diff options
| author | Peter Korsgaard <peter.korsgaard@barco.com> | 2011-01-10 22:11:23 +0100 |
|---|---|---|
| committer | Jean Delvare <khali@endymion.delvare> | 2011-01-10 22:11:23 +0100 |
| commit | 92ed1a76ca31774eb27de14b2215841367c68056 (patch) | |
| tree | f9becefa5dbcdaa8cfd65100e1735044cd3910d6 /include/linux | |
| parent | b18a5c80eb2e7e9c72d23f1960b09d78ddf7e5b0 (diff) | |
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 <peter.korsgaard@barco.com>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/gpio-i2cmux.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/include/linux/gpio-i2cmux.h b/include/linux/gpio-i2cmux.h new file mode 100644 index 00000000000..4a333bb0bd0 --- /dev/null +++ b/include/linux/gpio-i2cmux.h @@ -0,0 +1,38 @@ +/* + * gpio-i2cmux interface to platform code + * + * Peter Korsgaard <peter.korsgaard@barco.com> + * + * 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 */ |