The hardware uses a switch on the board to set the number of analog
input channels to either 16 single-ended or 8 differential channels.
Currently the switch setting is checked for every (*insn_read) operation
to validate the channel number.
Check the switch setting during the driver attach and initialize the
subdevice accordingly. This allows the core to handle the validation.
Signed-off-by: H Hartley Sweeten <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/drivers/cb_pcimdas.c | 34 +++++++++++++++++++----------
1 file changed, 22 insertions(+), 12 deletions(-)
diff --git a/drivers/staging/comedi/drivers/cb_pcimdas.c
b/drivers/staging/comedi/drivers/cb_pcimdas.c
index 70dd2c9..ddaa61c 100644
--- a/drivers/staging/comedi/drivers/cb_pcimdas.c
+++ b/drivers/staging/comedi/drivers/cb_pcimdas.c
@@ -109,20 +109,10 @@ static int cb_pcimdas_ai_rinsn(struct comedi_device *dev,
unsigned int d;
int chan = CR_CHAN(insn->chanspec);
unsigned short chanlims;
- int maxchans;
int ret;
/* only support sw initiated reads from a single channel */
- /* check channel number */
- if ((inb(devpriv->BADR3 + 2) & 0x20) == 0) /* differential mode */
- maxchans = s->n_chan / 2;
- else
- maxchans = s->n_chan;
-
- if (chan > (maxchans - 1))
- return -ETIMEDOUT; /* *** Wrong error code. Fixme. */
-
/* configure for sw initiated read */
d = inb(devpriv->BADR3 + 5);
if ((d & 0x03) > 0) { /* only reset if needed. */
@@ -181,6 +171,20 @@ static int cb_pcimdas_ao_insn_write(struct comedi_device
*dev,
return insn->n;
}
+static bool cb_pcimdas_is_ai_se(struct comedi_device *dev)
+{
+ struct cb_pcimdas_private *devpriv = dev->private;
+ unsigned int status;
+
+ /*
+ * The number of Analog Input channels is set with the
+ * Analog Input Mode Switch on the board. The board can
+ * have 16 single-ended or 8 differential channels.
+ */
+ status = inb(devpriv->BADR3 + 2);
+ return status & 0x20;
+}
+
static int cb_pcimdas_auto_attach(struct comedi_device *dev,
unsigned long context_unused)
{
@@ -209,8 +213,14 @@ static int cb_pcimdas_auto_attach(struct comedi_device
*dev,
/* dev->read_subdev=s; */
/* analog input subdevice */
s->type = COMEDI_SUBD_AI;
- s->subdev_flags = SDF_READABLE | SDF_GROUND;
- s->n_chan = 16;
+ s->subdev_flags = SDF_READABLE;
+ if (cb_pcimdas_is_ai_se(dev)) {
+ s->subdev_flags |= SDF_GROUND;
+ s->n_chan = 16;
+ } else {
+ s->subdev_flags |= SDF_DIFF;
+ s->n_chan = 8;
+ }
s->maxdata = 0xffff;
s->range_table = &range_unknown;
s->len_chanlist = 1; /* This is the maximum chanlist length that */
--
2.3.0
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