linux-kernel - Re: [PATCH v2 5/9] dt-bindings: display: bridge: Add ITE IT6263 LVDS to HDMI converter

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Message-ID: <d5d62f61-808f-4c40-bc71-4e168baf4b1b@nxp.com>
Date: Tue, 15 Oct 2024 14:28:01 +0800
From: Liu Ying <victor.liu@....com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
Cc: dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org,
 linux-kernel@...r.kernel.org, imx@...ts.linux.dev,
 linux-arm-kernel@...ts.infradead.org, andrzej.hajda@...el.com,
 neil.armstrong@...aro.org, rfoss@...nel.org,
 Laurent.pinchart@...asonboard.com, jonas@...boo.se,
 jernej.skrabec@...il.com, airlied@...il.com, simona@...ll.ch,
 maarten.lankhorst@...ux.intel.com, mripard@...nel.org, tzimmermann@...e.de,
 robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
 shawnguo@...nel.org, s.hauer@...gutronix.de, kernel@...gutronix.de,
 festevam@...il.com, catalin.marinas@....com, will@...nel.org,
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 nfraprado@...labora.com, o.rempel@...gutronix.de, y.moog@...tec.de,
 marex@...x.de, isaac.scott@...asonboard.com, biju.das.jz@...renesas.com
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 Mon, Oct 14, 2024 at 01:33:44PM +0800, Liu Ying wrote:
>> 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.
> 
> I'd prefer data-mapping.

Before I go ahead to use it, I'd like to get confirmation that
it'll cover data mapping which supports 30-bit RGB pixel transmission,
because it is something supported by IT6263 as I mentioned in v1
dt-binding discussion.  For now, data-mapping only supports jeida-18,
jeida-24 and vesa-24, see lvds-data-mapping.yaml.  And, I'm not
sure the 30-bit data mappings specified in IT6263 datasheet are
standard or not.

Note that if we use data-lanes instead, then this is not a concern
from DT PoV, as data mapping can be inferred by OS.

-- 
Regards,
Liu Ying