Use the core provided readback support to allow reading back the last
value written to the analog output channels.
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/das1800.c | 17 +++++++++--------
1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/staging/comedi/drivers/das1800.c
b/drivers/staging/comedi/drivers/das1800.c
index bb99efc..fa1e4bb 100644
--- a/drivers/staging/comedi/drivers/das1800.c
+++ b/drivers/staging/comedi/drivers/das1800.c
@@ -91,7 +91,6 @@ Unipolar and bipolar ranges cannot be mixed in the
channel/gain list.
TODO:
Make it automatically allocate irq and dma channels if they are not
specified
Add support for analog out on 'ao' cards
- read insn for analog out
*/
#include <linux/module.h>
@@ -371,8 +370,6 @@ struct das1800_private {
int dma_bits;
uint16_t *fifo_buf; /* bounce buffer for analog input FIFO */
unsigned long iobase2; /* secondary io address used for analog out on
'ao' boards */
- unsigned short ao_update_bits; /* remembers the last write to the
- * 'update' dac */
bool ai_is_unipolar;
};
@@ -1043,7 +1040,6 @@ static int das1800_ao_insn_write(struct comedi_device
*dev,
struct comedi_insn *insn,
unsigned int *data)
{
- struct das1800_private *devpriv = dev->private;
unsigned int chan = CR_CHAN(insn->chanspec);
unsigned int update_chan = s->n_chan - 1;
unsigned long flags;
@@ -1055,9 +1051,9 @@ static int das1800_ao_insn_write(struct comedi_device
*dev,
for (i = 0; i < insn->n; i++) {
unsigned int val = data[i];
+ s->readback[chan] = val;
+
val = comedi_offset_munge(s, val);
- if (chan == update_chan)
- devpriv->ao_update_bits = val;
/* load this channel (and update if it's the last channel) */
outb(DAC(chan), dev->iobase + DAS1800_SELECT);
@@ -1065,9 +1061,10 @@ static int das1800_ao_insn_write(struct comedi_device
*dev,
/* update all channels */
if (chan != update_chan) {
+ val = comedi_offset_munge(s, s->readback[update_chan]);
+
outb(DAC(update_chan), dev->iobase + DAS1800_SELECT);
- outw(devpriv->ao_update_bits,
- dev->iobase + DAS1800_DAC);
+ outw(val, dev->iobase + DAS1800_DAC);
}
}
spin_unlock_irqrestore(&dev->spinlock, flags);
@@ -1327,6 +1324,10 @@ static int das1800_attach(struct comedi_device *dev,
s->range_table = &range_bipolar10;
s->insn_write = das1800_ao_insn_write;
+ ret = comedi_alloc_subdev_readback(s);
+ if (ret)
+ return ret;
+
/* initialize all channels to 0V */
for (i = 0; i < s->n_chan; i++) {
outb(DAC(i), dev->iobase + DAS1800_SELECT);
--
2.6.3
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