[PATCH 04/30] staging: comedi: usbdux: clarify bipolar ai data
H Hartley Sweeten
hsweeten at visionengravers.com
Thu Jul 25 23:04:17 UTC 2013
Use the comedi_range_is_bipolar() helper instead of checking the
'range' index against a magic number.
Also, use the s->maxdata to calculate the value needed to munge the
value for bipolar data instead of the magic number.
Signed-off-by: H Hartley Sweeten <hsweeten at visionengravers.com>
Cc: Ian Abbott <abbotti at mev.co.uk>
Cc: Greg Kroah-Hartman <gregkh at linuxfondation.org>
---
drivers/staging/comedi/drivers/usbdux.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c
index a536fa3..a81b4b1 100644
--- a/drivers/staging/comedi/drivers/usbdux.c
+++ b/drivers/staging/comedi/drivers/usbdux.c
@@ -1002,8 +1002,10 @@ static int usbdux_ai_insn_read(struct comedi_device *dev,
goto ai_read_exit;
val = le16_to_cpu(devpriv->insn_buffer[1]);
- if (range <= 1)
- val ^= 0x800;
+
+ /* bipolar data is two's-complement */
+ if (comedi_range_is_bipolar(s, range))
+ val ^= ((s->maxdata + 1) >> 1);
data[i] = val;
}
--
1.8.3.2
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