1* Generic DMA Controller and DMA request bindings
2
3Generic binding to provide a way for a driver using DMA Engine to retrieve the
4DMA request or channel information that goes from a hardware device to a DMA
5controller.
6
7
8* DMA controller
9
10Required property:
11- #dma-cells: 		Must be at least 1. Used to provide DMA controller
12			specific information. See DMA client binding below for
13			more details.
14
15Optional properties:
16- dma-channels: 	Number of DMA channels supported by the controller.
17- dma-requests: 	Number of DMA request signals supported by the
18			controller.
19
20Example:
21
22	dma: dma@48000000 {
23		compatible = "ti,omap-sdma";
24		reg = <0x48000000 0x1000>;
25		interrupts = <0 12 0x4
26			      0 13 0x4
27			      0 14 0x4
28			      0 15 0x4>;
29		#dma-cells = <1>;
30		dma-channels = <32>;
31		dma-requests = <127>;
32	};
33
34
35* DMA client
36
37Client drivers should specify the DMA property using a phandle to the controller
38followed by DMA controller specific data.
39
40Required property:
41- dmas:			List of one or more DMA specifiers, each consisting of
42			- A phandle pointing to DMA controller node
43			- A number of integer cells, as determined by the
44			  #dma-cells property in the node referenced by phandle
45			  containing DMA controller specific information. This
46			  typically contains a DMA request line number or a
47			  channel number, but can contain any data that is
48			  required for configuring a channel.
49- dma-names: 		Contains one identifier string for each DMA specifier in
50			the dmas property. The specific strings that can be used
51			are defined in the binding of the DMA client device.
52			Multiple DMA specifiers can be used to represent
53			alternatives and in this case the dma-names for those
54			DMA specifiers must be identical (see examples).
55
56Examples:
57
581. A device with one DMA read channel, one DMA write channel:
59
60	i2c1: i2c@1 {
61		...
62		dmas = <&dma 2		/* read channel */
63			&dma 3>;	/* write channel */
64		dma-names = "rx", "tx";
65		...
66	};
67
682. A single read-write channel with three alternative DMA controllers:
69
70	dmas = <&dma1 5
71		&dma2 7
72		&dma3 2>;
73	dma-names = "rx-tx", "rx-tx", "rx-tx";
74
753. A device with three channels, one of which has two alternatives:
76
77	dmas = <&dma1 2			/* read channel */
78		&dma1 3			/* write channel */
79		&dma2 0			/* error read */
80		&dma3 0>;		/* alternative error read */
81	dma-names = "rx", "tx", "error", "error";
82