Re: [PATCH v3 5/6] iio: adc: ti-ads7950: switch to using devm_regulator_get_enable_read_voltage()

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 05 Mar 2026 11:21:56 -0800
Dmitry Torokhov <dmitry.torokhov@gmail.com> wrote:

> The regulator is enabled for the entire time the driver is bound to the
> device, and we only need to access it to fetch voltage, which can be
> done at probe time.
> 
> Switch to using devm_regulator_get_enable_read_voltage() which
> simplifies probing and unbinding code.
> 
> Suggested-by: David Lechner <dlechner@baylibre.com>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Hi.

I think this broke the ACPI case (where regulator isn't available).

Jonathan

> ---
>  drivers/iio/adc/ti-ads7950.c | 45 +++++++++++---------------------------------
>  1 file changed, 11 insertions(+), 34 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti-ads7950.c b/drivers/iio/adc/ti-ads7950.c
> index 273c35e03185..847e83baa876 100644
> --- a/drivers/iio/adc/ti-ads7950.c
> +++ b/drivers/iio/adc/ti-ads7950.c
> @@ -341,19 +341,9 @@ static int ti_ads7950_scan_direct(struct iio_dev *indio_dev, unsigned int ch)
>  	return st->single_rx;
>  }
>  
> -static int ti_ads7950_get_range(struct ti_ads7950_state *st)
> +static unsigned int ti_ads7950_get_range(struct ti_ads7950_state *st)
>  {
> -	int vref;
> -
> -	if (st->vref_mv) {
> -		vref = st->vref_mv;
> -	} else {
> -		vref = regulator_get_voltage(st->reg);
> -		if (vref < 0)
> -			return vref;
> -
> -		vref /= 1000;
> -	}
> +	unsigned int vref = st->vref_mv;
>  
>  	if (st->cmd_settings_bitmask & TI_ADS7950_CR_RANGE_5V)
>  		vref *= 2;
> @@ -382,11 +372,7 @@ static int ti_ads7950_read_raw(struct iio_dev *indio_dev,
>  
>  		return IIO_VAL_INT;
>  	case IIO_CHAN_INFO_SCALE:
> -		ret = ti_ads7950_get_range(st);
> -		if (ret < 0)
> -			return ret;
> -
> -		*val = ret;
> +		*val = ti_ads7950_get_range(st);
>  		*val2 = (1 << chan->scan_type.realbits) - 1;
>  
>  		return IIO_VAL_FRACTIONAL;
> @@ -580,30 +566,24 @@ static int ti_ads7950_probe(struct spi_device *spi)
>  	spi_message_init_with_transfers(&st->scan_single_msg,
>  					st->scan_single_xfer, 3);
>  
> +	ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");
> +	if (ret < 0)

I think you need to check for -ENODEV and if you see than then
see if the acpi route below applies.  Otherwise on ACPI this will fail
and we'll fail the probe.


> +		return dev_err_probe(&spi->dev, ret,
> +				     "Failed to get regulator \"vref\"\n");
> +
>  	/* Use hard coded value for reference voltage in ACPI case */
>  	if (ACPI_COMPANION(&spi->dev))
>  		st->vref_mv = TI_ADS7950_VA_MV_ACPI_DEFAULT;
> +	else
> +		st->vref_mv = ret / 1000;