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[PATCH RFC v2 7/7] iio: ti-adc128s052: Drop variable vref

Matti Vaittinen posted 7 patches 10 months, 1 week ago
There is a newer version of this series
[PATCH RFC v2 7/7] iio: ti-adc128s052: Drop variable vref
Posted by Matti Vaittinen 10 months, 1 week ago 
According to Jonathan, variable reference voltages are very rare. It is
unlikely it is needed, and supporting it makes the code a bit more
complex.

Simplify the driver and drop the variable vref support.

Suggested-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
---
Revision History:
 v2:
  - New patch
---
 drivers/iio/adc/ti-adc128s052.c | 29 ++++++-----------------------
 1 file changed, 6 insertions(+), 23 deletions(-)

diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
index 0f93c6266527..0bfe4e558c69 100644
--- a/drivers/iio/adc/ti-adc128s052.c
+++ b/drivers/iio/adc/ti-adc128s052.c
@@ -29,13 +29,12 @@ struct adc128_configuration {
 struct adc128 {
 	struct spi_device *spi;
 
-	struct regulator *reg;
 	/*
 	 * Serialize the SPI 'write-channel + read data' accesses and protect
 	 * the shared buffer.
 	 */
 	struct mutex lock;
-
+	int vref;
 	union {
 		__be16 rx_buffer;
 		u8 tx_buffer[2];
@@ -82,11 +81,7 @@ static int adc128_read_raw(struct iio_dev *indio_dev,
 
 	case IIO_CHAN_INFO_SCALE:
 
-		ret = regulator_get_voltage(adc->reg);
-		if (ret < 0)
-			return ret;
-
-		*val = ret / 1000;
+		*val = adc->vref / 1000;
 		*val2 = 12;
 		return IIO_VAL_FRACTIONAL_LOG2;
 
@@ -156,11 +151,6 @@ static const struct iio_info adc128_info = {
 	.read_raw = adc128_read_raw,
 };
 
-static void adc128_disable_regulator(void *reg)
-{
-	regulator_disable(reg);
-}
-
 static int adc128_probe(struct spi_device *spi)
 {
 	const struct adc128_configuration *config;
@@ -184,17 +174,10 @@ static int adc128_probe(struct spi_device *spi)
 	indio_dev->channels = config->channels;
 	indio_dev->num_channels = config->num_channels;
 
-	adc->reg = devm_regulator_get(&spi->dev, config->refname);
-	if (IS_ERR(adc->reg))
-		return PTR_ERR(adc->reg);
-
-	ret = regulator_enable(adc->reg);
-	if (ret < 0)
-		return ret;
-	ret = devm_add_action_or_reset(&spi->dev, adc128_disable_regulator,
-				       adc->reg);
-	if (ret)
-		return ret;
+	adc->vref = devm_regulator_get_enable_read_voltage(&spi->dev,
+							   config->refname);
+	if (adc->vref < 0)
+		return adc->vref;
 
 	if (config->num_other_regulators) {
 		ret = devm_regulator_bulk_get_enable(&spi->dev,
-- 
2.49.0
Re: [PATCH RFC v2 7/7] iio: ti-adc128s052: Drop variable vref
Posted by David Lechner 10 months, 1 week ago 
On 4/2/25 1:10 AM, Matti Vaittinen wrote:
> According to Jonathan, variable reference voltages are very rare. It is
> unlikely it is needed, and supporting it makes the code a bit more
> complex.

There is also around 60 other drivers where we could do something like this
in case anyone is bored. :-p

> 
> Simplify the driver and drop the variable vref support.
> 
> Suggested-by: Jonathan Cameron <jic23@kernel.org>
> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> ---
> Revision History:
>  v2:
>   - New patch
> ---
>  drivers/iio/adc/ti-adc128s052.c | 29 ++++++-----------------------
>  1 file changed, 6 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
> index 0f93c6266527..0bfe4e558c69 100644
> --- a/drivers/iio/adc/ti-adc128s052.c
> +++ b/drivers/iio/adc/ti-adc128s052.c
> @@ -29,13 +29,12 @@ struct adc128_configuration {
>  struct adc128 {
>  	struct spi_device *spi;
>  
> -	struct regulator *reg;
>  	/*
>  	 * Serialize the SPI 'write-channel + read data' accesses and protect
>  	 * the shared buffer.
>  	 */
>  	struct mutex lock;
> -
> +	int vref;

Units in the name are helpful: vref_uv.

