Re: [PATCH v2 2/6] hwmon: (adt7470) Fix fans stuck in manual mode on I2C errors

[sashiko-bot@kernel.org]

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

Pre-existing issues:
- [High] This problem wasn't introduced by this patch, but the driver violates hwmon subsystem guidelines by using a private mutex `data->lock` for sysfs attributes instead of the standard `hwmon_lock()` API.
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--- Patch [2]: [PATCH v2 2/6] hwmon: (adt7470) Fix fans stuck in manual mode on I2C errors ---
commit f5bf8b0ee6f2d048580f6d00a71e61df362fa4c6
Author: Luiz Angelo Daros de Luca <luizluca@gmail.com>

hwmon: (adt7470) Fix fans stuck in manual mode on I2C errors

This commit introduces a recovery path in adt7470_read_temperatures() to ensure
that original PWM configuration registers are restored if an I2C operation
fails after temporarily switching the fans to manual mode.

Closes: https://lore.kernel.org/r/20260716213252.EACA71F000E9@smtp.kernel.org

> diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
> index 664349756dc2b..481d51617f4be 100644
> --- a/drivers/hwmon/adt7470.c
> +++ b/drivers/hwmon/adt7470.c
> @@ -205,11 +205,12 @@ static inline int adt7470_write_word_data(struct adt7470_data *data, unsigned in
>  /* Probe for temperature sensors.  Assumes lock is held */
>  static int adt7470_read_temperatures(struct adt7470_data *data)
>  {

[Severity: High]
This isn't a bug introduced by this patch, but this driver appears to use a
private mutex (data->lock) for internal synchronization instead of the
standard hwmon_lock() API.

For example, it uses mutex_init(&data->lock) in adt7470_probe() and locks it
with mutex_lock(&data->lock) in sysfs attribute operations like
pwm_auto_temp_store().

Does this bypass the centralized hwmon core serialization mechanism and risk
logical race conditions with the thermal subsystem? Should this be updated
to follow the hwmon subsystem guidelines which mandate using hwmon_lock()
and hwmon_unlock() for attributes not registered via the info parameter?

[ ... ]

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Sashiko AI review · https://sashiko.dev/#/patchset/20260717-adt7470_thermalzone-v2-0-a55147958fad@gmail.com?part=2