dt-bindings: Add MSM DSI controller documentation

Signed-off-by: Hai Li <hali@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

Documentation/devicetree/bindings/drm/msm/dsi.txt

+Qualcomm Technologies Inc. adreno/snapdragon DSI output
+
+Required properties:
+- compatible:
+  * "qcom,mdss-dsi-ctrl"
+- reg: Physical base address and length of the registers of controller, PLL,
+  PHY and PHY regulator
+- reg-names: The names of register regions. The following regions are required:
+  * "dsi_ctrl"
+  * "dsi_pll"
+  * "dsi_phy"
+  * "dsi_phy_regulator"
+- qcom,dsi-host-index: The ID of DSI controller hardware instance. This should
+  be 0 or 1, since we have 2 DSI controllers at most for now.
+- interrupts: The interrupt signal from the DSI block.
+- power-domains: Should be <&mmcc MDSS_GDSC>.
+- clocks: device clocks
+  See Documentation/devicetree/bindings/clocks/clock-bindings.txt for details.
+- clock-names: the following clocks are required:
+  * "bus_clk"
+  * "byte_clk"
+  * "core_clk"
+  * "core_mmss_clk"
+  * "iface_clk"
+  * "mdp_core_clk"
+  * "pixel_clk"
+- #clock-cells: The value should be 1.
+- vdd-supply: phandle to vdd regulator device node
+- vddio-supply: phandle to vdd-io regulator device node
+- vdda-supply: phandle to vdda regulator device node
+
+Optional properties:
+- panel@0: Node of panel connected to this DSI controller.
+  See files in Documentation/devicetree/bindings/panel/ for each supported
+  panel.
+- qcom,dual-panel-mode: Boolean value indicating if the DSI controller is
+  driving a panel which needs 2 DSI links.
+- qcom,master-panel: Boolean value indicating if the DSI controller is driving
+  the master link of the 2-DSI panel.
+- qcom,sync-dual-panel: Boolean value indicating if the DSI controller is
+  driving a 2-DSI panel whose 2 links need receive command simultaneously.
+- interrupt-parent: phandle to the MDP block if the interrupt signal is routed
+  through MDP block
+
+Example:
+	mdss_dsi0: qcom,mdss_dsi@fd922800 {
+		compatible = "qcom,mdss-dsi-ctrl";
+		qcom,dsi-host-index = <0>;
+		interrupt-parent = <&mdss_mdp>;
+		interrupts = <4 0>;
+		reg-names =
+			"dsi_ctrl",
+			"dsi_pll",
+			"dsi_phy",
+			"dsi_phy_regulator",
+		reg =	<0xfd922800 0x200>,
+			<0xfd922a00 0xd4>,
+			<0xfd922b00 0x2b0>,
+			<0xfd922d80 0x7b>,
+			<0xfd828000 0x108>;
+		power-domains = <&mmcc MDSS_GDSC>;
+		clock-names =
+			"bus_clk",
+			"byte_clk",
+			"core_clk",
+			"core_mmss_clk",
+			"iface_clk",
+			"mdp_core_clk",
+			"pixel_clk";
+		clocks =
+			<&mmcc MDSS_AXI_CLK>,
+			<&mmcc MDSS_BYTE0_CLK>,
+			<&mmcc MDSS_ESC0_CLK>,
+			<&mmcc MMSS_MISC_AHB_CLK>,
+			<&mmcc MDSS_AHB_CLK>,
+			<&mmcc MDSS_MDP_CLK>,
+			<&mmcc MDSS_PCLK0_CLK>;
+		#clock-cells = <1>;
+		vdda-supply = <&pma8084_l2>;
+		vdd-supply = <&pma8084_l22>;
+		vddio-supply = <&pma8084_l12>;
+
+		qcom,dual-panel-mode;
+		qcom,master-panel;
+		qcom,sync-dual-panel;
+
+		panel: panel@0 {
+			compatible = "sharp,lq101r1sx01";
+			reg = <0>;
+			link2 = <&secondary>;
+
+			power-supply = <...>;
+			backlight = <...>;
+		};
+	};