Commit 8a844a91 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman

staging: comedi: me_daq: allow differential analog inputs

The ai (*insn_read) allows differential analog inputs but the subdevice
initialization is missing the SDF_DIFF subdev_flag to allow the user to
select this mode. Fix the subdevice init.

According to the manual, differential operation only works with the
first 8 channels and bipolar ranges. Add a check to the (*insn_read) to
ensure this.
Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 450a84e8
No related merge requests found
...@@ -246,6 +246,15 @@ static int me_ai_insn_read(struct comedi_device *dev, ...@@ -246,6 +246,15 @@ static int me_ai_insn_read(struct comedi_device *dev,
unsigned short val; unsigned short val;
int ret; int ret;
/*
* For differential operation, there are only 8 input channels
* and only bipolar ranges are available.
*/
if (aref & AREF_DIFF) {
if (chan > 7 || comedi_range_is_unipolar(s, range))
return -EINVAL;
}
/* stop any running conversion */ /* stop any running conversion */
devpriv->ctrl1 &= ~ME_CTRL1_ADC_MODE_MASK; devpriv->ctrl1 &= ~ME_CTRL1_ADC_MODE_MASK;
writew(devpriv->ctrl1, dev->mmio + ME_CTRL1_REG); writew(devpriv->ctrl1, dev->mmio + ME_CTRL1_REG);
...@@ -472,7 +481,7 @@ static int me_auto_attach(struct comedi_device *dev, ...@@ -472,7 +481,7 @@ static int me_auto_attach(struct comedi_device *dev,
s = &dev->subdevices[0]; s = &dev->subdevices[0];
s->type = COMEDI_SUBD_AI; s->type = COMEDI_SUBD_AI;
s->subdev_flags = SDF_READABLE | SDF_COMMON; s->subdev_flags = SDF_READABLE | SDF_COMMON | SDF_DIFF;
s->n_chan = 16; s->n_chan = 16;
s->maxdata = 0x0fff; s->maxdata = 0x0fff;
s->len_chanlist = 16; s->len_chanlist = 16;
......
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