Re: [PATCH v3 3/3] iio: flow: add Sensirion SLF3S liquid flow sensor driver

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Probe fails after a warm reboot or kexec because the sensor is not stopped before reading the product ID.
- [Medium] Missing power management (PM) operations causes device failure after system suspend/resume.
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commit f4e028602d040a62e916ee2e4f3679882fcd7b4e
Author: Wadim Mueller <wafgo01@gmail.com>

iio: flow: add Sensirion SLF3S liquid flow sensor driver

This adds a new IIO driver for the Sensirion SLF3S family of liquid-flow
sensors. The driver supports reporting volumetric flow rate and temperature
over I2C, and handles switching the calibration medium between water and
isopropyl alcohol at runtime.

> diff --git a/drivers/iio/flow/slf3s.c b/drivers/iio/flow/slf3s.c
> new file mode 100644
> index 0000000000000..497a56f59ff97
> --- /dev/null
> +++ b/drivers/iio/flow/slf3s.c

[ ... ]

> +static int slf3s_detect_variant(struct slf3s_data *sf)
> +{
> +	struct i2c_client *client = sf->client;
> +	u8 buf[SLF3S_PRODUCT_ID_LEN];
> +	int ret;
> +
> +	ret = slf3s_send_cmd(client, slf3s_cmd_prep_pid);
> +	if (ret)
> +		return ret;

[Severity: High]
If the system goes through a warm reboot or kexec, won't the sensor still be
running in continuous measurement mode since there is no .shutdown callback?

If the sensor is actively measuring, will it NACK the 'read product ID'
command sent here and cause the probe to unconditionally fail? Should a stop
measurement command be sent before trying to read the product ID?

[ ... ]

> +static struct i2c_driver slf3s_driver = {
> +	.driver = {
> +		.name		= "slf3s",
> +		.of_match_table	= slf3s_of_match,
> +	},
> +	.probe		= slf3s_probe,
> +	.id_table	= slf3s_id,
> +};
> +module_i2c_driver(slf3s_driver);

[Severity: Medium]
Since the driver lacks power management operations, what happens when the
system suspends and resumes?

If power is cut to the sensor during suspend, won't it reset to the IDLE
state and cause subsequent IIO reads to fail because the driver never
re-issues the start command? Or if power isn't cut, will leaving it actively
measuring waste power?

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Sashiko AI review · https://sashiko.dev/#/patchset/20260530205435.37326-1-wafgo01@gmail.com?part=3