Re: [PATCH v14 08/12] iio: frequency: adf41513: driver implementation

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The driver fails to restore the hardware register state during pm_resume if the device was placed in a software power-down state, leading to power leaks and cache corruption.
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commit 829389d24bcc81427dbc259466ce431d38418a05
Author: Rodrigo Alencar <rodrigo.alencar@analog.com>

iio: frequency: adf41513: driver implementation

This commit introduces a new driver for the Analog Devices ADF41513 PLL
Frequency Synthesizer. It supports Integer-N and fractional-N synthesis
modes, high-resolution frequency calculations, IIO debugfs interface,
and power management.

> diff --git a/drivers/iio/frequency/adf41513.c b/drivers/iio/frequency/adf41513.c
> new file mode 100644
> index 0000000000000..6f952ccc675e0
> --- /dev/null
> +++ b/drivers/iio/frequency/adf41513.c
[ ... ]
> +static int adf41513_pm_resume(struct device *dev)
> +{
> +	struct adf41513_state *st = dev_get_drvdata(dev);
> +
> +	guard(mutex)(&st->lock);
> +	if (st->powerdown)
> +		return 0; /* nothing to do */

[Severity: High]
Does returning early here when the device is in software power-down fail to
restore the hardware register state?

If the system loses power to the device during suspend, the hardware
registers will reset to their Power-On Reset defaults.

By returning immediately without writing any state to the hardware, won't
the hardware wake up in an unconfigured state rather than the requested
power-down state?

Additionally, the software cache regs_hw is not invalidated and still
holds the pre-suspend values. If a parameter is subsequently modified,
the sync function uses ADF41513_SYNC_DIFF and skips writing unmodified
registers since they falsely appear up-to-date in regs_hw.

Could this leave the hardware permanently in a corrupted mixed state of
reset defaults and newly written values?

> +
> +	return adf41513_resume(st);
> +}

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Sashiko AI review · https://sashiko.dev/#/patchset/20260524-adf41513-iio-driver-v14-0-06824d9c15f4@analog.com?part=8