Add description of Cavium Octeon and ThunderX SOC device tree bindings.

CC: Ulf Hansson <redacted>
CC: Rob Herring <redacted>
CC: Mark Rutland <redacted>
CC: devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org

Signed-off-by: Jan Glauber <jglauber-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
Signed-off-by: David Daney <david.daney-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
Signed-off-by: Steven J. Hill <steven.hill-YGCgFSpz5w/QT0dZR+AlfA@public.gmane.org>
---
 .../devicetree/bindings/mmc/cavium-mmc.txt         | 60 ++++++++++++++++++++++
 1 file changed, 60 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mmc/cavium-mmc.txt

diff --git a/Documentation/devicetree/bindings/mmc/cavium-mmc.txt b/Documentation/devicetree/bindings/mmc/cavium-mmc.txt
new file mode 100644
index 0000000..b79e356
--- /dev/null
+++ b/Documentation/devicetree/bindings/mmc/cavium-mmc.txt

@@ -0,0 +1,60 @@
+* Cavium Octeon & ThunderX MMC controller
+
+The highspeed MMC host controller on Caviums SoCs provides an interface
+for MMC and SD types of memory cards.
+
+Supported maximum speeds are the ones of the eMMC standard 4.41 as well
+as the speed of SD standard 4.0. Only 3.3 Volt is supported.
+
+Required properties:
+ - compatible : should be one of:
+   cavium,octeon-6130-mmc
+   cavium,octeon-6130-mmc-slot
+   cavium,octeon-7890-mmc
+   cavium,octeon-7890-mmc-slot
+   cavium,thunder-8190-mmc
+   cavium,thunder-8190-mmc-slot
+   cavium,thunder-8390-mmc
+   cavium,thunder-8390-mmc-slot
+ - reg : mmc controller base registers
+ - clocks : phandle
+
+Optional properties:
+ - for cd, bus-width and additional generic mmc parameters
+   please refer to mmc.txt within this directory
+ - cavium,cmd-clk-skew : number of coprocessor clocks before sampling command
+ - cavium,dat-clk-skew : number of coprocessor clocks before sampling data
+
+Deprecated properties:
+- spi-max-frequency : use max-frequency instead
+- cavium,bus-max-width : use bus-width instead
+
+Examples:
+       mmc_1_4: mmc@1,4 {
+               compatible = "cavium,thunder-8390-mmc";
+               reg = <0x0c00 0 0 0 0>; /* DEVFN = 0x0c (1:4) */
+               #address-cells = <1>;
+               #size-cells = <0>;
+               clocks = <&sclk>;
+
+               mmc-slot@0 {
+                       compatible = "cavium,thunder-8390-mmc-slot";
+                       reg = <0>;
+                       voltage-ranges = <3300 3300>;
+                       vmmc-supply = <&mmc_supply_3v3>;