[PATCH 1/2] dt-bindings: misc: add binding for Xilinx AXI-Stream FIFO

[Raiden Lumine]

The axis-fifo driver's compatible strings were undocumented, flagged
by checkpatch.pl as UNDOCUMENTED_DT_STRING. Add a devicetree binding
document 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: Raiden Lumine <2557597107@xxxxxx>
---
 .../bindings/misc/xlnx,axi-fifo-mm-s.yaml     | 191 ++++++++++++++++++
 1 file changed, 191 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..219a7de223cc
--- /dev/null
+++ b/Documentation/devicetree/bindings/misc/xlnx,axi-fifo-mm-s.yaml
@@ -0,0 +1,191 @@
+# 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#
+
+$defs:
+  xlnx-uint32-zero:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 0
+    description: Must be 0, this feature isn't supported.
+
+title: Xilinx AXI-Stream FIFO v4.1 IP core
+
+maintainers:
+  - Jacob Feder <jacobsfeder@xxxxxxxxx>
+
+description: |
+  This IP core has read and write AXI-Stream FIFOs, the contents of which can
+  be accessed from the AXI4 memory-mapped interface. This is useful for
+  transferring data from a processor into the FPGA fabric. The driver creates
+  a character device that can be read/written to with standard
+  open/read/write/close.
+
+  See Xilinx PG080 document for IP details.
+
+  Currently supports only store-forward mode with a 32-bit
+  AXI4-Lite interface. DOES NOT support:
+    - cut-through mode
+    - AXI4 (non-lite)
+
+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
+
+  interrupt-names:
+    const: interrupt
+
+  xlnx,axi-str-rxd-tdata-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 32
+    description: AXI-Stream RX data width, must be 32.
+
+  xlnx,axi-str-txd-tdata-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    const: 32
+    description: AXI-Stream TX data width, must be 32.
+
+  xlnx,rx-fifo-depth:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Depth of RX FIFO in words.
+
+  xlnx,tx-fifo-depth:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Depth of TX FIFO in words.
+
+  xlnx,use-rx-data:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1]
+    description: Set to 1 if RX FIFO is enabled, 0 otherwise.
+
+  xlnx,use-tx-data:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    enum: [0, 1]
+    description: Set to 1 if TX FIFO is enabled, 0 otherwise.
+
+  xlnx,axi-str-rxd-protocol:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: Ignored by the driver.
+
+  xlnx,axi-str-txc-protocol:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: Ignored by the driver.
+
+  xlnx,axi-str-txd-protocol:
+    $ref: /schemas/types.yaml#/definitions/string
+    description: Ignored by the driver.
+
+  xlnx,axi-str-txc-tdata-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,axis-tdest-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,axis-tid-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,axis-tuser-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,data-interface-type:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,has-axis-tdest:
+    $ref: '#/$defs/xlnx-uint32-zero'
+
+  xlnx,has-axis-tid:
+    $ref: '#/$defs/xlnx-uint32-zero'
+
+  xlnx,has-axis-tkeep:
+    $ref: '#/$defs/xlnx-uint32-zero'
+
+  xlnx,has-axis-tstrb:
+    $ref: '#/$defs/xlnx-uint32-zero'
+
+  xlnx,has-axis-tuser:
+    $ref: '#/$defs/xlnx-uint32-zero'
+
+  xlnx,rx-fifo-pe-threshold:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,rx-fifo-pf-threshold:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,s-axi-id-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,s-axi4-data-width:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,select-xpm:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,tx-fifo-pe-threshold:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,tx-fifo-pf-threshold:
+    $ref: /schemas/types.yaml#/definitions/uint32
+    description: Ignored by the driver.
+
+  xlnx,use-rx-cut-through:
+    $ref: '#/$defs/xlnx-uint32-zero'
+
+  xlnx,use-tx-ctrl:
+    $ref: '#/$defs/xlnx-uint32-zero'
+
+  xlnx,use-tx-cut-through:
+    $ref: '#/$defs/xlnx-uint32-zero'
+
+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_mm_s_0: axi-fifo-mm-s@43c00000 {
+        compatible = "xlnx,axi-fifo-mm-s-4.1";
+        interrupt-parent = <&intc>;
+        interrupts = <0 29 4>;
+        reg = <0x43c00000 0x10000>;
+        xlnx,axi-str-rxd-protocol = "XIL_AXI_STREAM_ETH_DATA";
+        xlnx,axi-str-rxd-tdata-width = <0x20>;
+        xlnx,axi-str-txc-protocol = "XIL_AXI_STREAM_ETH_CTRL";
+        xlnx,axi-str-txc-tdata-width = <0x20>;
+        xlnx,axi-str-txd-protocol = "XIL_AXI_STREAM_ETH_DATA";
+        xlnx,axi-str-txd-tdata-width = <0x20>;
+        xlnx,rx-fifo-depth = <0x200>;
+        xlnx,tx-fifo-depth = <0x8000>;
+        xlnx,use-rx-data = <0x0>;
+        xlnx,use-tx-data = <0x1>;
+    };
+...
-- 
2.55.0