1Microchip MCP2308/MCP23S08/MCP23017/MCP23S17 driver for 28-/16-bit I/O expander with serial interface (I2C/SPI) 3 4Required 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 31Required 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 45Optional 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 53Optional device specific properties: 54- microchip,irq-mirror: Sets the mirror flag in the IOCON register. Devices 55 with two interrupt outputs (these are the devices ending with 17 and 56 those that have 16 IOs) have two IO banks: IO 0-7 form bank 1 and 57 IO 8-15 are bank 2. These chips have two different interrupt outputs: 58 One for bank 1 and another for bank 2. If irq-mirror is set, both 59 interrupts are generated regardless of the bank that an input change 60 occurred on. If it is not set, the interrupt are only generated for the 61 bank they belong to. 62 On devices with only one interrupt output this property is useless. 63- microchip,irq-active-high: Sets the INTPOL flag in the IOCON register. This 64 configures the IRQ output polarity as active high. 65 66Example I2C (with interrupt): 67gpiom1: gpio@20 { 68 compatible = "microchip,mcp23017"; 69 gpio-controller; 70 #gpio-cells = <2>; 71 reg = <0x20>; 72 73 interrupt-parent = <&gpio1>; 74 interrupts = <17 IRQ_TYPE_LEVEL_LOW>; 75 interrupt-controller; 76 #interrupt-cells=<2>; 77 microchip,irq-mirror; 78}; 79 80Example SPI: 81gpiom1: gpio@0 { 82 compatible = "microchip,mcp23s17"; 83 gpio-controller; 84 #gpio-cells = <2>; 85 spi-present-mask = <0x01>; 86 reg = <0>; 87 spi-max-frequency = <1000000>; 88}; 89 90Pull-up configuration 91===================== 92 93If pins are used as output, they can also be configured with pull-ups. This is 94done with pinctrl. 95 96Please refer file <devicetree/bindings/pinctrl/pinctrl-bindings.txt> 97for details of the common pinctrl bindings used by client devices, 98including the meaning of the phrase "pin configuration node". 99 100Optional Pinmux properties: 101-------------------------- 102Following properties are required if default setting of pins are required 103at boot. 104- pinctrl-names: A pinctrl state named per <pinctrl-bindings.txt>. 105- pinctrl[0...n]: Properties to contain the phandle for pinctrl states per 106 <pinctrl-bindings.txt>. 107 108The pin configurations are defined as child of the pinctrl states node. Each 109sub-node have following properties: 110 111Required properties: 112------------------ 113- pins: List of pins. Valid values of pins properties are: 114 gpio0 ... gpio7 for the devices with 8 GPIO pins and 115 gpio0 ... gpio15 for the devices with 16 GPIO pins. 116 117Optional properties: 118------------------- 119The following optional property is defined in the pinmux DT binding document 120<pinctrl-bindings.txt>. Absence of this property will leave the configuration 121in its default state. 122 bias-pull-up 123 124Example with pinctrl to pull-up output pins: 125gpio21: gpio@21 { 126 compatible = "microchip,mcp23017"; 127 gpio-controller; 128 #gpio-cells = <0x2>; 129 reg = <0x21>; 130 interrupt-parent = <&socgpio>; 131 interrupts = <0x17 0x8>; 132 interrupt-names = "mcp23017@21 irq"; 133 interrupt-controller; 134 #interrupt-cells = <0x2>; 135 microchip,irq-mirror; 136 pinctrl-names = "default"; 137 pinctrl-0 = <&i2cgpio0irq &gpio21pullups>; 138 139 gpio21pullups: pinmux { 140 pins = "gpio0", "gpio1", "gpio2", "gpio3", 141 "gpio4", "gpio5", "gpio6", "gpio7", 142 "gpio8", "gpio9", "gpio10", "gpio11", 143 "gpio12", "gpio13", "gpio14", "gpio15"; 144 bias-pull-up; 145 }; 146}; 147