iio: dac: max5522: simplify probe with devm_regulator_get_enable_read_voltage()

Simplify probe by using devm_regulator_get_enable_read_voltage() to
get, enable and read the regulator voltage in a single call, caching
the value at probe time.

The reference voltage for this DAC is a fixed hardware configuration
that is not expected to change at runtime, so reading it once during
probe and caching the millivolt value is sufficient.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Signed-off-by: Antoniu Miclaus <antoniu.miclaus@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/dac/max5522.c b/drivers/iio/dac/max5522.c
index 1b8fe6b8d26ef37757621cbc15a726fab228f927..b52a9cc1da798fc63f7b49ff79e72c23495bdefb 100644 (file)
--- a/drivers/iio/dac/max5522.c
+++ b/drivers/iio/dac/max5522.c
@@ -14,6 +14,7 @@
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
+#include <linux/units.h>
 
 #include <linux/iio/iio.h>
 
@@ -34,7 +35,7 @@ struct max5522_state {
        struct regmap *regmap;
        const struct max5522_chip_info *chip_info;
        unsigned short dac_cache[2];
-       struct regulator *vrefin_reg;
+       int vref_mV;
 };
 
 #define MAX5522_CHANNEL(chan) {        \
@@ -79,17 +80,13 @@ static int max5522_read_raw(struct iio_dev *indio_dev,
                            int *val, int *val2, long info)
 {
        struct max5522_state *state = iio_priv(indio_dev);
-       int ret;
 
        switch (info) {
        case IIO_CHAN_INFO_RAW:
                *val = state->dac_cache[chan->channel];
                return IIO_VAL_INT;
        case IIO_CHAN_INFO_SCALE:
-               ret = regulator_get_voltage(state->vrefin_reg);
-               if (ret < 0)
-                       return -EINVAL;
-               *val = ret / 1000;
+               *val = state->vref_mV;
                *val2 = 10;
                return IIO_VAL_FRACTIONAL_LOG2;
        default:
@@ -147,16 +144,11 @@ static int max5522_spi_probe(struct spi_device *spi)
        if (!state->chip_info)
                return -EINVAL;
 
-       state->vrefin_reg = devm_regulator_get(&spi->dev, "vrefin");
-       if (IS_ERR(state->vrefin_reg))
-               return dev_err_probe(&spi->dev, PTR_ERR(state->vrefin_reg),
-                                    "Vrefin regulator not specified\n");
-
-       ret = regulator_enable(state->vrefin_reg);
-       if (ret) {
+       ret = devm_regulator_get_enable_read_voltage(&spi->dev, "vrefin");
+       if (ret < 0)
                return dev_err_probe(&spi->dev, ret,
-                                    "Failed to enable vref regulators\n");
-       }
+                                    "Failed to get vrefin regulator\n");
+       state->vref_mV = ret / (MICRO / MILLI);
 
        state->regmap = devm_regmap_init_spi(spi, &max5522_regmap_config);