diff options
author | Jean Delvare <khali@linux-fr.org> | 2012-04-28 09:32:06 -0400 |
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committer | Wolfram Sang <w.sang@pengutronix.de> | 2012-05-12 08:28:18 -0400 |
commit | e7065e20d9a6a8ee4a8b31ebe71d6c00a0f45354 (patch) | |
tree | 2f219f7db3371d477733bbcf6d8f56e5bac1cf69 /Documentation/i2c/muxes/i2c-mux-gpio | |
parent | 353f56b5f3093b6d75e81f523a8b10748a40f278 (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')
-rw-r--r-- | Documentation/i2c/muxes/i2c-mux-gpio | 65 |
1 files changed, 65 insertions, 0 deletions
diff --git a/Documentation/i2c/muxes/i2c-mux-gpio b/Documentation/i2c/muxes/i2c-mux-gpio new file mode 100644 index 000000000000..bd9b2299b739 --- /dev/null +++ b/Documentation/i2c/muxes/i2c-mux-gpio | |||
@@ -0,0 +1,65 @@ | |||
1 | Kernel driver i2c-gpio-mux | ||
2 | |||
3 | Author: Peter Korsgaard <peter.korsgaard@barco.com> | ||
4 | |||
5 | Description | ||
6 | ----------- | ||
7 | |||
8 | i2c-gpio-mux is an i2c mux driver providing access to I2C bus segments | ||
9 | from a master I2C bus and a hardware MUX controlled through GPIO pins. | ||
10 | |||
11 | E.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 | |||
23 | SCL/SDA of the master I2C bus is multiplexed to bus segment 1..M | ||
24 | according to the settings of the GPIO pins 1..N. | ||
25 | |||
26 | Usage | ||
27 | ----- | ||
28 | |||
29 | i2c-gpio-mux uses the platform bus, so you need to provide a struct | ||
30 | platform_device with the platform_data pointing to a struct | ||
31 | gpio_i2cmux_platform_data with the I2C adapter number of the master | ||
32 | bus, the number of bus segments to create and the GPIO pins used | ||
33 | to control it. See include/linux/i2c-gpio-mux.h for details. | ||
34 | |||
35 | E.G. something like this for a MUX providing 4 bus segments | ||
36 | controlled through 3 GPIO pins: | ||
37 | |||
38 | #include <linux/i2c-gpio-mux.h> | ||
39 | #include <linux/platform_device.h> | ||
40 | |||
41 | static const unsigned myboard_gpiomux_gpios[] = { | ||
42 | AT91_PIN_PC26, AT91_PIN_PC25, AT91_PIN_PC24 | ||
43 | }; | ||
44 | |||
45 | static const unsigned myboard_gpiomux_values[] = { | ||
46 | 0, 1, 2, 3 | ||
47 | }; | ||
48 | |||
49 | static 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 | |||
59 | static struct platform_device myboard_i2cmux = { | ||
60 | .name = "i2c-gpio-mux", | ||
61 | .id = 0, | ||
62 | .dev = { | ||
63 | .platform_data = &myboard_i2cmux_data, | ||
64 | }, | ||
65 | }; | ||