[PATCH] iio: st_sensors: fetch and enable regulators unconditionally

[PATCH] iio: st_sensors: fetch and enable regulators unconditionally

[Linus Walleij]

These sensors all have Vdd and Vdd_IO lines. This means the
supplies are *not* optional (optional means that the supply is
optional in the electrical sense, not the software sense)
so we need to get the and enable them at all times.

If the device tree or board file does not define suitable
regulators for the component, it will be substituted by a
dummy regulator, or, if regulators are disabled altogether,
by stubs. There is no need to use the IS_ERR_OR_NULL() check
that is considered harmful.

Cc: Giuseppe Barba <giuseppe.barba@st.com>
Cc: Denis Ciocca <denis.ciocca@st.com>
Cc: Crestez Dan Leonard <leonard.crestez@intel.com>
Cc: Gregor Boirie <gregor.boirie@parrot.com>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 drivers/iio/common/st_sensors/st_sensors_core.c | 55 +++++++++++--------------
 1 file changed, 24 insertions(+), 31 deletions(-)

diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
index 2d5282e05482..41bfe1c5f4e9 100644
--- a/drivers/iio/common/st_sensors/st_sensors_core.c
+++ b/drivers/iio/common/st_sensors/st_sensors_core.c
@@ -234,39 +234,35 @@ int st_sensors_power_enable(struct iio_dev *indio_dev)
 	int err;
 
 	/* Regulators not mandatory, but if requested we should enable them. */
-	pdata->vdd = devm_regulator_get_optional(indio_dev->dev.parent, "vdd");
-	if (!IS_ERR(pdata->vdd)) {
-		err = regulator_enable(pdata->vdd);
-		if (err != 0) {
-			dev_warn(&indio_dev->dev,
-				 "Failed to enable specified Vdd supply\n");
-			return err;
-		}
-	} else {
-		err = PTR_ERR(pdata->vdd);
-		if (err != -ENODEV)
-			return err;
+	pdata->vdd = devm_regulator_get(indio_dev->dev.parent, "vdd");
+	if (IS_ERR(pdata->vdd)) {
+		dev_err(&indio_dev->dev, "unable to get Vdd supply\n");
+		return PTR_ERR(pdata->vdd);
+	}
+	err = regulator_enable(pdata->vdd);
+	if (err != 0) {
+		dev_warn(&indio_dev->dev,
+			 "Failed to enable specified Vdd supply\n");
+		return err;
 	}
 
-	pdata->vdd_io = devm_regulator_get_optional(indio_dev->dev.parent, "vddio");
-	if (!IS_ERR(pdata->vdd_io)) {
-		err = regulator_enable(pdata->vdd_io);
-		if (err != 0) {
-			dev_warn(&indio_dev->dev,
-				 "Failed to enable specified Vdd_IO supply\n");
-			goto st_sensors_disable_vdd;
-		}
-	} else {
-		err = PTR_ERR(pdata->vdd_io);
-		if (err != -ENODEV)
-			goto st_sensors_disable_vdd;
+	pdata->vdd_io = devm_regulator_get(indio_dev->dev.parent, "vddio");
+	if (IS_ERR(pdata->vdd)) {
+		dev_err(&indio_dev->dev, "unable to get Vdd_IO supply\n");
+		err = PTR_ERR(pdata->vdd);
+		goto st_sensors_disable_vdd;
+	}
+	err = regulator_enable(pdata->vdd_io);
+	if (err != 0) {
+		dev_warn(&indio_dev->dev,
+			 "Failed to enable specified Vdd_IO supply\n");
+		goto st_sensors_disable_vdd;
 	}
 
 	return 0;
 
 st_sensors_disable_vdd:
-	if (!IS_ERR_OR_NULL(pdata->vdd))
-		regulator_disable(pdata->vdd);
+	regulator_disable(pdata->vdd);
 	return err;
 }
 EXPORT_SYMBOL(st_sensors_power_enable);
@@ -275,11 +271,8 @@ void st_sensors_power_disable(struct iio_dev *indio_dev)
 {
 	struct st_sensor_data *pdata = iio_priv(indio_dev);
 
