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authorH Hartley Sweeten <hsweeten@visionengravers.com>2014-02-05 14:59:53 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-02-22 12:41:27 -0800
commitdb438cf13a917c449d92c25deba7528fc323a43c (patch)
tree831c8d82de73007ebf2b828a719cd019f69233ed
parent88d48868cc91007df5f2b611df6fd843bdbd8dbe (diff)
downloadlinux-db438cf13a917c449d92c25deba7528fc323a43c.tar.gz
staging: comedi: adv_pci1710: fix analog output readback value
commit 1e85c1ea1ff2a60659e790ef8ec76c7339445841 upstream. The last value written to a analog output channel is cached in the private data of this driver for readback. Currently, the wrong value is cached in the (*insn_write) functions. The current code stores the data[n] value for readback afer the loop has written all the values. At this time 'n' points past the end of the data array. Fix the functions by using a local variable to hold the data being written to the analog output channel. This variable is then used after the loop is complete to store the readback value. The current value is retrieved before the loop in case no values are actually written.. 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>
-rw-r--r--drivers/staging/comedi/drivers/adv_pci1710.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/drivers/staging/comedi/drivers/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c
index f847bbc175e..acb66a9513c 100644
--- a/drivers/staging/comedi/drivers/adv_pci1710.c
+++ b/drivers/staging/comedi/drivers/adv_pci1710.c
@@ -489,6 +489,7 @@ static int pci171x_insn_write_ao(struct comedi_device *dev,
struct comedi_insn *insn, unsigned int *data)
{
struct pci1710_private *devpriv = dev->private;
+ unsigned int val;
int n, chan, range, ofs;
chan = CR_CHAN(insn->chanspec);
@@ -504,11 +505,14 @@ static int pci171x_insn_write_ao(struct comedi_device *dev,
outw(devpriv->da_ranges, dev->iobase + PCI171x_DAREF);
ofs = PCI171x_DA1;
}
+ val = devpriv->ao_data[chan];
- for (n = 0; n < insn->n; n++)
- outw(data[n], dev->iobase + ofs);
+ for (n = 0; n < insn->n; n++) {
+ val = data[n];
+ outw(val, dev->iobase + ofs);
+ }
- devpriv->ao_data[chan] = data[n];
+ devpriv->ao_data[chan] = val;
return n;
@@ -678,6 +682,7 @@ static int pci1720_insn_write_ao(struct comedi_device *dev,
struct comedi_insn *insn, unsigned int *data)
{
struct pci1710_private *devpriv = dev->private;
+ unsigned int val;
int n, rangereg, chan;
chan = CR_CHAN(insn->chanspec);
@@ -687,13 +692,15 @@ static int pci1720_insn_write_ao(struct comedi_device *dev,
outb(rangereg, dev->iobase + PCI1720_RANGE);
devpriv->da_ranges = rangereg;
}
+ val = devpriv->ao_data[chan];
for (n = 0; n < insn->n; n++) {
- outw(data[n], dev->iobase + PCI1720_DA0 + (chan << 1));
+ val = data[n];
+ outw(val, dev->iobase + PCI1720_DA0 + (chan << 1));
outb(0, dev->iobase + PCI1720_SYNCOUT); /* update outputs */
}
- devpriv->ao_data[chan] = data[n];
+ devpriv->ao_data[chan] = val;
return n;
}