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

[Tomi Valkeinen]

On 31/10/2023 14:18, Jan Kiszka wrote:
> On 31.10.23 11:53, Tomi Valkeinen wrote:
>> 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
>>
> 
> Yep, that does the trick.

Alright, good. I'll send a proper patch.

> Thanks,
> Jan
> 
> PS: Your mail client is mangling tabs - was already suspecting our
> server would reformat again.

Nah, the above was just a quick copy paste from my terminal window, and 
when copying from the terminal it's always just spaces.

  Tomi