Commit 8fbf1f45 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcl711: no need to calc the timer values twice 



The comedi core always calls the (*do_cmdtest) function to validate
a command before it calls the (*do_cmd) function.

Since the (*do_cmdtest) has already calculated the timer values in
order to validate the cmd->scan_begin_arg there is no reason to
recalc the values in the (*do_cmd).

This also fixes a bug in the driver. The (*do_cmdtest) was using a
time base value of 100 and but the (*do_cmd) was using a time base
of 500. These result in different timer values. The functions used
to calculate the values are actually the same due to a #define in
the 8253.h header.

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 326d875d

drivers/staging/comedi/drivers/pcl711.c

+8 −15
Original line number Diff line number Diff line
@@ -331,7 +331,6 @@ static int pcl711_ai_cmdtest(struct comedi_device *dev, 
		err |= cfc_check_trigger_arg_is(&cmd->scan_begin_arg, 0);

	} else {

#define MAX_SPEED 1000

#define TIMER_BASE 100

		err |= cfc_check_trigger_arg_min(&cmd->scan_begin_arg,

						 MAX_SPEED);

	}
@@ -352,7 +351,7 @@ static int pcl711_ai_cmdtest(struct comedi_device *dev, 


	if (cmd->scan_begin_src == TRIG_TIMER) {

		tmp = cmd->scan_begin_arg;

		i8253_cascade_ns_to_timer_2div(TIMER_BASE,

		i8253_cascade_ns_to_timer(500,		/* 2 Mhz */

					  &devpriv->divisor1,

					  &devpriv->divisor2,

					  &cmd->scan_begin_arg,
@@ -369,22 +368,16 @@ static int pcl711_ai_cmdtest(struct comedi_device *dev, 


static int pcl711_ai_cmd(struct comedi_device *dev, struct comedi_subdevice *s)

{

	int timer1, timer2;

	struct pcl711_private *devpriv = dev->private;

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



	pcl711_set_changain(dev, s, cmd->chanlist[0]);



	if (cmd->scan_begin_src == TRIG_TIMER) {

		timer1 = timer2 = 0;

		i8253_cascade_ns_to_timer(500,		/* 2 Mhz */

					  &timer1, &timer2,

					  &cmd->scan_begin_arg,

					  TRIG_ROUND_NEAREST);



		i8254_load(dev->iobase + PCL711_TIMER_BASE, 0,

			   1, timer1, I8254_MODE2 | I8254_BINARY);

			   1, devpriv->divisor1, I8254_MODE2 | I8254_BINARY);

		i8254_load(dev->iobase + PCL711_TIMER_BASE, 0,

			   2, timer2, I8254_MODE2 | I8254_BINARY);

			   2, devpriv->divisor2, I8254_MODE2 | I8254_BINARY);



		/* clear pending interrupts (just in case) */

		outb(0, dev->iobase + PCL711_CLRINTR);