From 92ed1a76ca31774eb27de14b2215841367c68056 Mon Sep 17 00:00:00 2001 From: Peter Korsgaard Date: Mon, 10 Jan 2011 22:11:23 +0100 Subject: i2c: Add generic I2C multiplexer using GPIO API Add an i2c mux driver providing access to i2c bus segments using a hardware MUX sitting on a master bus and controlled through gpio pins. E.G. something like: ---------- ---------- Bus segment 1 - - - - - | | SCL/SDA | |-------------- | | | |------------| | | | | | Bus segment 2 | | | Linux | GPIO 1..N | MUX |--------------- Devices | |------------| | | | | | | | Bus segment M | | | |---------------| | ---------- ---------- - - - - - SCL/SDA of the master I2C bus is multiplexed to bus segment 1..M according to the settings of the GPIO pins 1..N. Signed-off-by: Peter Korsgaard Signed-off-by: Jean Delvare --- include/linux/gpio-i2cmux.h | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 include/linux/gpio-i2cmux.h (limited to 'include/linux/gpio-i2cmux.h') diff --git a/include/linux/gpio-i2cmux.h b/include/linux/gpio-i2cmux.h new file mode 100644 index 000000000000..4a333bb0bd0d --- /dev/null +++ b/include/linux/gpio-i2cmux.h @@ -0,0 +1,38 @@ +/* + * gpio-i2cmux interface to platform code + * + * Peter Korsgaard + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _LINUX_GPIO_I2CMUX_H +#define _LINUX_GPIO_I2CMUX_H + +/* MUX has no specific idle mode */ +#define GPIO_I2CMUX_NO_IDLE ((unsigned)-1) + +/** + * struct gpio_i2cmux_platform_data - Platform-dependent data for gpio-i2cmux + * @parent: Parent I2C bus adapter number + * @base_nr: Base I2C bus number to number adapters from or zero for dynamic + * @values: Array of bitmasks of GPIO settings (low/high) for each + * position + * @n_values: Number of multiplexer positions (busses to instantiate) + * @gpios: Array of GPIO numbers used to control MUX + * @n_gpios: Number of GPIOs used to control MUX + * @idle: Bitmask to write to MUX when idle or GPIO_I2CMUX_NO_IDLE if not used + */ +struct gpio_i2cmux_platform_data { + int parent; + int base_nr; + const unsigned *values; + int n_values; + const unsigned *gpios; + int n_gpios; + unsigned idle; +}; + +#endif /* _LINUX_GPIO_I2CMUX_H */ -- cgit v1.2.2