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staging: comedi: skel: use comedi_timeout() 

Use comedi_timeout() to wait for the analog input end-of-conversion.

Since this is the sample skeleton driver, add comments about how the
callback function works with comedi_timeout().

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 2014-02-10 11:49:01 -07:00 committed by Greg Kroah-Hartman
parent 915064086e
commit f2426e4f72
1 changed files with 28 additions and 11 deletions
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39
drivers/staging/comedi/drivers/skel.c
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@ -141,6 +141,29 @@ static int skel_ns_to_timer(unsigned int *ns, int round)
return *ns; return *ns;
} }
/*
* This function doesn't require a particular form, this is just
* what happens to be used in some of the drivers. The comedi_timeout()
* helper uses this callback to check for the end-of-conversion while
* waiting for up to 1 second. This function should return 0 when the
* conversion is finished and -EBUSY to keep waiting. Any other errno
* will terminate comedi_timeout() and return that errno to the caller.
* If the timeout occurs, comedi_timeout() will return -ETIMEDOUT.
*/
static int skel_ai_eoc(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
unsigned long context)
{
unsigned int status;
/* status = inb(dev->iobase + SKEL_STATUS); */
status = 1;
if (status)
return 0;
return -EBUSY;
}
/* /*
* "instructions" read/write data in "one-shot" or "software-triggered" * "instructions" read/write data in "one-shot" or "software-triggered"
* mode. * mode.
@ -149,9 +172,9 @@ static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data) struct comedi_insn *insn, unsigned int *data)
{ {
const struct skel_board *thisboard = comedi_board(dev); const struct skel_board *thisboard = comedi_board(dev);
int n, i; int n;
unsigned int d; unsigned int d;
unsigned int status; int ret;
/* a typical programming sequence */ /* a typical programming sequence */
@ -165,17 +188,11 @@ static int skel_ai_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,
/* trigger conversion */ /* trigger conversion */
/* outw(0,dev->iobase + SKEL_CONVERT); */ /* outw(0,dev->iobase + SKEL_CONVERT); */
#define TIMEOUT 100
/* wait for conversion to end */ /* wait for conversion to end */
for (i = 0; i < TIMEOUT; i++) { ret = comedi_timeout(dev, s, insn, skel_ai_eoc, 0);
status = 1; if (ret) {
/* status = inb(dev->iobase + SKEL_STATUS); */
if (status)
break;
}
if (i == TIMEOUT) {
dev_warn(dev->class_dev, "ai timeout\n"); dev_warn(dev->class_dev, "ai timeout\n");
return -ETIMEDOUT; return ret;
} }
/* read data */ /* read data */