From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: [PATCH] i2c-mux-gpio: Update documentation Date: Tue, 2 Oct 2012 23:09:56 +0200 Message-ID: <20121002230956.49c4fe46@endymion.delvare> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Linux I2C Cc: Peter Korsgaard List-Id: linux-i2c@vger.kernel.org * 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(+) --- linux-3.7-rc0.orig/Documentation/i2c/muxes/i2c-mux-gpio 2012-07-21 22:58:29.000000000 +0200 +++ linux-3.7-rc0/Documentation/i2c/muxes/i2c-mux-gpio 2012-10-02 23:06:15.131690033 +0200 @@ -63,3 +63,21 @@ static struct platform_device myboard_i2 .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. -- Jean Delvare