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-rw-r--r--Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt28
1 files changed, 27 insertions, 1 deletions
diff --git a/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
index daa30174bcc1..3ddc7ccfe5f3 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
+++ b/Documentation/devicetree/bindings/gpio/gpio-mcp23s08.txt
@@ -38,12 +38,38 @@ Required device specific properties (only for SPI chips):
removed.
- spi-max-frequency = The maximum frequency this chip is able to handle
-Example I2C:
+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.
+NOTE: The interrupt functionality is only supported for i2c versions of the
+chips. The spi chips can also do the interrupts, but this is not supported by
+the linux driver yet.
+
+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
+ occured 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.
+
+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:

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