This makes use of the new devm_regulator_get_enable_read_voltage()
function to reduce boilerplate code.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---
 drivers/iio/adc/ad7266.c | 37 ++++++++++---------------------------
 1 file changed, 10 insertions(+), 27 deletions(-)

diff --git a/drivers/iio/adc/ad7266.c b/drivers/iio/adc/ad7266.c
index 353a97f9c086..026db1bedc0a 100644
--- a/drivers/iio/adc/ad7266.c
+++ b/drivers/iio/adc/ad7266.c
@@ -25,7 +25,6 @@
 
 struct ad7266_state {
 	struct spi_device	*spi;
-	struct regulator	*reg;
 	unsigned long		vref_mv;
 
 	struct spi_transfer	single_xfer[3];
@@ -377,11 +376,6 @@ static const char * const ad7266_gpio_labels[] = {
 	"ad0", "ad1", "ad2",
 };
 
-static void ad7266_reg_disable(void *reg)
-{
-	regulator_disable(reg);
-}
-
 static int ad7266_probe(struct spi_device *spi)
 {
 	struct ad7266_platform_data *pdata = spi->dev.platform_data;
@@ -396,28 +390,17 @@ static int ad7266_probe(struct spi_device *spi)
 
 	st = iio_priv(indio_dev);
 
-	st->reg = devm_regulator_get_optional(&spi->dev, "vref");
-	if (!IS_ERR(st->reg)) {
-		ret = regulator_enable(st->reg);
-		if (ret)
-			return ret;
-
-		ret = devm_add_action_or_reset(&spi->dev, ad7266_reg_disable, st->reg);
-		if (ret)
-			return ret;
-
-		ret = regulator_get_voltage(st->reg);
-		if (ret < 0)
-			return ret;
-
-		st->vref_mv = ret / 1000;
-	} else {
-		/* Any other error indicates that the regulator does exist */
-		if (PTR_ERR(st->reg) != -ENODEV)
-			return PTR_ERR(st->reg);
-		/* Use internal reference */
+	/*
+	 * Use external reference from vref if present, otherwise use 2.5V
+	 * internal reference.
+	 */
+	ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");
+	if (ret == -ENODEV)
 		st->vref_mv = 2500;
-	}
+	else if (ret < 0)
+		return ret;
+	else
+		st->vref_mv = ret / 1000;
 
 	if (pdata) {
 		st->fixed_addr = pdata->fixed_addr;

-- 
2.45.1

On Fri, 2024-05-31 at 16:19 -0500, David Lechner wrote:
> This makes use of the new devm_regulator_get_enable_read_voltage()
> function to reduce boilerplate code.
> 
> Signed-off-by: David Lechner <dlechner@baylibre.com>
> ---
>  drivers/iio/adc/ad7266.c | 37 ++++++++++---------------------------
>  1 file changed, 10 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad7266.c b/drivers/iio/adc/ad7266.c
> index 353a97f9c086..026db1bedc0a 100644
> --- a/drivers/iio/adc/ad7266.c
> +++ b/drivers/iio/adc/ad7266.c
> @@ -25,7 +25,6 @@
>  
>  struct ad7266_state {
>  	struct spi_device	*spi;
> -	struct regulator	*reg;
>  	unsigned long		vref_mv;
>  
>  	struct spi_transfer	single_xfer[3];
> @@ -377,11 +376,6 @@ static const char * const ad7266_gpio_labels[] = {
>  	"ad0", "ad1", "ad2",
>  };
>  
> -static void ad7266_reg_disable(void *reg)
> -{
> -	regulator_disable(reg);
> -}
> -
>  static int ad7266_probe(struct spi_device *spi)
>  {
>  	struct ad7266_platform_data *pdata = spi->dev.platform_data;
> @@ -396,28 +390,17 @@ static int ad7266_probe(struct spi_device *spi)
>  
>  	st = iio_priv(indio_dev);
>  
> -	st->reg = devm_regulator_get_optional(&spi->dev, "vref");
> -	if (!IS_ERR(st->reg)) {
> -		ret = regulator_enable(st->reg);
> -		if (ret)
> -			return ret;
> -
> -		ret = devm_add_action_or_reset(&spi->dev, ad7266_reg_disable, st-
> >reg);
> -		if (ret)
> -			return ret;
> -
> -		ret = regulator_get_voltage(st->reg);
> -		if (ret < 0)
> -			return ret;
> -
> -		st->vref_mv = ret / 1000;
> -	} else {
> -		/* Any other error indicates that the regulator does exist */
> -		if (PTR_ERR(st->reg) != -ENODEV)
> -			return PTR_ERR(st->reg);
> -		/* Use internal reference */
> +	/*
> +	 * Use external reference from vref if present, otherwise use 2.5V
> +	 * internal reference.
> +	 */

