iio: adc: ad7793: convert to device-managed functions

With the devm_ad_sd_setup_buffer_and_trigger() helper, it's a bit easier
now to convert the probe of the AD7793 driver to use device-managed
functions.

Only the regulator disable requires a devm_add_action_or_reset() callback.

This change does that, cleaning up the driver a bit.
Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210513120752.90074-7-aardelean@deviqon.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/ad7793.c

@@ -769,6 +769,11 @@ static const struct ad7793_chip_info ad7793_chip_info_tbl[] = {
 	},
 };
 
+static void ad7793_reg_disable(void *reg)
+{
+	regulator_disable(reg);
+}
+
 static int ad7793_probe(struct spi_device *spi)
 {
 	const struct ad7793_platform_data *pdata = spi->dev.platform_data;
@@ -803,11 +808,13 @@ static int ad7793_probe(struct spi_device *spi)
 		if (ret)
 			return ret;
 
+		ret = devm_add_action_or_reset(&spi->dev, ad7793_reg_disable, st->reg);
+		if (ret)
+			return ret;
+
 		vref_mv = regulator_get_voltage(st->reg);
-		if (vref_mv < 0) {
-			ret = vref_mv;
-			goto error_disable_reg;
-		}
+		if (vref_mv < 0)
+			return vref_mv;
 
 		vref_mv /= 1000;
 	} else {
@@ -817,50 +824,21 @@ static int ad7793_probe(struct spi_device *spi)
 	st->chip_info =
 		&ad7793_chip_info_tbl[spi_get_device_id(spi)->driver_data];
 
-	spi_set_drvdata(spi, indio_dev);
-
 	indio_dev->name = spi_get_device_id(spi)->name;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = st->chip_info->channels;
 	indio_dev->num_channels = st->chip_info->num_channels;
 	indio_dev->info = st->chip_info->iio_info;
 
-	ret = ad_sd_setup_buffer_and_trigger(indio_dev);
+	ret = devm_ad_sd_setup_buffer_and_trigger(&spi->dev, indio_dev);
 	if (ret)
-		goto error_disable_reg;
+		return ret;
 
 	ret = ad7793_setup(indio_dev, pdata, vref_mv);
 	if (ret)
-		goto error_remove_trigger;
-
-	ret = iio_device_register(indio_dev);
-	if (ret)
-		goto error_remove_trigger;
-
-	return 0;
-
-error_remove_trigger:
-	ad_sd_cleanup_buffer_and_trigger(indio_dev);
-error_disable_reg:
-	if (pdata->refsel != AD7793_REFSEL_INTERNAL)
-		regulator_disable(st->reg);
-
-	return ret;
-}
-
-static int ad7793_remove(struct spi_device *spi)
-{
-	const struct ad7793_platform_data *pdata = spi->dev.platform_data;
-	struct iio_dev *indio_dev = spi_get_drvdata(spi);
-	struct ad7793_state *st = iio_priv(indio_dev);
-
-	iio_device_unregister(indio_dev);
-	ad_sd_cleanup_buffer_and_trigger(indio_dev);
-
-	if (pdata->refsel != AD7793_REFSEL_INTERNAL)
-		regulator_disable(st->reg);
+		return ret;
 
-	return 0;
+	return devm_iio_device_register(&spi->dev, indio_dev);
 }
 
 static const struct spi_device_id ad7793_id[] = {
@@ -882,7 +860,6 @@ static struct spi_driver ad7793_driver = {
 		.name	= "ad7793",
 	},
 	.probe		= ad7793_probe,
-	.remove		= ad7793_remove,
 	.id_table	= ad7793_id,
 };
 module_spi_driver(ad7793_driver);