-	if (!IS_ERR_OR_NULL(pdata->vdd))
-		regulator_disable(pdata->vdd);
-
-	if (!IS_ERR_OR_NULL(pdata->vdd_io))
-		regulator_disable(pdata->vdd_io);
+	regulator_disable(pdata->vdd);
+	regulator_disable(pdata->vdd_io);
 }
 EXPORT_SYMBOL(st_sensors_power_disable);
 
-- 
2.7.4

Re: [PATCH] iio: st_sensors: fetch and enable regulators unconditionally

[Jonathan Cameron]

On 25/08/16 23:10, Linus Walleij wrote:
> These sensors all have Vdd and Vdd_IO lines. This means the
> supplies are *not* optional (optional means that the supply is
> optional in the electrical sense, not the software sense)
> so we need to get the and enable them at all times.
> 
> If the device tree or board file does not define suitable
> regulators for the component, it will be substituted by a
> dummy regulator, or, if regulators are disabled altogether,
> by stubs. There is no need to use the IS_ERR_OR_NULL() check
> that is considered harmful.
> 
> Cc: Giuseppe Barba <giuseppe.barba@st.com>
> Cc: Denis Ciocca <denis.ciocca@st.com>
> Cc: Crestez Dan Leonard <leonard.crestez@intel.com>
> Cc: Gregor Boirie <gregor.boirie@parrot.com>
> Cc: Mark Brown <broonie@kernel.org>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Yeah, there was a fair bit of missunderstanding around this
(including me) a while back so may well be more cases of
this kicking around in IIO.

Good to clear this one out.

Applied to the togreg branch of iio.git.
Will be initially pushed out as testing for the autobuilders to
play with it.

If Denis or Giuseppe has a chance to look at in in the next
few days that would be great as I doubt I'll send a pull to
Greg until towards the end of the week.

Thanks,

Jonathan
> ---
>  drivers/iio/common/st_sensors/st_sensors_core.c | 55 +++++++++++--------------
>  1 file changed, 24 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
> index 2d5282e05482..41bfe1c5f4e9 100644
> --- a/drivers/iio/common/st_sensors/st_sensors_core.c
> +++ b/drivers/iio/common/st_sensors/st_sensors_core.c
> @@ -234,39 +234,35 @@ int st_sensors_power_enable(struct iio_dev *indio_dev)
>  	int err;
>  
>  	/* Regulators not mandatory, but if requested we should enable them. */
> -	pdata->vdd = devm_regulator_get_optional(indio_dev->dev.parent, "vdd");
> -	if (!IS_ERR(pdata->vdd)) {
> -		err = regulator_enable(pdata->vdd);
> -		if (err != 0) {
> -			dev_warn(&indio_dev->dev,
> -				 "Failed to enable specified Vdd supply\n");
> -			return err;
> -		}
> -	} else {
> -		err = PTR_ERR(pdata->vdd);
> -		if (err != -ENODEV)
> -			return err;
> +	pdata->vdd = devm_regulator_get(indio_dev->dev.parent, "vdd");
> +	if (IS_ERR(pdata->vdd)) {
> +		dev_err(&indio_dev->dev, "unable to get Vdd supply\n");
> +		return PTR_ERR(pdata->vdd);
> +	}
> +	err = regulator_enable(pdata->vdd);
> +	if (err != 0) {
> +		dev_warn(&indio_dev->dev,
> +			 "Failed to enable specified Vdd supply\n");
> +		return err;
>  	}
>  
> -	pdata->vdd_io = devm_regulator_get_optional(indio_dev->dev.parent, "vddio");
> -	if (!IS_ERR(pdata->vdd_io)) {
> -		err = regulator_enable(pdata->vdd_io);
> -		if (err != 0) {
> -			dev_warn(&indio_dev->dev,
> -				 "Failed to enable specified Vdd_IO supply\n");
> -			goto st_sensors_disable_vdd;
> -		}
> -	} else {
> -		err = PTR_ERR(pdata->vdd_io);
> -		if (err != -ENODEV)
> -			goto st_sensors_disable_vdd;
> +	pdata->vdd_io = devm_regulator_get(indio_dev->dev.parent, "vddio");
> +	if (IS_ERR(pdata->vdd)) {
> +		dev_err(&indio_dev->dev, "unable to get Vdd_IO supply\n");
> +		err = PTR_ERR(pdata->vdd);
> +		goto st_sensors_disable_vdd;
> +	}
> +	err = regulator_enable(pdata->vdd_io);
> +	if (err != 0) {
> +		dev_warn(&indio_dev->dev,
> +			 "Failed to enable specified Vdd_IO supply\n");
> +		goto st_sensors_disable_vdd;
>  	}
>  
>  	return 0;
>  
>  st_sensors_disable_vdd:
> -	if (!IS_ERR_OR_NULL(pdata->vdd))
> -		regulator_disable(pdata->vdd);
> +	regulator_disable(pdata->vdd);
>  	return err;
>  }
>  EXPORT_SYMBOL(st_sensors_power_enable);
> @@ -275,11 +271,8 @@ void st_sensors_power_disable(struct iio_dev *indio_dev)
>  {
>  	struct st_sensor_data *pdata = iio_priv(indio_dev);
>  
> -	if (!IS_ERR_OR_NULL(pdata->vdd))
> -		regulator_disable(pdata->vdd);
> -
> -	if (!IS_ERR_OR_NULL(pdata->vdd_io))
> -		regulator_disable(pdata->vdd_io);
> +	regulator_disable(pdata->vdd);
> +	regulator_disable(pdata->vdd_io);
>  }
>  EXPORT_SYMBOL(st_sensors_power_disable);
>  
> 

