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staging: comedi: das1800: add analog output readback 

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 <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2016-04-08 12:41:47 -07:00 committed by Greg Kroah-Hartman
parent a5405cfa1b
commit 750bca653d
1 changed files with 9 additions and 8 deletions
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17
drivers/staging/comedi/drivers/das1800.c
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@ -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>
@ -341,8 +340,6 @@ 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;
};
@ -1017,7 +1014,6 @@ 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;
@ -1029,9 +1025,9 @@ 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);
@ -1039,9 +1035,10 @@ 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);
@ -1318,6 +1315,10 @@ 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);