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staging: comedi: pcmad: return errno if AI conversion times out

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Instead of returning invalid data, return -ETIME if the analog input
conversion times out.

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
2013-06-05 15:36:24 -07:00
committed by Greg Kroah-Hartman
parent 2a09cba62e
commit bcc01b4d85
1 changed files with 17 additions and 5 deletions
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22
drivers/staging/comedi/drivers/pcmad.c
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@@ -72,25 +72,37 @@ struct pcmad_priv_struct {
#define TIMEOUT 100
static int pcmad_ai_wait_for_eoc(struct comedi_device *dev,
int timeout)
{
int i;
for (i = 0; i < timeout; i++) {
if ((inb(dev->iobase + PCMAD_STATUS) & 0x3) == 0x3)
return 0;
}
return -ETIME;
}
static int pcmad_ai_insn_read(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
{
const struct pcmad_board_struct *board = comedi_board(dev);
struct pcmad_priv_struct *devpriv = dev->private;
int i;
int chan;
int n;
int ret;
chan = CR_CHAN(insn->chanspec);
for (n = 0; n < insn->n; n++) {
outb(chan, dev->iobase + PCMAD_CONVERT);
for (i = 0; i < TIMEOUT; i++) {
if ((inb(dev->iobase + PCMAD_STATUS) & 0x3) == 0x3)
break;
}
ret = pcmad_ai_wait_for_eoc(dev, TIMEOUT);
if (ret)
return ret;
data[n] = inb(dev->iobase + PCMAD_LSB);
data[n] |= (inb(dev->iobase + PCMAD_MSB) << 8);