Initialize the AO subdevice channels to mid-range data value so they are
in a known state. This allows us to support reading back the current
value in a later patch.
Signed-off-by: Ian Abbott <abbotti@xxxxxxxxx>
---
drivers/staging/comedi/drivers/das08.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/staging/comedi/drivers/das08.c b/drivers/staging/comedi/drivers/das08.c
index f9cba56..b2face0 100644
--- a/drivers/staging/comedi/drivers/das08.c
+++ b/drivers/staging/comedi/drivers/das08.c
@@ -391,6 +391,17 @@ static void das08_ao_set_data(struct comedi_device *dev,
}
}
+static void das08_ao_initialize(struct comedi_device *dev,
+ struct comedi_subdevice *s)
+{
+ int n;
+ unsigned int data;
+
+ data = s->maxdata / 2; /* should be about 0 volts */
+ for (n = 0; n < s->n_chan; n++)
+ das08_ao_set_data(dev, n, data);
+}
+
static int das08_ao_winsn(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
@@ -665,6 +676,7 @@ int das08_common_attach(struct comedi_device *dev, unsigned long iobase)
s->maxdata = (1 << thisboard->ao_nbits) - 1;
s->range_table = &range_bipolar5;
s->insn_write = das08_ao_winsn;
+ das08_ao_initialize(dev, s);
} else {
s->type = COMEDI_SUBD_UNUSED;
}
--
1.7.12
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