[PATCH] drm/bridge: tc358767: Support input format negotiation hook

[Tomi Valkeinen]

Hi Jan,

On 31/10/2023 08:24, Jan Kiszka wrote:
> On 30.10.23 20:28, Aradhya Bhatia wrote:
>> With new connector model, tc358767 will not create the connector, when
>> DRM_BRIDGE_ATTACH_NO_CONNECTOR is set and display-controller driver will
>> rely on format negotiation to setup the encoder format.
>>
>> Add the missing input-format negotiation hook in the
>> drm_bridge_funcs to complete DRM_BRIDGE_ATTACH_NO_CONNECTOR support.
>>
>> Input format is selected to MEDIA_BUS_FMT_RGB888_1X24 as default, as is
>> the case with older model.
>>
>> Reported-by: Jan Kiszka <jan.kiszka at siemens.com>
>> Signed-off-by: Aradhya Bhatia <a-bhatia1 at ti.com>
>> ---
>>
>> Notes:
>>
>>    * Since I do not have hardware with me, this was just build tested. I would
>>      appreciate it if someone could test and review it, especically somebody, who
>>      uses the bridge for DPI/DSI to eDP format conversion.
>>
>>    * The Toshiba TC358767 bridge is not enabled in arm64 defconfig by default,
>>      when it should be. Hence, I sent a quick patch[0] earlier.
>>
>> [0]: https://lore.kernel.org/all/20231030152834.18450-1-a-bhatia1@ti.com/
>>
>>   drivers/gpu/drm/bridge/tc358767.c | 25 +++++++++++++++++++++++++
>>   1 file changed, 25 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
>> index ef2e373606ba..0affcefdeb1c 100644
>> --- a/drivers/gpu/drm/bridge/tc358767.c
>> +++ b/drivers/gpu/drm/bridge/tc358767.c
>> @@ -1751,6 +1751,30 @@ tc_dpi_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
>>   	return input_fmts;
>>   }
>>   
>> +static u32 *
>> +tc_edp_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
>> +				 struct drm_bridge_state *bridge_state,
>> +				 struct drm_crtc_state *crtc_state,
>> +				 struct drm_connector_state *conn_state,
>> +				 u32 output_fmt,
>> +				 unsigned int *num_input_fmts)
>> +{
>> +	u32 *input_fmts;
>> +
>> +	*num_input_fmts = 0;
>> +
>> +	input_fmts = kcalloc(MAX_INPUT_SEL_FORMATS, sizeof(*input_fmts),
>> +			     GFP_KERNEL);
>> +	if (!input_fmts)
>> +		return NULL;
>> +
>> +	/* This is the DSI/DPI-end bus format */
>> +	input_fmts[0] = MEDIA_BUS_FMT_RGB888_1X24;
>> +	*num_input_fmts = 1;
>> +
>> +	return input_fmts;
>> +}
>> +
>>   static const struct drm_bridge_funcs tc_dpi_bridge_funcs = {
>>   	.attach = tc_dpi_bridge_attach,
>>   	.mode_valid = tc_dpi_mode_valid,
>> @@ -1777,6 +1801,7 @@ static const struct drm_bridge_funcs tc_edp_bridge_funcs = {
>>   	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
>>   	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
>>   	.atomic_reset = drm_atomic_helper_bridge_reset,
>> +	.atomic_get_input_bus_fmts = tc_edp_atomic_get_input_bus_fmts,
>>   };
>>   
>>   static bool tc_readable_reg(struct device *dev, unsigned int reg)
>>
>> base-commit: c503e3eec382ac708ee7adf874add37b77c5d312
> 
> Doesn't help, callback is never invoked. There must be more missing.
> 
> Regarding test setup: Maybe your colleague Preneeth can help to give you
> access, he just received some devices from us. Otherwise, drop me
> instrumentation patches.

Can you try with this change:

diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 0affcefdeb1c..137a9f5e3cad 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -1579,6 +1579,13 @@ static struct edid *tc_get_edid(struct drm_bridge *bridge,
                                 struct drm_connector *connector)
  {
         struct tc_data *tc = bridge_to_tc(bridge);
+       int ret;
+
+       ret = tc_get_display_props(tc);
+       if (ret < 0) {
+               dev_err(tc->dev, "failed to read display props: %d\n", ret);
+               return 0;
+       }
  
         return drm_get_edid(connector, &tc->aux.ddc);
  }

  Tomi