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| -rw-r--r-- | Documentation/devicetree/bindings/pinctrl/pinctrl-mcp23s08.txt | 148 |
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diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-mcp23s08.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-mcp23s08.txt new file mode 100644 index 000000000..2fa5edac7 --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-mcp23s08.txt @@ -0,0 +1,148 @@ +Microchip MCP2308/MCP23S08/MCP23017/MCP23S17 driver for +8-/16-bit I/O expander with serial interface (I2C/SPI) + +Required properties: +- compatible : Should be + - "mcp,mcp23s08" (DEPRECATED) for 8 GPIO SPI version + - "mcp,mcp23s17" (DEPRECATED) for 16 GPIO SPI version + - "mcp,mcp23008" (DEPRECATED) for 8 GPIO I2C version or + - "mcp,mcp23017" (DEPRECATED) for 16 GPIO I2C version of the chip + + - "microchip,mcp23s08" for 8 GPIO SPI version + - "microchip,mcp23s17" for 16 GPIO SPI version + - "microchip,mcp23s18" for 16 GPIO SPI version + - "microchip,mcp23008" for 8 GPIO I2C version or + - "microchip,mcp23017" for 16 GPIO I2C version of the chip + - "microchip,mcp23018" for 16 GPIO I2C version + NOTE: Do not use the old mcp prefix any more. It is deprecated and will be + removed. +- #gpio-cells : Should be two. + - first cell is the pin number + - second cell is used to specify flags as described in + 'Documentation/devicetree/bindings/gpio/gpio.txt'. Allowed values defined by + 'include/dt-bindings/gpio/gpio.h' (e.g. GPIO_ACTIVE_LOW). +- gpio-controller : Marks the device node as a GPIO controller. +- reg : For an address on its bus. I2C uses this a the I2C address of the chip. + SPI uses this to specify the chipselect line which the chip is + connected to. The driver and the SPI variant of the chip support + multiple chips on the same chipselect. Have a look at + microchip,spi-present-mask below. + +Required device specific properties (only for SPI chips): +- mcp,spi-present-mask (DEPRECATED) +- microchip,spi-present-mask : This is a present flag, that makes only sense for SPI + chips - as the name suggests. Multiple SPI chips can share the same + SPI chipselect. Set a bit in bit0-7 in this mask to 1 if there is a + chip connected with the corresponding spi address set. For example if + you have a chip with address 3 connected, you have to set bit3 to 1, + which is 0x08. mcp23s08 chip variant only supports bits 0-3. It is not + possible to mix mcp23s08 and mcp23s17 on the same chipselect. Set at + least one bit to 1 for SPI chips. + NOTE: Do not use the old mcp prefix any more. It is deprecated and will be + removed. +- spi-max-frequency = The maximum frequency this chip is able to handle + +Optional properties: +- #interrupt-cells : Should be two. + - first cell is the pin number + - second cell is used to specify flags. +- interrupt-controller: Marks the device node as a interrupt controller. +- drive-open-drain: Sets the ODR flag in the IOCON register. This configures + the IRQ output as open drain active low. +- reset-gpios: Corresponds to the active-low RESET# pin for the chip + +Optional device specific properties: +- microchip,irq-mirror: Sets the mirror flag in the IOCON register. Devices + with two interrupt outputs (these are the devices ending with 17 and + those that have 16 IOs) have two IO banks: IO 0-7 form bank 1 and + IO 8-15 are bank 2. These chips have two different interrupt outputs: + One for bank 1 and another for bank 2. If irq-mirror is set, both + interrupts are generated regardless of the bank that an input change + occurred on. If it is not set, the interrupt are only generated for the + bank they belong to. + On devices with only one interrupt output this property is useless. +- microchip,irq-active-high: Sets the INTPOL flag in the IOCON register. This + configures the IRQ output polarity as active high. + +Example I2C (with interrupt): +gpiom1: gpio@20 { + compatible = "microchip,mcp23017"; + gpio-controller; + #gpio-cells = <2>; + reg = <0x20>; + + interrupt-parent = <&gpio1>; + interrupts = <17 IRQ_TYPE_LEVEL_LOW>; + interrupt-controller; + #interrupt-cells=<2>; + microchip,irq-mirror; +}; + +Example SPI: +gpiom1: gpio@0 { + compatible = "microchip,mcp23s17"; + gpio-controller; + #gpio-cells = <2>; + microchip,spi-present-mask = <0x01>; + reg = <0>; + spi-max-frequency = <1000000>; +}; + +Pull-up configuration +===================== + +If pins are used as output, they can also be configured with pull-ups. This is +done with pinctrl. + +Please refer file <devicetree/bindings/pinctrl/pinctrl-bindings.txt> +for details of the common pinctrl bindings used by client devices, +including the meaning of the phrase "pin configuration node". + +Optional Pinmux properties: +-------------------------- +Following properties are required if default setting of pins are required +at boot. +- pinctrl-names: A pinctrl state named per <pinctrl-bindings.txt>. +- pinctrl[0...n]: Properties to contain the phandle for pinctrl states per + <pinctrl-bindings.txt>. + +The pin configurations are defined as child of the pinctrl states node. Each +sub-node have following properties: + +Required properties: +------------------ +- pins: List of pins. Valid values of pins properties are: + gpio0 ... gpio7 for the devices with 8 GPIO pins and + gpio0 ... gpio15 for the devices with 16 GPIO pins. + +Optional properties: +------------------- +The following optional property is defined in the pinmux DT binding document +<pinctrl-bindings.txt>. Absence of this property will leave the configuration +in its default state. + bias-pull-up + +Example with pinctrl to pull-up output pins: +gpio21: gpio@21 { + compatible = "microchip,mcp23017"; + gpio-controller; + #gpio-cells = <0x2>; + reg = <0x21>; + interrupt-parent = <&socgpio>; + interrupts = <0x17 0x8>; + interrupt-names = "mcp23017@21 irq"; + interrupt-controller; + #interrupt-cells = <0x2>; + microchip,irq-mirror; + pinctrl-names = "default"; + pinctrl-0 = <&i2cgpio0irq>, <&gpio21pullups>; + reset-gpios = <&gpio6 15 GPIO_ACTIVE_LOW>; + + gpio21pullups: pinmux { + pins = "gpio0", "gpio1", "gpio2", "gpio3", + "gpio4", "gpio5", "gpio6", "gpio7", + "gpio8", "gpio9", "gpio10", "gpio11", + "gpio12", "gpio13", "gpio14", "gpio15"; + bias-pull-up; + }; +}; |