dt-bindings: add register based devices' mux controller DT bindings

This adds device tree binding documentation for generic register based
multiplexer controlled by a bitfields in a parent device's register range.

since MMIO mux is a special case of generic register based mux, the
MMIO mux bindings have been subsumed in these bindings.
Signed-off-by: Pankaj Bansal <pankaj.bansal@nxp.com>
Signed-off-by: Peter Rosin <peda@axentia.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/mux/mmio-mux.txt

-MMIO register bitfield-based multiplexer controller bindings
-
-Define register bitfields to be used to control multiplexers. The parent
-device tree node must be a syscon node to provide register access.
-
-Required properties:
-- compatible : "mmio-mux"
-- #mux-control-cells : <1>
-- mux-reg-masks : an array of register offset and pre-shifted bitfield mask
-                  pairs, each describing a single mux control.
-* Standard mux-controller bindings as decribed in mux-controller.txt
-
-Optional properties:
-- idle-states : if present, the state the muxes will have when idle. The
-		special state MUX_IDLE_AS_IS is the default.
-
-The multiplexer state of each multiplexer is defined as the value of the
-bitfield described by the corresponding register offset and bitfield mask pair
-in the mux-reg-masks array, accessed through the parent syscon.
-
-Example:
-
-	syscon {
-		compatible = "syscon";
-
-		mux: mux-controller {
-			compatible = "mmio-mux";
-			#mux-control-cells = <1>;
-
-			mux-reg-masks = <0x3 0x30>, /* 0: reg 0x3, bits 5:4 */
-					<0x3 0x40>, /* 1: reg 0x3, bit 6 */
-			idle-states = <MUX_IDLE_AS_IS>, <0>;
-		};
-	};
-
-	video-mux {
-		compatible = "video-mux";
-		mux-controls = <&mux 0>;
-
-		ports {
-			/* inputs 0..3 */
-			port@0 {
-				reg = <0>;
-			};
-			port@1 {
-				reg = <1>;
-			};
-			port@2 {
-				reg = <2>;
-			};
-			port@3 {
-				reg = <3>;
-			};
-
-			/* output */
-			port@4 {
-				reg = <4>;
-			};
-		};
-	};

Documentation/devicetree/bindings/mux/reg-mux.txt

+Generic register bitfield-based multiplexer controller bindings
+
+Define register bitfields to be used to control multiplexers. The parent
+device tree node must be a device node to provide register r/w access.
+
+Required properties:
+- compatible : should be one of
+	"reg-mux" : if parent device of mux controller is not syscon device
+	"mmio-mux" : if parent device of mux controller is syscon device
+- #mux-control-cells : <1>
+- mux-reg-masks : an array of register offset and pre-shifted bitfield mask
+                  pairs, each describing a single mux control.
+* Standard mux-controller bindings as decribed in mux-controller.txt
+
+Optional properties:
+- idle-states : if present, the state the muxes will have when idle. The
+		special state MUX_IDLE_AS_IS is the default.
+
+The multiplexer state of each multiplexer is defined as the value of the
+bitfield described by the corresponding register offset and bitfield mask
+pair in the mux-reg-masks array.
+
+Example 1:
+The parent device of mux controller is not a syscon device.
+
+&i2c0 {
+	fpga@66 { // fpga connected to i2c
+		compatible = "fsl,lx2160aqds-fpga", "fsl,fpga-qixis-i2c",
+			     "simple-mfd";
+		reg = <0x66>;
+
+		mux: mux-controller {
+			compatible = "reg-mux";
+			#mux-control-cells = <1>;
+			mux-reg-masks = <0x54 0xf8>, /* 0: reg 0x54, bits 7:3 */
+					<0x54 0x07>; /* 1: reg 0x54, bits 2:0 */
+		};
+	};
+};
+
+mdio-mux-1 {
+	compatible = "mdio-mux-multiplexer";
+	mux-controls = <&mux 0>;
+	mdio-parent-bus = <&emdio1>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	mdio@0 {
+		reg = <0x0>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
+
+	mdio@8 {
+		reg = <0x8>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
+
+	..
+	..
+};
+
+mdio-mux-2 {
+	compatible = "mdio-mux-multiplexer";
+	mux-controls = <&mux 1>;
+	mdio-parent-bus = <&emdio2>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	mdio@0 {
+		reg = <0x0>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
+
+	mdio@1 {
+		reg = <0x1>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+	};
+
+	..
+	..
+};
+
+Example 2:
+The parent device of mux controller is syscon device.
+
+syscon {
+	compatible = "syscon";
+
+	mux: mux-controller {
+		compatible = "mmio-mux";
+		#mux-control-cells = <1>;
+
+		mux-reg-masks = <0x3 0x30>, /* 0: reg 0x3, bits 5:4 */
+				<0x3 0x40>, /* 1: reg 0x3, bit 6 */
+		idle-states = <MUX_IDLE_AS_IS>, <0>;
+	};
+};
+
+video-mux {
+	compatible = "video-mux";
+	mux-controls = <&mux 0>;
+	#address-cells = <1>;
+	#size-cells = <0>;
+
+	ports {
+		/* inputs 0..3 */
+		port@0 {
+			reg = <0>;
+		};
+		port@1 {
+			reg = <1>;
+		};
+		port@2 {
+			reg = <2>;
+		};
+		port@3 {
+			reg = <3>;
+		};
+
+		/* output */
+		port@4 {
+			reg = <4>;
+		};
+	};
+};