staging: comedi: pcl812: don't calc the timer divisors twice

The timer divisors are calculated in the (*do_cmdtest) before the (*do_cmd)
is called by the comedi core. Save the values in the private data so they
don't need to be recalced.

Refactor pcl812_start_pacer() to use the values from the private data.

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/pcl812.c b/drivers/staging/comedi/drivers/pcl812.c
index b34814d..0d7d3ae 100644 (file)
--- a/drivers/staging/comedi/drivers/pcl812.c
+++ b/drivers/staging/comedi/drivers/pcl812.c
@@ -529,6 +529,8 @@ struct pcl812_private {
        unsigned int last_dma_run;      /*  how many bytes to transfer on last DMA buffer */
        unsigned int max_812_ai_mode0_rangewait;        /*  setling time for gain */
        unsigned int ao_readback[2];    /*  data for AO readback */
+       unsigned int divisor1;
+       unsigned int divisor2;
 };
 
 static void setup_range_channel(struct comedi_device *dev,
@@ -537,9 +539,9 @@ static void setup_range_channel(struct comedi_device *dev,
 static int pcl812_ai_cancel(struct comedi_device *dev,
                            struct comedi_subdevice *s);
 
-static void pcl812_start_pacer(struct comedi_device *dev, bool load_timers,
-                              unsigned int divisor1, unsigned int divisor2)
+static void pcl812_start_pacer(struct comedi_device *dev, bool load_timers)
 {
+       struct pcl812_private *devpriv = dev->private;
        unsigned long timer_base = dev->iobase + PCL812_TIMER_BASE;
 
        i8254_set_mode(timer_base, 0, 2, I8254_MODE2 | I8254_BINARY);
@@ -547,8 +549,8 @@ static void pcl812_start_pacer(struct comedi_device *dev, bool load_timers,
        udelay(1);
 
        if (load_timers) {
-               i8254_write(timer_base, 0, 2, divisor2);
-               i8254_write(timer_base, 0, 1, divisor1);
+               i8254_write(timer_base, 0, 2, devpriv->divisor2);
+               i8254_write(timer_base, 0, 1, devpriv->divisor1);
        }
 }
 
@@ -687,7 +689,7 @@ static int pcl812_ai_cmdtest(struct comedi_device *dev,
        struct pcl812_private *devpriv = dev->private;
        int err = 0;
        unsigned int flags;
-       int tmp, divisor1, divisor2;
+       int tmp;
 
        /* Step 1 : check if triggers are trivially valid */
 
@@ -743,7 +745,8 @@ static int pcl812_ai_cmdtest(struct comedi_device *dev,
        if (cmd->convert_src == TRIG_TIMER) {
                tmp = cmd->convert_arg;
                i8253_cascade_ns_to_timer(I8254_OSC_BASE_2MHZ,
-                                         &divisor1, &divisor2,
+                                         &devpriv->divisor1,
+                                         &devpriv->divisor2,
                                          &cmd->convert_arg, cmd->flags);
                if (cmd->convert_arg < board->ai_ns_min)
                        cmd->convert_arg = board->ai_ns_min;
@@ -762,20 +765,11 @@ static int pcl812_ai_cmdtest(struct comedi_device *dev,
 */
 static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 {
-       const struct pcl812_board *board = comedi_board(dev);
        struct pcl812_private *devpriv = dev->private;
-       unsigned int divisor1 = 0, divisor2 = 0, i, dma_flags, bytes;
        struct comedi_cmd *cmd = &s->async->cmd;
+       unsigned int i, dma_flags, bytes;
 
-       if (cmd->convert_src == TRIG_TIMER) {
-               if (cmd->convert_arg < board->ai_ns_min)
-                       cmd->convert_arg = board->ai_ns_min;
-               i8253_cascade_ns_to_timer(I8254_OSC_BASE_2MHZ,
-                                         &divisor1, &divisor2,
-                                         &cmd->convert_arg, cmd->flags);
-       }
-
-       pcl812_start_pacer(dev, false, 0, 0);
+       pcl812_start_pacer(dev, false);
 
        memcpy(devpriv->ai_chanlist, cmd->chanlist,
               sizeof(unsigned int) * cmd->scan_end_arg);
@@ -869,7 +863,7 @@ static int pcl812_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 
        switch (cmd->convert_src) {
        case TRIG_TIMER:
-               pcl812_start_pacer(dev, true, divisor1, divisor2);
+               pcl812_start_pacer(dev, true);
                break;
        }
 
@@ -1154,7 +1148,7 @@ static int pcl812_ai_cancel(struct comedi_device *dev,
        outb(0, dev->iobase + PCL812_CLRINT);   /* clear INT request */
                                                        /* Stop A/D */
        outb(devpriv->mode_reg_int | 0, dev->iobase + PCL812_MODE);
-       pcl812_start_pacer(dev, false, 0, 0);
+       pcl812_start_pacer(dev, false);
        outb(0, dev->iobase + PCL812_CLRINT);   /* clear INT request */
        return 0;
 }
@@ -1182,7 +1176,7 @@ static void pcl812_reset(struct comedi_device *dev)
        case boardA821:
                outb(0, dev->iobase + PCL812_DA1_LO);
                outb(0, dev->iobase + PCL812_DA1_HI);
-               pcl812_start_pacer(dev, false, 0, 0);
+               pcl812_start_pacer(dev, false);
                outb(0, dev->iobase + PCL812_DO_HI);
                outb(0, dev->iobase + PCL812_DO_LO);
                outb(devpriv->mode_reg_int | 0, dev->iobase + PCL812_MODE);