dt-bindings: mailbox: Document armada-3700-rwtm-mailbox binding

This adds device tree binding documentation for the rWTM BIU mailbox
driver on the Armada 37xx SOC (EspressoBin, Turris Mox).

Signed-off-by: Marek Behun <marek.behun@nic.cz>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

diff --git a/Documentation/devicetree/bindings/mailbox/marvell,armada-3700-rwtm-mailbox.txt b/Documentation/devicetree/bindings/mailbox/marvell,armada-3700-rwtm-mailbox.txt
new file mode 100644 (file)
index 0000000..282ab81
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/marvell,armada-3700-rwtm-mailbox.txt
@@ -0,0 +1,16 @@
+* rWTM BIU Mailbox driver for Armada 37xx
+
+Required properties:
+- compatible:  must be "marvell,armada-3700-rwtm-mailbox"
+- reg:         physical base address of the mailbox and length of memory mapped
+               region
+- interrupts:  the IRQ line for the mailbox
+- #mbox-cells: must be 1
+
+Example:
+       rwtm: mailbox@b0000 {
+               compatible = "marvell,armada-3700-rwtm-mailbox";
+               reg = <0xb0000 0x100>;
+               interrupts = <GIC_SPI 18 IRQ_TYPE_LEVEL_HIGH>;
+               #mbox-cells = <1>;
+       };