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staging: comedi: aio_aio12_8: fix ai (*insn_read) 

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 <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 2015-10-12 12:16:35 -07:00 committed by Greg Kroah-Hartman
parent 1198f6b09f
commit ee4c7709fb
1 changed files with 12 additions and 4 deletions
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16
drivers/staging/comedi/drivers/aio_aio12_8.c
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@ -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;