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staging: comedi: ni_mio_common: tidy up ni_ao_munge()

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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>
This commit is contained in:
H Hartley Sweeten 2014-07-14 12:23:45 -07:00 committed by Greg Kroah-Hartman
parent a52b53e4a7
commit a10817d67f
1 changed files with 12 additions and 10 deletions
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22
drivers/staging/comedi/drivers/ni_mio_common.c
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@ -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;
}