[PATCH] dt-bindings: misc: add binding for Xilinx AXI-Stream FIFO

[Aditya Chari <adi25charis@gmail.com>]

The axis-fifo driver's compatible strings were undocumented, flagged
by checkpatch.pl as UNDOCUMENTED_DT_STRING. Add a devicetree
binding document describing the required properties
for drivers/staging/axis-fifo, derived from the properties
the driver reads via of_property_read_u32()
in axis_fifo_parse_dt().

Signed-off-by: Aditya Chari <adi25charis@gmail.com>
---
 .../bindings/misc/xlnx,axi-fifo-mm-s.yaml     | 95 +++++++++++++++++++
 1 file changed, 95 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 000000000..8ef0adde3
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml
@@ -0,0 +1,95 @@
+# 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 AXI-Stream FIFO (axis-fifo)
+
+maintainers:
+  - Jacob Feder <jacobsfeder@gmail.com>
+
+description:
+  The AXI-Stream FIFO (AXIS-FIFO) IP core provides a memory-mapped AXI4-Lite
+  interface for sending and receiving data over an AXI4-Stream interface
+  using FIFO buffers. See Xilinx PG080 for IP 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:
+    description:
+      Width in bits of the AXI4-Stream receive data interface. Only a
+      width of 32 is currently supported by the driver.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 32
+
+  xlnx,axi-str-txd-tdata-width:
+    description:
+      Width in bits of the AXI4-Stream transmit data interface. Only a
+      width of 32 is currently supported by the driver.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 32
+
+  xlnx,rx-fifo-depth:
+    description:
+      Depth in bytes of the receive FIFO, as configured in the IP core.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  xlnx,tx-fifo-depth:
+    description:
+      Depth in bytes of the transmit FIFO, as configured in the IP core.
+    $ref: /schemas/types.yaml#/definitions/uint32
+
+  xlnx,use-rx-data:
+    description:
+      Indicates whether the receive data path is present, as configured
+      in the IP core. A value of 1 enables the receive path, 0 disables it.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [ 0, 1 ]
+
+  xlnx,use-tx-data:
+    description:
+      Indicates whether the transmit data path is present, as configured
+      in the IP core. A value of 1 enables the transmit path, 0 disables it.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [ 0, 1 ]
+
+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:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+
+    axi_fifo_mm_s_0: axi-fifo-mm-s@40000000 {
+        compatible = "xlnx,axi-fifo-mm-s-4.1";
+        reg = <0x40000000 0x10000>;
+        interrupts = <0 29 IRQ_TYPE_LEVEL_HIGH>;
+        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>;
+    };
-- 
2.53.0