According to the user manual, analog input bipolar data is 2's
complement and unipolar is straight binry. Use the core helpers
to munge the data appropriately.
Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/drivers/aio_aio12_8.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/comedi/drivers/aio_aio12_8.c
b/drivers/staging/comedi/drivers/aio_aio12_8.c
index 2262da0..e76a130 100644
--- a/drivers/staging/comedi/drivers/aio_aio12_8.c
+++ b/drivers/staging/comedi/drivers/aio_aio12_8.c
@@ -120,13 +120,15 @@ static int aio_aio12_8_ai_eoc(struct comedi_device *dev,
static int aio_aio12_8_ai_read(struct comedi_device *dev,
struct comedi_subdevice *s,
- struct comedi_insn *insn, unsigned int *data)
+ struct comedi_insn *insn,
+ unsigned int *data)
{
unsigned int chan = CR_CHAN(insn->chanspec);
unsigned int range = CR_RANGE(insn->chanspec);
+ unsigned int val;
unsigned char control;
int ret;
- int n;
+ int i;
/*
* Setup the control byte for internal 2MHz clock, 3uS conversion,
@@ -138,7 +140,7 @@ static int aio_aio12_8_ai_read(struct comedi_device *dev,
/* Read status to clear EOC latch */
inb(dev->iobase + AIO12_8_STATUS_REG);
- for (n = 0; n < insn->n; n++) {
+ for (i = 0; i < insn->n; i++) {
/* Setup and start conversion */
outb(control, dev->iobase + AIO12_8_ADC_REG);
@@ -147,7 +149,13 @@ static int aio_aio12_8_ai_read(struct comedi_device *dev,
if (ret)
return ret;
- data[n] = inw(dev->iobase + AIO12_8_ADC_REG) & s->maxdata;
+ val = inw(dev->iobase + AIO12_8_ADC_REG) & s->maxdata;
+
+ /* munge bipolar 2's complement data to offset binary */
+ if (comedi_range_is_bipolar(s, range))
+ val = comedi_offset_munge(s, val);
+
+ data[i] = val;
}
return insn->n;
--
2.5.1
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