drivers/gpio: add support for MAX7320 i2c i/o expander
This commit adds support for the MAX7320 (and clones) gpio expander.
Signed-off-by: Hannes Schmelzer <hannes.schmelzer@br-automation.com>
diff --git a/doc/device-tree-bindings/gpio/gpio-max7320.txt b/doc/device-tree-bindings/gpio/gpio-max7320.txt
new file mode 100644
index 0000000..87b703b
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+++ b/doc/device-tree-bindings/gpio/gpio-max7320.txt
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+* MAX7320 I/O expanders
+
+The original maxim 7320 i/o expander offers 8 bit push/pull outputs.
+There exists some clones which offers 16 bit.
+
+Required Properties:
+
+ - compatible: should be one of the following.
+ - "maxim,max7320"
+
+ - reg: I2C slave address.
+
+ - gpio-controller: Marks the device node as a gpio controller.
+ - #gpio-cells: Should be 2. The first cell is the GPIO number and the second
+ cell specifies GPIO flags, as defined in <dt-bindings/gpio/gpio.h>. Only the
+ GPIO_ACTIVE_HIGH and GPIO_ACTIVE_LOW flags are supported.
+
+Optional Properties:
+
+ - ngpios: tell the driver how many gpios the device offers.
+ if the property is omitted, 8bit (original maxim) is assumed.
+
+Please refer to gpio.txt in this directory for details of the common GPIO
+bindings used by client devices.
+
+Example: MAX7320 I/O expander node
+
+ ledgpio: max7320@5d {
+ status = "okay";
+ compatible = "maxim,max7320";
+ reg = <0x5d>;
+ #gpio-cells = <2>;
+ gpio-controller;
+ ngpios = <16>;
+ };
+