evie/android_kernel_oneplus_msm8998
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staging: comedi: skel: use comedi_subdevice 'readback'

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Use the new comedi_subdevice 'readback' member and the core provided
(*insn_read) for the readback of the analog output subdevice channels.

For aesthetics, rename the (*insn_write) function and tidy it up a bit.

Add a comment about the 'readback' member.

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 2014-08-25 16:03:55 -07:00 • committed by Greg Kroah-Hartman
parent d276206692
commit b1598f9403
1 changed files with 35 additions and 31 deletions
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66
drivers/staging/comedi/drivers/skel.c
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@ -114,11 +114,7 @@ static const struct skel_board skel_boards[] = {
feel free to suggest moving the variable to the struct comedi_device struct.
*/
struct skel_private {
int data;
/* Used for AO readback */
unsigned int ao_readback[2];
};
/* This function doesn't require a particular form, this is just
@ -305,38 +301,29 @@ static int skel_ai_cmdtest(struct comedi_device *dev,
return 0;
}
static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
static int skel_ao_insn_write(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned int *data)
{
struct skel_private *devpriv = dev->private;
unsigned int chan = CR_CHAN(insn->chanspec);
unsigned int val = s->readback[chan];
int i;
int chan = CR_CHAN(insn->chanspec);
/* Writing a list of values to an AO channel is probably not
* very useful, but that's how the interface is defined. */
/*
* Writing a list of values to an AO channel is probably not
* very useful, but that's how the interface is defined.
*/
for (i = 0; i < insn->n; i++) {
val = data[i];
/* a typical programming sequence */
/* outw(data[i],dev->iobase + SKEL_DA0 + chan); */
devpriv->ao_readback[chan] = data[i];
/* outw(data[i], dev->iobase + SKEL_DA0 + chan); */
}
/* save the last value for readback */
s->readback[chan] = val;
/* return the number of samples read/written */
return i;
}
/* AO subdevices should have a read insn as well as a write insn.
* Usually this means copying a value stored in devpriv. */
static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
{
struct skel_private *devpriv = dev->private;
int i;
int chan = CR_CHAN(insn->chanspec);
for (i = 0; i < insn->n; i++)
data[i] = devpriv->ao_readback[chan];
return i;
return insn->n;
}
/*
@ -446,8 +433,25 @@ static int skel_common_attach(struct comedi_device *dev)
s->n_chan = 1;
s->maxdata = 0xffff;
s->range_table = &range_bipolar5;
s->insn_write = skel_ao_winsn;
s->insn_read = skel_ao_rinsn;
s->insn_write = skel_ao_insn_write;
/*
* AO subdevices should have a (*insn_read) as well. Usually the
* hardware is not readable so the channel values need to be stored
* somewhere for readback. The comedi_subdevice has a 'readback'
* member to handle this.
*
* The comedi_readback_insn_read() function provides the (*insn_read)
* to return the 'readback' values.
*
* The comedi_alloc_subdev_readback() function will allocate memory
* for s->n_chan 'readback' values. The core will kfree the memory
* when the driver is detached.
*/
s->insn_read = comedi_readback_insn_read;
ret = comedi_alloc_subdev_readback(s);
if (ret)
return ret;
s = &dev->subdevices[2];
/* digital i/o subdevice */