Not sure the comment brings any added value. The code is fairly self explanatory
IMO...

> +	ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");
> +	if (ret == -ENODEV)
>  		st->vref_mv = 2500;
> -	}
> +	else if (ret < 0)
> +		return ret;
> +	else

I think it would be better (as that is the typical pattern) to first check for
errors. Also the 'return' in the middle of the else if () is a bit weird to me...
Maybe something like this?

if (ret < 0 && ret != -ENODEV)
	return ret;
if (ret == -ENODEV)
	st->vref_mv = 2500;
else
	st->vref_mv = ret / 1000;

or even replacing the if() else by
st->vref_mv = ret == -ENODEV ? 2500 : ret / 1000;

- Nuno Sá

On 6/4/24 6:19 AM, Nuno Sá wrote:
> On Fri, 2024-05-31 at 16:19 -0500, David Lechner wrote:
>> This makes use of the new devm_regulator_get_enable_read_voltage()
>> function to reduce boilerplate code.
>>
>> Signed-off-by: David Lechner <dlechner@baylibre.com>
>> ---
>>  drivers/iio/adc/ad7266.c | 37 ++++++++++---------------------------
>>  1 file changed, 10 insertions(+), 27 deletions(-)
>>
>> diff --git a/drivers/iio/adc/ad7266.c b/drivers/iio/adc/ad7266.c
>> index 353a97f9c086..026db1bedc0a 100644
>> --- a/drivers/iio/adc/ad7266.c
>> +++ b/drivers/iio/adc/ad7266.c
>> @@ -25,7 +25,6 @@
>>  
>>  struct ad7266_state {
>>  	struct spi_device	*spi;
>> -	struct regulator	*reg;
>>  	unsigned long		vref_mv;
>>  
>>  	struct spi_transfer	single_xfer[3];
>> @@ -377,11 +376,6 @@ static const char * const ad7266_gpio_labels[] = {
>>  	"ad0", "ad1", "ad2",
>>  };
>>  
>> -static void ad7266_reg_disable(void *reg)
>> -{
>> -	regulator_disable(reg);
>> -}
>> -
>>  static int ad7266_probe(struct spi_device *spi)
>>  {
>>  	struct ad7266_platform_data *pdata = spi->dev.platform_data;
>> @@ -396,28 +390,17 @@ static int ad7266_probe(struct spi_device *spi)
>>  
>>  	st = iio_priv(indio_dev);
>>  
>> -	st->reg = devm_regulator_get_optional(&spi->dev, "vref");
>> -	if (!IS_ERR(st->reg)) {
>> -		ret = regulator_enable(st->reg);
>> -		if (ret)
>> -			return ret;
>> -
>> -		ret = devm_add_action_or_reset(&spi->dev, ad7266_reg_disable, st-
>>> reg);
>> -		if (ret)
>> -			return ret;
>> -
>> -		ret = regulator_get_voltage(st->reg);
>> -		if (ret < 0)
>> -			return ret;
>> -
>> -		st->vref_mv = ret / 1000;
>> -	} else {
>> -		/* Any other error indicates that the regulator does exist */
>> -		if (PTR_ERR(st->reg) != -ENODEV)
>> -			return PTR_ERR(st->reg);
>> -		/* Use internal reference */
>> +	/*
>> +	 * Use external reference from vref if present, otherwise use 2.5V
>> +	 * internal reference.
>> +	 */
> 
> Not sure the comment brings any added value. The code is fairly self explanatory
> IMO...

