mirror/linux
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

staging: comedi: cb_pcimdda: cleanup the analog out read/write

Browse Source 
Use the register map define to work out the i/o address.

Cleanup the comments about the simultaneous transfer mode for
the analog outputs.

Change the return to 'insn->n', the comedi core expects the return
to be the number of data elements used. Technically the 'i' value
is correct but 'insn->n' just makes it clearer.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten
2012-08-16 19:54:32 -07:00
committed by Greg Kroah-Hartman
parent b9616b18c1
commit aee815b53b
1 changed files with 25 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

61
drivers/staging/comedi/drivers/cb_pcimdda.c
View File

@@ -110,62 +110,51 @@ static int cb_pcimdda_ao_winsn(struct comedi_device *dev,
unsigned int *data)
{
struct cb_pcimdda_private *devpriv = dev->private;
unsigned int chan = CR_CHAN(insn->chanspec);
unsigned long offset = dev->iobase + PCIMDDA_DA_CHAN(chan);
unsigned int val = 0;
int i;
int chan = CR_CHAN(insn->chanspec);
unsigned long offset = dev->iobase + chan * 2;
/* 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++) {
/* first, load the low byte */
outb((char)(data[i] & 0x00ff), offset);
/* next, write the high byte -- only after this is written is
the channel voltage updated in the DAC, unless
we're in simultaneous xfer mode (jumper on card)
then a rinsn is necessary to actually update the DAC --
see cb_pcimdda_ao_rinsn() below... */
outb((char)(data[i] >> 8 & 0x00ff), offset + 1);
val = data[i];
/* for testing only.. the actual rinsn SHOULD do an inw!
(see the stuff about simultaneous XFER mode on this board) */
devpriv->ao_readback[chan] = data[i];
/*
* Write the LSB then MSB.
*
* If the simultaneous xfer mode is selected by the
* jumper on the card, a read instruction is needed
* in order to initiate the simultaneous transfer.
* Otherwise, the DAC will be updated when the MSB
* is written.
*/
outb(val & 0x00ff, offset);
outb((val >> 8) & 0x00ff, offset + 1);
}
/* return the number of samples read/written */
return i;
/* Cache the last value for readback */
devpriv->ao_readback[chan] = val;
return insn->n;
}
/* AO subdevices should have a read insn as well as a write insn.
Usually this means copying a value stored in devpriv->ao_readback.
However, since this board has this jumper setting called "Simultaneous
Xfer mode" (off by default), we will support it. Simultaneaous xfer
mode is accomplished by loading ALL the values you want for AO in all the
channels, then READing off one of the AO registers to initiate the
instantaneous simultaneous update of all DAC outputs, which makes
all AO channels update simultaneously. This is useful for some control
applications, I would imagine.
*/
static int cb_pcimdda_ao_rinsn(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned int *data)
{
struct cb_pcimdda_private *devpriv = dev->private;
int i;
int chan = CR_CHAN(insn->chanspec);
unsigned long offset = dev->iobase + PCIMDDA_DA_CHAN(chan);
int i;
for (i = 0; i < insn->n; i++) {
inw(dev->iobase + chan * 2);
/*
* should I set data[i] to the result of the actual read
* on the register or the cached unsigned int in
* devpriv->ao_readback[]?
*/
/* Initiate the simultaneous transfer */
inw(offset);
data[i] = devpriv->ao_readback[chan];
}
return i;
return insn->n;
}
static struct pci_dev *cb_pcimdda_probe(struct comedi_device *dev,