[PATCH 1/4] ARM: dts: add support for hdmi to exynos4

[Rahul Sharma]

On Fri, Feb 1, 2013 at 3:55 AM, Kukjin Kim <kgene.kim at samsung.com> wrote:
> Rahul Sharma wrote:
>
> [...]
>
>> >>>> +       hdmi {
>> >>>> +               compatible = "samsung,exynos4-hdmi14";
>> >>>
>> >>>
>> >>>
>> >>> What "-hdmi14" signifies here ? And to which Exynos4 SoC revisions
> this
>> >>> compatible property is supposed to apply ?
>> >>>
>> >>
>> >> -hdmi14 signifies 1.4 compliant Hdmi IP like in Exynos4412, while
>> >> Exynos4210 has 1.3
>> >> compliant HDMI block. I have done a mistake here. I should have kept
>> >> it in 4412.dtsi. OR
>> >> I can move it to 4x12.dtsi but not sure whether all 4x12 socs have 1.4
>> >> hdmi.
>> >
>> >
>> > Exynos4210 also have the HDMI IP. I'm not sure how much common those
>> IP's
>> > are
>> > among Exynos4 series SoCs. I suppose it makes sense to create a hdmi
>> node in
>> > exynos4.dtsi and override what's required either in exynos4x12.dtsi or
>> > exynos4412.dtsi file.
>> >
>> > What is worring me is that you're trying to just append the supported
>> > HDMI standard version to the string, and there might be more differences
>> > in the IPs across all Exynos4 SoC series. What if there are two
> different
>> > SoCs that support e.g. HDMI v1.4 but there are some differences in the
>> > HDMI IPs ? You would likely need to invent new properties and pass them
>> > to the driver. Appending specific SoC name to the compatible string
> looks
>> > like a better alternative to me.
>> >
>>
>> I agree to it. Putting compatible string with first soc having the IP,
>> is a better
>> approach altogether. I will incorporate the change in next version.
>>
> Well, in this case, why should we use the SoC name? If just we need specific
> name here. I think, putting SoC name in compatible is a way to identify and
> when the version of IP is available, we can the version instead...like
> following, as some guy said before.
>
> compatible = "samsung,hdmi-1.4"
>
> If there is for hdmi 1.4a,
>
> compatible = "samsung,hdmi-1.4a"
>
> Thanks.
>
> - Kukjin
>

Hi Mr. Kim,

Putting hdmi version in compatible string is safe only if we are
sure that there will not be any changes in HDMI IPs for a given
hdmi version number in all upcoming exynos family SoCs. But
it seems unlikely to happen.

This point is getting discussed in details in the following thread.
https://patchwork.kernel.org/patch/1948061/

-- 
Regards,
Rahul Sharma,
email to: rahul.sharma at samsung.com
Samsung India.