Well, you do this every day. :-)

For someone who never wrote an IIO driver, it could be helpful.

> 
>> +	ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vref");
>> +	if (ret == -ENODEV)
>>  		st->vref_mv = 2500;
>> -	}
>> +	else if (ret < 0)
>> +		return ret;
>> +	else
> 
> I think it would be better (as that is the typical pattern) to first check for
> errors. Also the 'return' in the middle of the else if () is a bit weird to me...
> Maybe something like this?
> 
> if (ret < 0 && ret != -ENODEV)
> 	return ret;
> if (ret == -ENODEV)
> 	st->vref_mv = 2500;
> else
> 	st->vref_mv = ret / 1000;
> 
> or even replacing the if() else by
> st->vref_mv = ret == -ENODEV ? 2500 : ret / 1000;
> 
> - Nuno Sá
> 

I think I like that better too.

On Tue, 2024-06-04 at 09:10 -0500, David Lechner wrote:
> On 6/4/24 6:19 AM, Nuno Sá wrote:
> > On Fri, 2024-05-31 at 16:19 -0500, David Lechner wrote:
> > > This makes use of the new devm_regulator_get_enable_read_voltage()
> > > function to reduce boilerplate code.
> > > 
> > > Signed-off-by: David Lechner <dlechner@baylibre.com>
> > > ---
> > >  drivers/iio/adc/ad7266.c | 37 ++++++++++---------------------------
> > >  1 file changed, 10 insertions(+), 27 deletions(-)
> > > 
> > > diff --git a/drivers/iio/adc/ad7266.c b/drivers/iio/adc/ad7266.c
> > > index 353a97f9c086..026db1bedc0a 100644
> > > --- a/drivers/iio/adc/ad7266.c
> > > +++ b/drivers/iio/adc/ad7266.c
> > > @@ -25,7 +25,6 @@
> > >  
> > >  struct ad7266_state {
> > >  	struct spi_device	*spi;
> > > -	struct regulator	*reg;
> > >  	unsigned long		vref_mv;
> > >  
> > >  	struct spi_transfer	single_xfer[3];
> > > @@ -377,11 +376,6 @@ static const char * const ad7266_gpio_labels[] = {
> > >  	"ad0", "ad1", "ad2",
> > >  };
> > >  
> > > -static void ad7266_reg_disable(void *reg)
> > > -{
> > > -	regulator_disable(reg);
> > > -}
> > > -
> > >  static int ad7266_probe(struct spi_device *spi)
> > >  {
> > >  	struct ad7266_platform_data *pdata = spi->dev.platform_data;
> > > @@ -396,28 +390,17 @@ static int ad7266_probe(struct spi_device *spi)
> > >  
> > >  	st = iio_priv(indio_dev);
> > >  
> > > -	st->reg = devm_regulator_get_optional(&spi->dev, "vref");
> > > -	if (!IS_ERR(st->reg)) {
> > > -		ret = regulator_enable(st->reg);
> > > -		if (ret)
> > > -			return ret;
> > > -
> > > -		ret = devm_add_action_or_reset(&spi->dev,
> > > ad7266_reg_disable, st-
> > > > reg);
> > > -		if (ret)
> > > -			return ret;
> > > -
> > > -		ret = regulator_get_voltage(st->reg);
> > > -		if (ret < 0)
> > > -			return ret;
> > > -
> > > -		st->vref_mv = ret / 1000;
> > > -	} else {
> > > -		/* Any other error indicates that the regulator does
> > > exist */
> > > -		if (PTR_ERR(st->reg) != -ENODEV)
> > > -			return PTR_ERR(st->reg);
> > > -		/* Use internal reference */
> > > +	/*
> > > +	 * Use external reference from vref if present, otherwise use
> > > 2.5V
> > > +	 * internal reference.
> > > +	 */
> > 
> > Not sure the comment brings any added value. The code is fairly self
> > explanatory
> > IMO...
> 
> Well, you do this every day. :-)

I guess... still not an excuse :)

> 
> For someone who never wrote an IIO driver, it could be helpful.

Still dunno but no strong feelings anyways...

- Nuno Sá