xref: /freebsd/sys/contrib/device-tree/Bindings/iio/adc/xilinx-xadc.txt (revision 6be3386466ab79a84b48429ae66244f21526d3df)
1Xilinx XADC device driver
2
3This binding document describes the bindings for both of them since the
4bindings are very similar. The Xilinx XADC is a ADC that can be found in the
5series 7 FPGAs from Xilinx. The XADC has a DRP interface for communication.
6Currently two different frontends for the DRP interface exist. One that is only
7available on the ZYNQ family as a hardmacro in the SoC portion of the ZYNQ. The
8other one is available on all series 7 platforms and is a softmacro with a AXI
9interface. This binding document describes the bindings for both of them since
10the bindings are very similar.
11
12Required properties:
13	- compatible: Should be one of
14		* "xlnx,zynq-xadc-1.00.a": When using the ZYNQ device
15		  configuration interface to interface to the XADC hardmacro.
16		* "xlnx,axi-xadc-1.00.a": When using the axi-xadc pcore to
17		  interface to the XADC hardmacro.
18	- reg: Address and length of the register set for the device
19	- interrupts: Interrupt for the XADC control interface.
20	- clocks: When using the ZYNQ this must be the ZYNQ PCAP clock,
21	  when using the AXI-XADC pcore this must be the clock that provides the
22	  clock to the AXI bus interface of the core.
23
24Optional properties:
25	- xlnx,external-mux:
26		* "none": No external multiplexer is used, this is the default
27		  if the property is omitted.
28		* "single": External multiplexer mode is used with one
29		   multiplexer.
30		* "dual": External multiplexer mode is used with two
31		  multiplexers for simultaneous sampling.
32	- xlnx,external-mux-channel: Configures which pair of pins is used to
33	  sample data in external mux mode.
34	  Valid values for single external multiplexer mode are:
35		0: VP/VN
36		1: VAUXP[0]/VAUXN[0]
37		2: VAUXP[1]/VAUXN[1]
38		...
39		16: VAUXP[15]/VAUXN[15]
40	  Valid values for dual external multiplexer mode are:
41		1: VAUXP[0]/VAUXN[0] - VAUXP[8]/VAUXN[8]
42		2: VAUXP[1]/VAUXN[1] - VAUXP[9]/VAUXN[9]
43		...
44		8: VAUXP[7]/VAUXN[7] - VAUXP[15]/VAUXN[15]
45
46	  This property needs to be present if the device is configured for
47	  external multiplexer mode (either single or dual). If the device is
48	  not using external multiplexer mode the property is ignored.
49	- xnlx,channels: List of external channels that are connected to the ADC
50	  Required properties:
51		* #address-cells: Should be 1.
52		* #size-cells: Should be 0.
53
54	  The child nodes of this node represent the external channels which are
55	  connected to the ADC. If the property is no present no external
56	  channels will be assumed to be connected.
57
58	  Each child node represents one channel and has the following
59	  properties:
60		Required properties:
61			* reg: Pair of pins the channel is connected to.
62				0: VP/VN
63				1: VAUXP[0]/VAUXN[0]
64				2: VAUXP[1]/VAUXN[1]
65				...
66				16: VAUXP[15]/VAUXN[15]
67			  Note each channel number should only be used at most
68			  once.
69		Optional properties:
70			* xlnx,bipolar: If set the channel is used in bipolar
71			  mode.
72
73
74Examples:
75	xadc@f8007100 {
76		compatible = "xlnx,zynq-xadc-1.00.a";
77		reg = <0xf8007100 0x20>;
78		interrupts = <0 7 4>;
79		interrupt-parent = <&gic>;
80		clocks = <&pcap_clk>;
81
82		xlnx,channels {
83			#address-cells = <1>;
84			#size-cells = <0>;
85			channel@0 {
86				reg = <0>;
87			};
88			channel@1 {
89				reg = <1>;
90			};
91			channel@8 {
92				reg = <8>;
93			};
94		};
95	};
96
97	xadc@43200000 {
98		compatible = "xlnx,axi-xadc-1.00.a";
99		reg = <0x43200000 0x1000>;
100		interrupts = <0 53 4>;
101		interrupt-parent = <&gic>;
102		clocks = <&fpga1_clk>;
103
104		xlnx,channels {
105			#address-cells = <1>;
106			#size-cells = <0>;
107			channel@0 {
108				reg = <0>;
109				xlnx,bipolar;
110			};
111		};
112	};
113