Re: [PATCH v2 2/2] ASoC: codecs: nau8822: add support for supply regulators

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Manually disabling regulators in the I2C `remove` callback breaks the LIFO teardown order, causing I2C operations to fail during `devm` component teardown.
- [Medium] Unconditional regulator disable in the `remove` callback can cause an unbalanced disable if the device is removed following a resume failure.
--

commit 9b4fbe6b13298617ee870787131ce69e29d799b3
Author: Alexey Charkov <alchark@flipper.net>

ASoC: codecs: nau8822: add support for supply regulators

This commit adds support for the four power supply pins on the NAU8822
codec by requesting and enabling them at init time. It also adds a brief
delay after power up to allow the device to stabilize before register access.

> diff --git a/sound/soc/codecs/nau8822.c b/sound/soc/codecs/nau8822.c
> --- a/sound/soc/codecs/nau8822.c
> +++ b/sound/soc/codecs/nau8822.c
[ ... ]
>  	ret = devm_snd_soc_register_component(dev, &soc_component_dev_nau8822,
>  						&nau8822_dai, 1);
>  	if (ret != 0) {
>  		dev_err(&i2c->dev, "Failed to register CODEC: %d\n", ret);
> -		return ret;
> +		goto err_reg;
>  	}
>  
>  	return 0;
> +
> +err_reg:
> +	regulator_bulk_disable(NAU8822_NUM_SUPPLIES, nau8822->supplies);
> +	return ret;
> +}
> +
> +static void nau8822_i2c_remove(struct i2c_client *i2c)
> +{
> +	struct nau8822 *nau8822 = i2c_get_clientdata(i2c);
> +
> +	regulator_bulk_disable(NAU8822_NUM_SUPPLIES, nau8822->supplies);

[Severity: High]
Can this manual regulator disable cause I2C bus errors during teardown?

The ASoC component is registered with devm_snd_soc_register_component(),
which means the subsystem will unregister the component during the devres
cleanup phase. This happens after nau8822_i2c_remove() has already
returned.

Because the regulators are disabled here, the hardware will be unpowered
while the ASoC component is still active. During devres cleanup, the
subsystem will call snd_soc_dapm_shutdown() and transition the bias level
to SND_SOC_BIAS_OFF.

Will the resulting I2C register writes to the unpowered codec fail or
time out, potentially stalling the driver unbind?

[Severity: Medium]
Could this unconditional regulator disable also result in an unbalanced
disable warning?

If the system resumes but nau8822_resume() fails to re-enable the
regulators, they will remain in the disabled state set during
nau8822_suspend().

If the driver is later unbound, this call will execute again. Will this
attempt to drop the regulator reference count below zero and trigger a
kernel warning?

>  }

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260525-nau8822-reg-v2-0-7d37ae393e46@flipper.net?part=2