Re: [PATCH v3 2/2] ARM: EXYNOS: Add Gscaler device from DT

[Sylwester Nawrocki <s.nawrocki@samsung.com>]

On 08/01/2012 09:48 AM, Thomas Abraham wrote:
> On 1 August 2012 12:10, Kukjin Kim <kgene.kim@samsung.com> wrote:
>> Shaik Ameer Basha wrote:
> 
> [...]
> 
>>> +* Samsung Exynos5 Gscaler device
>>> +
>>> +Gscaler is used for scaling and color space conversion on EXYNOS5 SoCs.
>>> +
>>> +Required properties:
>>> +- compatible: should be "samsung,exynos5250-gsc"
>>
>> IMO, should be "samsung,exynos5-gsc" because upcoming EXYNOS5 SoCs can use
>> same gscaler driver.

In addition to the below explanation, perhaps it's obvious, but the driver
can claim compatibility with multiple devices, i.e. match with multiple
'compatible' properties.

Regards,
Sylwester

> The compatible string should always be specific and it should clearly
> identify the type of the controller. If there are other variants of
> the GSC controller in previous of upcoming SoC's, then those
> controllers will have a different compatible value.
> 
> This allows device drivers to know the type of the controller and
> handle the differences among them. And, the node in the dts/dtsi file
> should always claim compatibility to the base version of the
> controller that the platform supports.
> 
> So the compatible value "samsung,exynos5250-gsc" is right one. If a
> new SoC in the Exynos5 family has the same GSC controller as that in
> Exynos5250 (no difference at all), then GSC device node in its dts
> file can continue to claim compatibility to Exynos5250 type. The
> "samsung,s3c2410-wdt is an example of this case which has been used on
> all Samsung SoC's .
> 
> Thanks,
> Thomas.