[PATCH RFC v3 8/8] iio: ti-adc128s052: Drop variable vref

Matti Vaittinen
2025-04-07T11:37:59Z

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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 => v3:
- Rename vref => vref_mv to make units visible
- Divide vref once in the probe to avoid division every time the scale
is requested
v2:
- New patch
---
drivers/iio/adc/ti-adc128s052.c | 29 +++++++----------------------
1 file changed, 7 insertions(+), 22 deletions(-)

diff --git a/drivers/iio/adc/ti-adc128s052.c b/drivers/iio/adc/ti-adc128s052.c
index d4721ad90f2c..c38468f299ce 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_mv;
union {
__be16 buffer16;
u8 buffer[2];
@@ -81,11 +80,7 @@ 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_mv;
*val2 = 12;
return IIO_VAL_FRACTIONAL_LOG2;

@@ -155,11 +150,6 @@ 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;
@@ -183,17 +173,12 @@ 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);
+ adc->vref_mv = devm_regulator_get_enable_read_voltage(&spi->dev,
+ config->refname);
+ if (adc->vref_mv < 0)
+ return adc->vref_mv;

- 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_mv /= 1000;

if (config->num_other_regulators) {
ret = devm_regulator_bulk_get_enable(&spi->dev,