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

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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>
This commit is contained in:
Jonathan Cameron 2011-12-05 22:18:26 +00:00 • committed by Greg Kroah-Hartman
parent 3ca34cc462
commit c0e9e6ba34
1 changed files with 0 additions and 33 deletions

33
drivers/staging/iio/ring_sw.c
View file

@ -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,