iio: dln2-adc: fix iio_triggered_buffer_postenable() position

The iio_triggered_buffer_postenable() hook should be called first to
attach the poll function. The iio_triggered_buffer_predisable() hook is
called last (as is it should).

This change moves iio_triggered_buffer_postenable() to be called first. It
adds iio_triggered_buffer_predisable() on the error paths of the postenable
hook.
For the predisable hook, some code-paths have been changed to make sure
that the iio_triggered_buffer_predisable() hook gets called in case there
is an error before it.
Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/dln2-adc.c

@@ -524,6 +524,10 @@ static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev)
 	u16 conflict;
 	unsigned int trigger_chan;
 
+	ret = iio_triggered_buffer_postenable(indio_dev);
+	if (ret)
+		return ret;
+
 	mutex_lock(&dln2->mutex);
 
 	/* Enable ADC */
@@ -537,6 +541,7 @@ static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev)
 				(int)conflict);
 			ret = -EBUSY;
 		}
+		iio_triggered_buffer_predisable(indio_dev);
 		return ret;
 	}
 
@@ -550,6 +555,7 @@ static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev)
 		mutex_unlock(&dln2->mutex);
 		if (ret < 0) {
 			dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
+			iio_triggered_buffer_predisable(indio_dev);
 			return ret;
 		}
 	} else {
@@ -557,12 +563,12 @@ static int dln2_adc_triggered_buffer_postenable(struct iio_dev *indio_dev)
 		mutex_unlock(&dln2->mutex);
 	}
 
-	return iio_triggered_buffer_postenable(indio_dev);
+	return 0;
 }
 
 static int dln2_adc_triggered_buffer_predisable(struct iio_dev *indio_dev)
 {
-	int ret;
+	int ret, ret2;
 	struct dln2_adc *dln2 = iio_priv(indio_dev);
 
 	mutex_lock(&dln2->mutex);
@@ -577,12 +583,14 @@ static int dln2_adc_triggered_buffer_predisable(struct iio_dev *indio_dev)
 	ret = dln2_adc_set_port_enabled(dln2, false, NULL);
 
 	mutex_unlock(&dln2->mutex);
-	if (ret < 0) {
+	if (ret < 0)
 		dev_dbg(&dln2->pdev->dev, "Problem in %s\n", __func__);
-		return ret;
-	}
 
-	return iio_triggered_buffer_predisable(indio_dev);
+	ret2 = iio_triggered_buffer_predisable(indio_dev);
+	if (ret == 0)
+		ret = ret2;
+
+	return ret;
 }
 
 static const struct iio_buffer_setup_ops dln2_adc_buffer_setup_ops = {