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1Microchip MCP2308/MCP23S08/MCP23017/MCP23S17 driver for28-/16-bit I/O expander with serial interface (I2C/SPI)3 4Required properties:5- compatible : Should be6 - "mcp,mcp23s08" (DEPRECATED) for 8 GPIO SPI version7 - "mcp,mcp23s17" (DEPRECATED) for 16 GPIO SPI version8 - "mcp,mcp23008" (DEPRECATED) for 8 GPIO I2C version or9 - "mcp,mcp23017" (DEPRECATED) for 16 GPIO I2C version of the chip10 11 - "microchip,mcp23s08" for 8 GPIO SPI version12 - "microchip,mcp23s17" for 16 GPIO SPI version13 - "microchip,mcp23s18" for 16 GPIO SPI version14 - "microchip,mcp23008" for 8 GPIO I2C version or15 - "microchip,mcp23017" for 16 GPIO I2C version of the chip16 - "microchip,mcp23018" for 16 GPIO I2C version17 NOTE: Do not use the old mcp prefix any more. It is deprecated and will be18 removed.19- #gpio-cells : Should be two.20 - first cell is the pin number21 - second cell is used to specify flags as described in22 'Documentation/devicetree/bindings/gpio/gpio.txt'. Allowed values defined by23 '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 is27 connected to. The driver and the SPI variant of the chip support28 multiple chips on the same chipselect. Have a look at29 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 SPI34 chips - as the name suggests. Multiple SPI chips can share the same35 SPI chipselect. Set a bit in bit0-7 in this mask to 1 if there is a36 chip connected with the corresponding spi address set. For example if37 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 not39 possible to mix mcp23s08 and mcp23s17 on the same chipselect. Set at40 least one bit to 1 for SPI chips.41 NOTE: Do not use the old mcp prefix any more. It is deprecated and will be42 removed.43- spi-max-frequency = The maximum frequency this chip is able to handle44 45Optional properties:46- #interrupt-cells : Should be two.47 - first cell is the pin number48 - 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 configures51 the IRQ output as open drain active low.52- reset-gpios: Corresponds to the active-low RESET# pin for the chip53 54Optional device specific properties:55- microchip,irq-mirror: Sets the mirror flag in the IOCON register. Devices56 with two interrupt outputs (these are the devices ending with 17 and57 those that have 16 IOs) have two IO banks: IO 0-7 form bank 1 and58 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, both60 interrupts are generated regardless of the bank that an input change61 occurred on. If it is not set, the interrupt are only generated for the62 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. This65 configures the IRQ output polarity as active high.66 67Example I2C (with interrupt):68gpiom1: 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 81Example SPI:82gpiom1: 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 91Pull-up configuration92=====================93 94If pins are used as output, they can also be configured with pull-ups. This is95done with pinctrl.96 97Please refer file <devicetree/bindings/pinctrl/pinctrl-bindings.txt>98for details of the common pinctrl bindings used by client devices,99including the meaning of the phrase "pin configuration node".100 101Optional Pinmux properties:102--------------------------103Following properties are required if default setting of pins are required104at boot.105- pinctrl-names: A pinctrl state named per <pinctrl-bindings.txt>.106- pinctrl[0...n]: Properties to contain the phandle for pinctrl states per107 <pinctrl-bindings.txt>.108 109The pin configurations are defined as child of the pinctrl states node. Each110sub-node have following properties:111 112Required properties:113------------------114- pins: List of pins. Valid values of pins properties are:115 gpio0 ... gpio7 for the devices with 8 GPIO pins and116 gpio0 ... gpio15 for the devices with 16 GPIO pins.117 118Optional properties:119-------------------120The following optional property is defined in the pinmux DT binding document121<pinctrl-bindings.txt>. Absence of this property will leave the configuration122in its default state.123 bias-pull-up124 125Example with pinctrl to pull-up output pins:126gpio21: 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};149