staging: comedi: pcl711: no need to calc the timer values twice

The comedi core always calls the (*do_cmdtest) function to validate
a command before it calls the (*do_cmd) function.

Since the (*do_cmdtest) has already calculated the timer values in
order to validate the cmd->scan_begin_arg there is no reason to
recalc the values in the (*do_cmd).

This also fixes a bug in the driver. The (*do_cmdtest) was using a
time base value of 100 and but the (*do_cmd) was using a time base
of 500. These result in different timer values. The functions used
to calculate the values are actually the same due to a #define in
the 8253.h header.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/pcl711.c b/drivers/staging/comedi/drivers/pcl711.c
index 8f068ebc7609a05ad5adb146657091a2f206df32..60b7137195607ee87a672946441fdf6db3ce58d0 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl711.c
+++ b/drivers/staging/comedi/drivers/pcl711.c
@@ -331,7 +331,6 @@ static int pcl711_ai_cmdtest(struct comedi_device *dev,
                err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);
        } else {
 #define MAX_SPEED 1000
-#define TIMER_BASE 100
                err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,
                                                 MAX_SPEED);
        }
@@ -352,11 +351,11 @@ static int pcl711_ai_cmdtest(struct comedi_device *dev,
 
        if (cmd->scan_begin_src == TRIG_TIMER) {
                tmp = cmd->scan_begin_arg;
-               i8253_cascade_ns_to_timer_2div(TIMER_BASE,
-                                              &devpriv->divisor1,
-                                              &devpriv->divisor2,
-                                              &cmd->scan_begin_arg,
-                                              cmd->flags & TRIG_ROUND_MASK);
+               i8253_cascade_ns_to_timer(500,          /* 2 Mhz */
+                                         &devpriv->divisor1,
+                                         &devpriv->divisor2,
+                                         &cmd->scan_begin_arg,
+                                         cmd->flags & TRIG_ROUND_MASK);
                if (tmp != cmd->scan_begin_arg)
                        err++;
        }
@@ -369,22 +368,16 @@ static int pcl711_ai_cmdtest(struct comedi_device *dev,
 
 static int pcl711_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 {
-       int timer1, timer2;
+       struct pcl711_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
 
        pcl711_set_changain(dev, s, cmd->chanlist[0]);
 
        if (cmd->scan_begin_src == TRIG_TIMER) {
-               timer1 = timer2 = 0;
-               i8253_cascade_ns_to_timer(500,          /* 2 Mhz */
-                                         &timer1, &timer2,
-                                         &cmd->scan_begin_arg,
-                                         TRIG_ROUND_NEAREST);
-
                i8254_load(dev->iobase + PCL711_TIMER_BASE, 0,
-                          1, timer1, I8254_MODE2 | I8254_BINARY);
+                          1, devpriv->divisor1, I8254_MODE2 | I8254_BINARY);
                i8254_load(dev->iobase + PCL711_TIMER_BASE, 0,
-                          2, timer2, I8254_MODE2 | I8254_BINARY);
+                          2, devpriv->divisor2, I8254_MODE2 | I8254_BINARY);
 
                /* clear pending interrupts (just in case) */
                outb(0, dev->iobase + PCL711_CLRINTR);