[PATCH v1] drm/bridge: simple-bridge: Add support for TI TDP158

[Arnaud Vrac]

On 28/05/2024 09:43, Maxime Ripard wrote:
> Hi,
> 
> On Mon, May 27, 2024 at 06:03:56PM GMT, Marc Gonzalez wrote:
>> From: Arnaud Vrac <avrac at freebox.fr>
>>
>> The TI TDP158 is an AC-Coupled HDMI signal to TMDS Redriver supporting
>> DVI 1.0 and HDMI 1.4b and 2.0b output signals.
>>
>> Since it's an I2C-programmable bridge, it could have a proper driver,
>> but the default settings work fine, thus simple bridge is sufficient.
> 
> No it doesn't. That bridge supports HDMI 2.0 which means you'll need to
> change the TMDS clock ratio when programming a TMDS character rate
> higher than 340MHz. And you'll need hotplug support to deal with it
> properly too.
> 
> So sorry, you need a real driver there.

Hello, this is an HDMI redriver, which simply cleans up the HDMI signal, so no programming is needed to support HDMI 2.0.

Dmitry's comment on v2 also indicates a driver is needed to power on the chip properly, so a dedicated driver does seem to be needed anyway.

> 
>> Signed-off-by: Arnaud Vrac <avrac at freebox.fr>
>> Signed-off-by: Marc Gonzalez <mgonzalez at freebox.fr>
>> ---
>>   drivers/gpu/drm/bridge/simple-bridge.c | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/bridge/simple-bridge.c b/drivers/gpu/drm/bridge/simple-bridge.c
>> index 5813a2c4fc5ee..b138279864750 100644
>> --- a/drivers/gpu/drm/bridge/simple-bridge.c
>> +++ b/drivers/gpu/drm/bridge/simple-bridge.c
>> @@ -292,6 +292,11 @@ static const struct of_device_id simple_bridge_match[] = {
>>   			.timings = &ti_ths8134_bridge_timings,
>>   			.connector_type = DRM_MODE_CONNECTOR_VGA,
>>   		},
>> +	}, {
>> +		.compatible = "ti,tdp158",
>> +		.data = &(const struct simple_bridge_info) {
>> +			.connector_type = DRM_MODE_CONNECTOR_HDMIA,
>> +		},
> 
> You'll need a DT binding for that too.
> 

Ack.

Thanks,
-Arnaud