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

[Conor Dooley]

On Tue, Oct 06, 2026 at 07:29:54PM +0800, Raiden Lumine wrote:
> 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>

pw-bot: changes-requested

Please see previously explained (multiple times) rationale for why this
is not a simple conversion:
lore.kernel.org/all/?q=dfn:axis-fifo

Thanks,
Conor.

> ---
>  .../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
>

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