Re: [PATCH v3] media: i2c: add lt6911uxe hdmi bridge driver

["Yan, Dongcheng" <dongcheng.yan@linux.intel.com>]

Hi Hans,

On 10/25/2024 3:05 PM, Hans Verkuil wrote:
> On 25/10/2024 08:49, Sakari Ailus wrote:
>> Hi Hans,
>>
>> On Wed, Oct 23, 2024 at 02:28:02PM +0200, Hans Verkuil wrote:
>>> Hi Dongcheng,
>>>
>>> Since this is an HDMI receiver, you need to implement the DV Timings API.
>>
>> "Must"? Why?
> 
> The DV Timings API is used to deal with the HDMI interface part.
> 
>>
>> I don't know the tc358743 driver but it'd unlikely to work with current
>> CSI-2 RX drivers. They expect the LINK_FREQ control for instance, not the
>> DV timing API.
>> <URL:https://hverkuil.home.xs4all.nl/spec/driver-api/tx-rx.html#transmitter-receiver>
>>
> 
> The tc358743 predates these controls. It just uses get_mbus_config. The CSI
> configuration is defined in the dts:
> 
> Documentation/devicetree/bindings/media/i2c/tc358743.txt
> 

the lt6911uxe driver gets mbus_config in lt6911uxe_fwnode_parse, however 
we still need to support v4l2_ctl link_freq and pixel_rate for the 
related sensor users who follow the CSI-2 rules, like Intel IPU.

Thanks,
Dongcheng

> It is fine to add support for these controls, but the DV Timings API to deal
> with the HDMI interface is required for HDMI receivers.
> 
> The CSI lanes/frequencies are typically fixed for HDMI receivers (i.e. they
> don't change if the resolution changes).
> 
> Regards,
> 
> 	Hans
>