Re: [PATCH v6 14/16] iio: frequency: ad9910: show channel priority in debugfs

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] The parallel data port logic in the debugfs source attributes is dead code because the driver does not configure IIO buffers and omits `.scan_index` for the parallel channels.
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commit 1430aa5467e635315d439ae21891376a98143557
Author: Rodrigo Alencar <rodrigo.alencar@analog.com>

iio: frequency: ad9910: show channel priority in debugfs

Expose frequency_source, phase_source and amplitude_source attributes in
debugfs. The implementation follows the priority table found in the
datasheet.

> diff --git a/drivers/iio/frequency/ad9910.c b/drivers/iio/frequency/ad9910.c
> index 890499f67bd56..b39eeb8d9cd45 100644
> --- a/drivers/iio/frequency/ad9910.c
> +++ b/drivers/iio/frequency/ad9910.c
[ ... ]
> @@ -1960,6 +1974,158 @@ static int ad9910_setup(struct device *dev, struct ad9910_state *st,
>  	return ad9910_io_update(st);
>  }
>  
> +static inline const char *ad9910_frequency_source_get(struct iio_dev *indio_dev)
> +{
[ ... ]
> +	/* Parallel data port enabled and data destination is frequency */
> +	mode_en = FIELD_GET(AD9910_CFR2_PARALLEL_DATA_PORT_EN_MSK,
> +			    st->reg[AD9910_REG_CFR2].val32);
> +	if (mode_en && indio_dev->active_scan_mask &&
> +	    test_bit(AD9910_SCAN_IDX_FREQ, indio_dev->active_scan_mask))
> +		return ad9910_channel_str[AD9910_CHAN_IDX_PARALLEL_FREQ];

[Severity: Medium]
Is this logic effectively dead code?

The driver configures INDIO_DIRECT_MODE without setting up any IIO buffers,
so the IIO core will never allocate active_scan_mask.  This means
indio_dev->active_scan_mask will permanently evaluate to NULL and the
condition will evaluate to false.

Furthermore, even if buffers were enabled, the channel specifications for
the parallel channels do not populate the .scan_index field, so the bits
would never be set by the IIO core anyway:

drivers/iio/frequency/ad9910.c:ad9910_channels[] = {
	...
	[AD9910_CHAN_IDX_PARALLEL_FREQ] = {
		.type = IIO_FREQUENCY,
		.indexed = 1,
		.output = 1,
		.channel = AD9910_CHANNEL_PARALLEL,
		.address = AD9910_CHAN_IDX_PARALLEL_FREQ,
	...
}

Could this debugfs output silently fail to report the parallel data port and
fall through to incorrect fallback states?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260618-ad9910-iio-driver-v6-0-79125ffbe430@analog.com?part=14