dt-bindings: mailbox: Document Hi6220 mailbox driver

Document DT binding for Hisilicon Hi6220 mailbox driver.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Jassi Brar <jaswinder.singh@linaro.org>

1 files changed, 74 insertions, 0 deletions

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+Hisilicon Hi6220 Mailbox Driver
+===============================
+
+Hisilicon Hi6220 mailbox supports up to 32 channels. Each channel
+is unidirectional with a maximum message size of 8 words. I/O is
+performed using register access (there is no DMA) and the cell
+raises an interrupt when messages are received.
+
+Mailbox Device Node:
+====================
+
+Required properties:
+--------------------
+- compatible:           Shall be "hisilicon,hi6220-mbox"
+- reg:                  Contains the mailbox register address range (base
+                        address and length); the first item is for IPC
+                        registers, the second item is shared buffer for
+                        slots.
+- #mbox-cells:          Common mailbox binding property to identify the number
+                        of cells required for the mailbox specifier. Must be 3.
+                        <&phandle slot_id dst_irq ack_irq>
+                          phandle: Label name of mailbox controller
+                          slot_id: Slot id used either for TX or RX
+                          dst_irq: IRQ identifier index number which used by MCU
+                          ack_irq: IRQ identifier index number with generating a
+                                   TX/RX interrupt to application processor,
+                                   mailbox driver uses it to acknowledge interrupt
+- interrupts:           Contains the interrupt information for the mailbox
+                        device. The format is dependent on which interrupt
+                        controller the SoCs use.
+
+Optional Properties:
+--------------------
+- hi6220,mbox-tx-noirq: Property of MCU firmware's feature, so mailbox driver
+                        use this flag to ask MCU to enable "automatic idle
+                        flag" mode or IRQ generated mode to acknowledge a TX
+                        completion.
+
+Example:
+--------
+
+        mailbox: mailbox@f7510000 {
+                compatible = "hisilicon,hi6220-mbox";
+                reg = <0x0 0xf7510000 0x0 0x1000>, /* IPC_S */
+                      <0x0 0x06dff800 0x0 0x0800>; /* Mailbox */
+                interrupt-parent = <&gic>;
+                interrupts = <GIC_SPI 94 IRQ_TYPE_LEVEL_HIGH>;
+                #mbox-cells = <3>;
+        };
+
+
+Mailbox client
+===============
+
+Required properties:
+--------------------
+- compatible:           Many (See the client docs).
+- mboxes:               Standard property to specify a Mailbox (See ./mailbox.txt)
+                        Cells must match 'mbox-cells' (See Mailbox Device Node above).
+
+Optional Properties:
+--------------------
+- mbox-names:           Name given to channels seen in the 'mboxes' property.
+
+Example:
+--------
+
+        stub_clock: stub_clock {
+                compatible = "hisilicon,hi6220-stub-clk";
+                hisilicon,hi6220-clk-sram = <&sram>;
+                #clock-cells = <1>;
+                mbox-names = "mbox-tx", "mbox-rx";
+                mboxes = <&mailbox 1 0 11>, <&mailbox 0 1 10>;
+        };