Re: [PATCH 1/4] omapdrm: fix compatible string for td028ttec1

[H. Nikolaus Schaller]

Hi Laurent,

> Am 09.11.2017 um 07:35 schrieb Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>:
> 
> Hi Nikolaus,
> 
> On Thursday, 9 November 2017 08:05:15 EET H. Nikolaus Schaller wrote:
>>> Am 09.11.2017 um 04:33 schrieb Laurent Pinchart:
>>> On Wednesday, 8 November 2017 23:09:29 EET H. Nikolaus Schaller wrote:
>>>> The vendor name was "toppoly" but other panels and the vendor list
>>>> have defined it as "tpo". So let's fix it in driver and bindings.
>>>> 
>>>> Signed-off-by: H. Nikolaus Schaller <hns@xxxxxxxxxxxxx>
>>>> ---
>>>> .../display/panel/{toppoly,td028ttec1.txt => tpo,td028ttec1.txt} | 4 ++--
>>>> drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c           | 4
>>>> ++--
>>>> drivers/video/fbdev/omap2/omapfb/displays/panel-tpo-td028ttec1.c  | 4
>>>> ++--
>>>> 3 files changed, 6 insertions(+), 6 deletions(-)
>>>> rename
>>>> Documentation/devicetree/bindings/display/panel/{toppoly,td028ttec1.txt
>>>> =>
>>>> tpo,td028ttec1.txt} (84%)
>>>> 
>>>> diff --git
>>>> a/Documentation/devicetree/bindings/display/panel/toppoly,td028ttec1.txt
>>>> b/Documentation/devicetree/bindings/display/panel/tpo,td028ttec1.txt
>>>> similarity index 84%
>>>> rename from
>>>> Documentation/devicetree/bindings/display/panel/toppoly,td028ttec1.txt
>>>> rename to
>>>> Documentation/devicetree/bindings/display/panel/tpo,td028ttec1.txt index
>>>> 7175dc3740ac..ed34253d9fb1 100644
>>>> ---
>>>> a/Documentation/devicetree/bindings/display/panel/toppoly,td028ttec1.txt
>>>> +++ b/Documentation/devicetree/bindings/display/panel/tpo,td028ttec1.txt
>>>> @@ -2,7 +2,7 @@ Toppoly TD028TTEC1 Panel
>>>> ========================
>>>> 
>>>> Required properties:
>>>> -- compatible: "toppoly,td028ttec1"
>>>> +- compatible: "tpo,td028ttec1"
>>>> 
>>>> Optional properties:
>>>> - label: a symbolic name for the panel
>>>> @@ -14,7 +14,7 @@ Example
>>>> -------
>>>> 
>>>> lcd-panel: td028ttec1@0 {
>>>> -	compatible = "toppoly,td028ttec1";
>>>> +	compatible = "tpo,td028ttec1";
>>>> 
>>>> 	reg = <0>;
>>>> 	spi-max-frequency = <100000>;
>>>> 	spi-cpol;
>>>> 
>>>> diff --git a/drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c
>>>> b/drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c index
>>>> 0a38a0e8c925..2dab491478c2 100644
>>>> --- a/drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c
>>>> +++ b/drivers/gpu/drm/omapdrm/displays/panel-tpo-td028ttec1.c
>>>> @@ -452,7 +452,7 @@ static int td028ttec1_panel_remove(struct spi_device
>>>> *spi)
>>>> }
>>>> 
>>>> static const struct of_device_id td028ttec1_of_match[] = {
>>>> -	{ .compatible = "omapdss,toppoly,td028ttec1", },
>>>> +	{ .compatible = "omapdss,tpo,td028ttec1", },
>>> 
>>> Doesn't this break backward compatibility with existing DT ?
>> 
>> Yes, it does. But I am only aware of the GTA04 which uses it and
>> there is a separate fix).
> 
> DT is supposed to be an ABI. In theory at least, one could boot a GTA04 with 
> an existing DT and a new kernel, and no regression should be noticed.

Yes, indeed...

> There 
> could also be other devices using this panel that you are not aware of.
> 
> For how to apply the theory to real life, I'll defer to Tomi :-)

Yes, Tomi should decide if we should keep the old compatible string in
the driver (in second place so to avoid a speed penalty)...

BR and thanks,
Nikolaus Schaller