staging: comedi: addi_apci_3120: tidy up timer programming in apci3120_ai_cmd()

Tidy up the programming of timers 0 and 1 so that only one local variable is
required.

Also, remove the unnecessary clear of devpriv->timer_mode. This value will get
set correctly by each apci3120_timer_set_mode() call. It's not necessary to
clear it first.

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/addi-data/hwdrv_apci3120.c b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3120.c
index 8fc7803..3656f9d 100644 (file)
--- a/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3120.c
+++ b/drivers/staging/comedi/drivers/addi-data/hwdrv_apci3120.c
@@ -373,12 +373,10 @@ static int apci3120_ai_cmd(struct comedi_device *dev,
 {
        struct apci3120_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
-       unsigned int divisor1 = 0;
-       unsigned int divisor0;
+       unsigned int divisor;
 
-       /*  clear software  registers */
-       devpriv->timer_mode = 0;
        devpriv->mode = 0;
+       outb(devpriv->mode, dev->iobase + APCI3120_MODE_REG);
 
        /* Clear Timer Write TC int */
        outl(APCI3120_CLEAR_WRITE_TC_INT,
@@ -391,12 +389,6 @@ static int apci3120_ai_cmd(struct comedi_device *dev,
        /* load chanlist for command scan */
        apci3120_set_chanlist(dev, s, cmd->chanlist_len, cmd->chanlist);
 
-       divisor0 = apci3120_ns_to_timer(dev, 0, cmd->convert_arg, cmd->flags);
-       if (cmd->scan_begin_src == TRIG_TIMER) {
-               divisor1 = apci3120_ns_to_timer(dev, 1, cmd->scan_begin_arg,
-                                               cmd->flags);
-       }
-
        if (cmd->start_src == TRIG_EXT) {
                devpriv->b_ExttrigEnable = 1;
                apci3120_exttrig_enable(dev, true);
@@ -404,27 +396,24 @@ static int apci3120_ai_cmd(struct comedi_device *dev,
                devpriv->b_ExttrigEnable = 0;
        }
 
-       if (cmd->scan_begin_src == TRIG_FOLLOW) {
-               /*  init timer0 in mode 2 */
-               apci3120_timer_set_mode(dev, 0, APCI3120_TIMER_MODE2);
-
-               /* Set the conversion time */
-               apci3120_timer_write(dev, 0, divisor0);
-       } else {        /* TRIG_TIMER */
-               /*  init timer1 in mode 2 */
+       if (cmd->scan_begin_src == TRIG_TIMER) {
+               /*
+                * Timer 1 is used in MODE2 (rate generator) to set the
+                * start time for each scan.
+                */
+               divisor = apci3120_ns_to_timer(dev, 1, cmd->scan_begin_arg,
+                                              cmd->flags);
                apci3120_timer_set_mode(dev, 1, APCI3120_TIMER_MODE2);
-
-               /* Set the scan begin time */
-               apci3120_timer_write(dev, 1, divisor1);
-
-               /*  init timer0 in mode 2 */
-               apci3120_timer_set_mode(dev, 0, APCI3120_TIMER_MODE2);
-
-               /* Set the conversion time */
-               apci3120_timer_write(dev, 0, divisor0);
+               apci3120_timer_write(dev, 1, divisor);
        }
 
-       outb(devpriv->mode, dev->iobase + APCI3120_MODE_REG);
+       /*
+        * Timer 0 is used in MODE2 (rate generator) to set the conversion
+        * time for each acquisition.
+        */
+       divisor = apci3120_ns_to_timer(dev, 0, cmd->convert_arg, cmd->flags);
+       apci3120_timer_set_mode(dev, 0, APCI3120_TIMER_MODE2);
+       apci3120_timer_write(dev, 0, divisor);
 
        if (devpriv->us_UseDma) {
                devpriv->b_InterruptMode = APCI3120_DMA_MODE;
@@ -459,12 +448,9 @@ static int apci3120_ai_cmd(struct comedi_device *dev,
                }
        }
 
-       if (cmd->scan_begin_src == TRIG_FOLLOW) {
-               apci3120_timer_enable(dev, 0, true);
-       } else {        /* TRIG_TIMER */
+       if (cmd->scan_begin_src == TRIG_TIMER)
                apci3120_timer_enable(dev, 1, true);
-               apci3120_timer_enable(dev, 0, true);
-       }
+       apci3120_timer_enable(dev, 0, true);
 
        return 0;
 }