staging: comedi: adv_pci1710: only calc the pacer divisors once

When the cmd->convert_src == TRIG_TIMER the divisors needed to
generate the pacer time are calculated in the (*do_cmdtest) to
validate the cmd->convert_arg. The core always does the (*do_cmdtest)
before the (*do_cmd) so there is no reason to recalc the divisors.

Save the calculated divisors in the private data as 'next_divisor[12]'.
The (*do_cmd) then transfers them to the private data 'divisor[12]' so
that they can be used to set the timer for the command immediately or
later when the cmd->start_src is TRIG_EXT (mode 2 in this driver).

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/adv_pci1710.c b/drivers/staging/comedi/drivers/adv_pci1710.c
index 6bdd915..7941a3e 100644 (file)
--- a/drivers/staging/comedi/drivers/adv_pci1710.c
+++ b/drivers/staging/comedi/drivers/adv_pci1710.c
@@ -305,7 +305,10 @@ struct pci1710_private {
        unsigned char ai_et;
        unsigned int ai_et_CntrlReg;
        unsigned int ai_et_MuxVal;
-       unsigned int ai_et_div1, ai_et_div2;
+       unsigned int next_divisor1;
+       unsigned int next_divisor2;
+       unsigned int divisor1;
+       unsigned int divisor2;
        unsigned int act_chanlist[32];  /*  list of scanned channel */
        unsigned char saved_seglen;     /* len of the non-repeating chanlist */
        unsigned char da_ranges;        /*  copy of D/A outpit range register */
@@ -939,7 +942,7 @@ static irqreturn_t interrupt_service_pci1710(int irq, void *d)
                outw(devpriv->ai_et_MuxVal, dev->iobase + PCI171x_MUX);
                outw(devpriv->CntrlReg, dev->iobase + PCI171x_CONTROL);
                /*  start pacer */
-               start_pacer(dev, 1, devpriv->ai_et_div1, devpriv->ai_et_div2);
+               start_pacer(dev, 1, devpriv->divisor1, devpriv->divisor2);
                return IRQ_HANDLED;
        }
 
@@ -955,7 +958,6 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
 {
        struct pci1710_private *devpriv = dev->private;
        struct comedi_cmd *cmd = &s->async->cmd;
-       unsigned int divisor1 = 0, divisor2 = 0;
        int mode;
 
        if (cmd->convert_src == TRIG_TIMER) {
@@ -982,6 +984,9 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
        if ((cmd->flags & TRIG_WAKE_EOS) == 0)
                devpriv->CntrlReg |= Control_ONEFH;
 
+       devpriv->divisor1 = devpriv->next_divisor1;
+       devpriv->divisor2 = devpriv->next_divisor2;
+
        switch (mode) {
        case 1:
        case 2:
@@ -995,17 +1000,11 @@ static int pci171x_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)
                } else {
                        devpriv->ai_et = 0;
                }
-               i8253_cascade_ns_to_timer(devpriv->i8254_osc_base,
-                                         &divisor1, &divisor2,
-                                         &cmd->convert_arg,
-                                         cmd->flags);
                outw(devpriv->CntrlReg, dev->iobase + PCI171x_CONTROL);
                if (mode != 2) {
                        /*  start pacer */
-                       start_pacer(dev, mode, divisor1, divisor2);
-               } else {
-                       devpriv->ai_et_div1 = divisor1;
-                       devpriv->ai_et_div2 = divisor2;
+                       start_pacer(dev, mode,
+                                   devpriv->divisor1, devpriv->divisor2);
                }
                break;
        case 3:
@@ -1028,7 +1027,6 @@ static int pci171x_ai_cmdtest(struct comedi_device *dev,
        struct pci1710_private *devpriv = dev->private;
        int err = 0;
        int tmp;
-       unsigned int divisor1 = 0, divisor2 = 0;
 
        /* Step 1 : check if triggers are trivially valid */
 
@@ -1078,7 +1076,8 @@ static int pci171x_ai_cmdtest(struct comedi_device *dev,
        if (cmd->convert_src == TRIG_TIMER) {
                tmp = cmd->convert_arg;
                i8253_cascade_ns_to_timer(devpriv->i8254_osc_base,
-                                         &divisor1, &divisor2,
+                                         &devpriv->next_divisor1,
+                                         &devpriv->next_divisor2,
                                          &cmd->convert_arg, cmd->flags);
                if (cmd->convert_arg < this_board->ai_ns_min)
                        cmd->convert_arg = this_board->ai_ns_min;