[PATCH 4/5] dt-bindings: serial: create binding for mcf-uart

[PATCH 4/5] dt-bindings: serial: create binding for mcf-uart

[Greg Ungerer]

Create documentation for a new binding to support the Freescale ColdFire
UART hardware block. This is found on pretty much all variants of the
M68K derived Freescale ColdFire family of System-on-Chip devices.

It is not compatible with any other known UARTs.

Signed-off-by: Greg Ungerer <gerg@linux-m68k.org>
---
 .../bindings/serial/fsl,mcf-uart.yaml         | 43 +++++++++++++++++++
 1 file changed, 43 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml

diff --git a/Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml b/Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml
new file mode 100644
index 000000000000..d1dba518f67a
--- /dev/null
+++ b/Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml
@@ -0,0 +1,43 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/serial/fsl-mcf-uart.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Freescale ColdFire UART
+
+maintainers:
+  - Greg Ungerer <gerg@linux-m68k.org>
+
+allof:
+  - $ref: serial.yaml#
+
+properties:
+  compatible:
+    const: fsl,mcf-uart
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - clocks
+
+unevaluatedProperties: false
+
+examples:
+  - |
+    uart0: serial@fc060000 {
+        compatible = "fsl,mcf-uart";
+        reg = <0xfc060000 0x80>;
+        interrupts = <90>;
+        clocks = <&coreclk>;
+    };
-- 
2.55.0

Re: [PATCH 4/5] dt-bindings: serial: create binding for mcf-uart

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] dt-bindings: $id path mismatch breaks schema cross-referencing
- [Medium] dt-bindings: schema keyword typo allof prevents base serial schema evaluation
--

commit c5bd98e903d69d54479e4a7058d0ad59884cfb54
Author: Greg Ungerer <gerg@linux-m68k.org>

dt-bindings: serial: create binding for mcf-uart

This commit creates documentation for a new binding to support the Freescale
ColdFire UART hardware block. This hardware block is found on M68K derived
Freescale ColdFire family of SoC devices.

> diff --git a/Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml b/Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml
> new file mode 100644
> index 0000000000000..d1dba518f67af
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml
> @@ -0,0 +1,43 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/serial/fsl-mcf-uart.yaml#

[Severity: Medium]
Will this schema mismatch cause a regression by breaking cross referencing?

In Documentation/devicetree/bindings/serial/fsl,mcf-uart.yaml, the file is
named with a comma, but the id is defined with a hyphen.

The device tree bindings subsystem guidelines require that the path in the id
field exactly match the file path relative to
Documentation/devicetree/bindings/. The dt_binding_check tooling will
encounter this mismatch and silently skip or fail validation because the
paths do not correspond.

> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Freescale ColdFire UART
> +
> +maintainers:
> +  - Greg Ungerer <gerg@linux-m68k.org>
> +
> +allof:
> +  - $ref: serial.yaml#

[Severity: Medium]
Could this typo cause a regression where the base serial schema is not
evaluated?

JSON Schema keywords are case-sensitive. The binding uses allof instead of
allOf, meaning the reference directive is silently ignored. 

When running dt_binding_check on device trees utilizing this compatible
string, it will not enforce necessary properties or allow standard UART
properties because it fails to inherit the base serial schema.

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261013120831.1046590-1-gerg@linux-m68k.org?part=4