                        remote-endpoint = <&ldb_lvds_ch1>;
>>>> +                    };
>>>> +                };
>>>> +
>>>> +                port@2 {
>>>> +                    reg = <2>;
>>>> +
>>>> +                    it6263_out_dual: endpoint {
>>>> +                        remote-endpoint = <&hdmi_in>;
>>>> +                    };
>>>> +                };
>>>> +            };
>>>> +        };
>>>> +    };
>>>> -- 
>>>> 2.34.1
>>>>
>>>
>>
>> -- 
>> Regards,
>> Liu Ying
>>
> 

-- 
Regards,
Liu Ying

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