drm/mediatek: Add mt8195 DisplayPort driver

This patch adds a DisplayPort driver for the Mediatek mt8195 SoC and a
according phy driver mediatek-dp-phy.

It supports both functional units on the mt8195, the embedded
DisplayPort as well as the external DisplayPort units. It offers
hot-plug-detection, audio up to 8 channels, and DisplayPort 1.4 with up
to 4 lanes.

The driver creates a child device for the phy. The child device will
never exist without the parent being active. As they are sharing a
register range, the parent passes a regmap pointer to the child so that
both can work with the same register range. The phy driver sets device
data that is read by the parent to get the phy device that can be used
to control the phy properties.

This driver is based on an initial version by
Jason-JH.Lin <jason-jh.lin@mediatek.com>.

Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>

drivers/gpu/drm/mediatek/Kconfig

@@ -28,3 +28,10 @@ config DRM_MEDIATEK_HDMI
 	select PHY_MTK_HDMI
 	help
 	  DRM/KMS HDMI driver for Mediatek SoCs
+
+config MTK_DPTX_SUPPORT
+	tristate "DRM DPTX Support for Mediatek SoCs"
+	depends on DRM_MEDIATEK
+	select PHY_MTK_DP
+	help
+	  DRM/KMS Display Port driver for Mediatek SoCs.

drivers/gpu/drm/mediatek/Makefile

@@ -21,3 +21,5 @@ mediatek-drm-hdmi-objs := mtk_cec.o \
 			  mtk_hdmi_ddc.o
 
 obj-$(CONFIG_DRM_MEDIATEK_HDMI) += mediatek-drm-hdmi.o
+
+obj-$(CONFIG_MTK_DPTX_SUPPORT) += mtk_dp.o