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

[H Hartley Sweeten]

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

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/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

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