iio: Remove get_bytes_per_datum() from iio_buffer_access_funcs

There haven't been any users of the get_bytes_per_datum() callback for a
while. The core assumes that the number of bytes per datum can be calculated
based on the enabled channels and the storage size of the channel and
iio_compute_scan_bytes() is used to compute this number. So remove the
callback.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/kfifo_buf.c

@@ -66,11 +66,6 @@ static struct attribute_group iio_kfifo_attribute_group = {
 	.name = "buffer",
 };
 
-static int iio_get_bytes_per_datum_kfifo(struct iio_buffer *r)
-{
-	return r->bytes_per_datum;
-}
-
 static int iio_mark_update_needed_kfifo(struct iio_buffer *r)
 {
 	struct iio_kfifo *kf = iio_to_kfifo(r);
@@ -159,7 +154,6 @@ static const struct iio_buffer_access_funcs kfifo_access_funcs = {
 	.read_first_n = &iio_read_first_n_kfifo,
 	.data_available = iio_kfifo_buf_data_available,
 	.request_update = &iio_request_update_kfifo,
-	.get_bytes_per_datum = &iio_get_bytes_per_datum_kfifo,
 	.set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo,
 	.get_length = &iio_get_length_kfifo,
 	.set_length = &iio_set_length_kfifo,

drivers/staging/iio/Documentation/ring.txt

@@ -39,8 +39,8 @@ request_update
   If parameters have changed that require reinitialization or configuration of
   the buffer this will trigger it.
 
-get_bytes_per_datum, set_bytes_per_datum
-  Get/set the number of bytes for a complete scan. (All samples + timestamp)
+set_bytes_per_datum
+  Set the number of bytes for a complete scan. (All samples + timestamp)
 
 get_length / set_length
   Get/set the number of complete scans that may be held by the buffer.

drivers/staging/iio/accel/sca3000_ring.c

@@ -135,12 +135,6 @@ static int sca3000_ring_get_length(struct iio_buffer *r)
 	return 64;
 }
 
-/* only valid if resolution is kept at 11bits */
-static int sca3000_ring_get_bytes_per_datum(struct iio_buffer *r)
-{
-	return 6;
-}
-
 static bool sca3000_ring_buf_data_available(struct iio_buffer *r)
 {
 	return r->stufftoread;
@@ -278,7 +272,6 @@ static void sca3000_ring_release(struct iio_buffer *r)
 static const struct iio_buffer_access_funcs sca3000_ring_access_funcs = {
 	.read_first_n = &sca3000_read_first_n_hw_rb,
 	.get_length = &sca3000_ring_get_length,
-	.get_bytes_per_datum = &sca3000_ring_get_bytes_per_datum,
 	.data_available = sca3000_ring_buf_data_available,
 	.release = sca3000_ring_release,
 };

include/linux/iio/buffer.h

@@ -25,7 +25,6 @@ struct iio_buffer;
  *			available.
  * @request_update:	if a parameter change has been marked, update underlying
  *			storage.
- * @get_bytes_per_datum:get current bytes per datum
  * @set_bytes_per_datum:set number of bytes per datum
  * @get_length:		get number of datums in buffer
  * @set_length:		set number of datums in buffer
@@ -49,7 +48,6 @@ struct iio_buffer_access_funcs {
 
 	int (*request_update)(struct iio_buffer *buffer);
 
-	int (*get_bytes_per_datum)(struct iio_buffer *buffer);
 	int (*set_bytes_per_datum)(struct iio_buffer *buffer, size_t bpd);
 	int (*get_length)(struct iio_buffer *buffer);
 	int (*set_length)(struct iio_buffer *buffer, int length);