2021-01-13 01:36:15

by H. Nikolaus Schaller

Subject: What ist the standard way to define connector type and bus format with device tree?

Hi,
according to bindings/display/panel/panel-common.yaml
and by using "panel-simple" as compatible string we
can define almost all properties of a DSI panel by a
device tree entry.

Except the connector and bus format which can only be
set by adding the same information to the panel-simple tables.

This leads to big problems because DRM can't match the
display with any lcd controller. The least issue is a
warning:

[ 0.313431] panel-simple claa070vc01: Specify missing connector_type

Are we missing some documentation or code that reads
some "connector-type" and "bus-format" property?

BR and thanks,
Nikolaus

2021-01-31 13:52:43

by H. Nikolaus Schaller

Subject: Re: [Letux-kernel] What ist the standard way to define connector type and bus format with device tree?

ping?

> Am 12.01.2021 um 12:41 schrieb H. Nikolaus Schaller <[email protected]>:
>
> Hi,
> according to bindings/display/panel/panel-common.yaml
> and by using "panel-simple" as compatible string we
> can define almost all properties of a DSI panel by a
> device tree entry.
>
> Except the connector type and bus format which can only be
> set by adding the information to the panel-simple tables.
>
> This leads to big problems because DRM can't match the
> display with any lcd controller. A smaller issue is a
> warning:
>
> [ 0.313431] panel-simple claa070vc01: Specify missing connector_type
>
> Are we missing some documentation or code that reads
> some "connector-type" and "bus-format" property?
>
> BR and thanks,
> Nikolaus

2021-02-28 23:27:49

by H. Nikolaus Schaller

Subject: Q: What ist the standard way to define connector type and bus format with device tree?

No expert available?

Let me refine the question:

By using the descriptions of panel-common.yaml and panel-timing.yaml it
is possible to define a simple-panel by pure DTS means.

This timing setup is done by code through:

git blame drivers/gpu/drm/panel/panel-simple.c | grep of_get_display_timing
4a1d0dbc8332231 (Sam Ravnborg 2020-02-16 19:15:13 +0100 431) ret = of_get_display_timing(np, "panel-timing", timing);
4a1d0dbc8332231 (Sam Ravnborg 2020-02-16 19:15:13 +0100 566) if (!of_get_display_timing(dev->of_node, "panel-timing", &dt))

But it seems to lack a mechanism to define the connector type and bus format
which is needed to make a panel finally work.

Are we missing something or is the code/property missing?

If it is the first, please let us know so that we can use it.
If code is missing, please let us know so that we can suggest a patch.

BR and thanks,
Nikolaus


> Am 31.01.2021 um 11:54 schrieb H. Nikolaus Schaller <[email protected]>:
>
> ping?
>
>> Am 12.01.2021 um 12:41 schrieb H. Nikolaus Schaller <[email protected]>:
>>
>> Hi,
>> according to bindings/display/panel/panel-common.yaml
>> and by using "panel-simple" as compatible string we
>> can define almost all properties of a DSI panel by a
>> device tree entry.
>>
>> Except the connector type and bus format which can only be
>> set by adding the information to the panel-simple tables.
>>
>> This leads to big problems because DRM can't match the
>> display with any lcd controller. A smaller issue is a
>> warning:
>>
>> [ 0.313431] panel-simple claa070vc01: Specify missing connector_type
>>
>> Are we missing some documentation or code that reads
>> some "connector-type" and "bus-format" property?
>>
>> BR and thanks,
>> Nikolaus
>