staging: comedi: das16m1: don't calc pacer divisors twice

The analog input async command can use the pacer for the convert_src. The
(*do_cmdtest) calculates the divisors when validating the cmd argument.

There is no reason to recalc the divisors in the (*do_cmd). Just use the
values from the private data.

Refactor das16m1_set_pacer() to use the i8254_set_mode() and i8254_write()
helpers instead of i8254_load(). This allows us to use the I8254_* defines
when setting the mode to clarify the code.

Tidy up das16m1_cmd_exec() a bit. The pacer only needs to be set when the
convert_src is TRIG_TIMER.

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/das16m1.c b/drivers/staging/comedi/drivers/das16m1.c
index a9cd21068ea89df337dbecb2e62c29e8837e4813..4fe30cc254e3f46310ed5bb5eb60dec8cd50e208 100644 (file)
--- a/drivers/staging/comedi/drivers/das16m1.c
+++ b/drivers/staging/comedi/drivers/das16m1.c
@@ -254,26 +254,16 @@ static int das16m1_cmd_test(struct comedi_device *dev,
        return 0;
 }
 
-/* This function takes a time in nanoseconds and sets the     *
- * 2 pacer clocks to the closest frequency possible. It also  *
- * returns the actual sampling period.                        */
-static unsigned int das16m1_set_pacer(struct comedi_device *dev,
-                                     unsigned int ns, int rounding_flags)
+static void das16m1_set_pacer(struct comedi_device *dev)
 {
        struct das16m1_private_struct *devpriv = dev->private;
+       unsigned long timer_base = dev->iobase + DAS16M1_8254_SECOND;
 
-       i8253_cascade_ns_to_timer_2div(I8254_OSC_BASE_10MHZ,
-                                      &devpriv->divisor1,
-                                      &devpriv->divisor2,
-                                      &ns, rounding_flags);
+       i8254_set_mode(timer_base, 0, 1, I8254_MODE2 | I8254_BINARY);
+       i8254_set_mode(timer_base, 0, 2, I8254_MODE2 | I8254_BINARY);
 
-       /* Write the values of ctr1 and ctr2 into counters 1 and 2 */
-       i8254_load(dev->iobase + DAS16M1_8254_SECOND, 0, 1, devpriv->divisor1,
-                  2);
-       i8254_load(dev->iobase + DAS16M1_8254_SECOND, 0, 2, devpriv->divisor2,
-                  2);
-
-       return ns;
+       i8254_write(timer_base, 0, 1, devpriv->divisor1);
+       i8254_write(timer_base, 0, 2, devpriv->divisor2);
 }
 
 static int das16m1_cmd_exec(struct comedi_device *dev,
@@ -307,10 +297,14 @@ static int das16m1_cmd_exec(struct comedi_device *dev,
                outb(byte, dev->iobase + DAS16M1_QUEUE_DATA);
        }
 
-       /* set counter mode and counts */
-       cmd->convert_arg =
-           das16m1_set_pacer(dev, cmd->convert_arg,
-                             cmd->flags & TRIG_ROUND_MASK);
+       /* enable interrupts and set internal pacer counter mode and counts */
+       devpriv->control_state &= ~PACER_MASK;
+       if (cmd->convert_src == TRIG_TIMER) {
+               das16m1_set_pacer(dev);
+               devpriv->control_state |= INT_PACER;
+       } else {        /* TRIG_EXT */
+               devpriv->control_state |= EXT_PACER;
+       }
 
        /*  set control & status register */
        byte = 0;
@@ -323,13 +317,6 @@ static int das16m1_cmd_exec(struct comedi_device *dev,
        /* clear interrupt bit */
        outb(0, dev->iobase + DAS16M1_CLEAR_INTR);
 
-       /* enable interrupts and internal pacer */
-       devpriv->control_state &= ~PACER_MASK;
-       if (cmd->convert_src == TRIG_TIMER)
-               devpriv->control_state |= INT_PACER;
-       else
-               devpriv->control_state |= EXT_PACER;
-
        devpriv->control_state |= INTE;
        outb(devpriv->control_state, dev->iobase + DAS16M1_INTR_CONTROL);