iio: Specify supported modes for buffers

For each buffer type specify the supported device modes for this buffer.
This allows us for devices which support multiple different operating modes
to pick the correct operating mode based on the modes supported by the
attached buffers.

It also prevents that buffers with conflicting modes are attached
to a device at the same time or that a buffer with a non-supported mode is
attached to a device (e.g. in-kernel callback buffer to a device only
supporting hardware mode).

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

1 files changed, 3 insertions, 0 deletions

diff --git a/include/linux/iio/buffer.h b/include/linux/iio/buffer.h
index eb8622b78ec9..1600c55828e0 100644
--- a/include/linux/iio/buffer.h
+++ b/include/linux/iio/buffer.h
@@ -29,6 +29,7 @@ struct iio_buffer;
  * @set_length:         set number of datums in buffer
  * @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
  *
  * The purpose of this structure is to make the buffer element
  * modular as event for a given driver, different usecases may require
@@ -51,6 +52,8 @@ struct iio_buffer_access_funcs {
         int (*set_length)(struct iio_buffer *buffer, int length);
 
         void (*release)(struct iio_buffer *buffer);
+
+        unsigned int modes;
 };
 
 /**