[PATCH v2 02/14] staging: comedi: multiq3: tidy up multiq3_ai_insn_read()
H Hartley Sweeten
hsweeten at visionengravers.com
Mon Oct 5 22:33:08 UTC 2015
For aesthetics, use the proper symbol when reading the A/D data register
to get the 16-bit sample data.
Use the comedi_offset_munge() to do the 2's complement to offset binary
munging of the sample data.
Tidy up the function a bit.
Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
Cc: Ian Abbott <abbotti at mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
drivers/staging/comedi/drivers/multiq3.c | 24 ++++++++++++++----------
1 file changed, 14 insertions(+), 10 deletions(-)
diff --git a/drivers/staging/comedi/drivers/multiq3.c b/drivers/staging/comedi/drivers/multiq3.c
index 42ef1a6..fabc321 100644
--- a/drivers/staging/comedi/drivers/multiq3.c
+++ b/drivers/staging/comedi/drivers/multiq3.c
@@ -100,14 +100,14 @@ static int multiq3_ai_status(struct comedi_device *dev,
static int multiq3_ai_insn_read(struct comedi_device *dev,
struct comedi_subdevice *s,
- struct comedi_insn *insn, unsigned int *data)
+ struct comedi_insn *insn,
+ unsigned int *data)
{
- int n;
- int chan;
- unsigned int hi, lo;
+ unsigned int chan = CR_CHAN(insn->chanspec);
+ unsigned int val;
int ret;
+ int i;
- chan = CR_CHAN(insn->chanspec);
outw(MULTIQ3_CONTROL_MUST | MULTIQ3_AD_MUX_EN | (chan << 3),
dev->iobase + MULTIQ3_CONTROL);
@@ -116,7 +116,7 @@ static int multiq3_ai_insn_read(struct comedi_device *dev,
if (ret)
return ret;
- for (n = 0; n < insn->n; n++) {
+ for (i = 0; i < insn->n; i++) {
outw(0, dev->iobase + MULTIQ3_AD_CS);
ret = comedi_timeout(dev, s, insn, multiq3_ai_status,
@@ -124,12 +124,16 @@ static int multiq3_ai_insn_read(struct comedi_device *dev,
if (ret)
return ret;
- hi = inb(dev->iobase + MULTIQ3_AD_CS);
- lo = inb(dev->iobase + MULTIQ3_AD_CS);
- data[n] = (((hi << 8) | lo) + 0x1000) & 0x1fff;
+ /* get a 16-bit sample; mask it to the subdevice resolution */
+ val = inb(dev->iobase + MULTIQ3_AD_DATA) << 8;
+ val |= inb(dev->iobase + MULTIQ3_AD_DATA);
+ val &= s->maxdata;
+
+ /* munge the 2's complement value to offset binary */
+ data[i] = comedi_offset_munge(s, val);
}
- return n;
+ return insn->n;
}
static int multiq3_ao_insn_write(struct comedi_device *dev,
--
2.5.1
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