From 600a711cfeb10769e386c4ce7d39e9f0cc4b471a Mon Sep 17 00:00:00 2001 From: Jean Delvare Date: Fri, 5 Oct 2012 22:23:54 +0200 Subject: i2c-mux-gpio: Update documentation * Document the possibility to pass relative GPIO pin numbers. * Document what platform device IDs to use, so that they do not collide. Signed-off-by: Jean Delvare Cc: Peter Korsgaard --- Documentation/i2c/muxes/i2c-mux-gpio | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/Documentation/i2c/muxes/i2c-mux-gpio b/Documentation/i2c/muxes/i2c-mux-gpio index bd9b2299b73..d4d91a53fc3 100644 --- a/Documentation/i2c/muxes/i2c-mux-gpio +++ b/Documentation/i2c/muxes/i2c-mux-gpio @@ -63,3 +63,21 @@ static struct platform_device myboard_i2cmux = { .platform_data = &myboard_i2cmux_data, }, }; + +If you don't know the absolute GPIO pin numbers at registration time, +you can instead provide a chip name (.chip_name) and relative GPIO pin +numbers, and the i2c-gpio-mux driver will do the work for you, +including deferred probing if the GPIO chip isn't immediately +available. + +Device Registration +------------------- + +When registering your i2c-gpio-mux device, you should pass the number +of any GPIO pin it uses as the device ID. This guarantees that every +instance has a different ID. + +Alternatively, if you don't need a stable device name, you can simply +pass PLATFORM_DEVID_AUTO as the device ID, and the platform core will +assign a dynamic ID to your device. If you do not know the absolute +GPIO pin numbers at registration time, this is even the only option. -- cgit v1.2.3