RE: [PATCH] iio: st_sensors: fetch and enable regulators unconditionally

[Giuseppe BARBA]

> -----Original Message-----
> From: Jonathan Cameron [mailto:jic23@kernel.org]
> Sent: Monday, August 29, 2016 8:43 PM
> To: Linus Walleij <linus.walleij@linaro.org>; linux-iio@vger.kernel.org
> Cc: Giuseppe BARBA <giuseppe.barba@st.com>; Denis CIOCCA
> <denis.ciocca@st.com>; Crestez Dan Leonard <leonard.crestez@intel.com>;
> Gregor Boirie <gregor.boirie@parrot.com>; Mark Brown
> <broonie@kernel.org>
> Subject: Re: [PATCH] iio: st_sensors: fetch and enable regulators
> unconditionally
> 
> On 25/08/16 23:10, Linus Walleij wrote:
> > These sensors all have Vdd and Vdd_IO lines. This means the supplies
> > are *not* optional (optional means that the supply is optional in the
> > electrical sense, not the software sense) so we need to get the and
> > enable them at all times.
> >
> > If the device tree or board file does not define suitable regulators
> > for the component, it will be substituted by a dummy regulator, or, if
> > regulators are disabled altogether, by stubs. There is no need to use
> > the IS_ERR_OR_NULL() check that is considered harmful.
> >
> > Cc: Giuseppe Barba <giuseppe.barba@st.com>
> > Cc: Denis Ciocca <denis.ciocca@st.com>
> > Cc: Crestez Dan Leonard <leonard.crestez@intel.com>
> > Cc: Gregor Boirie <gregor.boirie@parrot.com>
> > Cc: Mark Brown <broonie@kernel.org>
> > Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> Yeah, there was a fair bit of missunderstanding around this (including me) a
> while back so may well be more cases of this kicking around in IIO.
> 
> Good to clear this one out.
> 
> Applied to the togreg branch of iio.git.
> Will be initially pushed out as testing for the autobuilders to play with it.
> 
> If Denis or Giuseppe has a chance to look at in in the next few days that
> would be great as I doubt I'll send a pull to Greg until towards the end of the
> week.
> 
> Thanks,
> 
> Jonathan
> > ---
> >  drivers/iio/common/st_sensors/st_sensors_core.c | 55
> > +++++++++++--------------
> >  1 file changed, 24 insertions(+), 31 deletions(-)
> >
> > diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c
> > b/drivers/iio/common/st_sensors/st_sensors_core.c
> > index 2d5282e05482..41bfe1c5f4e9 100644
> > --- a/drivers/iio/common/st_sensors/st_sensors_core.c
> > +++ b/drivers/iio/common/st_sensors/st_sensors_core.c
> > @@ -234,39 +234,35 @@ int st_sensors_power_enable(struct iio_dev
> *indio_dev)
> >  	int err;
> >
> >  	/* Regulators not mandatory, but if requested we should enable
> them. */
> > -	pdata->vdd = devm_regulator_get_optional(indio_dev->dev.parent,
> "vdd");
> > -	if (!IS_ERR(pdata->vdd)) {
> > -		err = regulator_enable(pdata->vdd);
> > -		if (err != 0) {
> > -			dev_warn(&indio_dev->dev,
> > -				 "Failed to enable specified Vdd supply\n");
> > -			return err;
> > -		}
> > -	} else {
> > -		err = PTR_ERR(pdata->vdd);
> > -		if (err != -ENODEV)
> > -			return err;
> > +	pdata->vdd = devm_regulator_get(indio_dev->dev.parent, "vdd");
> > +	if (IS_ERR(pdata->vdd)) {
> > +		dev_err(&indio_dev->dev, "unable to get Vdd supply\n");
> > +		return PTR_ERR(pdata->vdd);
> > +	}
> > +	err = regulator_enable(pdata->vdd);
> > +	if (err != 0) {
> > +		dev_warn(&indio_dev->dev,
> > +			 "Failed to enable specified Vdd supply\n");
> > +		return err;
> >  	}
> >
> > -	pdata->vdd_io = devm_regulator_get_optional(indio_dev-
> >dev.parent, "vddio");
> > -	if (!IS_ERR(pdata->vdd_io)) {
> > -		err = regulator_enable(pdata->vdd_io);
> > -		if (err != 0) {
> > -			dev_warn(&indio_dev->dev,
> > -				 "Failed to enable specified Vdd_IO
> supply\n");
> > -			goto st_sensors_disable_vdd;
> > -		}
> > -	} else {
> > -		err = PTR_ERR(pdata->vdd_io);
> > -		if (err != -ENODEV)
> > -			goto st_sensors_disable_vdd;
> > +	pdata->vdd_io = devm_regulator_get(indio_dev->dev.parent,
> "vddio");
> > +	if (IS_ERR(pdata->vdd)) {
I think this check is not correct: you have to check the pdata->vdd_io and not
the pdata->vdd (that is already checked before).

