> +
> + reg-names:
> + items:
> + - const: local
> + - const: remote-icu0
> + - const: remote-icu1
> + - const: remote-icu2
> +
> + interrupts:
> + maxItems: 1
> +
> + '#mbox-cells':
> + const: 2
> + description: |
> + Specifies the number of cells needed to encode the mailbox specifier.
> + The mailbox specifier consists of two cells:
> + - Destination CPU ID.
> + - Type, which can be one of the following:
> + - 0:
> + - TX & RX channels share the same channel.
> + - Equipped with 7 info registers to facilitate data sharing.
> + - Supports IRQ for signaling.
> + - 1:
> + - TX & RX operate as doorbell channels.
> + - Does not have dedicated info registers.
> + - Lacks ACK support.
It appears that these types are not describing hardware, but the protocol used
by the Linux driver to glue two unidirectional hardware channels together to
make a virtual bidirectional channel. This is really the responsibility of the
mailbox client to know what protocol it needs, not the devicetree.
Regards,
Samuel
> +
> +required:
> + - compatible
> + - reg
> + - reg-names
> + - interrupts
> + - '#mbox-cells'
> +
> +additionalProperties: false
> +
> +examples:
> + - |
> +
> + soc {
> + #address-cells = <2>;
> + #size-cells = <2>;
> + mailbox@ffffc38000 {
> + compatible = "thead,th1520-mbox";
> + reg = <0xff 0xffc38000 0x0 0x4000>,
> + <0xff 0xffc44000 0x0 0x1000>,
> + <0xff 0xffc4c000 0x0 0x1000>,
> + <0xff 0xffc54000 0x0 0x1000>;
> + reg-names = "local", "remote-icu0", "remote-icu1", "remote-icu2";
> + interrupts = <28>;
> + #mbox-cells = <2>;
> + };
> + };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0655c6ba5435..7401c7cb6533 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -19951,6 +19951,7 @@ L: linux-riscv@xxxxxxxxxxxxxxxxxxx
> S: Maintained
> T: git https://github.com/pdp7/linux.git
> F: Documentation/devicetree/bindings/clock/thead,th1520-clk-ap.yaml
> +F: Documentation/devicetree/bindings/mailbox/thead,th1520-mbox.yaml
> F: arch/riscv/boot/dts/thead/
> F: drivers/clk/thead/clk-th1520-ap.c
> F: drivers/mailbox/mailbox-th1520.c
