dt-bindings: mailbox: Add Amlogic Meson MHU Bindings

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

diff --git a/Documentation/devicetree/bindings/mailbox/meson-mhu.txt b/Documentation/devicetree/bindings/mailbox/meson-mhu.txt
new file mode 100644 (file)
index 0000000..a530310
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+Amlogic Meson MHU Mailbox Driver
+================================
+
+The Amlogic's Meson SoCs Message-Handling-Unit (MHU) is a mailbox controller
+that has 3 independent channels/links to communicate with remote processor(s).
+MHU links are hardwired on a platform. A link raises interrupt for any
+received data. However, there is no specified way of knowing if the sent
+data has been read by the remote. This driver assumes the sender polls
+STAT register and the remote clears it after having read the data.
+
+Mailbox Device Node:
+====================
+
+Required properties:
+--------------------
+- compatible:          Shall be "amlogic,meson-gxbb-mhu"
+- reg:                 Contains the mailbox register address range (base
+                       address and length)
+- #mbox-cells          Shall be 1 - the index of the channel needed.
+- interrupts:          Contains the interrupt information corresponding to
+                       each of the 2 links of MHU.
+
+Example:
+--------
+
+       mailbox: mailbox@c883c404 {
+               #mbox-cells = <1>;
+               compatible = "amlogic,meson-gxbb-mhu";
+               reg = <0 0xc883c404 0 0x4c>;
+               interrupts = <0 208 IRQ_TYPE_EDGE_RISING>,
+                            <0 209 IRQ_TYPE_EDGE_RISING>,
+                            <0 210 IRQ_TYPE_EDGE_RISING>;
+               #mbox-cells = <1>;
+       };