Re: [PATCH 3/4] mfd: mt6397-core: add mt6323 AUXADC support

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] Unvalidated parent pointer dereference causes a kernel oops on invalid Device Tree.
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commit d38d038f6b60f5f733b7e5174e9d4dc5a41d7cec
Author: Roman Vivchar <rva333@protonmail.com>

mfd: mt6397-core: add mt6323 AUXADC support

This commit registers the AUXADC in the mt6323 devices array to allow the
corresponding driver to probe using the newly added compatible string.

> diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
> index 3e58d0764c7e0..013b0857fb548 100644
> --- a/drivers/mfd/mt6397-core.c
> +++ b/drivers/mfd/mt6397-core.c
> @@ -125,6 +125,9 @@ static const struct resource mt6323_pwrc_resources[] = {
>  
>  static const struct mfd_cell mt6323_devs[] = {
>  	{
> +		.name = "mt6323-auxadc",
> +		.of_compatible = "mediatek,mt6323-auxadc",

[Severity: High]
Does adding this compatible string expose an unhandled edge case in the
auxadc driver?

If this device is instantiated directly from a Device Tree without an MFD
parent (e.g., at the DT root), dev->parent could be the platform bus
(which has a NULL parent) or NULL itself.

Looking at mt6323_auxadc_probe() in drivers/iio/adc/mt6323-auxadc.c:

    regmap = dev_get_regmap(dev->parent->parent, NULL);

Could blindly dereferencing dev->parent->parent here, or passing a NULL
device to dev_get_regmap() (which calls devres_find()), result in a
kernel oops if probed as a root node?

> +	}, {
>  		.name = "mt6323-rtc",
>  		.num_resources = ARRAY_SIZE(mt6323_rtc_resources),

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260602-mt6323-adc-v1-0-68ec737508ee@protonmail.com?part=3