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staging: comedi: cb_pcidas: use subdevice readback for 'dac08_value'

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Use the comedi_subdevice 'readback' member and the core provided (*insn_read)
to handle the readback of the write-only dac08 calib subdevice. Remove the
then unused 'dac08_value' member from the private data.

The dac08 calib subdevice only has one channel. For consistency in the driver,
modify the subdevice init so that a loop is used to initialize the channels and
readback values.

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 2014-11-20 15:07:29 -07:00 committed by Greg Kroah-Hartman
parent 9c034da124
commit e42151f945
1 changed files with 13 additions and 19 deletions
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32
drivers/staging/comedi/drivers/cb_pcidas.c
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@ -356,7 +356,6 @@ struct cb_pcidas_private {
/* divisors of master clock for analog output pacing */
unsigned int ao_divisor1;
unsigned int ao_divisor2;
unsigned int dac08_value;
unsigned int calibration_source;
};
@ -650,31 +649,20 @@ static int cb_pcidas_dac08_insn_write(struct comedi_device *dev,
struct comedi_insn *insn,
unsigned int *data)
{
struct cb_pcidas_private *devpriv = dev->private;
unsigned int chan = CR_CHAN(insn->chanspec);
if (insn->n) {
unsigned int val = data[insn->n - 1];
if (devpriv->dac08_value != val) {
if (s->readback[chan] != val) {
dac08_write(dev, val);
devpriv->dac08_value = val;
s->readback[chan] = val;
}
}
return insn->n;
}
static int dac08_read_insn(struct comedi_device *dev,
struct comedi_subdevice *s, struct comedi_insn *insn,
unsigned int *data)
{
struct cb_pcidas_private *devpriv = dev->private;
data[0] = devpriv->dac08_value;
return 1;
}
static int trimpot_7376_write(struct comedi_device *dev, uint8_t value)
{
struct cb_pcidas_private *devpriv = dev->private;
@ -1531,11 +1519,17 @@ static int cb_pcidas_auto_attach(struct comedi_device *dev,
s->type = COMEDI_SUBD_CALIB;
s->subdev_flags = SDF_READABLE | SDF_WRITABLE | SDF_INTERNAL;
s->n_chan = NUM_CHANNELS_DAC08;
s->insn_read = dac08_read_insn;
s->insn_write = cb_pcidas_dac08_insn_write;
s->maxdata = 0xff;
dac08_write(dev, s->maxdata / 2);
devpriv->dac08_value = s->maxdata / 2;
s->insn_write = cb_pcidas_dac08_insn_write;
ret = comedi_alloc_subdev_readback(s);
if (ret)
return ret;
for (i = 0; i < s->n_chan; i++) {
dac08_write(dev, s->maxdata / 2);
s->readback[i] = s->maxdata / 2;
}
} else
s->type = COMEDI_SUBD_UNUSED;