1* Atmel AT91 Pinmux Controller
2
3The AT91 Pinmux Controler, enables the IC
4to share one PAD to several functional blocks. The sharing is done by
5multiplexing the PAD input/output signals. For each PAD there are up to
68 muxing options (called periph modes). Since different modules require
7different PAD settings (like pull up, keeper, etc) the contoller controls
8also the PAD settings parameters.
9
10Please refer to pinctrl-bindings.txt in this directory for details of the
11common pinctrl bindings used by client devices, including the meaning of the
12phrase "pin configuration node".
13
14Atmel AT91 pin configuration node is a node of a group of pins which can be
15used for a specific device or function. This node represents both mux and config
16of the pins in that group. The 'pins' selects the function mode(also named pin
17mode) this pin can work on and the 'config' configures various pad settings
18such as pull-up, multi drive, etc.
19
20Required properties for iomux controller:
21- compatible: "atmel,at91rm9200-pinctrl"
22- atmel,mux-mask: array of mask (periph per bank) to describe if a pin can be
23  configured in this periph mode. All the periph and bank need to be describe.
24
25How to create such array:
26
27Each column will represent the possible peripheral of the pinctrl
28Each line will represent a pio bank
29
30Take an example on the 9260
31Peripheral: 2 ( A and B)
32Bank: 3 (A, B and C)
33=>
34
35  /*    A         B     */
36  0xffffffff 0xffc00c3b  /* pioA */
37  0xffffffff 0x7fff3ccf  /* pioB */
38  0xffffffff 0x007fffff  /* pioC */
39
40For each peripheral/bank we will descibe in a u32 if a pin can can be
41configured in it by putting 1 to the pin bit (1 << pin)
42
43Let's take the pioA on peripheral B
44From the datasheet Table 10-2.
45Peripheral B
46PA0	MCDB0
47PA1	MCCDB
48PA2
49PA3	MCDB3
50PA4	MCDB2
51PA5	MCDB1
52PA6
53PA7
54PA8
55PA9
56PA10	ETX2
57PA11	ETX3
58PA12
59PA13
60PA14
61PA15
62PA16
63PA17
64PA18
65PA19
66PA20
67PA21
68PA22	ETXER
69PA23	ETX2
70PA24	ETX3
71PA25	ERX2
72PA26	ERX3
73PA27	ERXCK
74PA28	ECRS
75PA29	ECOL
76PA30	RXD4
77PA31	TXD4
78
79=> 0xffc00c3b
80
81Required properties for pin configuration node:
82- atmel,pins: 4 integers array, represents a group of pins mux and config
83  setting. The format is atmel,pins = <PIN_BANK PIN_BANK_NUM PERIPH CONFIG>.
84  The PERIPH 0 means gpio.
85
86Bits used for CONFIG:
87PULL_UP		(1 << 0): indicate this pin need a pull up.
88MULTIDRIVE	(1 << 1): indicate this pin need to be configured as multidrive.
89DEGLITCH	(1 << 2): indicate this pin need deglitch.
90PULL_DOWN	(1 << 3): indicate this pin need a pull down.
91DIS_SCHMIT	(1 << 4): indicate this pin need to disable schmit trigger.
92DEBOUNCE	(1 << 16): indicate this pin need debounce.
93DEBOUNCE_VAL	(0x3fff << 17): debounce val.
94
95NOTE:
96Some requirements for using atmel,at91rm9200-pinctrl binding:
971. We have pin function node defined under at91 controller node to represent
98   what pinmux functions this SoC supports.
992. The driver can use the function node's name and pin configuration node's
100   name describe the pin function and group hierarchy.
101   For example, Linux at91 pinctrl driver takes the function node's name
102   as the function name and pin configuration node's name as group name to
103   create the map table.
1043. Each pin configuration node should have a phandle, devices can set pins
105   configurations by referring to the phandle of that pin configuration node.
1064. The gpio controller must be describe in the pinctrl simple-bus.
107
108Examples:
109
110pinctrl@fffff400 {
111	#address-cells = <1>;
112	#size-cells = <1>;
113	ranges;
114	compatible = "atmel,at91rm9200-pinctrl", "simple-bus";
115	reg = <0xfffff400 0x600>;
116
117	atmel,mux-mask = <
118	      /*    A         B     */
119	       0xffffffff 0xffc00c3b  /* pioA */
120	       0xffffffff 0x7fff3ccf  /* pioB */
121	       0xffffffff 0x007fffff  /* pioC */
122	      >;
123
124	/* shared pinctrl settings */
125	dbgu {
126		pinctrl_dbgu: dbgu-0 {
127			atmel,pins =
128				<1 14 0x1 0x0	/* PB14 periph A */
129				 1 15 0x1 0x1>;	/* PB15 periph with pullup */
130		};
131	};
132};
133
134dbgu: serial@fffff200 {
135	compatible = "atmel,at91sam9260-usart";
136	reg = <0xfffff200 0x200>;
137	interrupts = <1 4 7>;
138	pinctrl-names = "default";
139	pinctrl-0 = <&pinctrl_dbgu>;
140	status = "disabled";
141};
142