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 <hswee...@visionengravers.com>
Cc: Ian Abbott <abbo...@mev.co.uk>
Cc: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
drivers/staging/comedi/drivers/skel.c | 39 +++++++++++++++++++++++++----------
1 file changed, 28 insertions(+), 11 deletions(-)
diff --git a/drivers/staging/comedi/drivers/skel.c
b/drivers/staging/comedi/drivers/skel.c
index e800e73..a493368 100644
--- a/drivers/staging/comedi/drivers/skel.c
+++ b/drivers/staging/comedi/drivers/skel.c
@@ -142,6 +142,29 @@ static int skel_ns_to_timer(unsigned int *ns, int round)
}
/*
+ * 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"
* 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)
{
const struct skel_board *thisboard = comedi_board(dev);
- int n, i;
+ int n;
unsigned int d;
- unsigned int status;
+ int ret;
/* a typical programming sequence */
@@ -165,17 +188,11 @@ static int skel_ai_rinsn(struct comedi_device *dev,
struct comedi_subdevice *s,
/* trigger conversion */
/* outw(0,dev->iobase + SKEL_CONVERT); */
-#define TIMEOUT 100
/* wait for conversion to end */
- for (i = 0; i < TIMEOUT; i++) {
- status = 1;
- /* status = inb(dev->iobase + SKEL_STATUS); */
- if (status)
- break;
- }
- if (i == TIMEOUT) {
+ ret = comedi_timeout(dev, s, insn, skel_ai_eoc, 0);
+ if (ret) {
dev_warn(dev->class_dev, "ai timeout\n");
- return -ETIMEDOUT;
+ return ret;
}
/* read data */
--
1.8.5.2
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