Re: [PATCH v5 3/5] dt-bindings: mfd: x-powers,axp152: Document AXP318W

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] The driver statically assigns hard-coded `.id` values inside its `mfd_cell` arrays and bypasses automatic ID allocation by passing `PLATFORM_DEVID_NONE` to `mfd_add_devices()`, violating the MFD subsystem guidelines.
--

--- Patch [3]: [PATCH v5 3/5] dt-bindings: mfd: x-powers,axp152: Document AXP318W ---
commit 0c5a5d45e78382d3cb52bdfeed22ad1c54a031fd
Author: Andre Przywara <andre.przywara@arm.com>

dt-bindings: mfd: x-powers,axp152: Document AXP318W

The X-Powers AXP318W is a PMIC used on some newer Allwinner devices.
Among a large number of both DCDC and LDO regulators it features the usual
ADC/IRQ/power key parts. Like other recent PMICs, it lacks the DC/DC converter
PWM frequency control register, that rate is fixed here.

> diff --git a/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml b/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml
> index 45f015d63df16..38556c32417b3 100644
> --- a/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml
> +++ b/Documentation/devicetree/bindings/mfd/x-powers,axp152.yaml

[ ... ]

> @@ -277,7 +303,7 @@ properties:
>            Defines the work frequency of DC-DC in kHz.
>  
>      patternProperties:
> -      "^(([a-f])?ldo[0-9]|dcdc[0-7a-e]|ldo(_|-)io(0|1)|(dc1)?sw|rtc(_|-)ldo|cpusldo|drivevbus|dc5ldo|boost)$":
> +      "^(([a-f])?ldo[0-9]|dcdc[0-9a-e]|ldo(_|-)io(0|1)|(dc1)?sw|swout[1-2]|rtc(_|-)ldo|cpusldo|drivevbus|dc5ldo|boost)$":
>          $ref: /schemas/regulator/regulator.yaml#
>          type: object
>          unevaluatedProperties: false

[Severity: High]
This is a pre-existing issue, but while reviewing these changes, I noticed
a potential problem with how the driver handles cell IDs in
drivers/mfd/axp20x.c.

The mfd_cell array explicitly hardcodes the subdevice cell ID to 1:

drivers/mfd/axp20x.c:axp313a_cells[] {
    ...
    MFD_CELL_BASIC("axp20x-regulator", NULL, NULL, 0, 1),
    ...
}

The driver then forces the platform bus to consume these hard-coded cell IDs
rather than generating safe dynamic IDs:

drivers/mfd/axp20x.c:axp20x_device_probe() {
    ...
    ret = mfd_add_devices(axp20x->dev, PLATFORM_DEVID_NONE, axp20x->cells,
                          axp20x->nr_cells, NULL, 0, NULL);
    ...
}

Could this lead to device naming collisions in sysfs and driver load failures
if multiple MFD instances of the same type are instantiated?

If multiple PMICs sharing the same cell definitions are present, they might
attempt to register subdevices with the same hardcoded name and ID.

This would result in a fatal probe failure for the colliding subdevices.

Should this code use PLATFORM_DEVID_AUTO instead of PLATFORM_DEVID_NONE to
ensure automatic cell indexing?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260720-axp318-regulator-v5-0-a1afa7ee24f9@baylibre.com?part=3