staging:iio:ring_sw don't provide read last function.

No longer needed as we don't have drivers providing sysfs access
to buffered data.

Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/iio/ring_sw.c b/drivers/staging/iio/ring_sw.c
index 98fe81932047ffaefdd71868e37c4adbc5b85499..37d26e658de190b64b42fe7a4fd9aefeff3d3610 100644 (file)
--- a/drivers/staging/iio/ring_sw.c
+++ b/drivers/staging/iio/ring_sw.c
@@ -23,7 +23,6 @@
  * @data:              the ring buffer memory
  * @read_p:            read pointer (oldest available)
  * @write_p:           write pointer
- * @last_written_p:    read pointer (newest available)
  * @half_p:            half buffer length behind write_p (event generation)
  * @use_count:         reference count to prevent resizing when in use
  * @update_needed:     flag to indicated change in size requested
@@ -37,7 +36,6 @@ struct iio_sw_ring_buffer {
        unsigned char           *data;
        unsigned char           *read_p;
        unsigned char           *write_p;
-       unsigned char           *last_written_p;
        /* used to act as a point at which to signal an event */
        unsigned char           *half_p;
        int                     use_count;
@@ -56,7 +54,6 @@ static inline int __iio_allocate_sw_ring_buffer(struct iio_sw_ring_buffer *ring,
        ring->data = kmalloc(length*ring->buf.bytes_per_datum, GFP_ATOMIC);
        ring->read_p = NULL;
        ring->write_p = NULL;
-       ring->last_written_p = NULL;
        ring->half_p = NULL;
        return ring->data ? 0 : -ENOMEM;
 }
@@ -115,7 +112,6 @@ static int iio_store_to_sw_ring(struct iio_sw_ring_buffer *ring,
         * Always valid as either points to latest or second latest value.
         * Before this runs it is null and read attempts fail with -EAGAIN.
         */
-       ring->last_written_p = ring->write_p;
        barrier();
        /* temp_ptr used to ensure we never have an invalid pointer
         * it may be slightly lagging, but never invalid
@@ -305,34 +301,6 @@ static int iio_store_to_sw_rb(struct iio_buffer *r,
        return iio_store_to_sw_ring(ring, data, timestamp);
 }
 
-static int iio_read_last_from_sw_ring(struct iio_sw_ring_buffer *ring,
-                                     unsigned char *data)
-{
-       unsigned char *last_written_p_copy;
-
-       iio_mark_sw_rb_in_use(&ring->buf);
-again:
-       barrier();
-       last_written_p_copy = ring->last_written_p;
-       barrier(); /*unnessecary? */
-       /* Check there is anything here */
-       if (last_written_p_copy == NULL)
-               return -EAGAIN;
-       memcpy(data, last_written_p_copy, ring->buf.bytes_per_datum);
-
-       if (unlikely(ring->last_written_p != last_written_p_copy))
-               goto again;
-
-       iio_unmark_sw_rb_in_use(&ring->buf);
-       return 0;
-}
-
-static int iio_read_last_from_sw_rb(struct iio_buffer *r,
-                            unsigned char *data)
-{
-       return iio_read_last_from_sw_ring(iio_to_sw_ring(r), data);
-}
-
 static int iio_request_update_sw_rb(struct iio_buffer *r)
 {
        int ret = 0;
@@ -435,7 +403,6 @@ const struct iio_buffer_access_funcs ring_sw_access_funcs = {
        .mark_in_use = &iio_mark_sw_rb_in_use,
        .unmark_in_use = &iio_unmark_sw_rb_in_use,
        .store_to = &iio_store_to_sw_rb,
-       .read_last = &iio_read_last_from_sw_rb,
        .read_first_n = &iio_read_first_n_sw_rb,
        .mark_param_change = &iio_mark_update_needed_sw_rb,
        .request_update = &iio_request_update_sw_rb,