[PATCH] iio:st_magn: enable trigger before enabling sensor

[Denis Ciocca <denis.ciocca@st.com>]

>From logical point of view driver should be ready to
receive irqs before enabling the sensor itself.
This patch is fixing also an issue related to
sensors that generate interrupts unconditionally,
(DRDY pads) when interrupt level is used.

Signed-off-by: Martin Kelly <martin@martingkelly.com>
Signed-off-by: Denis Ciocca <denis.ciocca@st.com>
---
 drivers/iio/magnetometer/st_magn_buffer.c | 33 +++++++++++------------
 1 file changed, 16 insertions(+), 17 deletions(-)

diff --git a/drivers/iio/magnetometer/st_magn_buffer.c b/drivers/iio/magnetometer/st_magn_buffer.c
index 0a9e8fadfa9d..097e6e88a464 100644
--- a/drivers/iio/magnetometer/st_magn_buffer.c
+++ b/drivers/iio/magnetometer/st_magn_buffer.c
@@ -30,11 +30,6 @@ int st_magn_trig_set_state(struct iio_trigger *trig, bool state)
 	return st_sensors_set_dataready_irq(indio_dev, state);
 }
 
-static int st_magn_buffer_preenable(struct iio_dev *indio_dev)
-{
-	return st_sensors_set_enable(indio_dev, true);
-}
-
 static int st_magn_buffer_postenable(struct iio_dev *indio_dev)
 {
 	int err;
@@ -42,40 +37,44 @@ static int st_magn_buffer_postenable(struct iio_dev *indio_dev)
 
 	mdata->buffer_data = kmalloc(indio_dev->scan_bytes, GFP_KERNEL);
 	if (mdata->buffer_data == NULL) {
-		err = -ENOMEM;
-		goto allocate_memory_error;
+		return -ENOMEM;
 	}
 
 	err = iio_triggered_buffer_postenable(indio_dev);
 	if (err < 0)
-		goto st_magn_buffer_postenable_error;
+		goto st_magn_buffer_free_buffer_data;
+
+	err = st_sensors_set_enable(indio_dev, true);
+	if (err < 0)
+		goto st_magn_buffer_buffer_predisable;
 
 	return err;
 
-st_magn_buffer_postenable_error:
+st_magn_buffer_buffer_predisable:
+	iio_triggered_buffer_predisable(indio_dev);
+st_magn_buffer_free_buffer_data:
 	kfree(mdata->buffer_data);
-allocate_memory_error:
 	return err;
 }
 
 static int st_magn_buffer_predisable(struct iio_dev *indio_dev)
 {
-	int err;
+	int err = 0, err2;
 	struct st_sensor_data *mdata = iio_priv(indio_dev);
 
-	err = iio_triggered_buffer_predisable(indio_dev);
-	if (err < 0)
-		goto st_magn_buffer_predisable_error;
+	err2 = st_sensors_set_enable(indio_dev, false);
+	if (err2 < 0)
+		err = err2;
 
-	err = st_sensors_set_enable(indio_dev, false);
+	err2 = iio_triggered_buffer_predisable(indio_dev);
+	if (err2 < 0)
+		err = err2;
 
-st_magn_buffer_predisable_error:
 	kfree(mdata->buffer_data);
 	return err;
 }
 
 static const struct iio_buffer_setup_ops st_magn_buffer_setup_ops = {
-	.preenable = &st_magn_buffer_preenable,
 	.postenable = &st_magn_buffer_postenable,
 	.predisable = &st_magn_buffer_predisable,
 };
-- 
2.19.1