Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 83 insertions, 0 deletions

diff --git a/kernel/Documentation/i2c/muxes/i2c-mux-gpio b/kernel/Documentation/i2c/muxes/i2c-mux-gpio
new file mode 100644
index 000000000..d4d91a53f
--- /dev/null
+++ b/kernel/Documentation/i2c/muxes/i2c-mux-gpio
@@ -0,0 +1,83 @@
+Kernel driver i2c-gpio-mux
+
+Author: Peter Korsgaard <peter.korsgaard@barco.com>
+
+Description
+-----------
+
+i2c-gpio-mux is an i2c mux driver providing access to I2C bus segments
+from a master I2C bus and a hardware MUX controlled through GPIO pins.
+
+E.G.:
+
+  ----------              ----------  Bus segment 1   - - - - -
+ |          | SCL/SDA    |          |-------------- |           |
+ |          |------------|          |
+ |          |            |          | Bus segment 2 |           |
+ |  Linux   | GPIO 1..N  |   MUX    |---------------   Devices
+ |          |------------|          |               |           |
+ |          |            |          | Bus segment M
+ |          |            |          |---------------|           |
+  ----------              ----------                  - - - - -
+
+SCL/SDA of the master I2C bus is multiplexed to bus segment 1..M
+according to the settings of the GPIO pins 1..N.
+
+Usage
+-----
+
+i2c-gpio-mux uses the platform bus, so you need to provide a struct
+platform_device with the platform_data pointing to a struct
+gpio_i2cmux_platform_data with the I2C adapter number of the master
+bus, the number of bus segments to create and the GPIO pins used
+to control it. See include/linux/i2c-gpio-mux.h for details.
+
+E.G. something like this for a MUX providing 4 bus segments
+controlled through 3 GPIO pins:
+
+#include <linux/i2c-gpio-mux.h>
+#include <linux/platform_device.h>
+
+static const unsigned myboard_gpiomux_gpios[] = {
+	AT91_PIN_PC26, AT91_PIN_PC25, AT91_PIN_PC24
+};
+
+static const unsigned myboard_gpiomux_values[] = {
+	0, 1, 2, 3
+};
+
+static struct gpio_i2cmux_platform_data myboard_i2cmux_data = {
+	.parent		= 1,
+	.base_nr	= 2, /* optional */
+	.values		= myboard_gpiomux_values,
+	.n_values	= ARRAY_SIZE(myboard_gpiomux_values),
+	.gpios		= myboard_gpiomux_gpios,
+	.n_gpios	= ARRAY_SIZE(myboard_gpiomux_gpios),
+	.idle		= 4, /* optional */
+};
+
+static struct platform_device myboard_i2cmux = {
+	.name		= "i2c-gpio-mux",
+	.id		= 0,
+	.dev		= {
+		.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.