dt-bindings: msm/dsi: Add assigned clocks bindings

The PLL in the DSI PHY block generates 2 clock outputs (Byte and Pixel
clocks) that are fed into the Multimedia Clock Controller (MMCC). The MMCC
uses these as source clocks for some of its RCGs to generate clocks that
finally feed to the DSI host controller.

Use the assigned clocks DT bindings to set up the MMCC RCGs that feed to
the DSI host. Use the DSI PHY provided clocks to set up the parents
of these assigned clocks.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@gmail.com>

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

@@ -12,7 +12,6 @@ Required properties:
 - 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:
   * "mdp_core_clk"
   * "iface_clk"
@@ -23,6 +22,10 @@ Required properties:
   * "core_clk"
   For DSIv2, we need an additional clock:
    * "src_clk"
+- assigned-clocks: Parents of "byte_clk" and "pixel_clk" for the given platform.
+- assigned-clock-parents: The Byte clock and Pixel clock PLL outputs provided
+  by a DSI PHY block.
+  See Documentation/devicetree/bindings/clocks/clock-bindings.txt for details.
 - 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
@@ -96,6 +99,8 @@ Required properties:
   * "dsi_pll"
   * "dsi_phy"
   * "dsi_phy_regulator"
+- clock-cells: Must be 1. The DSI PHY block acts as a clock provider, creating
+  2 clocks: A byte clock (index 0), and a pixel clock (index 1).
 - qcom,dsi-phy-index: The ID of DSI PHY hardware instance. This should
   be 0 or 1, since we have 2 DSI PHYs at most for now.
 - power-domains: Should be <&mmcc MDSS_GDSC>.
@@ -134,6 +139,14 @@ Example:
 			<&mmcc MDSS_AHB_CLK>,
 			<&mmcc MDSS_MDP_CLK>,
 			<&mmcc MDSS_PCLK0_CLK>;
+
+		assigned-clocks =
+				 <&mmcc BYTE0_CLK_SRC>,
+				 <&mmcc PCLK0_CLK_SRC>;
+		assigned-clock-parents =
+				 <&mdss_dsi_phy0 0>,
+				 <&mdss_dsi_phy0 1>;
+
 		vdda-supply = <&pma8084_l2>;
 		vdd-supply = <&pma8084_l22>;
 		vddio-supply = <&pma8084_l12>;
@@ -197,6 +210,7 @@ Example:
 			<0xfd922d80 0x7b>;
 		clock-names = "iface_clk";
 		clocks = <&mmcc MDSS_AHB_CLK>;
+		#clock-cells = <1>;
 		vddio-supply = <&pma8084_l12>;
 
 		qcom,dsi-phy-regulator-ldo-mode;