staging:iio:buffer: pull computation of scan length into a utility function.

Principal reason is to make later patches more coherent and easier to review
but this set in itself separates a logical entity out nicely wihin the code.

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

1 files changed, 20 insertions, 8 deletions

diff --git a/drivers/staging/iio/industrialio-buffer.c b/drivers/staging/iio/industrialio-buffer.c
index 59b0caf5deab..389fe16872b4 100644
--- a/drivers/staging/iio/industrialio-buffer.c
+++ b/drivers/staging/iio/industrialio-buffer.c
@@ -508,29 +508,41 @@ static const unsigned long *iio_scan_mask_match(const unsigned long *av_masks,
         return NULL;
 }
 
-int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
+static int iio_compute_scan_bytes(struct iio_dev *indio_dev, const long *mask,
+                                  bool timestamp)
 {
-        struct iio_buffer *buffer = indio_dev->buffer;
         const struct iio_chan_spec *ch;
         unsigned bytes = 0;
         int length, i;
-        dev_dbg(&indio_dev->dev, "%s\n", __func__);
 
         /* How much space will the demuxed element take? */
-        for_each_set_bit(i, buffer->scan_mask,
+        for_each_set_bit(i, mask,
                          indio_dev->masklength) {
                 ch = iio_find_channel_from_si(indio_dev, i);
-                length = ch->scan_type.storagebits/8;
+                length = ch->scan_type.storagebits / 8;
                 bytes = ALIGN(bytes, length);
                 bytes += length;
         }
-        if (buffer->scan_timestamp) {
+        if (timestamp) {
                 ch = iio_find_channel_from_si(indio_dev,
-                                              buffer->scan_index_timestamp);
-                length = ch->scan_type.storagebits/8;
+                                              indio_dev
+                                              ->buffer->scan_index_timestamp);
+                length = ch->scan_type.storagebits / 8;
                 bytes = ALIGN(bytes, length);
                 bytes += length;
         }
+        return bytes;
+}
+
+int iio_sw_buffer_preenable(struct iio_dev *indio_dev)
+{
+        struct iio_buffer *buffer = indio_dev->buffer;
+        unsigned bytes;
+        dev_dbg(&indio_dev->dev, "%s\n", __func__);
+
+        /* How much space will the demuxed element take? */
+        bytes = iio_compute_scan_bytes(indio_dev, buffer->scan_mask,
+                                       buffer->scan_timestamp);
         buffer->access->set_bytes_per_datum(buffer, bytes);
 
         /* What scan mask do we actually have ?*/