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

[Sylwester Nawrocki <sylvester.nawrocki@gmail.com>]

On 08/02/2012 06:33 PM, Olof Johansson wrote:
> On Wed, Aug 1, 2012 at 12:03 PM, Sylwester Nawrocki
> <sylvester.nawrocki@gmail.com>  wrote:
> 
>> It wouldn't be clear what specific SoCs the "samsung,exynos5-gsc" compatible
>> string applies to, would it ? I believe there are already minor differences
>> in GScaler parameters on currently available exynos5 SoC. The variant data
>> structures are used to handle this and the compatible string determines which
>> variant data structure is selected during driver's initialization.
>> If you use a wildcard 'compatible' string this won't be possible any more.
>>
>> Also it would look odd IMO to have two compatible strings like:
>> compatible = "samsung,exynos5-gsc", "samsung,exynos5400-gsc";
> 
> In this particular case, since you're saying that there are subtle
> differences between different part numbers, I'm guessing there's good
> reason to go specific, but in general there's no need to avoid
> exynos5-gsc.
> 
> Your example is also false, since the strings would be in reverse
> order (from specific to generic). That would look perfectly normal.

You're right, but my intention was more to say that there would have been 
two entries in the driver's of_match_table, where "samsung,exynos5-gsc"
wouldn't have obvious meaning. Devices within these SoCs tend to differ 
across part numbers and usually there is one common driver handling them.

I can't tell for sure now there are differences, but I would have been
surprised if there wouldn't.

> So, bottom line: I agree in this particular instance, but I disagree
> that it's a hard generic rule.

Thanks, sorry if it sounded like I'm advocating it as a general rule. 
I'm no DT expert whatsoever, but in this particular case it just sounded 
messy to use only exynos5-gsc.

--
Regards,
Sylwester