staging:iio: ring core cleanups + check if read_last available in lis3l02dq

Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/staging/iio/accel/lis3l02dq_ring.c b/drivers/staging/iio/accel/lis3l02dq_ring.c
index 5029c51fe91..c8f29bc73f6 100644
--- a/drivers/staging/iio/accel/lis3l02dq_ring.c
+++ b/drivers/staging/iio/accel/lis3l02dq_ring.c
@@ -50,9 +50,13 @@ ssize_t lis3l02dq_read_accel_from_ring(struct iio_ring_buffer *ring,
 {
         int ret;
         s16 *data;
+
         if (!iio_scan_mask_query(ring, index))
                 return -EINVAL;
 
+        if (!ring->access->read_last)
+                return -EBUSY;
+
         data = kmalloc(ring->access->get_bytes_per_datum(ring),
                        GFP_KERNEL);
         if (data == NULL)
@@ -61,9 +65,10 @@ ssize_t lis3l02dq_read_accel_from_ring(struct iio_ring_buffer *ring,
         ret = ring->access->read_last(ring, (u8 *)data);
         if (ret)
                 goto error_free_data;
-        *val = data[iio_scan_mask_count_to_right(ring, index)];
+        *val = data[bitmap_weight(&ring->scan_mask, index)];
 error_free_data:
         kfree(data);
+
         return ret;
 }