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authorJean Delvare <khali@linux-fr.org>2012-04-28 09:32:06 -0400
committerWolfram Sang <w.sang@pengutronix.de>2012-05-12 08:28:18 -0400
commite7065e20d9a6a8ee4a8b31ebe71d6c00a0f45354 (patch)
tree2f219f7db3371d477733bbcf6d8f56e5bac1cf69 /Documentation/i2c/muxes/i2c-mux-gpio
parent353f56b5f3093b6d75e81f523a8b10748a40f278 (diff)
i2c: Rename last mux driver to standard pattern
Update the MAINTAINERS entry and all other references accordingly. Based on an original patch by Wolfram Sang. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Peter Korsgaard <peter.korsgaard@barco.com> [wsa: fixed merge conflict due to rework in i2c_add_mux_adapter()] Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Diffstat (limited to 'Documentation/i2c/muxes/i2c-mux-gpio')
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diff --git a/Documentation/i2c/muxes/i2c-mux-gpio b/Documentation/i2c/muxes/i2c-mux-gpio
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1Kernel driver i2c-gpio-mux
2
3Author: Peter Korsgaard <peter.korsgaard@barco.com>
4
5Description
6-----------
7
8i2c-gpio-mux is an i2c mux driver providing access to I2C bus segments
9from a master I2C bus and a hardware MUX controlled through GPIO pins.
10
11E.G.:
12
13 ---------- ---------- Bus segment 1 - - - - -
14 | | SCL/SDA | |-------------- | |
15 | |------------| |
16 | | | | Bus segment 2 | |
17 | Linux | GPIO 1..N | MUX |--------------- Devices
18 | |------------| | | |
19 | | | | Bus segment M
20 | | | |---------------| |
21 ---------- ---------- - - - - -
22
23SCL/SDA of the master I2C bus is multiplexed to bus segment 1..M
24according to the settings of the GPIO pins 1..N.
25
26Usage
27-----
28
29i2c-gpio-mux uses the platform bus, so you need to provide a struct
30platform_device with the platform_data pointing to a struct
31gpio_i2cmux_platform_data with the I2C adapter number of the master
32bus, the number of bus segments to create and the GPIO pins used
33to control it. See include/linux/i2c-gpio-mux.h for details.
34
35E.G. something like this for a MUX providing 4 bus segments
36controlled through 3 GPIO pins:
37
38#include <linux/i2c-gpio-mux.h>
39#include <linux/platform_device.h>
40
41static const unsigned myboard_gpiomux_gpios[] = {
42 AT91_PIN_PC26, AT91_PIN_PC25, AT91_PIN_PC24
43};
44
45static const unsigned myboard_gpiomux_values[] = {
46 0, 1, 2, 3
47};
48
49static struct gpio_i2cmux_platform_data myboard_i2cmux_data = {
50 .parent = 1,
51 .base_nr = 2, /* optional */
52 .values = myboard_gpiomux_values,
53 .n_values = ARRAY_SIZE(myboard_gpiomux_values),
54 .gpios = myboard_gpiomux_gpios,
55 .n_gpios = ARRAY_SIZE(myboard_gpiomux_gpios),
56 .idle = 4, /* optional */
57};
58
59static struct platform_device myboard_i2cmux = {
60 .name = "i2c-gpio-mux",
61 .id = 0,
62 .dev = {
63 .platform_data = &myboard_i2cmux_data,
64 },
65};