On Wed, 09 Feb 2022, Sascha Hauer <s.hauer@xxxxxxxxxxxxxx> wrote:
> David, Daniel,
>
> I'll need a word from you regarding this patch. It's needed in patch
> 22/23 in this series.
> vop2_crtc_atomic_enable() needs to control the mux which routes the
> display output to the different encoders. Which encoder is used is
> described in the of_graph port, so I need a way to identify the encoder
> in the device tree.
I think the question is how useful is this going to be in general. IMO
we should not be adding members that are useful in a single driver only.
For example i915 wraps encoders with:
struct intel_encoder {
struct drm_encoder base;
/* i915 specific stuff here*/
};
So that we can add stuff of our own there. Of course, it does mean a
bunch of overhead for the first time you need to do it. But adding
driver specific stuff to struct drm_encoder adds overhead for everyone.
All that said, *I* don't know how useful the port member would be in
drivers that use device tree. Maybe it's worth it.
BR,
Jani.
>
> Sascha
>
> On Wed, Feb 09, 2022 at 10:53:28AM +0100, Sascha Hauer wrote:
>> Add a device node to drm_encoder which corresponds with the port node
>> in the DT description of the encoder. This allows drivers to find the
>> of_graph link between a crtc and an encoder.
>>
>> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
>> ---
>> include/drm/drm_encoder.h | 2 ++
>> 1 file changed, 2 insertions(+)
>>
>> diff --git a/include/drm/drm_encoder.h b/include/drm/drm_encoder.h
>> index 6e91a0280f31..3acd054b1eb3 100644
>> --- a/include/drm/drm_encoder.h
>> +++ b/include/drm/drm_encoder.h
>> @@ -99,6 +99,8 @@ struct drm_encoder {
>> struct drm_device *dev;
>> struct list_head head;
>>
>> + struct device_node *port;
>> +
>> struct drm_mode_object base;
>> char *name;
>> /**
>> --
>> 2.30.2
>>
>>
--
Jani Nikula, Intel Open Source Graphics Center
