From mboxrd@z Thu Jan  1 00:00:00 1970
From: laurent.pinchart@ideasonboard.com (Laurent Pinchart)
Date: Mon, 17 Oct 2016 14:40 +0300
Subject: [PATCH 2/2] ARM: dts: da850: add a node for the LCD controller
In-Reply-To: <7a2ffcd0-fe1d-c887-53b7-7cb5e1e61222@ti.com>
References: <1475672732-17111-1-git-send-email-bgolaszewski@baylibre.com>
 <65fde145-0820-794d-d345-621f66cdacc0@ti.com>
 <7a2ffcd0-fe1d-c887-53b7-7cb5e1e61222@ti.com>
Message-ID: <4975084.EGQPv58AK6@avalon>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hello,

On Monday 17 Oct 2016 10:33:58 Tomi Valkeinen wrote:
> On 17/10/16 10:12, Sekhar Nori wrote:
>> On Monday 17 October 2016 11:26 AM, Tomi Valkeinen wrote:
>>> On 15/10/16 20:42, Sekhar Nori wrote:
>>>>> diff --git a/arch/arm/boot/dts/da850.dtsi
>>>>> b/arch/arm/boot/dts/da850.dtsi
>>>>> index f79e1b9..32908ae 100644
>>>>> --- a/arch/arm/boot/dts/da850.dtsi
>>>>> +++ b/arch/arm/boot/dts/da850.dtsi
>>>>> @@ -399,6 +420,14 @@
>>>>>  				<&edma0 0 1>;
>>>>>  			dma-names = "tx", "rx";
>>>>>  		};
>>>>> +
>>>>> +		display: display at 213000 {
>>>>> +			compatible = "ti,am33xx-tilcdc", "ti,da850-tilcdc";
>>>> 
>>>> This should instead be:
>>>> 
>>>> compatible = "ti,da850-tilcdc", "ti,am33xx-tilcdc";
>>>> 
>>>> as the closest match should appear first in the list.
>>> 
>>> Actually I don't think that's correct. The LCDC on da850 is not
>>> compatible with the LCDC on AM335x. I think it should be just
>>> "ti,da850-tilcdc".
>> 
>> So if "ti,am33xx-tilcdc" is used, the display wont work at all? If thats
>> the case, I wonder how the patch passed testing. Bartosz?
> 
> AM3 has "version 2" of LCDC, whereas DA850 is v1. They are quite
> similar, but different.
> 
> The driver gets the version number from LCDC's register, and acts based
> on that, so afaik the compatible string doesn't really affect the
> functionality (as long as it matches).
> 
> But even if it works with the current driver, I don't think
> "ti,am33xx-tilcdc" and "ti,da850-tilcdc" are compatible in the HW level.

If the hardware provides IP revision information, how about just "ti,lcdc" ?

-- 
Regards,

Laurent Pinchart