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Documentation / devicetree / bindings / mmc / synopsys-dw-mshc.txt




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Based on kernel version 4.9. Page generated on 2016-12-21 14:31 EST.

1	* Synopsys Designware Mobile Storage Host Controller
2	
3	The Synopsys designware mobile storage host controller is used to interface
4	a SoC with storage medium such as eMMC or SD/MMC cards. This file documents
5	differences between the core mmc properties described by mmc.txt and the
6	properties used by the Synopsys Designware Mobile Storage Host Controller.
7	
8	Required Properties:
9	
10	* compatible: should be
11		- snps,dw-mshc: for controllers compliant with synopsys dw-mshc.
12	* #address-cells: should be 1.
13	* #size-cells: should be 0.
14	
15	# Slots: The slot specific information are contained within child-nodes with
16	  each child-node representing a supported slot. There should be atleast one
17	  child node representing a card slot. The name of the child node representing
18	  the slot is recommended to be slot@n where n is the unique number of the slot
19	  connnected to the controller. The following are optional properties which
20	  can be included in the slot child node.
21	
22		* reg: specifies the physical slot number. The valid values of this
23		  property is 0 to (num-slots -1), where num-slots is the value
24		  specified by the num-slots property.
25	
26		* bus-width: as documented in mmc core bindings.
27	
28		* wp-gpios: specifies the write protect gpio line. The format of the
29		  gpio specifier depends on the gpio controller. If a GPIO is not used
30		  for write-protect, this property is optional.
31	
32		* disable-wp: If the wp-gpios property isn't present then (by default)
33		  we'd assume that the write protect is hooked up directly to the
34		  controller's special purpose write protect line (accessible via
35		  the WRTPRT register).  However, it's possible that we simply don't
36		  want write protect.  In that case specify 'disable-wp'.
37		  NOTE: This property is not required for slots known to always
38		  connect to eMMC or SDIO cards.
39	
40	Optional properties:
41	
42	* resets: phandle + reset specifier pair, intended to represent hardware
43	  reset signal present internally in some host controller IC designs.
44	  See Documentation/devicetree/bindings/reset/reset.txt for details.
45	
46	* reset-names: request name for using "resets" property. Must be "reset".
47		(It will be used together with "resets" property.)
48	
49	* clocks: from common clock binding: handle to biu and ciu clocks for the
50	  bus interface unit clock and the card interface unit clock.
51	
52	* clock-names: from common clock binding: Shall be "biu" and "ciu".
53	  If the biu clock is missing we'll simply skip enabling it.  If the
54	  ciu clock is missing we'll just assume that the clock is running at
55	  clock-frequency.  It is an error to omit both the ciu clock and the
56	  clock-frequency.
57	
58	* clock-frequency: should be the frequency (in Hz) of the ciu clock.  If this
59	  is specified and the ciu clock is specified then we'll try to set the ciu
60	  clock to this at probe time.
61	
62	* clock-freq-min-max: Minimum and Maximum clock frequency for card output
63	  clock(cclk_out). If it's not specified, max is 200MHZ and min is 400KHz by default.
64	
65	* num-slots: specifies the number of slots supported by the controller.
66	  The number of physical slots actually used could be equal or less than the
67	  value specified by num-slots. If this property is not specified, the value
68	  of num-slot property is assumed to be 1.
69	
70	* fifo-depth: The maximum size of the tx/rx fifo's. If this property is not
71	  specified, the default value of the fifo size is determined from the
72	  controller registers.
73	
74	* card-detect-delay: Delay in milli-seconds before detecting card after card
75	  insert event. The default value is 0.
76	
77	* supports-highspeed (DEPRECATED): Enables support for high speed cards (up to 50MHz)
78				   (use "cap-mmc-highspeed" or "cap-sd-highspeed" instead)
79	
80	* broken-cd: as documented in mmc core bindings.
81	
82	* vmmc-supply: The phandle to the regulator to use for vmmc.  If this is
83	  specified we'll defer probe until we can find this regulator.
84	
85	* dmas: List of DMA specifiers with the controller specific format as described
86	  in the generic DMA client binding. Refer to dma.txt for details.
87	
88	* dma-names: request names for generic DMA client binding. Must be "rx-tx".
89	  Refer to dma.txt for details.
90	
91	Aliases:
92	
93	- All the MSHC controller nodes should be represented in the aliases node using
94	  the following format 'mshc{n}' where n is a unique number for the alias.
95	
96	Example:
97	
98	The MSHC controller node can be split into two portions, SoC specific and
99	board specific portions as listed below.
100	
101		dwmmc0@12200000 {
102			compatible = "snps,dw-mshc";
103			clocks = <&clock 351>, <&clock 132>;
104			clock-names = "biu", "ciu";
105			reg = <0x12200000 0x1000>;
106			interrupts = <0 75 0>;
107			#address-cells = <1>;
108			#size-cells = <0>;
109			resets = <&rst 20>;
110			reset-names = "reset";
111		};
112	
113	[board specific internal DMA resources]
114	
115		dwmmc0@12200000 {
116			clock-frequency = <400000000>;
117			clock-freq-min-max = <400000 200000000>;
118			num-slots = <1>;
119			broken-cd;
120			fifo-depth = <0x80>;
121			card-detect-delay = <200>;
122			vmmc-supply = <&buck8>;
123			bus-width = <8>;
124			cap-mmc-highspeed;
125			cap-sd-highspeed;
126		};
127	
128	[board specific generic DMA request binding]
129	
130		dwmmc0@12200000 {
131			clock-frequency = <400000000>;
132			clock-freq-min-max = <400000 200000000>;
133			num-slots = <1>;
134			broken-cd;
135			fifo-depth = <0x80>;
136			card-detect-delay = <200>;
137			vmmc-supply = <&buck8>;
138			bus-width = <8>;
139			cap-mmc-highspeed;
140			cap-sd-highspeed;
141			dmas = <&pdma 12>;
142			dma-names = "rx-tx";
143		};
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