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, 41 insertions, 0 deletions

diff --git a/kernel/drivers/staging/iio/Documentation/dac/max517 b/kernel/drivers/staging/iio/Documentation/dac/max517
new file mode 100644
index 000000000..e60ec2f91
--- /dev/null
+++ b/kernel/drivers/staging/iio/Documentation/dac/max517
@@ -0,0 +1,41 @@
+Kernel driver max517
+====================
+
+Supported chips:
+  * Maxim MAX517, MAX518, MAX519
+    Prefix: 'max517'
+    Datasheet: Publicly available at the Maxim website
+               http://www.maxim-ic.com/
+
+Author:
+        Roland Stigge <stigge@antcom.de>
+
+Description
+-----------
+
+The Maxim MAX517/518/519 is an 8-bit DAC on the I2C bus. The following table
+shows the different feature sets of the variants MAX517, MAX518 and MAX519:
+
+Feature                              MAX517 MAX518 MAX519
+--------------------------------------------------------------------------
+One output channel                   X
+Two output channels                         X      X
+Simultaneous output updates                 X      X
+Supply voltage as reference                 X
+Separate reference input             X
+Reference input for each DAC                       X
+
+Via the iio sysfs interface, there are three attributes available: out1_raw,
+out2_raw and out12_raw. With out1_raw and out2_raw, the current output values
+(0..255) of the DACs can be written to the device. out12_raw can be used to set
+both output channel values simultaneously.
+
+With MAX517, only out1_raw is available.
+
+Via out1_scale (and where appropriate, out2_scale), the current scaling factor
+in mV can be read.
+
+When the operating system goes to a power down state, the Power Down function
+of the chip is activated, reducing the supply current to 4uA.
+
+On power-up, the device is in 0V-output state.