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

[Lee Jones <lee@kernel.org>]

Interesting.  Has this been considered?

/* Sashiko Automation: Issues Found (1 Findings) */

On Tue, 02 Jun 2026, Roman Vivchar via B4 Relay wrote:

> From: Roman Vivchar <rva333@protonmail.com>
> 
> The mt6323 PMIC includes an AUXADC. Register the AUXADC in the mt6323
> devices array to allow the corresponding driver to probe using compatible
> string.
> 
> Tested-by: Ben Grisdale <bengris32@protonmail.ch> # Amazon Echo Dot (2nd Generation)
> Signed-off-by: Roman Vivchar <rva333@protonmail.com>
> ---
>  drivers/mfd/mt6397-core.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
> index 3e58d0764c7e..013b0857fb54 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),
>  		.resources = mt6323_rtc_resources,
> 
> -- 
> 2.54.0
> 
> 

-- 
Lee Jones