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Commit f4985a79 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcl818: 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. The extra sanity checks in the (*do_cmd) are
not necessary, the values returned from i8253_cascade_ns_to_timer() will be
greater than 1. Save the values in the private data so they don't need to be
recalced.

Refactor pcl818_start_pacer() to use the values from the private data.

Signed-off-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f8d863e4

drivers/staging/comedi/drivers/pcl818.c

+12 −25
Original line number Diff line number Diff line
@@ -341,6 +341,8 @@ struct pcl818_private { 
	unsigned int ai_timer2;

	unsigned char usefifo;	/*  1=use fifo */

	unsigned int ao_readback[2];

	unsigned int divisor1;

	unsigned int divisor2;

};



static const unsigned int muxonechan[] = { 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77,	/*  used for gain list programming */
@@ -361,9 +363,9 @@ static int check_channel_list(struct comedi_device *dev, 
static int pcl818_ai_cancel(struct comedi_device *dev,

			    struct comedi_subdevice *s);



static void pcl818_start_pacer(struct comedi_device *dev, bool load_counters,

			       unsigned int divisor1, unsigned int divisor2)

static void pcl818_start_pacer(struct comedi_device *dev, bool load_counters)

{

	struct pcl818_private *devpriv = dev->private;

	unsigned long timer_base = dev->iobase + PCL818_TIMER_BASE;



	i8254_set_mode(timer_base, 0, 2, I8254_MODE2 | I8254_BINARY);
@@ -371,8 +373,8 @@ static void pcl818_start_pacer(struct comedi_device *dev, bool load_counters, 
	udelay(1);



	if (load_counters) {

		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);

	}

}
@@ -836,13 +838,12 @@ static int pcl818_ai_cmd_mode(int mode, struct comedi_device *dev, 
{

	struct pcl818_private *devpriv = dev->private;

	struct comedi_cmd *cmd = &s->async->cmd;

	int divisor1 = 0, divisor2 = 0;

	unsigned int seglen;



	if (devpriv->irq_blocked)

		return -EBUSY;



	pcl818_start_pacer(dev, false, 0, 0);

	pcl818_start_pacer(dev, false);



	seglen = check_channel_list(dev, s, devpriv->ai_chanlist,

				    cmd->chanlist_len);
@@ -860,21 +861,6 @@ static int pcl818_ai_cmd_mode(int mode, struct comedi_device *dev, 
	devpriv->act_chanlist_pos = 0;

	devpriv->dma_runs_to_end = 0;



	if (mode == 1) {

		i8253_cascade_ns_to_timer(devpriv->i8253_osc_base,

					  &divisor1, &divisor2,

					  &cmd->convert_arg,

					  TRIG_ROUND_NEAREST);

		if (divisor1 == 1) {	/* PCL718/818 crash if any divisor is set to 1 */

			divisor1 = 2;

			divisor2 /= 2;

		}

		if (divisor2 == 1) {

			divisor2 = 2;

			divisor1 /= 2;

		}

	}



	outb(0, dev->iobase + PCL818_CNTENABLE);	/* enable pacer */



	switch (devpriv->dma) {
@@ -911,7 +897,7 @@ static int pcl818_ai_cmd_mode(int mode, struct comedi_device *dev, 
		}

	}



	pcl818_start_pacer(dev, mode == 1, divisor1, divisor2);

	pcl818_start_pacer(dev, mode == 1);



	return 0;

}
@@ -1021,7 +1007,7 @@ static int ai_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s, 
	const struct pcl818_board *board = comedi_board(dev);

	struct pcl818_private *devpriv = dev->private;

	int err = 0;

	int tmp, divisor1 = 0, divisor2 = 0;

	int tmp;



	/* Step 1 : check if triggers are trivially valid */
@@ -1070,7 +1056,8 @@ static int ai_cmdtest(struct comedi_device *dev, struct comedi_subdevice *s, 
	if (cmd->convert_src == TRIG_TIMER) {

		tmp = cmd->convert_arg;

		i8253_cascade_ns_to_timer(devpriv->i8253_osc_base,

					  &divisor1, &divisor2,

					  &devpriv->divisor1,

					  &devpriv->divisor2,

					  &cmd->convert_arg, cmd->flags);

		if (cmd->convert_arg < board->ns_min)

			cmd->convert_arg = board->ns_min;
@@ -1157,7 +1144,7 @@ static int pcl818_ai_cancel(struct comedi_device *dev, 
#endif

			outb(inb(dev->iobase + PCL818_CONTROL) & 0x73, dev->iobase + PCL818_CONTROL);	/* Stop A/D */

			udelay(1);

			pcl818_start_pacer(dev, false, 0, 0);

			pcl818_start_pacer(dev, false);

			outb(0, dev->iobase + PCL818_AD_LO);

			pcl818_ai_get_sample(dev, s, NULL);

			outb(0, dev->iobase + PCL818_CLRINT);	/* clear INT request */