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staging: comedi: das08: Support read-back of AO subdevice

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Stash the last value written to each AO channel in private data and
support the INSN_READ instruction to read it back.  Don't bother setting
the SDF_READABLE subdevice flag though as the hardware isn't really
readable - we're just faking it.

Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ian Abbott 2012-08-31 20:41:44 +01:00 committed by Greg Kroah-Hartman
parent 8432eb35a9
commit f0ba1d6e19
2 changed files with 20 additions and 1 deletions
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20
drivers/staging/comedi/drivers/das08.c
View File

@ -373,6 +373,7 @@ static void das08_ao_set_data(struct comedi_device *dev,
unsigned int chan, unsigned int data)
{
const struct das08_board_struct *thisboard = comedi_board(dev);
struct das08_private_struct *devpriv = dev->private;
unsigned char lsb;
unsigned char msb;
@ -389,6 +390,7 @@ static void das08_ao_set_data(struct comedi_device *dev,
/* load DACs */
inb(dev->iobase + DAS08AO_AO_UPDATE);
}
devpriv->ao_readback[chan] = data;
}
static void das08_ao_initialize(struct comedi_device *dev,
@ -417,6 +419,22 @@ static int das08_ao_winsn(struct comedi_device *dev,
return n;
}
static int das08_ao_rinsn(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
{
struct das08_private_struct *devpriv = dev->private;
unsigned int n;
unsigned int chan;
chan = CR_CHAN(insn->chanspec);
for (n = 0; n < insn->n; n++)
data[n] = devpriv->ao_readback[chan];
return n;
}
static void i8254_initialize(struct comedi_device *dev)
{
const struct das08_board_struct *thisboard = comedi_board(dev);
@ -670,12 +688,12 @@ int das08_common_attach(struct comedi_device *dev, unsigned long iobase)
/* ao */
if (thisboard->ao_nbits) {
s->type = COMEDI_SUBD_AO;
/* XXX lacks read-back insn */
s->subdev_flags = SDF_WRITABLE;
s->n_chan = 2;
s->maxdata = (1 << thisboard->ao_nbits) - 1;
s->range_table = &range_bipolar5;
s->insn_write = das08_ao_winsn;
s->insn_read = das08_ao_rinsn;
das08_ao_initialize(dev, s);
} else {
s->type = COMEDI_SUBD_UNUSED;

1
drivers/staging/comedi/drivers/das08.h
View File

@ -52,6 +52,7 @@ struct das08_private_struct {
unsigned int do_bits; /* bits for do register on boards with register dedicated to digital out only */
const unsigned int *pg_gainlist;
struct pci_dev *pdev; /* struct for pci-das08 */
unsigned int ao_readback[2]; /* assume 2 AO channels */
};
int das08_common_attach(struct comedi_device *dev, unsigned long iobase);