i2c: mv64xxx: Document the newly introduced Armada XP A0 compatible

commit f8b94beb7e6a374cb0de531b72377c49857b35ca upstream.

The first variants of Armada XP SoCs (A0 stepping) have issues related
to the i2c controller which prevent to use the offload mechanism and
lead to a kernel hang during boot.

The commit introduces a new the compatible string
marvell,mv78230-a0-i2c for the i2c controller.

Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
cc: devicetree@vger.kernel.org
Fixes: 930ab3d403ae (i2c: mv64xxx: Add I2C Transaction Generator support)
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
index 82e8f6f..582b465 100644 (file)
--- a/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c-mv64xxx.txt
@@ -5,7 +5,11 @@ Required properties :
 
  - reg             : Offset and length of the register set for the device
  - compatible      : Should be "marvell,mv64xxx-i2c" or "allwinner,sun4i-i2c"
-                     or "marvell,mv78230-i2c"
+                     or "marvell,mv78230-i2c" or "marvell,mv78230-a0-i2c"
+                     Note: Only use "marvell,mv78230-a0-i2c" for a very rare,
+                     initial version of the SoC which had broken offload
+                     support.  Linux auto-detects this and sets it
+                     appropriately.
  - interrupts      : The interrupt number
 
 Optional properties :