iio: frequency: ad9523: Use devm_regulator_get_enable()

This driver only turns the power on at probe and off via a custom
devm_add_action_or_reset() callback. The new devm_regulator_get_enable()
replaces this boilerplate code.

Note that in event of an error on the devm_regulator_get() the driver
would have continued without enabling the regulator which is probably
not a good idea.  So here we handle any error as a reason to fail the
probe(). In theory this may expose breakage on a platform that was
previously papered over but it seems low risk.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michael Hennerich <michael.hennerich@analog.com>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Nuno Sá <nuno.sa@analog.com>
Link: https://lore.kernel.org/r/20221016163409.320197-9-jic23@kernel.org

drivers/iio/frequency/ad9523.c

@@ -265,7 +265,6 @@ enum {
 
 struct ad9523_state {
 	struct spi_device		*spi;
-	struct regulator		*reg;
 	struct ad9523_platform_data	*pdata;
 	struct iio_chan_spec		ad9523_channels[AD9523_NUM_CHAN];
 	struct gpio_desc		*pwrdown_gpio;
@@ -969,13 +968,6 @@ static int ad9523_setup(struct iio_dev *indio_dev)
 	return 0;
 }
 
-static void ad9523_reg_disable(void *data)
-{
-	struct regulator *reg = data;
-
-	regulator_disable(reg);
-}
-
 static int ad9523_probe(struct spi_device *spi)
 {
 	struct ad9523_platform_data *pdata = spi->dev.platform_data;
@@ -996,17 +988,9 @@ static int ad9523_probe(struct spi_device *spi)
 
 	mutex_init(&st->lock);
 
-	st->reg = devm_regulator_get(&spi->dev, "vcc");
-	if (!IS_ERR(st->reg)) {
-		ret = regulator_enable(st->reg);
-		if (ret)
-			return ret;
-
-		ret = devm_add_action_or_reset(&spi->dev, ad9523_reg_disable,
-					       st->reg);
-		if (ret)
-			return ret;
-	}
+	ret = devm_regulator_get_enable(&spi->dev, "vcc");
+	if (ret)
+		return ret;
 
 	st->pwrdown_gpio = devm_gpiod_get_optional(&spi->dev, "powerdown",
 		GPIOD_OUT_HIGH);