From 91891f7cc6453bec358a3bc2a0cf9a0b2f8223d5 Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Thu, 25 Jul 2013 16:04:17 -0700 Subject: [PATCH] staging: comedi: usbdux: clarify bipolar ai data 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 Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- 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 a536fa3b6858..a81b4b17b297 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; } -- 2.20.1