[PATCH] dt-bindings: misc: add binding for Xilinx AXI4-Stream FIFO MM S

[Daniel28972897 <danyboy28sep@gmail.com>]

The axis-fifo driver (drivers/staging/axis-fifo/axis-fifo.c) has
supported the "xlnx,axi-fifo-mm-s-4.1", "xlnx,axi-fifo-mm-s-4.2" and
"xlnx,axi-fifo-mm-s-4.3" compatible strings since it was added, but no
devicetree binding schema exists for them, which checkpatch.pl flags:

  WARNING: DT compatible string "xlnx,axi-fifo-mm-s-4.1" appears
  un-documented -- check ./Documentation/devicetree/bindings/

Add a schema documenting the compatible strings and the six
xlnx,*-prefixed properties the driver reads in
axis_fifo_parse_dt(), all of which are currently required by the
driver's own error handling.

Validated with:
  make dt_binding_check DT_SCHEMA_FILES=Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml

Signed-off-by: Daniel28972897 <danyboy28sep@gmail.com>
---
 .../bindings/misc/xlnx,axi-fifo-mm-s.yaml     | 91 +++++++++++++++++++
 1 file changed, 91 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml

diff --git a/Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml b/Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml
new file mode 100644
index 000000000000..56d58b37b71e
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml
@@ -0,0 +1,91 @@
+# SPDX-License-Identifier: GPL-2.0 OR BSD-2-Clause
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/misc/xlnx,axi-fifo-mm-s.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Xilinx AXI4-Stream FIFO MM S IP core
+
+maintainers:
+  - Daniel <danyboy28sep@gmail.com>
+
+description:
+  The Xilinx AXI4-Stream FIFO MM S IP core provides a simple interface
+  to move data between the AXI4-Stream and AXI4 memory-mapped domains.
+  See Xilinx PG080 for details.
+
+properties:
+  compatible:
+    enum:
+      - xlnx,axi-fifo-mm-s-4.1
+      - xlnx,axi-fifo-mm-s-4.2
+      - xlnx,axi-fifo-mm-s-4.3
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  xlnx,axi-str-rxd-tdata-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 32
+    description:
+      Width, in bits, of the AXI4-Stream receive data interface.
+      Only 32 is currently supported by the driver.
+
+  xlnx,axi-str-txd-tdata-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 32
+    description:
+      Width, in bits, of the AXI4-Stream transmit data interface.
+      Only 32 is currently supported by the driver.
+
+  xlnx,rx-fifo-depth:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Depth, in bytes, of the receive FIFO.
+
+  xlnx,tx-fifo-depth:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Depth, in bytes, of the transmit FIFO.
+
+  xlnx,use-rx-data:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1]
+    description:
+      Whether the receive data path is present in this IP core instance.
+
+  xlnx,use-tx-data:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1]
+    description:
+      Whether the transmit data path is present in this IP core instance.
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - xlnx,axi-str-rxd-tdata-width
+  - xlnx,axi-str-txd-tdata-width
+  - xlnx,rx-fifo-depth
+  - xlnx,tx-fifo-depth
+  - xlnx,use-rx-data
+  - xlnx,use-tx-data
+
+additionalProperties: false
+
+examples:
+  - |
+    fifo@40000000 {
+        compatible = "xlnx,axi-fifo-mm-s-4.1";
+        reg = <0x40000000 0x10000>;
+        interrupts = <0 29 4>;
+        xlnx,axi-str-rxd-tdata-width = <32>;
+        xlnx,axi-str-txd-tdata-width = <32>;
+        xlnx,rx-fifo-depth = <2048>;
+        xlnx,tx-fifo-depth = <2048>;
+        xlnx,use-rx-data = <1>;
+        xlnx,use-tx-data = <1>;
+    };
-- 
2.34.1