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staging: comedi: adv_pci1724: use subdevice readback for 'gain_value' 

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

The private data is now unnecessary. Remove it and the allocation.

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 15:10:46 -07:00 committed by Greg Kroah-Hartman
parent 38020b55e7
commit 5081162d6c
1 changed files with 6 additions and 40 deletions
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46
drivers/staging/comedi/drivers/adv_pci1724.c
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@ -125,11 +125,6 @@ static const struct comedi_lrange ao_ranges_1724 = {
}
};
/* this structure is for data unique to this hardware driver. */
struct adv_pci1724_private {
int gain_value[NUM_AO_CHANNELS];
};
static int wait_for_dac_idle(struct comedi_device *dev)
{
static const int timeout = 10000;
@ -209,7 +204,6 @@ static int gain_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;
@ -221,31 +215,12 @@ static int gain_write_insn(struct comedi_device *dev,
retval = set_dac(dev, DAC_GAIN_MODE, channel, data[i]);
if (retval < 0)
return retval;
devpriv->gain_value[channel] = data[i];
s->readback[channel] = data[i];
}
return insn->n;
}
static int gain_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->gain_value[channel] < 0) {
dev_err(dev->class_dev,
"Cannot read back channels which have not yet been written to\n");
return -EIO;
}
for (i = 0; i < insn->n; i++)
data[i] = devpriv->gain_value[channel];
return insn->n;
}
/* Allocate and initialize the subdevice structures.
*/
static int setup_subdevices(struct comedi_device *dev)
@ -287,9 +262,12 @@ 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 = gain_read_insn;
s->insn_write = gain_write_insn;
s->maxdata = 0x3fff;
s->insn_write = gain_write_insn;
ret = comedi_alloc_subdev_readback(s);
if (ret)
return ret;
return 0;
}
@ -298,21 +276,9 @@ static int adv_pci1724_auto_attach(struct comedi_device *dev,
unsigned long context_unused)
{
struct pci_dev *pcidev = comedi_to_pci_dev(dev);
struct adv_pci1724_private *devpriv;
int i;
int retval;
unsigned int board_id;
devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));
if (!devpriv)
return -ENOMEM;
/* 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->gain_value[i] = -1;
}
retval = comedi_pci_enable(dev);
if (retval)
return retval;