[PATCH V4 2/2] video: drm: exynos: Add device tree support

Inki Dae inki.dae at samsung.com
Fri Sep 7 03:09:44 EDT 2012

2012/9/7 Inki Dae <inki.dae at samsung.com>:
> Hi
> 2012/9/7 Leela Krishna Amudala <l.krishna at samsung.com>:
>> Hi,
>> On Thu, Sep 6, 2012 at 4:35 PM, Sylwester Nawrocki
>> <s.nawrocki at samsung.com> wrote:
>>> Hi,
>>> On 09/06/2012 09:21 AM, InKi Dae wrote:
>>>>>> +Required properties:
>>>>>> + - compatible: Should be "samsung,exynos5-fimd" or "samsung,exynos4-fb" for
>>>>> Doesn't better to use single word? fimd or fb?. I think 'fb' is used
>>>>> for framebuffer historically.
>>>>> but now it's used both fb and drm, so fimd is neutral and architecture
>>>>> specific.
>>>>> To do this, Modify arch-exynos first and update it at each drivers it properly.
>>>>> Thank you,
>>>>> Kyungmin Park
>>>> I agree with Kyungmin but I'd like to use as is. the reason we used
>>>> 'exynos4-fb' as device name, is for that it uses fimd driver's
>>>> platform device commonly and gets fimd clock. so I think that dts file
>>>> should be defined with hardware specific name but not driver name such
>>>> as 'exynos4-fb'. but with this, we can't get fimd clock with device's
>>>> name because 'exynos4-fb' is used as device name of fimd clock. so to
>>>> use 'exynos4-fimd', we should modify the device name of fimd clock
>>>> from 'exynos4-fb'  to 'exynos4-fimd' and also ids definitions of
>>>> s3c-fb and drm fimd driver. so my conclusion is that it merges this
>>> I think it's good moment to put those things in order, i.e. use uniform
>>> 'compatible' names: "samsung,exynos4-fimd", "samsung,exynos5-fimd".
>>> Platform device names are separate issue, but could perhaps be unified
>>> at this time as well.
>> Yes, Platform device name is independent of compatible string.
>> Will change the compatible string to "samsung,exynos4-fimd" and will keep the
>> device name as exynos4-fb for now. Will change the platform device
>> names to exynosX-fimd
>> later.
> I'm not sure that clk_get is worked well with this change. I think,
> when driver called clk_get(), first of all, it tries to get a clk from
> the registered list of clock providers in the dts file and next in
> legacy way. but now legacy way(needing clock name and device' name)
> would be failed if the dts file has no the list because platform
> device's name differs from device name of clock. so I think we should
> change device name of clock and also ids of related drivers for
> compatibility with non-dt. for this, we need some patch sets, changing
> arch/arm/mach-exynos/common.c and changing
> arch/arm/mach-exynos/clock-exynos4/5.c and changing s3c-fb.c and last
> this patch. if there are no other opinions, I'd like to merge this
> patch set(v5) and next we can update others(maybe common.c,
> clock-exynos4/5.c and s3c-fb.c) later.

there is my missing point. with dt, platform device's name is set by
OF_DEV_AUXDATA's name so it doesn't need to modify things related to
exynos4 anymore. we just need to update things related to exynos5.

Inki Dae

> Thanks.
> Inki Dae
>>>> patch set as is and then let's modify related things later.
>>>> any opinions, welcome~ anytime.
>>>> Thanks.
>>>> Inki Dae
>>> --
>>> Regards,
>>> Sylwester
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