staging: drm/imx: Add LDB support

This adds support for the LVDS Display Bridge contained
in i.MX5 and i.MX6 SoCs.

Bit mapping, data width, and video timings are configurable
via device tree. Dual-channel mode is supported for a single
high-resolution source.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 99 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/staging/imx-drm/ldb.txt b/Documentation/devicetree/bindings/staging/imx-drm/ldb.txt
new file mode 100644
index 000000000000..ed9377811ee2
--- /dev/null
+++ b/Documentation/devicetree/bindings/staging/imx-drm/ldb.txt
@@ -0,0 +1,99 @@
+Device-Tree bindings for LVDS Display Bridge (ldb)
+
+LVDS Display Bridge
+===================
+
+The LVDS Display Bridge device tree node contains up to two lvds-channel
+nodes describing each of the two LVDS encoder channels of the bridge.
+
+Required properties:
+ - #address-cells : should be <1>
+ - #size-cells : should be <0>
+ - compatible : should be "fsl,imx53-ldb" or "fsl,imx6q-ldb".
+                Both LDB versions are similar, but i.MX6 has an additional
+                multiplexer in the front to select any of the four IPU display
+                interfaces as input for each LVDS channel.
+ - gpr : should be <&gpr> on i.MX53 and i.MX6q.
+         The phandle points to the iomuxc-gpr region containing the LVDS
+         control register.
+- clocks, clock-names : phandles to the LDB divider and selector clocks and to
+                        the display interface selector clocks, as described in
+                        Documentation/devicetree/bindings/clock/clock-bindings.txt
+        The following clocks are expected on i.MX53:
+                "di0_pll" - LDB LVDS channel 0 mux
+                "di1_pll" - LDB LVDS channel 1 mux
+                "di0" - LDB LVDS channel 0 gate
+                "di1" - LDB LVDS channel 1 gate
+                "di0_sel" - IPU1 DI0 mux
+                "di1_sel" - IPU1 DI1 mux
+        On i.MX6q the following additional clocks are needed:
+                "di2_sel" - IPU2 DI0 mux
+                "di3_sel" - IPU2 DI1 mux
+        The needed clock numbers for each are documented in
+        Documentation/devicetree/bindings/clock/imx5-clock.txt, and in
+        Documentation/devicetree/bindings/clock/imx6q-clock.txt.
+
+Optional properties:
+ - pinctrl-names : should be "default" on i.MX53, not used on i.MX6q
+ - pinctrl-0 : a phandle pointing to LVDS pin settings on i.MX53,
+               not used on i.MX6q
+ - fsl,dual-channel : boolean. if it exists, only LVDS channel 0 should
+   be configured - one input will be distributed on both outputs in dual
+   channel mode
+
+LVDS Channel
+============
+
+Each LVDS Channel has to contain a display-timings node that describes the
+video timings for the connected LVDS display. For detailed information, also
+have a look at Documentation/devicetree/bindings/video/display-timing.txt.
+
+Required properties:
+ - reg : should be <0> or <1>
+ - crtcs : a list of phandles with index pointing to the IPU display interfaces
+           that can be used as video source for this channel.
+ - fsl,data-mapping : should be "spwg" or "jeida"
+                      This describes how the color bits are laid out in the
+                      serialized LVDS signal.
+ - fsl,data-width : should be <18> or <24>
+
+example:
+
+gpr: iomuxc-gpr@53fa8000 {
+	/* ... */
+};
+
+ldb: ldb@53fa8008 {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	compatible = "fsl,imx53-ldb";
+	gpr = <&gpr>;
+	clocks = <&clks 122>, <&clks 120>,
+		 <&clks 115>, <&clks 116>,
+		 <&clks 123>, <&clks 85>;
+	clock-names = "di0_pll", "di1_pll",
+		      "di0_sel", "di1_sel",
+		      "di0", "di1";
+
+	lvds-channel@0 {
+		reg = <0>;
+		crtcs = <&ipu 0>;
+		fsl,data-mapping = "spwg";
+		fsl,data-width = <24>;
+
+		display-timings {
+			/* ... */
+		};
+	};
+
+	lvds-channel@1 {
+		reg = <1>;
+		crtcs = <&ipu 1>;
+		fsl,data-mapping = "spwg";
+		fsl,data-width = <24>;
+
+		display-timings {
+			/* ... */
+		};
+	};
+};