According to the user's manual, the A/D converter uses 2's complement
coding. Use the comedi_offset_munge() helper to convert the data to
the offset binary format used by comedi.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/mf6x4.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/staging/comedi/drivers/mf6x4.c b/drivers/staging/comedi/drivers/mf6x4.c
index ff4ba15..1e4f080 100644
--- a/drivers/staging/comedi/drivers/mf6x4.c
+++ b/drivers/staging/comedi/drivers/mf6x4.c
@@ -38,7 +38,7 @@
#define MF6X4_GPIOC_DACEN BIT(26)
/* BAR1 registers */
-#define MF6X4_ADDATA_R 0x00
+#define MF6X4_ADDATA_REG 0x00
#define MF6X4_ADCTRL_REG 0x00
#define MF6X4_ADCTRL_CHAN(x) BIT(chan)
#define MF6X4_DIN_R 0x10
@@ -134,9 +134,9 @@ static int mf6x4_ai_insn_read(struct comedi_device *dev,
unsigned int *data)
{
unsigned int chan = CR_CHAN(insn->chanspec);
+ unsigned int d;
int ret;
int i;
- int d;
/* Set the ADC channel number in the scan list */
iowrite16(MF6X4_ADCTRL_CHAN(chan), dev->mmio + MF6X4_ADCTRL_REG);
@@ -150,9 +150,10 @@ static int mf6x4_ai_insn_read(struct comedi_device *dev,
return ret;
/* Read the actual value */
- d = ioread16(dev->mmio + MF6X4_ADDATA_R);
+ d = ioread16(dev->mmio + MF6X4_ADDATA_REG);
d &= s->maxdata;
- data[i] = d;
+ /* munge the 2's complement data to offset binary */
+ data[i] = comedi_offset_munge(s, d);
}
iowrite16(0x0, dev->mmio + MF6X4_ADCTRL_REG);
--
2.5.1
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