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Documentation / devicetree / bindings / net / mdio-mux-mmioreg.txt




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Based on kernel version 3.9. Page generated on 2013-05-02 22:59 EST.

1	Properties for an MDIO bus multiplexer controlled by a memory-mapped device
2	
3	This is a special case of a MDIO bus multiplexer.  A memory-mapped device,
4	like an FPGA, is used to control which child bus is connected.  The mdio-mux
5	node must be a child of the memory-mapped device.  The driver currently only
6	supports devices with eight-bit registers.
7	
8	Required properties in addition to the generic multiplexer properties:
9	
10	- compatible : string, must contain "mdio-mux-mmioreg"
11	
12	- reg : integer, contains the offset of the register that controls the bus
13		multiplexer.  The size field in the 'reg' property is the size of
14		register, and must therefore be 1.
15	
16	- mux-mask : integer, contains an eight-bit mask that specifies which
17		bits in the register control the actual bus multiplexer.  The
18		'reg' property of each child mdio-mux node must be constrained by
19		this mask.
20	
21	Example:
22	
23	The FPGA node defines a memory-mapped FPGA with a register space of 0x30 bytes.
24	For the "EMI2" MDIO bus, register 9 (BRDCFG1) controls the mux on that bus.
25	A bitmask of 0x6 means that bits 1 and 2 (bit 0 is lsb) are the bits on
26	BRDCFG1 that control the actual mux.
27	
28		/* The FPGA node */
29		fpga: board-control@3,0 {
30			#address-cells = <1>;
31			#size-cells = <1>;
32			compatible = "fsl,p5020ds-fpga", "fsl,fpga-ngpixis";
33			reg = <3 0 0x30>;
34			ranges = <0 3 0 0x30>;
35	
36			mdio-mux-emi2 {
37				compatible = "mdio-mux-mmioreg", "mdio-mux";
38				mdio-parent-bus = <&xmdio0>;
39				#address-cells = <1>;
40				#size-cells = <0>;
41				reg = <9 1>; // BRDCFG1
42				mux-mask = <0x6>; // EMI2
43	
44				emi2_slot1: mdio@0 {	// Slot 1 XAUI (FM2)
45					reg = <0>;
46					#address-cells = <1>;
47					#size-cells = <0>;
48	
49					phy_xgmii_slot1: ethernet-phy@0 {
50						compatible = "ethernet-phy-ieee802.3-c45";
51						reg = <4>;
52					};
53				};
54	
55				emi2_slot2: mdio@2 {	// Slot 2 XAUI (FM1)
56					reg = <2>;
57					#address-cells = <1>;
58					#size-cells = <0>;
59	
60					phy_xgmii_slot2: ethernet-phy@4 {
61						compatible = "ethernet-phy-ieee802.3-c45";
62						reg = <0>;
63					};
64				};
65			};
66		};
67	
68		/* The parent MDIO bus. */
69		xmdio0: mdio@f1000 {
70			#address-cells = <1>;
71			#size-cells = <0>;
72			compatible = "fsl,fman-xmdio";
73			reg = <0xf1000 0x1000>;
74			interrupts = <100 1 0 0>;
75		};
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