w1: add 1-wire master driver for i.MX27 / i.MX31

This patch adds support for the 1-wire master interface for i.MX27 and
i.MX31.

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Evgeniy Polyakov <zbr@ioremap.net>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/w1/masters/mxc-w1 b/Documentation/w1/masters/mxc-w1
new file mode 100644
index 0000000..97f6199
--- /dev/null
+++ b/Documentation/w1/masters/mxc-w1
@@ -0,0 +1,11 @@
+Kernel driver mxc_w1
+====================
+
+Supported chips:
+  * Freescale MX27, MX31 and probably other i.MX SoCs
+    Datasheets:
+        http://www.freescale.com/files/32bit/doc/data_sheet/MCIMX31.pdf?fpsp=1
+	http://www.freescale.com/files/dsp/MCIMX27.pdf?fpsp=1
+
+Author: Originally based on Freescale code, prepared for mainline by
+	Sascha Hauer <s.hauer@pengutronix.de>