[PATCH 13/17] staging: comedi: quatech_daqp_cs: introduce daqp_clear_events()

[H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>]

Introduce a helper function for the common code used to clear any
pending interrupts.

Signed-off-by: H Hartley Sweeten <hsweeten@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/staging/comedi/drivers/quatech_daqp_cs.c | 52 ++++++++++++------------
 1 file changed, 25 insertions(+), 27 deletions(-)

diff --git a/drivers/staging/comedi/drivers/quatech_daqp_cs.c b/drivers/staging/comedi/drivers/quatech_daqp_cs.c
index 899340a..fb12665 100644
--- a/drivers/staging/comedi/drivers/quatech_daqp_cs.c
+++ b/drivers/staging/comedi/drivers/quatech_daqp_cs.c
@@ -151,6 +151,23 @@ static const struct comedi_lrange range_daqp_ai = {
 	}
 };
 
+static int daqp_clear_events(struct comedi_device *dev, int loops)
+{
+	unsigned int status;
+
+	/*
+	 * Reset any pending interrupts (my card has a tendency to require
+	 * require multiple reads on the status register to achieve this).
+	 */
+	while (--loops) {
+		status = inb(dev->iobase + DAQP_STATUS);
+		if ((status & DAQP_STATUS_EVENTS) == 0)
+			return 0;
+	}
+	dev_err(dev->class_dev, "couldn't clear events in status register\n");
+	return -EBUSY;
+}
+
 static int daqp_ai_cancel(struct comedi_device *dev,
 			  struct comedi_subdevice *s)
 {
@@ -277,9 +294,8 @@ static int daqp_ai_insn_read(struct comedi_device *dev,
 			     unsigned int *data)
 {
 	struct daqp_private *devpriv = dev->private;
-	int ret = 0;
+	int ret;
 	int i;
-	int counter = 10000;
 
 	if (devpriv->stop)
 		return -EIO;
@@ -296,18 +312,9 @@ static int daqp_ai_insn_read(struct comedi_device *dev,
 	/* one-shot internal trigger, no pacer, no interrupts */
 	outb(0, dev->iobase + DAQP_CONTROL);
 
-	/* Reset any pending interrupts (my card has a tendency to require
-	 * require multiple reads on the status register to achieve this)
-	 */
-
-	while (--counter
-	       && (inb(dev->iobase + DAQP_STATUS) & DAQP_STATUS_EVENTS))
-		;
-	if (!counter) {
-		dev_err(dev->class_dev,
-			"couldn't clear interrupts in status register\n");
-		return -1;
-	}
+	ret = daqp_clear_events(dev, 10000);
+	if (ret)
+		return ret;
 
 	for (i = 0; i < insn->n; i++) {
 		/* Start conversion */
@@ -433,8 +440,8 @@ static int daqp_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 {
 	struct daqp_private *devpriv = dev->private;
 	struct comedi_cmd *cmd = &s->async->cmd;
-	int counter;
 	int threshold;
+	int ret;
 
 	if (devpriv->stop)
 		return -EIO;
@@ -552,18 +559,9 @@ static int daqp_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 	     DAQP_CONTROL_TRIGGER_CONTINUOUS | DAQP_CONTROL_TRIGGER_INTERNAL,
 	     dev->iobase + DAQP_CONTROL);
 
-	/* Reset any pending interrupts (my card has a tendency to require
-	 * require multiple reads on the status register to achieve this)
-	 */
-	counter = 100;
-	while (--counter
-	       && (inb(dev->iobase + DAQP_STATUS) & DAQP_STATUS_EVENTS))
-		;
-	if (!counter) {
-		dev_err(dev->class_dev,
-			"couldn't clear interrupts in status register\n");
-		return -1;
-	}
+	ret = daqp_clear_events(dev, 100);
+	if (ret)
+		return ret;
 
 	/* Start conversion */
 	outb(DAQP_COMMAND_ARM | DAQP_COMMAND_FIFO_DATA | devpriv->scanrate,
-- 
2.5.1

_______________________________________________
devel mailing list
devel@xxxxxxxxxxxxxxxxxxxxxx
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel