Re: [PATCH] iio: adc: ad7124: fix channel lookup in syscalib functions

[Jonathan Cameron <jic23@kernel.org>]

On Sat, 26 Jul 2025 11:28:48 -0500
David Lechner <dlechner@baylibre.com> wrote:

> Fix possible incorrect channel lookup in the syscalib functions by using
> the correct channel address instead of the channel number.
> 
> In the ad7124 driver, the channel field of struct iio_chan_spec is the
> input pin number of the positive input of the channel. This can be, but
> is not always the same as the index in the channels array. The correct
> index in the channels array is stored in the address field (and also
> scan_index). We use the address field to perform the correct lookup.
> 
> Fixes: 47036a03a303 ("iio: adc: ad7124: Implement internal calibration at probe time")
> Signed-off-by: David Lechner <dlechner@baylibre.com>
Seems fine to me and i'll queue it up, but I would welcome another set of
eyes on this one.

Thanks,

Jonathan

> ---
>  drivers/iio/adc/ad7124.c | 14 +++++++-------
>  1 file changed, 7 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad7124.c b/drivers/iio/adc/ad7124.c
> index 9808df2e92424283a86e9c105492c7447d071e44..4d8c6bafd1c3171054c72a0d2b13d6b1afc4e51a 100644
> --- a/drivers/iio/adc/ad7124.c
> +++ b/drivers/iio/adc/ad7124.c
> @@ -849,7 +849,7 @@ enum {
>  static int ad7124_syscalib_locked(struct ad7124_state *st, const struct iio_chan_spec *chan)
>  {
>  	struct device *dev = &st->sd.spi->dev;
> -	struct ad7124_channel *ch = &st->channels[chan->channel];
> +	struct ad7124_channel *ch = &st->channels[chan->address];
>  	int ret;
>  
>  	if (ch->syscalib_mode == AD7124_SYSCALIB_ZERO_SCALE) {
> @@ -865,8 +865,8 @@ static int ad7124_syscalib_locked(struct ad7124_state *st, const struct iio_chan
>  		if (ret < 0)
>  			return ret;
>  
> -		dev_dbg(dev, "offset for channel %d after zero-scale calibration: 0x%x\n",
> -			chan->channel, ch->cfg.calibration_offset);
> +		dev_dbg(dev, "offset for channel %lu after zero-scale calibration: 0x%x\n",
> +			chan->address, ch->cfg.calibration_offset);
>  	} else {
>  		ch->cfg.calibration_gain = st->gain_default;
>  
> @@ -880,8 +880,8 @@ static int ad7124_syscalib_locked(struct ad7124_state *st, const struct iio_chan
>  		if (ret < 0)
>  			return ret;
>  
> -		dev_dbg(dev, "gain for channel %d after full-scale calibration: 0x%x\n",
> -			chan->channel, ch->cfg.calibration_gain);
> +		dev_dbg(dev, "gain for channel %lu after full-scale calibration: 0x%x\n",
> +			chan->address, ch->cfg.calibration_gain);
>  	}
>  
>  	return 0;
> @@ -924,7 +924,7 @@ static int ad7124_set_syscalib_mode(struct iio_dev *indio_dev,
>  {
>  	struct ad7124_state *st = iio_priv(indio_dev);
>  
> -	st->channels[chan->channel].syscalib_mode = mode;
> +	st->channels[chan->address].syscalib_mode = mode;
>  
>  	return 0;
>  }
> @@ -934,7 +934,7 @@ static int ad7124_get_syscalib_mode(struct iio_dev *indio_dev,
>  {
>  	struct ad7124_state *st = iio_priv(indio_dev);
>  
> -	return st->channels[chan->channel].syscalib_mode;
> +	return st->channels[chan->address].syscalib_mode;
>  }
>  
>  static const struct iio_enum ad7124_syscalib_mode_enum = {
> 
> ---
> base-commit: e4d9886ad25adae72f38f2b12f41649b101581ae
> change-id: 20250726-iio-adc-ad7124-fix-channel-lookup-in-syscalib-e28c933ead2a
> 
> Best regards,