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>

diff --git a/drivers/staging/comedi/drivers/skel.c b/drivers/staging/comedi/drivers/skel.c
index e800e73..a493368 100644 (file)
--- 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 */