path: root/Documentation/i2c
diff options
authorJean Delvare <khali@linux-fr.org>2012-10-05 22:23:54 +0200
committerJean Delvare <khali@endymion.delvare>2012-10-05 22:23:54 +0200
commit600a711cfeb10769e386c4ce7d39e9f0cc4b471a (patch)
treea922d6b426495e70e93d6c144dc15fad22c9d2ae /Documentation/i2c
parente7ee51405835cac72e7b6e0ff26dba608cf186cc (diff)
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 <khali@linux-fr.org> Cc: Peter Korsgaard <peter.korsgaard@barco.com>
Diffstat (limited to 'Documentation/i2c')
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/i2c/muxes/i2c-mux-gpio b/Documentation/i2c/muxes/i2c-mux-gpio
index bd9b2299b739..d4d91a53fc39 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
+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.

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