Re: [PATCH v2] iio: dac: ad5380: Fix probe failure when no external reference is supplied

From: Jonathan Cameron
Date: Sun Jul 24 2016 - 06:03:48 EST


On 19/07/16 07:12, PaweÅ GrudziÅski wrote:
> From: Pawel Grudzinski <pgrudzinski@xxxxxxxxxxxxxxx>
>
> Driver fails to load when there is no external Vref regulator defined,
> leaving no way to use internal reference. ad5380_probe function tries to
> obtain regulator with demv_regulator_get and checks for error, in which
> case it would use internal reference. Even without "Vref" regulator defined
> devm_regulator_get returns dummy regulator which makes function omit use of
> internal reference and causes failure on regulator_get_voltage.
>
> Replace demv_regulator_get with demv_regulator_get_optional, which returns
> error instead of dummy regulator if it does not find one which is specified
> by the caller to make ad5380_probe configure internal reference when no
> "Vref" regulator is supplied.
>
> Initialize internal regulator only if returned error is ENODEV, otherwise
> propagate the error to the caller of probe.
>
> Signed-off-by: PaweÅ GrudziÅski <pgrudzinski@xxxxxxxxxxxxxxx>
> ---
> Changes in v2:
> - Add error type checking to enable internal reference only on ENODEV and
> return any other error to the caller.
>
> drivers/iio/dac/ad5380.c | 11 ++++++++---
> 1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/dac/ad5380.c b/drivers/iio/dac/ad5380.c
> index 97d2c51..144cfdc 100644
> --- a/drivers/iio/dac/ad5380.c
> +++ b/drivers/iio/dac/ad5380.c
> @@ -401,7 +401,7 @@ static int ad5380_probe(struct device *dev, struct regmap *regmap,
> if (st->chip_info->int_vref == 2500)
> ctrl |= AD5380_CTRL_INT_VREF_2V5;
>
> - st->vref_reg = devm_regulator_get(dev, "vref");
> + st->vref_reg = devm_regulator_get_optional(dev, "vref");
> if (!IS_ERR(st->vref_reg)) {
> ret = regulator_enable(st->vref_reg);
> if (ret) {
> @@ -416,8 +416,13 @@ static int ad5380_probe(struct device *dev, struct regmap *regmap,
>
> st->vref = ret / 1000;
> } else {
> - st->vref = st->chip_info->int_vref;
> - ctrl |= AD5380_CTRL_INT_VREF_EN;
> + if (PTR_ERR(st->vref_reg) == -ENODEV) {
> + st->vref = st->chip_info->int_vref;
> + ctrl |= AD5380_CTRL_INT_VREF_EN;
> + } else {
> + ret = st->vref_reg;
Autobuilder picked it up an issue. This should be ret = PTR_ERR(st->vref_reg) I think?

Jonathan
> + goto error_free_reg;
> + }
> }
>
> ret = regmap_write(st->regmap, AD5380_REG_SF_CTRL, ctrl);
>