Use the comedi_subdevice 'readback' member and the core provided (*insn_read)
to handle the readback of the write-only offset calib subdevice. Remove the
then unused 'offset_value' member from the private data.
Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/adv_pci1724.c | 31 ++++++----------------------
1 file changed, 6 insertions(+), 25 deletions(-)
diff --git a/drivers/staging/comedi/drivers/adv_pci1724.c b/drivers/staging/comedi/drivers/adv_pci1724.c
index 7bbd36a..4aa1631 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 offset_value[NUM_AO_CHANNELS];
int gain_value[NUM_AO_CHANNELS];
};
@@ -189,7 +188,6 @@ static int offset_write_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 retval;
int i;
@@ -201,27 +199,8 @@ static int offset_write_insn(struct comedi_device *dev,
retval = set_dac(dev, DAC_OFFSET_MODE, channel, data[i]);
if (retval < 0)
return retval;
- devpriv->offset_value[channel] = data[i];
- }
-
- return insn->n;
-}
-
-static int offset_read_insn(struct comedi_device *dev,
- struct comedi_subdevice *s,
- struct comedi_insn *insn, unsigned int *data)
-{
- struct adv_pci1724_private *devpriv = dev->private;
- unsigned int channel = CR_CHAN(insn->chanspec);
- int i;
-
- if (devpriv->offset_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->offset_value[channel];
return insn->n;
}
@@ -296,9 +275,12 @@ static int setup_subdevices(struct comedi_device *dev)
s->type = COMEDI_SUBD_CALIB;
s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_INTERNAL;
s->n_chan = NUM_AO_CHANNELS;
- s->insn_read = offset_read_insn;
- s->insn_write = offset_write_insn;
s->maxdata = 0x3fff;
+ s->insn_write = offset_write_insn;
+
+ ret = comedi_alloc_subdev_readback(s);
+ if (ret)
+ return ret;
/* gain calibration */
s = &dev->subdevices[2];
@@ -328,7 +310,6 @@ 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->offset_value[i] = -1;
devpriv->gain_value[i] = -1;
}
--
2.0.3
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