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

Inki Dae inki.dae at samsung.com
Fri Sep 7 02:07:06 EDT 2012


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.

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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