Could also consider doing division in probe and storing vref_mv instead
since we never use the microvolts part.

>  	union {
>  		__be16 rx_buffer;
>  		u8 tx_buffer[2];
Re: [PATCH RFC v2 7/7] iio: ti-adc128s052: Drop variable vref
Posted by Jonathan Cameron 10 months, 1 week ago 
On Wed, 2 Apr 2025 15:49:01 -0500
David Lechner <dlechner@baylibre.com> wrote:

> On 4/2/25 1:10 AM, Matti Vaittinen wrote:
> > According to Jonathan, variable reference voltages are very rare. It is
> > unlikely it is needed, and supporting it makes the code a bit more
> > complex.  
> 
> There is also around 60 other drivers where we could do something like this
> in case anyone is bored. :-p

Hmm. It would be a gamble but also a nice cleanup.

We 'might' meet a case where someone notices it but seems fairly unlikely...

J
> 
> > 
> > Simplify the driver and drop the variable vref support.
> > 
> > Suggested-by: Jonathan Cameron <jic23@kernel.org>
> > Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
> > ---
> > Revision History:
> >  v2:
> >   - New patch
> > ---
> >  drivers/iio/adc/ti-adc128s052.c | 29 ++++++-----------------------
> >  1 file changed, 6 insertions(+), 23 deletions(-)
> > 
> > diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
> > index 0f93c6266527..0bfe4e558c69 100644
> > --- a/drivers/iio/adc/ti-adc128s052.c
> > +++ b/drivers/iio/adc/ti-adc128s052.c
> > @@ -29,13 +29,12 @@ struct adc128_configuration {
> >  struct adc128 {
> >  	struct spi_device *spi;
> >  
> > -	struct regulator *reg;
> >  	/*
> >  	 * Serialize the SPI 'write-channel + read data' accesses and protect
> >  	 * the shared buffer.
> >  	 */
> >  	struct mutex lock;
> > -
> > +	int vref;  
> 
> Units in the name are helpful: vref_uv.
> 
> Could also consider doing division in probe and storing vref_mv instead
> since we never use the microvolts part.
> 
> >  	union {
> >  		__be16 rx_buffer;
> >  		u8 tx_buffer[2];  
>
Re: [PATCH RFC v2 7/7] iio: ti-adc128s052: Drop variable vref
Posted by Matti Vaittinen 10 months, 1 week ago 
On 02/04/2025 23:49, David Lechner wrote:
> On 4/2/25 1:10 AM, Matti Vaittinen wrote:
>> According to Jonathan, variable reference voltages are very rare. It is
>> unlikely it is needed, and supporting it makes the code a bit more
>> complex.
> 
> There is also around 60 other drivers where we could do something like this
> in case anyone is bored. :-p
> 
>>
>> Simplify the driver and drop the variable vref support.
>>
>> Suggested-by: Jonathan Cameron <jic23@kernel.org>
>> Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
>> ---
>> Revision History:
>>   v2:
>>    - New patch
>> ---
>>   drivers/iio/adc/ti-adc128s052.c | 29 ++++++-----------------------
>>   1 file changed, 6 insertions(+), 23 deletions(-)
>>
>> diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
>> index 0f93c6266527..0bfe4e558c69 100644
>> --- a/drivers/iio/adc/ti-adc128s052.c
>> +++ b/drivers/iio/adc/ti-adc128s052.c
>> @@ -29,13 +29,12 @@ struct adc128_configuration {
>>   struct adc128 {
>>   	struct spi_device *spi;
>>   
>> -	struct regulator *reg;
>>   	/*
>>   	 * Serialize the SPI 'write-channel + read data' accesses and protect
>>   	 * the shared buffer.
>>   	 */
>>   	struct mutex lock;
>> -
>> +	int vref;
> 
> Units in the name are helpful: vref_uv.
> 
> Could also consider doing division in probe and storing vref_mv instead
> since we never use the microvolts part.

Ah, thanks for the suggestions. I agree with both.

> 
>>   	union {
>>   		__be16 rx_buffer;
>>   		u8 tx_buffer[2];
> 

Yours,
	-- Matti

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