Add devicetree YAML binding for brcmstb bcm74110 mailbox used
for communicating with a co-processor.

Signed-off-by: Justin Chen <justin.chen@broadcom.com>
---
v2
        Renamed brcm,brcm_{tx|rx} to brcm,{tx|rx}.
        Removed brcm,shmem node. Not necessary to keep in dt.
        Fixed example and added scmi node.

 .../bindings/mailbox/brcm,bcm74110-mbox.yaml  | 70 +++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mailbox/brcm,bcm74110-mbox.yaml

diff --git a/Documentation/devicetree/bindings/mailbox/brcm,bcm74110-mbox.yaml b/Documentation/devicetree/bindings/mailbox/brcm,bcm74110-mbox.yaml
new file mode 100644
index 000000000000..8c3dfffa515f
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/brcm,bcm74110-mbox.yaml
@@ -0,0 +1,70 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/brcm,bcm74110-mbox.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Broadcom BCM74110 Mailbox
+
+maintainers:
+  - Justin Chen <justin.chen@broadcom.com>
+  - Florian Fainelli <florian.fainelli@broadcom.com>
+
+description: Broadcom mailbox hardware first introduced with 74110
+
+properties:
+  compatible:
+    enum:
+      - brcm,bcm74110-mbox
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 2
+
+  "#mbox-cells":
+    const: 2
+    description:
+      The first cell is channel type and second cell is shared memory slot
+
+  brcm,tx:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Mailbox transmit doorbell
+
+  brcm,rx:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Mailbox receive doorbell
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - "#mbox-cells"
+  - brcm,tx
+  - brcm,rx
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    brcm_mailbox: brcm_mailbox@a552000 {
+        #mbox-cells = <0x2>;
+        brcm,rx = <0x7>;
+        brcm,tx = <0x6>;
+        compatible = "brcm,bcm74110-mbox";
+        reg = <0xa552000 0x1104>;
+        interrupts = <0x0 0x67 0x4>, /* DQM 7 */
+                     <0x0 0x66 0x4>; /* DQM 6 */
+    };
+
+    scmi {
+        compatible = "arm,scmi";
+        mboxes = <&brcm_mailbox 0x2 0x0>;
+        mbox-names = "tx";
+        shmem = <&PMCMBOX>;
+        #address-cells = <0x1>;
+        #size-cells = <0x0>;
+    };
-- 
2.34.1

On Wed, Apr 02, 2025 at 03:36:18PM -0700, Justin Chen wrote:
> diff --git a/Documentation/devicetree/bindings/mailbox/brcm,bcm74110-mbox.yaml b/Documentation/devicetree/bindings/mailbox/brcm,bcm74110-mbox.yaml
> new file mode 100644
> index 000000000000..8c3dfffa515f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mailbox/brcm,bcm74110-mbox.yaml
> @@ -0,0 +1,70 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mailbox/brcm,bcm74110-mbox.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Broadcom BCM74110 Mailbox
> +

A nit, subject: drop second/last, redundant "devicetree binding for". The
"dt-bindings" prefix is already stating that these are bindings.
See also:
https://elixir.bootlin.com/linux/v6.7-rc8/source/Documentation/devicetree/bindings/submitting-patches.rst#L18

> +maintainers:
> +  - Justin Chen <justin.chen@broadcom.com>
> +  - Florian Fainelli <florian.fainelli@broadcom.com>
> +
> +description: Broadcom mailbox hardware first introduced with 74110
> +
> +properties:
> +  compatible:
> +    enum:
> +      - brcm,bcm74110-mbox
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 2

This changed... You need now list items instead.

> +
> +  "#mbox-cells":
> +    const: 2
> +    description:
> +      The first cell is channel type and second cell is shared memory slot
> +
> +  brcm,tx:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: Mailbox transmit doorbell
> +
> +  brcm,rx:
> +    $ref: /schemas/types.yaml#/definitions/uint32
> +    description: Mailbox receive doorbell
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - "#mbox-cells"
> +  - brcm,tx
> +  - brcm,rx
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/irq.h>

... and where do you use it?

> +
> +    brcm_mailbox: brcm_mailbox@a552000 {

Only partially improved.

Node names should be generic. See also an explanation and list of
examples (not exhaustive) in DT specification:
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation

> +        #mbox-cells = <0x2>;
> +        brcm,rx = <0x7>;
> +        brcm,tx = <0x6>;
> +        compatible = "brcm,bcm74110-mbox";

Nothing improved. Didi you read the DTS coding style?

> +        reg = <0xa552000 0x1104>;
> +        interrupts = <0x0 0x67 0x4>, /* DQM 7 */
> +                     <0x0 0x66 0x4>; /* DQM 6 */

Looks like standard flags, so use proper defines.

> +    };
> +
> +    scmi {

Drop the node, not related.

Best regards,
Krzysztof