drm/panel: Add support for ARM Versatile panels

The ARM reference designs "Versatile AB" and "Versatile PB"
contain panel connectors with autodetection of the connected
panel type. This adds a small driver utilizing the MFD syscon
look-up to read the autodetection register and set up the
corresponding panel appropriately.

In the source file there is a bit of elaboration of the
panel types and interfaces on these boards.

This was tested with the PL111 DRM driver on the ARM Versatile
AB with the IB2 daughterboard.

Reviewed-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20180205192013.5349-2-linus.walleij@linaro.org
diff --git a/drivers/gpu/drm/panel/Makefile b/drivers/gpu/drm/panel/Makefile
index 6d251eb..3d2a88d 100644
--- a/drivers/gpu/drm/panel/Makefile
+++ b/drivers/gpu/drm/panel/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
+obj-$(CONFIG_DRM_PANEL_ARM_VERSATILE) += panel-arm-versatile.o
 obj-$(CONFIG_DRM_PANEL_LVDS) += panel-lvds.o
 obj-$(CONFIG_DRM_PANEL_SIMPLE) += panel-simple.o
 obj-$(CONFIG_DRM_PANEL_ILITEK_IL9322) += panel-ilitek-ili9322.o