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

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

[Paweł Grudziński]

From: Pawel Grudzinski <pgrudzinski@openmailbox.org>

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: Paweł Grudziński <pgrudzinski@openmailbox.org>
---
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;
+			goto error_free_reg;
+		}
 	}
 
 	ret = regmap_write(st->regmap, AD5380_REG_SF_CTRL, ctrl);
-- 
2.8.0

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

[kbuild test robot]

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Hi,

[auto build test WARNING on iio/togreg]
[also build test WARNING on v4.7-rc7 next-20160722]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Pawe-Grudzi-ski/iio-dac-ad5380-Fix-probe-failure-when-no-external-reference-is-supplied/20160723-221946
base:   https://git.kernel.org/pub/scm/linux/kernel/git/jic23/iio.git togreg
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        # save the attached .config to linux build tree
        make ARCH=x86_64 

All warnings (new ones prefixed by >>):

   drivers/iio/dac/ad5380.c: In function 'ad5380_probe':
>> drivers/iio/dac/ad5380.c:423:8: warning: assignment makes integer from pointer without a cast [-Wint-conversion]
       ret = st->vref_reg;
           ^

vim +423 drivers/iio/dac/ad5380.c

   407			if (ret) {
   408				dev_err(dev, "Failed to enable vref regulators: %d\n",
   409					ret);
   410				goto error_free_reg;
   411			}
   412	
   413			ret = regulator_get_voltage(st->vref_reg);
   414			if (ret < 0)
   415				goto error_disable_reg;
   416	
   417			st->vref = ret / 1000;
   418		} else {
   419			if (PTR_ERR(st->vref_reg) == -ENODEV) {
   420				st->vref = st->chip_info->int_vref;
   421				ctrl |= AD5380_CTRL_INT_VREF_EN;
   422			} else {
 > 423				ret = st->vref_reg;
   424				goto error_free_reg;
   425			}
   426		}
   427	
   428		ret = regmap_write(st->regmap, AD5380_REG_SF_CTRL, ctrl);
   429		if (ret) {
   430			dev_err(dev, "Failed to write to device: %d\n", ret);
   431			goto error_disable_reg;

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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

[Jonathan Cameron]

On 19/07/16 07:12, Paweł Grudziński wrote:
> From: Pawel Grudzinski <pgrudzinski@openmailbox.org>
> 
> 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: Paweł Grudziński <pgrudzinski@openmailbox.org>
> ---
> 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);
>