Use the comedi_subdevice 'readback' member and the core provided (*insn_read)
to handle the readback of the write-only analog output subdevice. Remove the
then unused 'ao_value' member from the private data.
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/adv_pci1724.c | 29 +++++-----------------------
1 file changed, 5 insertions(+), 24 deletions(-)
diff --git a/drivers/staging/comedi/drivers/adv_pci1724.c
b/drivers/staging/comedi/drivers/adv_pci1724.c
index 2697758..7bbd36a 100644
--- a/drivers/staging/comedi/drivers/adv_pci1724.c
+++ b/drivers/staging/comedi/drivers/adv_pci1724.c
@@ -127,7 +127,6 @@ static const struct comedi_lrange ao_ranges_1724 = {
/* this structure is for data unique to this hardware driver. */
struct adv_pci1724_private {
- int ao_value[NUM_AO_CHANNELS];
int offset_value[NUM_AO_CHANNELS];
int gain_value[NUM_AO_CHANNELS];
};
@@ -170,7 +169,6 @@ static int set_dac(struct comedi_device *dev, unsigned
mode, unsigned channel,
static int ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
{
- struct adv_pci1724_private *devpriv = dev->private;
int channel = CR_CHAN(insn->chanspec);
int retval;
int i;
@@ -182,27 +180,8 @@ static int ao_winsn(struct comedi_device *dev, struct
comedi_subdevice *s,
retval = set_dac(dev, DAC_NORMAL_MODE, channel, data[i]);
if (retval < 0)
return retval;
- devpriv->ao_value[channel] = data[i];
- }
- return insn->n;
-}
-
-static int ao_readback_insn(struct comedi_device *dev,
- struct comedi_subdevice *s,
- struct comedi_insn *insn, unsigned int *data)
-{
- struct adv_pci1724_private *devpriv = dev->private;
- int channel = CR_CHAN(insn->chanspec);
- int i;
-
- if (devpriv->ao_value[channel] < 0) {
- dev_err(dev->class_dev,
- "Cannot read back channels which have not yet been
written to\n");
- return -EIO;
+ s->readback[channel] = data[i];
}
- for (i = 0; i < insn->n; i++)
- data[i] = devpriv->ao_value[channel];
-
return insn->n;
}
@@ -306,9 +285,12 @@ static int setup_subdevices(struct comedi_device *dev)
s->n_chan = NUM_AO_CHANNELS;
s->maxdata = 0x3fff;
s->range_table = &ao_ranges_1724;
- s->insn_read = ao_readback_insn;
s->insn_write = ao_winsn;
+ ret = comedi_alloc_subdev_readback(s);
+ if (ret)
+ return ret;
+
/* offset calibration */
s = &dev->subdevices[1];
s->type = COMEDI_SUBD_CALIB;
@@ -346,7 +328,6 @@ static int adv_pci1724_auto_attach(struct comedi_device
*dev,
/* init software copies of output values to indicate we don't know
* what the output value is since it has never been written. */
for (i = 0; i < NUM_AO_CHANNELS; ++i) {
- devpriv->ao_value[i] = -1;
devpriv->offset_value[i] = -1;
devpriv->gain_value[i] = -1;
}
--
2.0.3
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