drm/meson: add support for MIPI-DSI transceiver

The Amlogic AXg SoCs embeds a Synopsys DW-MIPI-DSI transceiver (ver 1.21a), with a custom
glue managing the IP resets, clock and data input similar to the DW-HDMI Glue on other
Amlogic SoCs.

This adds support for the Glue managing the transceiver, mimicing the init flow provided
by Amlogic to setup the ENCl encoder, the glue, the transceiver, the digital D-PHY and the
Analog PHY in the proper way.

The DW-MIPI-DSI transceiver + D-PHY are directly clocked by the VCLK2 clock, which pixel clock
is derived and feeds the ENCL encoder and the VIU pixel reader.

An optional "MEAS" clock can be enabled to measure the delay between each vsync feeding the
DW-MIPI-DSI transceiver.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>

drivers/gpu/drm/meson/Kconfig

@@ -16,3 +16,10 @@ config DRM_MESON_DW_HDMI
 	default y if DRM_MESON
 	select DRM_DW_HDMI
 	imply DRM_DW_HDMI_I2S_AUDIO
+
+config DRM_MESON_DW_MIPI_DSI
+	tristate "MIPI DSI Synopsys Controller support for Amlogic Meson Display"
+	depends on DRM_MESON
+	default y if DRM_MESON
+	select DRM_DW_MIPI_DSI
+	select GENERIC_PHY_MIPI_DPHY

drivers/gpu/drm/meson/Makefile

@@ -5,3 +5,4 @@ meson-drm-y += meson_rdma.o meson_osd_afbcd.o
 
 obj-$(CONFIG_DRM_MESON) += meson-drm.o
 obj-$(CONFIG_DRM_MESON_DW_HDMI) += meson_dw_hdmi.o
+obj-$(CONFIG_DRM_MESON_DW_MIPI_DSI) += meson_dw_mipi_dsi.o