[PATCH] drm/exynos: Get HDMI version from device tree

[Sean Paul]

On Tue, Jan 8, 2013 at 11:38 AM, Stephen Warren <swarren at wwwdotorg.org> wrote:
> On 01/07/2013 04:12 PM, Sean Paul wrote:
>>
>> On Jan 7, 2013 5:32 PM, "Stephen Warren" <swarren at wwwdotorg.org
>> <mailto:swarren at wwwdotorg.org>> wrote:
>>>
>>> On 01/07/2013 01:43 PM, Sean Paul wrote:
>>> > Add a property to the hdmi node so we can specify the HDMI version in
>>> > the device tree instead of just defaulting to v1.4 with the existence of
>>> > the dt node.
>>>
>>> > diff --git a/Documentation/devicetree/bindings/drm/exynos/hdmi.txt
>> b/Documentation/devicetree/bindings/drm/exynos/hdmi.txt
>>>
>>> > @@ -11,6 +11,8 @@ Required properties:
>>> >       c) pin function mode.
>>> >       d) optional flags and pull up/down.
>>> >       e) drive strength.
>>> > +- samsung,supports-hdmi-1.4: Define if device supports HDMI v1.4
>>> > +- samsung,supports-hdmi-1.3: Define if device supports HDMI v1.3
>>>
>>> Which device; the HDMI controller in the SoC, or the HDMI sink?
>>>
>>
>> It's the controller.
>
> Ah OK. Is it different versions of the controller HW IP block that
> support the different HDMI versions, or is it some kind of
> fusing/configuration with the same HW block?

I think the answer is yes :). I'm not 100% sure, maybe the Samsung
guys can chime in, but this is what I've inferred. Exynos5 is purely
v1.4, Exynos4 can be v1.3 or v1.4. However an IP block that is
compatible with 1.4 is *not* compatible with 1.3.

So I think encoding the version as an integer makes sense since it
prevents us from defining both (which is incorrect but harmless in the
current version), and is future-safe.

Sound good?

Sean

> If different versions of
> HW, wouldn't this difference usually be represented by different
> compatible values, that indicate the exact HW version? I guess if the
> only difference really is just the HDMI support and there are no other
> bugs/quirks/enhancements, a separate property might make sense.