staging: comedi: ni_mio_common: tidy up ni_ao_munge()

Use the bytes_per_sample() helper instead of 'sizeof(short)' to clarify
the length calculation.

Use comedi_offset_munge() to handle the unsigned to two's complement
munge of the data for bipolar ranges.

Tidy up the local variables.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/ni_mio_common.c b/drivers/staging/comedi/drivers/ni_mio_common.c
index b5b4a7b7db205a9567a3d56cced17ed419455d27..13270b348f821fcdabde9a2cca6ca9317fdeedc9 100644 (file)
--- a/drivers/staging/comedi/drivers/ni_mio_common.c
+++ b/drivers/staging/comedi/drivers/ni_mio_common.c
@@ -2886,28 +2886,30 @@ static int ni_ai_insn_config(struct comedi_device *dev,
        return -EINVAL;
 }
 
-/* munge data from unsigned to 2's complement for analog output bipolar modes */
 static void ni_ao_munge(struct comedi_device *dev, struct comedi_subdevice *s,
                        void *data, unsigned int num_bytes,
                        unsigned int chan_index)
 {
-       const struct ni_board_struct *board = comedi_board(dev);
-       struct comedi_async *async = s->async;
-       struct comedi_cmd *cmd = &async->cmd;
-       unsigned int length = num_bytes / sizeof(short);
-       unsigned int offset = 1 << (board->aobits - 1);
+       struct comedi_cmd *cmd = &s->async->cmd;
+       unsigned int length = num_bytes / bytes_per_sample(s);
        unsigned short *array = data;
-       unsigned int range;
        unsigned int i;
 
        for (i = 0; i < length; i++) {
-               range = CR_RANGE(cmd->chanlist[chan_index]);
+               unsigned int range = CR_RANGE(cmd->chanlist[chan_index]);
+               unsigned short val = array[i];
 
+               /*
+                * Munge data from unsigned to two's complement for
+                * bipolar ranges.
+                */
                if (comedi_range_is_bipolar(s, range))
-                       array[i] -= offset;
+                       val = comedi_offset_munge(s, val);
 #ifdef PCIDMA
-               array[i] = cpu_to_le16(array[i]);
+               val = cpu_to_le16(val);
 #endif
+               array[i] = val;
+
                chan_index++;
                chan_index %= cmd->chanlist_len;
        }