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

MAINTAINERS

@@ -4442,6 +4442,13 @@ T:	git git://anongit.freedesktop.org/drm/drm-misc
 S:	Supported
 F:	drivers/gpu/drm/pl111/
 
+DRM DRIVER FOR ARM VERSATILE TFT PANELS
+M:	Linus Walleij <linus.walleij@linaro.org>
+T:	git git://anongit.freedesktop.org/drm/drm-misc
+S:	Maintained
+F:	drivers/gpu/drm/panel/panel-arm-versatile.c
+F:	Documentation/devicetree/bindings/display/panel/arm,versatile-tft-panel.txt
+
 DRM DRIVER FOR AST SERVER GRAPHICS CHIPS
 M:	Dave Airlie <airlied@redhat.com>
 S:	Odd Fixes

drivers/gpu/drm/panel/Kconfig

@@ -7,6 +7,16 @@ config DRM_PANEL
 menu "Display Panels"
 	depends on DRM && DRM_PANEL
 
+config DRM_PANEL_ARM_VERSATILE
+	tristate "ARM Versatile panel driver"
+	depends on OF
+	depends on MFD_SYSCON
+	select VIDEOMODE_HELPERS
+	help
+	  This driver supports the ARM Versatile panels connected to ARM
+	  reference designs. The panel is detected using special registers
+	  in the Versatile family syscon registers.
+
 config DRM_PANEL_LVDS
 	tristate "Generic LVDS panel driver"
 	depends on OF

drivers/gpu/drm/panel/Makefile

 # 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