iio: gyro: st_gyro: use devm_iio_triggered_buffer_setup() for buffer

The st_gyro_allocate_ring() function calls iio_triggered_buffer_setup() to
allocate a triggered buffer.

But the same can be done with devm_iio_triggered_buffer_setup() and then
the st_gyro_common_remove() no longer needs to manually deallocate it.

We know that the parent of the IIO device is used to manage other instances
of the devm unwind, so it can be used in the st_gyro_allocate_ring() as
well.

Signed-off-by: Alexandru Ardelean <aardelean@deviqon.com>
Link: https://lore.kernel.org/r/20210720074642.223293-4-aardelean@deviqon.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/gyro/st_gyro.h

@@ -26,7 +26,6 @@
 
 #ifdef CONFIG_IIO_BUFFER
 int st_gyro_allocate_ring(struct iio_dev *indio_dev);
-void st_gyro_deallocate_ring(struct iio_dev *indio_dev);
 int st_gyro_trig_set_state(struct iio_trigger *trig, bool state);
 #define ST_GYRO_TRIGGER_SET_STATE (&st_gyro_trig_set_state)
 #else /* CONFIG_IIO_BUFFER */
@@ -34,9 +33,6 @@ static inline int st_gyro_allocate_ring(struct iio_dev *indio_dev)
 {
 	return 0;
 }
-static inline void st_gyro_deallocate_ring(struct iio_dev *indio_dev)
-{
-}
 #define ST_GYRO_TRIGGER_SET_STATE NULL
 #endif /* CONFIG_IIO_BUFFER */
 

drivers/iio/gyro/st_gyro_buffer.c

@@ -61,13 +61,8 @@ static const struct iio_buffer_setup_ops st_gyro_buffer_setup_ops = {
 
 int st_gyro_allocate_ring(struct iio_dev *indio_dev)
 {
-	return iio_triggered_buffer_setup(indio_dev, NULL,
-		&st_sensors_trigger_handler, &st_gyro_buffer_setup_ops);
-}
-
-void st_gyro_deallocate_ring(struct iio_dev *indio_dev)
-{
-	iio_triggered_buffer_cleanup(indio_dev);
+	return devm_iio_triggered_buffer_setup(indio_dev->dev.parent, indio_dev,
+		NULL, &st_sensors_trigger_handler, &st_gyro_buffer_setup_ops);
 }
 
 MODULE_AUTHOR("Denis Ciocca <denis.ciocca@st.com>");

drivers/iio/gyro/st_gyro_core.c

@@ -512,7 +512,7 @@ int st_gyro_common_probe(struct iio_dev *indio_dev)
 		err = st_sensors_allocate_trigger(indio_dev,
 						  ST_GYRO_TRIGGER_OPS);
 		if (err < 0)
-			goto st_gyro_probe_trigger_error;
+			return err;
 	}
 
 	err = iio_device_register(indio_dev);
@@ -527,8 +527,6 @@ int st_gyro_common_probe(struct iio_dev *indio_dev)
 st_gyro_device_register_error:
 	if (gdata->irq > 0)
 		st_sensors_deallocate_trigger(indio_dev);
-st_gyro_probe_trigger_error:
-	st_gyro_deallocate_ring(indio_dev);
 	return err;
 }
 EXPORT_SYMBOL(st_gyro_common_probe);
@@ -540,8 +538,6 @@ void st_gyro_common_remove(struct iio_dev *indio_dev)
 	iio_device_unregister(indio_dev);
 	if (gdata->irq > 0)
 		st_sensors_deallocate_trigger(indio_dev);
-
-	st_gyro_deallocate_ring(indio_dev);
 }
 EXPORT_SYMBOL(st_gyro_common_remove);