Re: [PATCH v2 1/2] dt-bindings: dpll: zl3073x: ZL30643 is compatible

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The DT binding adds a fallback string for the ZL30643 device, but the corresponding driver strictly checks the hardware chip ID against a hardcoded whitelist, causing probe to deterministically fail for the new hardware.
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--- Patch [1]: [PATCH v2 1/2] dt-bindings: dpll: zl3073x: ZL30643 is compatible ---
commit f6998893262610471dd1ffc9397a1a575b09a8ed
Author: Vincent Jardin <vjardin@free.fr>

dt-bindings: dpll: zl3073x: ZL30643 is compatible

The Microchip ZL30643 (chip ID 0x0E3B) is a member of the ZL3064x line card
timing family. It is register compatible with the 3-channel ZL30733
(chip ID 0x0E95), so it is added with a fallback compatible string.

> diff --git a/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml b/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml
> index fa5a8f8e390cd..17983e6c35975 100644
> --- a/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml
> +++ b/Documentation/devicetree/bindings/dpll/microchip,zl30731.yaml
[ ... ]
>    compatible:
> -    enum:
> -      - microchip,zl30731
> -      - microchip,zl30732
> -      - microchip,zl30733
> -      - microchip,zl30734
> -      - microchip,zl30735
> +    oneOf:
> +      - enum:
> +          - microchip,zl30731
> +          - microchip,zl30732
> +          - microchip,zl30733
> +          - microchip,zl30734
> +          - microchip,zl30735
> +      - items:
> +          - const: microchip,zl30643
> +          - const: microchip,zl30733

[Severity: Medium]
Will this device fail to probe because its chip ID is missing from the
driver's whitelist?

The commit message indicates the ZL30643 has chip ID 0x0E3B. However, in
drivers/dpll/zl3073x/core.c, zl3073x_dev_probe() explicitly validates the
read hardware ID against zl3073x_chip_ids:

drivers/dpll/zl3073x/core.c:zl3073x_dev_probe() {
	...
	rc = zl3073x_read_u16(zldev, ZL_REG_ID, &id);
	...
	/* Detect chip variant */
	for (i = 0; i < ARRAY_SIZE(zl3073x_chip_ids); i++) {
		if (zl3073x_chip_ids[i].id == id)
			break;
	}

	if (i == ARRAY_SIZE(zl3073x_chip_ids))
		return dev_err_probe(zldev->dev, -ENODEV,
				     "Unknown chip ID: 0x%04x\n", id);
	...
}

Since 0x0E3B is not present in zl3073x_chip_ids, it appears the fallback
compatibility will still result in the driver returning -ENODEV and
aborting the probe.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260730-for-upstream-zl30643-v2-0-0ea0bbd03755@free.fr?part=1