Re: [PATCH v2 4/7] iio: adc: ti-ads1262: Add excitation current support

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 28 Jun 2026 00:36:05 -0500
Kurt Borja <kuurtb@gmail.com> wrote:

> Support the two IDAC excitation current sources. Each channel can route
> its IDAC1/IDAC2 outputs to a pin via the "excitation-channels" property
> and select a magnitude via "excitation-current-nanoamp".
> 
> Signed-off-by: Kurt Borja <kuurtb@gmail.com>
> ---
>  drivers/iio/adc/ti-ads1262.c | 78 ++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 76 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti-ads1262.c b/drivers/iio/adc/ti-ads1262.c
> index ece97a0c2b1304ad..8921eaae537f6b0a 100644
> --- a/drivers/iio/adc/ti-ads1262.c
> +++ b/drivers/iio/adc/ti-ads1262.c
> @@ -193,6 +193,22 @@ enum {
>  	ADS1262_INPMUX_LAST
>  };
>  
> +enum {
> +	ADS1262_IDACMUX_AIN0,
> +	ADS1262_IDACMUX_AIN1,
> +	ADS1262_IDACMUX_AIN2,
> +	ADS1262_IDACMUX_AIN3,
> +	ADS1262_IDACMUX_AIN4,
> +	ADS1262_IDACMUX_AIN5,
> +	ADS1262_IDACMUX_AIN6,
> +	ADS1262_IDACMUX_AIN7,
> +	ADS1262_IDACMUX_AIN8,
> +	ADS1262_IDACMUX_AIN9,
> +	ADS1262_IDACMUX_AINCOM,
> +	ADS1262_IDACMUX_NO_CONN,
> +	ADS1262_IDACMUX_LAST

_LAST usually means inclusive. So probably call this NUM or something like that
to show that it should be one more than last value.

> +};

> @@ -450,7 +468,7 @@ static int ads1262_dev_read_by_cmd(struct ads1262 *st, u8 cmd, __be32 *val)
>  static int ads1262_channel_enable(struct ads1262 *st,
>  				  struct ads1262_channel *chan)
>  {
> -	u8 mode0, mode1, mode2, inpmux, refmux;
> +	u8 mode0, mode1, mode2, inpmux, idacmux, idacmag, refmux;
>  	int ret;
>  
>  	/* Avoid using guard() here to mitigate AB/BA deadlock warning */
> @@ -464,6 +482,10 @@ static int ads1262_channel_enable(struct ads1262 *st,
>  		FIELD_PREP(ADS1262_MODE2_BYPASS_MASK, chan->pga_bypass);
>  	inpmux = FIELD_PREP(ADS1262_INPMUX_MUXN_MASK, chan->input[1]) |
>  		 FIELD_PREP(ADS1262_INPMUX_MUXP_MASK, chan->input[0]);
> +	idacmux = FIELD_PREP(ADS1262_IDACMUX_MUX1_MASK, chan->idac_mux[0]) |
> +		  FIELD_PREP(ADS1262_IDACMUX_MUX2_MASK, chan->idac_mux[1]);
> +	idacmag = FIELD_PREP(ADS1262_IDACMAG_MAG1_MASK, chan->idac_mag[0]) |
> +		  FIELD_PREP(ADS1262_IDACMAG_MAG2_MASK, chan->idac_mag[1]);

This presumably feeds into the discussion of locking that you were having
with David, but I'd find this a lot easier to read if these were just
above where the values are used. Then we can clearly see the match between
masks and fields.  If you have to do it like this, then add variables up
here for the masks as well.


>  	refmux = FIELD_PREP(ADS1262_REFMUX_RMUXN_MASK, chan->reference[1]) |
>  		 FIELD_PREP(ADS1262_REFMUX_RMUXP_MASK, chan->reference[0]);
>  	mutex_unlock(&st->chan_lock);