iio: adc: ti-adc161s626: Use devm managed functions for all of probe.

Simplifies error handling and allows us to drop remove entirely.

The regulator handling in this driver was unusual as it would try to
acquire the regulator, but if that failed with an error would continue.

We should get a stub regulator if one isn't provided in DT and an error
could indicate an actual problem preventing the device being powered
(perhaps a need to defer). So this handling is cleaned up (arguably
that might be a fix but given no one has run into it, I haven't broken
it out separately.
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Matt Ranostay <matt.ranostay@konsulko.com>
Acked-by: Matt Ranostay <matt.ranostay@konsulko.com>
Reviewed-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210516172520.1398835-9-jic23@kernel.org

drivers/iio/adc/ti-adc161s626.c

@@ -169,6 +169,11 @@ static const struct iio_info ti_adc_info = {
 	.read_raw = ti_adc_read_raw,
 };
 
+static void ti_adc_reg_disable(void *reg)
+{
+	regulator_disable(reg);
+}
+
 static int ti_adc_probe(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev;
@@ -182,7 +187,6 @@ static int ti_adc_probe(struct spi_device *spi)
 	indio_dev->info = &ti_adc_info;
 	indio_dev->name = TI_ADC_DRV_NAME;
 	indio_dev->modes = INDIO_DIRECT_MODE;
-	spi_set_drvdata(spi, indio_dev);
 
 	data = iio_priv(indio_dev);
 	data->spi = spi;
@@ -203,42 +207,24 @@ static int ti_adc_probe(struct spi_device *spi)
 	}
 
 	data->ref = devm_regulator_get(&spi->dev, "vdda");
-	if (!IS_ERR(data->ref)) {
-		ret = regulator_enable(data->ref);
-		if (ret < 0)
-			return ret;
-	}
+	if (IS_ERR(data->ref))
+		return PTR_ERR(data->ref);
 
-	ret = iio_triggered_buffer_setup(indio_dev, NULL,
-					 ti_adc_trigger_handler, NULL);
-	if (ret)
-		goto error_regulator_disable;
+	ret = regulator_enable(data->ref);
+	if (ret < 0)
+		return ret;
 
-	ret = iio_device_register(indio_dev);
+	ret = devm_add_action_or_reset(&spi->dev, ti_adc_reg_disable,
+				       data->ref);
 	if (ret)
-		goto error_unreg_buffer;
-
-	return 0;
+		return ret;
 
-error_unreg_buffer:
-	iio_triggered_buffer_cleanup(indio_dev);
-
-error_regulator_disable:
-	regulator_disable(data->ref);
-
-	return ret;
-}
-
-static int ti_adc_remove(struct spi_device *spi)
-{
-	struct iio_dev *indio_dev = spi_get_drvdata(spi);
-	struct ti_adc_data *data = iio_priv(indio_dev);
-
-	iio_device_unregister(indio_dev);
-	iio_triggered_buffer_cleanup(indio_dev);
-	regulator_disable(data->ref);
+	ret = devm_iio_triggered_buffer_setup(&spi->dev, indio_dev, NULL,
+					      ti_adc_trigger_handler, NULL);
+	if (ret)
+		return ret;
 
-	return 0;
+	return devm_iio_device_register(&spi->dev, indio_dev);
 }
 
 static const struct of_device_id ti_adc_dt_ids[] = {
@@ -261,7 +247,6 @@ static struct spi_driver ti_adc_driver = {
 		.of_match_table = ti_adc_dt_ids,
 	},
 	.probe		= ti_adc_probe,
-	.remove		= ti_adc_remove,
 	.id_table	= ti_adc_id,
 };
 module_spi_driver(ti_adc_driver);