[PATCH v5 1/8] dt-bindings: mailbox: apple: Add DockChannel mailbox

[Michael Reeves via B4 Relay <devnull+michael.reeves077.gmail.com@kernel.org>]

From: Michael Reeves <michael.reeves077@gmail.com>

DockChannel is a FIFO and interrupt block used by Apple coprocessors
to exchange byte-stream traffic with the AP.

Describe it as a mailbox provider for HID and serial clients. The FIFO
interrupt pair is configurable because MTP and DebugUSB use different
pairs.

Suggested-by: Yureka Lilian <yureka@cyberchaos.dev>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Michael Reeves <michael.reeves077@gmail.com>
---
 .../bindings/mailbox/apple,t8112-dockchannel.yaml  | 88 ++++++++++++++++++++++
 MAINTAINERS                                        |  1 +
 2 files changed, 89 insertions(+)

diff --git a/Documentation/devicetree/bindings/mailbox/apple,t8112-dockchannel.yaml b/Documentation/devicetree/bindings/mailbox/apple,t8112-dockchannel.yaml
new file mode 100644
index 000000000000..9afd58613074
--- /dev/null
+++ b/Documentation/devicetree/bindings/mailbox/apple,t8112-dockchannel.yaml
@@ -0,0 +1,88 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mailbox/apple,t8112-dockchannel.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Apple DockChannel FIFO Mailbox
+
+maintainers:
+  - Michael Reeves <michael.reeves077@gmail.com>
+
+description:
+  DockChannel is a hardware FIFO and interrupt block used on Apple SoCs for
+  low-latency byte stream communication with co-processors.
+
+properties:
+  compatible:
+    oneOf:
+      - items:
+          - const: apple,t8112-dockchannel
+      - items:
+          - enum:
+              - apple,t6020-dockchannel
+              - apple,t6030-dockchannel
+              - apple,t6031-dockchannel
+              - apple,t8122-dockchannel
+          - const: apple,t8112-dockchannel
+
+  reg:
+    items:
+      - description: Interrupt control registers
+      - description: FIFO configuration registers
+      - description: FIFO data registers
+
+  reg-names:
+    items:
+      - const: irq
+      - const: config
+      - const: data
+
+  interrupts:
+    maxItems: 1
+
+  "#mbox-cells":
+    const: 0
+
+  apple,irq-index:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    maximum: 15
+    default: 1
+    description: |
+      Index of the FIFO interrupt pair in the interrupt control registers.
+      TX uses bit (2 * index) and RX uses bit (2 * index + 1). The configuration
+      and data register resources must describe the corresponding FIFO.
+      If absent, pair 1 is used for compatibility with older keyboard nodes.
+
+  nonposted-mmio: true
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - "#mbox-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/apple-aic.h>
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    soc {
+        #address-cells = <2>;
+        #size-cells = <2>;
+
+        mailbox@24eb14000 {
+            compatible = "apple,t8112-dockchannel";
+            reg = <0x2 0x4eb14000 0x0 0x4000>,
+                  <0x2 0x4eb30000 0x0 0x4000>,
+                  <0x2 0x4eb34000 0x0 0x4000>;
+            reg-names = "irq", "config", "data";
+            interrupt-parent = <&aic>;
+            interrupts = <AIC_IRQ 850 IRQ_TYPE_LEVEL_HIGH>;
+            #mbox-cells = <0>;
+            apple,irq-index = <1>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index b2eaee98852f..0c1963150f04 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -2720,6 +2720,7 @@ F:	Documentation/devicetree/bindings/iommu/apple,dart.yaml
 F:	Documentation/devicetree/bindings/iommu/apple,sart.yaml
 F:	Documentation/devicetree/bindings/leds/backlight/apple,dwi-bl.yaml
 F:	Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
+F:	Documentation/devicetree/bindings/mailbox/apple,t8112-dockchannel.yaml
 F:	Documentation/devicetree/bindings/mfd/apple,smc.yaml
 F:	Documentation/devicetree/bindings/net/bluetooth/brcm,bcm4377-bluetooth.yaml
 F:	Documentation/devicetree/bindings/nvme/apple,nvme-ans.yaml

-- 
2.56.0