[PATCH v4 3/3] dt-bindings: misc: Add binding for Xilinx AXI-Stream FIFO

[Pramod Maurya]

Add a YAML schema for the Xilinx AXI-Stream FIFO IP core (PG080).
The binding documents the three supported compatible strings and the
vendor-specific properties that the axis-fifo staging driver reads from
the device tree.

This resolves the following checkpatch.pl warnings in
drivers/staging/axis-fifo/axis-fifo.c:
  WARNING: DT compatible string "xlnx,axi-fifo-mm-s-4.1" appears un-documented
  WARNING: DT compatible string "xlnx,axi-fifo-mm-s-4.2" appears un-documented
  WARNING: DT compatible string "xlnx,axi-fifo-mm-s-4.3" appears un-documented

Signed-off-by: Pramod Maurya <pramod.nexgen@xxxxxxxxx>
---
 .../bindings/misc/xlnx,axi-fifo-mm-s.yaml     | 93 +++++++++++++++++++
 MAINTAINERS                                   |  6 ++
 2 files changed, 99 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..f4ef7c277cd7
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml
@@ -0,0 +1,93 @@
+# SPDX-License-Identifier: (GPL-2.0-only 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
+
+maintainers:
+  - Jacob Feder <jacobsfeder@xxxxxxxxx>
+
+description:
+  The Xilinx AXI-Stream FIFO (PG080) provides a memory-mapped interface to
+  an AXI-Stream FIFO IP core. It allows a processor to transmit and receive
+  AXI-Stream packets via simple MMIO register reads and writes. Currently
+  only store-forward mode with a 32-bit AXI4-Lite interface is supported.
+
+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
+    description:
+      Width of the receive AXI-Stream data bus in bits. Currently only 32
+      is supported.
+    const: 32
+
+  xlnx,axi-str-txd-tdata-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Width of the transmit AXI-Stream data bus in bits. Currently only 32
+      is supported.
+    const: 32
+
+  xlnx,rx-fifo-depth:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Depth of the receive FIFO in words.
+
+  xlnx,tx-fifo-depth:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Depth of the transmit FIFO in words.
+
+  xlnx,use-rx-data:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Set to 1 if the receive data FIFO is enabled, 0 otherwise.
+    enum: [0, 1]
+
+  xlnx,use-tx-data:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description:
+      Set to 1 if the transmit data FIFO is enabled, 0 otherwise.
+    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:
+  - |
+    axi_fifo: fifo@43c00000 {
+        compatible = "xlnx,axi-fifo-mm-s-4.3";
+        reg = <0x43c00000 0x10000>;
+        interrupts = <0 30 4>;
+        interrupt-parent = <&intc>;
+        xlnx,axi-str-rxd-tdata-width = <32>;
+        xlnx,axi-str-txd-tdata-width = <32>;
+        xlnx,rx-fifo-depth = <0x1000>;
+        xlnx,tx-fifo-depth = <0x1000>;
+        xlnx,use-rx-data = <1>;
+        xlnx,use-tx-data = <1>;
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 58d35c17704d..bbb6b8c20ed6 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -29164,6 +29164,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/adc/xlnx,zynqmp-ams.yaml
 F:	drivers/iio/adc/xilinx-ams.c
 
+XILINX AXI-STREAM FIFO DRIVER
+M:	Jacob Feder <jacobsfeder@xxxxxxxxx>
+S:	Maintained
+F:	Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml
+F:	drivers/staging/axis-fifo/
+
 XILINX AXI ETHERNET DRIVER
 M:	Radhey Shyam Pandey <radhey.shyam.pandey@xxxxxxx>
 S:	Maintained
-- 
2.52.0