The hardware returns two's complement values for the analog input
samples. These need to be converted to the unsigned binary format
that the comedi core expects. Introduce a helper function to handle
this.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/me4000.c | 23 +++++++++++++----------
1 file changed, 13 insertions(+), 10 deletions(-)
diff --git a/drivers/staging/comedi/drivers/me4000.c b/drivers/staging/comedi/drivers/me4000.c
index b17183d..3974f59 100644
--- a/drivers/staging/comedi/drivers/me4000.c
+++ b/drivers/staging/comedi/drivers/me4000.c
@@ -445,6 +445,16 @@ static void me4000_reset(struct comedi_device *dev)
outl(0x1, dev->iobase + ME4000_DIO_CTRL_REG);
}
+static unsigned int me4000_ai_get_sample(struct comedi_device *dev,
+ struct comedi_subdevice *s)
+{
+ unsigned int val;
+
+ /* read two's complement value and munge to offset binary */
+ val = inl(dev->iobase + ME4000_AI_DATA_REG);
+ return comedi_offset_munge(s, val);
+}
+
static int me4000_ai_eoc(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
@@ -515,8 +525,7 @@ static int me4000_ai_insn_read(struct comedi_device *dev,
if (ret)
break;
- /* read two's complement value and munge to offset binary */
- val = inl(dev->iobase + ME4000_AI_DATA_REG);
+ val = me4000_ai_get_sample(dev, s);
data[i] = comedi_offset_munge(s, val);
}
@@ -953,10 +962,7 @@ static irqreturn_t me4000_ai_isr(int irq, void *dev_id)
}
for (i = 0; i < c; i++) {
- /* Read value from data fifo */
- lval = inl(dev->iobase + ME4000_AI_DATA_REG) & 0xFFFF;
- lval ^= 0x8000;
-
+ lval = me4000_ai_get_sample(dev, s);
if (!comedi_buf_write_samples(s, &lval, 1))
break;
}
@@ -976,10 +982,7 @@ static irqreturn_t me4000_ai_isr(int irq, void *dev_id)
/* Poll data until fifo empty */
while (inl(dev->iobase + ME4000_AI_STATUS_REG) &
ME4000_AI_STATUS_EF_DATA) {
- /* Read value from data fifo */
- lval = inl(dev->iobase + ME4000_AI_DATA_REG) & 0xFFFF;
- lval ^= 0x8000;
-
+ lval = me4000_ai_get_sample(dev, s);
if (!comedi_buf_write_samples(s, &lval, 1))
break;
}
--
2.4.3
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