drm/exynos: Enable DP clock to fix display on Exynos5250 and other

After adding display power domain for Exynos5250 in commit
2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250") the
display on Chromebook Snow and others stopped working after boot.

The reason for this suggested Andrzej Hajda: the DP clock was disabled.
This clock is required by Display Port and is enabled by bootloader.
However when FIMD driver probing was deferred, the display power domain
was turned off. This effectively reset the value of DP clock enable
register.

When exynos-dp is later probed, the clock is not enabled and display is
not properly configured:

exynos-dp 145b0000.dp-controller: Timeout of video streamclk ok
exynos-dp 145b0000.dp-controller: unable to config video

Fixes: 2d2c9a8d0a4f ("ARM: dts: add display power domain for exynos5250")
Cc: <stable@vger.kernel.org>

Signed-off-by: Krzysztof Kozlowski <k.kozlowski@samsung.com>
Reported-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Tested-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Inki Dae <inki.dae@samsung.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/video/samsung_fimd.h b/include/video/samsung_fimd.h
index 513242827b07..0530e5a4c6b1 100644
--- a/include/video/samsung_fimd.h
+++ b/include/video/samsung_fimd.h
@@ -441,6 +441,12 @@
 #define BLENDCON_NEW_8BIT_ALPHA_VALUE           (1 << 0)
 #define BLENDCON_NEW_4BIT_ALPHA_VALUE           (0 << 0)
 
+/* Display port clock control */
+#define DP_MIE_CLKCON                           0x27c
+#define DP_MIE_CLK_DISABLE                      0x0
+#define DP_MIE_CLK_DP_ENABLE                    0x2
+#define DP_MIE_CLK_MIE_ENABLE                   0x3
+
 /* Notes on per-window bpp settings
  *
  * Value        Win0     Win1     Win2     Win3     Win 4