The analog outputs can use an external reference to create the D/A output
range. Add an entry to the comedi_lrange table for it and modify the
(*insn_write) to support it.
Note that the D/A output range is 0 to +Vref with a -Vref. The comedi_lrange
does not include the sign of the range. It simmply allows the user to convert
between the 12-bit samples values (0x0000 - 0x0fff) and a physical value (0.0
to 1.0) using the comedilib comedi_to_phys() and comedi_from_phys() functions.
A physical value of 0.0 would actually be 0V with a -Vref and -V with a +Vref
and 1.0 would be +V with a -Vref and 0V with a -Vref. Ths user will need to
work this out but at least they can now use the external reference.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/adv_pci1710.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c
index cc451f1..aafcb8a 100644
--- a/drivers/staging/comedi/drivers/adv_pci1710.c
+++ b/drivers/staging/comedi/drivers/adv_pci1710.c
@@ -65,6 +65,8 @@
#define PCI171X_CLRFIFO_REG 0x09 /* W: clear FIFO */
#define PCI171X_DA_REG(x) (0x0a + ((x) * 2)) /* W: D/A register */
#define PCI171X_DAREF_REG 0x0e /* W: D/A reference control */
+#define PCI171X_DAREF(c, r) (((r) & 0x3) << ((c) * 2))
+#define PCI171X_DAREF_MASK(c) PCI171X_DAREF((c), 0x3)
#define PCI171X_DI_REG 0x10 /* R: digital inputs */
#define PCI171X_DO_REG 0x10 /* W: digital outputs */
#define PCI171X_TIMER_BASE 0x18 /* R/W: 8254 timer */
@@ -111,9 +113,10 @@ static const struct comedi_lrange pci1711_ai_range = {
};
static const struct comedi_lrange pci171x_ao_range = {
- 2, {
- UNI_RANGE(5),
- UNI_RANGE(10)
+ 3, {
+ UNI_RANGE(5), /* internal -5V ref */
+ UNI_RANGE(10), /* internal -10V ref */
+ RANGE_ext(0, 1) /* external -Vref (+/-10V max) */
}
};
@@ -631,8 +634,8 @@ static int pci1710_ao_insn_write(struct comedi_device *dev,
unsigned int val = s->readback[chan];
int i;
- devpriv->da_ranges &= ~(1 << (chan << 1));
- devpriv->da_ranges |= (range << (chan << 1));
+ devpriv->da_ranges &= ~PCI171X_DAREF_MASK(chan);
+ devpriv->da_ranges |= PCI171X_DAREF(chan, range);
outw(devpriv->da_ranges, dev->iobase + PCI171X_DAREF_REG);
for (i = 0; i < insn->n; i++) {
--
2.5.1
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