2 files changed, 23 insertions, 1 deletions

diff --git a/Documentation/i2c/busses/i2c-viapro b/Documentation/i2c/busses/i2c-viapro
index 2e758b0e9456..b88f91ae580e 100644
--- a/Documentation/i2c/busses/i2c-viapro
+++ b/Documentation/i2c/busses/i2c-viapro
@@ -20,7 +20,10 @@ Supported adapters:
     Datasheet: available on http://linux.via.com.tw
 
   * VIA Technologies, Inc. VX855/VX875
-    Datasheet: Availability unknown
+    Datasheet: available on http://linux.via.com.tw
+
+  * VIA Technologies, Inc. VX900
+    Datasheet: available on http://linux.via.com.tw
 
 Authors:
         Kyösti Mälkki <kmalkki@cc.hut.fi>,
@@ -57,6 +60,7 @@ Your lspci -n listing must show one of these :
  device 1106:8324   (CX700)
  device 1106:8353   (VX800/VX820)
  device 1106:8409   (VX855/VX875)
+ device 1106:8410   (VX900)
 
 If none of these show up, you should look in the BIOS for settings like
 enable ACPI / SMBus or even USB.
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
+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.