iio: Add buffer enable/disable callbacks

This patch adds a enable and disable callback that is called when the
buffer is enabled/disabled. This can be used by buffer implementations that
need to do some setup or teardown work. E.g. a DMA based buffer can use
this to start/stop the DMA transfer.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index 4d99a53d1fe7..2ec3ad58e8a0 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -33,6 +33,11 @@ struct iio_buffer;
  *			storage.
  * @set_bytes_per_datum:set number of bytes per datum
  * @set_length:		set number of datums in buffer
+ * @enable:             called if the buffer is attached to a device and the
+ *                      device starts sampling. Calls are balanced with
+ *                      @disable.
+ * @disable:            called if the buffer is attached to a device and the
+ *                      device stops sampling. Calles are balanced with @enable.
  * @release:		called when the last reference to the buffer is dropped,
  *			should free all resources allocated by the buffer.
  * @modes:		Supported operating modes by this buffer type
@@ -58,6 +63,9 @@ struct iio_buffer_access_funcs {
 	int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
 	int (*set_length)(struct iio_buffer *buffer, int length);
 
+	int (*enable)(struct iio_buffer *buffer, struct iio_dev *indio_dev);
+	int (*disable)(struct iio_buffer *buffer, struct iio_dev *indio_dev);
+
 	void (*release)(struct iio_buffer *buffer);
 
 	unsigned int modes;