1 Microchip MCP2308/MCP23S08/MCP23017/MCP23S17 driver for
2 8-/16-bit I/O expander with serial interface (I2C/SPI)
3
4 Required properties:
5 - compatible : Should be
6 - "mcp,mcp23s08" (DEPRECATED) for 8 GPIO SPI version
7 - "mcp,mcp23s17" (DEPRECATED) for 16 GPIO SPI version
8 - "mcp,mcp23008" (DEPRECATED) for 8 GPIO I2C version or
9 - "mcp,mcp23017" (DEPRECATED) for 16 GPIO I2C version of the chip
10
11 - "microchip,mcp23s08" for 8 GPIO SPI version
12 - "microchip,mcp23s17" for 16 GPIO SPI version
13 - "microchip,mcp23s18" for 16 GPIO SPI version
14 - "microchip,mcp23008" for 8 GPIO I2C version or
15 - "microchip,mcp23017" for 16 GPIO I2C version of the chip
16 - "microchip,mcp23018" for 16 GPIO I2C version
17 NOTE: Do not use the old mcp prefix any more. It is deprecated and will be
18 removed.
19 - #gpio-cells : Should be two.
20 - first cell is the pin number
21 - second cell is used to specify flags as described in
22 'Documentation/devicetree/bindings/gpio/gpio.txt'. Allowed values defined by
23 'include/dt-bindings/gpio/gpio.h' (e.g. GPIO_ACTIVE_LOW).
24 - gpio-controller : Marks the device node as a GPIO controller.
25 - reg : For an address on its bus. I2C uses this a the I2C address of the chip.
26 SPI uses this to specify the chipselect line which the chip is
27 connected to. The driver and the SPI variant of the chip support
28 multiple chips on the same chipselect. Have a look at
29 microchip,spi-present-mask below.
30
31 Required device specific properties (only for SPI chips):
32 - mcp,spi-present-mask (DEPRECATED)
33 - microchip,spi-present-mask : This is a present flag, that makes only sense for SPI
34 chips - as the name suggests. Multiple SPI chips can share the same
35 SPI chipselect. Set a bit in bit0-7 in this mask to 1 if there is a
36 chip connected with the corresponding spi address set. For example if
37 you have a chip with address 3 connected, you have to set bit3 to 1,
38 which is 0x08. mcp23s08 chip variant only supports bits 0-3. It is not
39 possible to mix mcp23s08 and mcp23s17 on the same chipselect. Set at
40 least one bit to 1 for SPI chips.
41 NOTE: Do not use the old mcp prefix any more. It is deprecated and will be
42 removed.
43 - spi-max-frequency = The maximum frequency this chip is able to handle
44
45 Optional properties:
46 - #interrupt-cells : Should be two.
47 - first cell is the pin number
48 - second cell is used to specify flags.
49 - interrupt-controller: Marks the device node as a interrupt controller.
50 - drive-open-drain: Sets the ODR flag in the IOCON register. This configures
51 the IRQ output as open drain active low.
52 - reset-gpios: Corresponds to the active-low RESET# pin for the chip
53
54 Optional device specific properties:
55 - microchip,irq-mirror: Sets the mirror flag in the IOCON register. Devices
56 with two interrupt outputs (these are the devices ending with 17 and
57 those that have 16 IOs) have two IO banks: IO 0-7 form bank 1 and
58 IO 8-15 are bank 2. These chips have two different interrupt outputs:
59 One for bank 1 and another for bank 2. If irq-mirror is set, both
60 interrupts are generated regardless of the bank that an input change
61 occurred on. If it is not set, the interrupt are only generated for the
62 bank they belong to.
63 On devices with only one interrupt output this property is useless.
64 - microchip,irq-active-high: Sets the INTPOL flag in the IOCON register. This
65 configures the IRQ output polarity as active high.
66
67 Example I2C (with interrupt):
68 gpiom1: gpio@20 {
69 compatible = "microchip,mcp23017";
70 gpio-controller;
71 #gpio-cells = <2>;
72 reg = <0x20>;
73
74 interrupt-parent = <&gpio1>;
75 interrupts = <17 IRQ_TYPE_LEVEL_LOW>;
76 interrupt-controller;
77 #interrupt-cells=<2>;
78 microchip,irq-mirror;
79 };
80
81 Example SPI:
82 gpiom1: gpio@0 {
83 compatible = "microchip,mcp23s17";
84 gpio-controller;
85 #gpio-cells = <2>;
86 microchip,spi-present-mask = <0x01>;
87 reg = <0>;
88 spi-max-frequency = <1000000>;
89 };
90
91 Pull-up configuration
92 =====================
93
94 If pins are used as output, they can also be configured with pull-ups. This is
95 done with pinctrl.
96
97 Please refer file <devicetree/bindings/pinctrl/pinctrl-bindings.txt>
98 for details of the common pinctrl bindings used by client devices,
99 including the meaning of the phrase "pin configuration node".
100
101 Optional Pinmux properties:
102 --------------------------
103 Following properties are required if default setting of pins are required
104 at boot.
105 - pinctrl-names: A pinctrl state named per <pinctrl-bindings.txt>.
106 - pinctrl[0...n]: Properties to contain the phandle for pinctrl states per
107 <pinctrl-bindings.txt>.
108
109 The pin configurations are defined as child of the pinctrl states node. Each
110 sub-node have following properties:
111
112 Required properties:
113 ------------------
114 - pins: List of pins. Valid values of pins properties are:
115 gpio0 ... gpio7 for the devices with 8 GPIO pins and
116 gpio0 ... gpio15 for the devices with 16 GPIO pins.
117
118 Optional properties:
119 -------------------
120 The following optional property is defined in the pinmux DT binding document
121 <pinctrl-bindings.txt>. Absence of this property will leave the configuration
122 in its default state.
123 bias-pull-up
124
125 Example with pinctrl to pull-up output pins:
126 gpio21: gpio@21 {
127 compatible = "microchip,mcp23017";
128 gpio-controller;
129 #gpio-cells = <0x2>;
130 reg = <0x21>;
131 interrupt-parent = <&socgpio>;
132 interrupts = <0x17 0x8>;
133 interrupt-names = "mcp23017@21 irq";
134 interrupt-controller;
135 #interrupt-cells = <0x2>;
136 microchip,irq-mirror;
137 pinctrl-names = "default";
138 pinctrl-0 = <&i2cgpio0irq>, <&gpio21pullups>;
139 reset-gpios = <&gpio6 15 GPIO_ACTIVE_LOW>;
140
141 gpio21pullups: pinmux {
142 pins = "gpio0", "gpio1", "gpio2", "gpio3",
143 "gpio4", "gpio5", "gpio6", "gpio7",
144 "gpio8", "gpio9", "gpio10", "gpio11",
145 "gpio12", "gpio13", "gpio14", "gpio15";
146 bias-pull-up;
147 };
148 };
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