Use the register map define to work out the i/o address.
Cleanup the comments about the simultaneous transfer mode for
the analog outputs.
Change the return to 'insn->n', the comedi core expects the return
to be the number of data elements used. Technically the 'i' value
is correct but 'insn->n' just makes it clearer.
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_pcimdda.c | 63 ++++++++++++-----------------
1 file changed, 26 insertions(+), 37 deletions(-)
diff --git a/drivers/staging/comedi/drivers/cb_pcimdda.c
b/drivers/staging/comedi/drivers/cb_pcimdda.c
index a5e055f..350c807 100644
--- a/drivers/staging/comedi/drivers/cb_pcimdda.c
+++ b/drivers/staging/comedi/drivers/cb_pcimdda.c
@@ -110,62 +110,51 @@ static int cb_pcimdda_ao_winsn(struct comedi_device *dev,
unsigned int *data)
{
struct cb_pcimdda_private *devpriv = dev->private;
+ unsigned int chan = CR_CHAN(insn->chanspec);
+ unsigned long offset = dev->iobase + PCIMDDA_DA_CHAN(chan);
+ unsigned int val = 0;
int i;
- int chan = CR_CHAN(insn->chanspec);
- unsigned long offset = dev->iobase + chan * 2;
- /* Writing a list of values to an AO channel is probably not
- * very useful, but that's how the interface is defined. */
for (i = 0; i < insn->n; i++) {
- /* first, load the low byte */
- outb((char)(data[i] & 0x00ff), offset);
- /* next, write the high byte -- only after this is written is
- the channel voltage updated in the DAC, unless
- we're in simultaneous xfer mode (jumper on card)
- then a rinsn is necessary to actually update the DAC --
- see cb_pcimdda_ao_rinsn() below... */
- outb((char)(data[i] >> 8 & 0x00ff), offset + 1);
-
- /* for testing only.. the actual rinsn SHOULD do an inw!
- (see the stuff about simultaneous XFER mode on this board) */
- devpriv->ao_readback[chan] = data[i];
+ val = data[i];
+
+ /*
+ * Write the LSB then MSB.
+ *
+ * If the simultaneous xfer mode is selected by the
+ * jumper on the card, a read instruction is needed
+ * in order to initiate the simultaneous transfer.
+ * Otherwise, the DAC will be updated when the MSB
+ * is written.
+ */
+ outb(val & 0x00ff, offset);
+ outb((val >> 8) & 0x00ff, offset + 1);
}
- /* return the number of samples read/written */
- return i;
-}
+ /* Cache the last value for readback */
+ devpriv->ao_readback[chan] = val;
-/* AO subdevices should have a read insn as well as a write insn.
+ return insn->n;
+}
- Usually this means copying a value stored in devpriv->ao_readback.
- However, since this board has this jumper setting called "Simultaneous
- Xfer mode" (off by default), we will support it. Simultaneaous xfer
- mode is accomplished by loading ALL the values you want for AO in all the
- channels, then READing off one of the AO registers to initiate the
- instantaneous simultaneous update of all DAC outputs, which makes
- all AO channels update simultaneously. This is useful for some control
- applications, I would imagine.
-*/
static int cb_pcimdda_ao_rinsn(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned int *data)
{
struct cb_pcimdda_private *devpriv = dev->private;
- int i;
int chan = CR_CHAN(insn->chanspec);
+ unsigned long offset = dev->iobase + PCIMDDA_DA_CHAN(chan);
+ int i;
for (i = 0; i < insn->n; i++) {
- inw(dev->iobase + chan * 2);
- /*
- * should I set data[i] to the result of the actual read
- * on the register or the cached unsigned int in
- * devpriv->ao_readback[]?
- */
+ /* Initiate the simultaneous transfer */
+ inw(offset);
+
data[i] = devpriv->ao_readback[chan];
}
- return i;
+ return insn->n;
}
static struct pci_dev *cb_pcimdda_probe(struct comedi_device *dev,
--
1.7.11
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