> > +		dev_err(&indio_dev->dev, "unable to get Vdd_IO
> supply\n");
> > +		err = PTR_ERR(pdata->vdd);
And here you should use the pdata->vdd_io.

> > +		goto st_sensors_disable_vdd;
> > +	}
> > +	err = regulator_enable(pdata->vdd_io);
> > +	if (err != 0) {
> > +		dev_warn(&indio_dev->dev,
> > +			 "Failed to enable specified Vdd_IO supply\n");
> > +		goto st_sensors_disable_vdd;
> >  	}
> >
> >  	return 0;
> >
> >  st_sensors_disable_vdd:
> > -	if (!IS_ERR_OR_NULL(pdata->vdd))
> > -		regulator_disable(pdata->vdd);
> > +	regulator_disable(pdata->vdd);
> >  	return err;
> >  }
> >  EXPORT_SYMBOL(st_sensors_power_enable);
> > @@ -275,11 +271,8 @@ void st_sensors_power_disable(struct iio_dev
> > *indio_dev)  {
> >  	struct st_sensor_data *pdata = iio_priv(indio_dev);
> >
> > -	if (!IS_ERR_OR_NULL(pdata->vdd))
> > -		regulator_disable(pdata->vdd);
> > -
> > -	if (!IS_ERR_OR_NULL(pdata->vdd_io))
> > -		regulator_disable(pdata->vdd_io);
> > +	regulator_disable(pdata->vdd);
> > +	regulator_disable(pdata->vdd_io);
> >  }
> >  EXPORT_SYMBOL(st_sensors_power_disable);
> >
> >

Giuseppe.

Re: [PATCH] iio: st_sensors: fetch and enable regulators unconditionally

[Linus Walleij]

On Tue, Aug 30, 2016 at 9:21 AM, Giuseppe BARBA <giuseppe.barba@st.com> wrote:

>> > +   pdata->vdd_io = devm_regulator_get(indio_dev->dev.parent,
>> "vddio");
>> > +   if (IS_ERR(pdata->vdd)) {
> I think this check is not correct: you have to check the pdata->vdd_io and not
> the pdata->vdd (that is already checked before).
>
>> > +           dev_err(&indio_dev->dev, "unable to get Vdd_IO
>> supply\n");
>> > +           err = PTR_ERR(pdata->vdd);
> And here you should use the pdata->vdd_io.

Ah, of course, and I've even done that mistake before :(

I'll send a follow-up patch to fix the fix.

Yours,
Linus Walleij