drm/exynos: Add atomic modesetting support

[Gustavo Padovan]

Hi Tobias,

2015-05-19 Tobias Jakobi <tjakobi at math.uni-bielefeld.de>:

> OK,
> 
> so Daniel helped me track down this issue. It came from an incorrect
> 'clock-frequency' entry in my DTS. The freq was 500000. Daniel recommended
> 70600000 which works 'fine' (and according to modetest produces a 59Hz
> mode). I say 'fine' because I can't confirm that FIMD is actually working. I
> just see that with that change I no longer get any div-by-zeros in the
> kernel.

That is good to hear! So maybe we are now ready to have the atomic
modesetting patches merged in. I'll send a new version with the last
fix to avoid crashes with null CRTC.

> 
> So fimd_calc_clkdiv needs some sanitizing for 'ideal_clk' at least.
> 
> What still bothers me though is the fact that FIMD actually gets enabled.
> I'm just calling 'modetest -M exynos', so it's just doing probing. Why does
> that trigger dpms?

That comes from restore_fbdev_mode() when modetest closes the file
descriptor, but I'm not sure why a update happens at this time.

	Gustavo