drm/vc4: Add DPI driver

The DPI interface involves taking a ton of our GPIOs to be used as
outputs, and routing display signals over them in parallel.

v2: Use display_info.bus_formats[] to replace our custom DT
    properties.
v3: Rebase on V3D documentation changes.
v4: Fix rebase detritus from V3D documentation changes.

Signed-off-by: Eric Anholt <eric@anholt.net>
Acked-by: Rob Herring <robh@kernel.org>

Documentation/devicetree/bindings/display/brcm,bcm-vc4.txt

@@ -35,12 +35,22 @@ Optional properties for HDMI:
 		  as an interrupt/status bit in the HDMI controller
 		  itself).  See bindings/pinctrl/brcm,bcm2835-gpio.txt
 
+Required properties for DPI:
+- compatible:	Should be "brcm,bcm2835-dpi"
+- reg:		Physical base address and length of the registers
+- clocks:	a) core: The core clock the unit runs on
+		b) pixel: The pixel clock that feeds the pixelvalve
+- port:		Port node with a single endpoint connecting to the panel
+		  device, as defined in [1]
+
 Required properties for V3D:
 - compatible:	Should be "brcm,bcm2835-v3d"
 - reg:		Physical base address and length of the V3D's registers
 - interrupts:	The interrupt number
 		  See bindings/interrupt-controller/brcm,bcm2835-armctrl-ic.txt
 
+[1] Documentation/devicetree/bindings/media/video-interfaces.txt
+
 Example:
 pixelvalve@7e807000 {
 	compatible = "brcm,bcm2835-pixelvalve2";
@@ -66,6 +76,22 @@ hdmi: hdmi@7e902000 {
 	clock-names = "pixel", "hdmi";
 };
 
+dpi: dpi@7e208000 {
+	compatible = "brcm,bcm2835-dpi";
+	reg = <0x7e208000 0x8c>;
+	clocks = <&clocks BCM2835_CLOCK_VPU>,
+	         <&clocks BCM2835_CLOCK_DPI>;
+	clock-names = "core", "pixel";
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	port {
+		dpi_out: endpoint@0 {
+			remote-endpoint = <&panel_in>;
+		};
+	};
+};
+
 v3d: v3d@7ec00000 {
 	compatible = "brcm,bcm2835-v3d";
 	reg = <0x7ec00000 0x1000>;
@@ -75,3 +101,13 @@ v3d: v3d@7ec00000 {
 vc4: gpu {
 	compatible = "brcm,bcm2835-vc4";
 };
+
+panel: panel {
+	compatible = "ontat,yx700wv03", "simple-panel";
+
+	port {
+		panel_in: endpoint {
+			remote-endpoint = <&dpi_out>;
+		};
+	};
+};

drivers/gpu/drm/vc4/Kconfig

@@ -5,6 +5,7 @@ config DRM_VC4
 	select DRM_KMS_HELPER
 	select DRM_KMS_CMA_HELPER
 	select DRM_GEM_CMA_HELPER
+	select DRM_PANEL
 	help
 	  Choose this option if you have a system that has a Broadcom
 	  VC4 GPU, such as the Raspberry Pi or other BCM2708/BCM2835.

drivers/gpu/drm/vc4/Makefile

@@ -7,6 +7,7 @@ vc4-y := \
 	vc4_bo.o \
 	vc4_crtc.o \
 	vc4_drv.o \
+	vc4_dpi.o \
 	vc4_kms.o \
 	vc4_gem.o \
 	vc4_hdmi.o \

drivers/gpu/drm/vc4/vc4_debugfs.c

@@ -17,6 +17,7 @@
 
 static const struct drm_info_list vc4_debugfs_list[] = {
 	{"bo_stats", vc4_bo_stats_debugfs, 0},
+	{"dpi_regs", vc4_dpi_debugfs_regs, 0},
 	{"hdmi_regs", vc4_hdmi_debugfs_regs, 0},
 	{"hvs_regs", vc4_hvs_debugfs_regs, 0},
 	{"crtc0_regs", vc4_crtc_debugfs_regs, 0, (void *)(uintptr_t)0},