path: root/Documentation/devicetree/bindings/gpio
diff options
authorLars Poeschel <poeschel@lemonage.de>2014-01-16 11:44:15 +0100
committerLinus Walleij <linus.walleij@linaro.org>2014-01-17 15:30:14 +0100
commit4e47f91bf741e011a90ceb6241b8d78141709733 (patch)
tree1febf3cbbf59a1202dc5d944d392ce28b6b851fe /Documentation/devicetree/bindings/gpio
parent785acec3eecf4c21bab9e24afb5d354b57a72e03 (diff)
gpio: mcp23s08: Add irq functionality for i2c chips
This adds interrupt functionality for i2c chips to the driver. They can act as a interrupt-controller and generate interrupts, if the inputs change. This is tested with a mcp23017 chip on an arm based platform. v3: - be a bit more clear that the irq functionality is also available on spi versions of the chips, but the linux driver does not support this yet v2: - some more word about irq-mirror property in binding doc - use of_read_bool instead of of_find_property for "interrupt-contrller" and "irq-mirror" - cache the "interrupt-controller" for remove function - do set the irq-mirror bit only if device is marked as interrupt-controller - do create the irq mapping and setup of irq_desc of all possible interrupts in probe path instead of in gpio_to_irq - mark gpios as in use as interrupts in irq in irq_startup and unlock it in irq_shutdown - rename virq to child_irq - remove dev argument from mcp23s08_irq_setup function - move gpiochip_add before mcp23s08_irq_setup in probe path Signed-off-by: Lars Poeschel <poeschel@lemonage.de> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Diffstat (limited to 'Documentation/devicetree/bindings/gpio')
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):
- 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-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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