Commit 1265c22f authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: das1800: don't calc pacer divisors twice 



The analog input async command can use the pacer for the scan_begin_src
or the convert_src. The (*do_cmdtest) calculates the divisors when
validating the cmd argument.

There is no reason to recalc the divisors in the (*do_cmd). Just use the
values from the private data.

For aesthetics, rename the setup_counters() function so it has namespace
associated with the driver. Refactor the function to use the values from
the private data and absorb das1800_set_frequency() to clarify the code.
Refactor the function to use the i8254_set_mode() and i8254_write()
helpers instead of i8254_load(). This allows us to use the I8254_* defines
when setting the mode to clarify the code.

This function will not fail so change the return type to void to simplify
the (*do_cmd) a bit.

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 66fea98e

drivers/staging/comedi/drivers/das1800.c

+16 −60
Original line number Diff line number Diff line
@@ -962,68 +962,29 @@ static int control_c_bits(const struct comedi_cmd *cmd) 
	return control_c;

}



/* loads counters with divisor1, divisor2 from private structure */

static int das1800_set_frequency(struct comedi_device *dev)

{

	struct das1800_private *devpriv = dev->private;

	int err = 0;



	/*  counter 1, mode 2 */

	if (i8254_load(dev->iobase + DAS1800_COUNTER, 0, 1, devpriv->divisor1,

		       2))

		err++;

	/*  counter 2, mode 2 */

	if (i8254_load(dev->iobase + DAS1800_COUNTER, 0, 2, devpriv->divisor2,

		       2))

		err++;

	if (err)

		return -1;



	return 0;

}



/* sets up counters */

static int setup_counters(struct comedi_device *dev,

static void das1800_setup_counters(struct comedi_device *dev,

				   const struct comedi_cmd *cmd)

{

	struct das1800_private *devpriv = dev->private;

	unsigned int period;

	unsigned long timer_base = dev->iobase + DAS1800_COUNTER;



	/* setup cascaded counters for conversion/scan frequency */

	switch (cmd->scan_begin_src) {

	case TRIG_FOLLOW:	/*  not in burst mode */

		if (cmd->convert_src == TRIG_TIMER) {

			/* set conversion frequency */

			period = cmd->convert_arg;

			i8253_cascade_ns_to_timer(I8254_OSC_BASE_5MHZ,

						  &devpriv->divisor1,

						  &devpriv->divisor2,

						  &period, cmd->flags);

			if (das1800_set_frequency(dev) < 0)

				return -1;

		}

		break;

	case TRIG_TIMER:	/*  in burst mode */

		/* set scan frequency */

		period = cmd->scan_begin_arg;

		i8253_cascade_ns_to_timer(I8254_OSC_BASE_5MHZ,

					  &devpriv->divisor1,

					  &devpriv->divisor2,

					  &period, cmd->flags);

		if (das1800_set_frequency(dev) < 0)

			return -1;

		break;

	default:

		break;

	if ((cmd->scan_begin_src == TRIG_FOLLOW ||

	     cmd->scan_begin_src == TRIG_TIMER) &&

	    cmd->convert_src == TRIG_TIMER) {

		i8254_set_mode(timer_base, 0, 1, I8254_MODE2 | I8254_BINARY);

		i8254_set_mode(timer_base, 0, 2, I8254_MODE2 | I8254_BINARY);



		i8254_write(timer_base, 0, 1, devpriv->divisor1);

		i8254_write(timer_base, 0, 2, devpriv->divisor2);

	}



	/* setup counter 0 for 'about triggering' */

	if (cmd->stop_src == TRIG_EXT) {

		/*  load counter 0 in mode 0 */

		i8254_load(dev->iobase + DAS1800_COUNTER, 0, 0, 1, 0);

	}

		i8254_set_mode(timer_base, 0, 0, I8254_MODE0 | I8254_BINARY);



	return 0;

		i8254_write(timer_base, 0, 0, 1);

	}

}



/* utility function that suggests a dma transfer size based on the conversion period 'ns' */
@@ -1136,7 +1097,6 @@ static int das1800_ai_do_cmd(struct comedi_device *dev, 
			     struct comedi_subdevice *s)

{

	struct das1800_private *devpriv = dev->private;

	int ret;

	int control_a, control_c;

	struct comedi_async *async = s->async;

	const struct comedi_cmd *cmd = &async->cmd;
@@ -1167,11 +1127,7 @@ static int das1800_ai_do_cmd(struct comedi_device *dev, 


	/* setup card and start */

	program_chanlist(dev, cmd);

	ret = setup_counters(dev, cmd);

	if (ret < 0) {

		comedi_error(dev, "Error setting up counters");

		return ret;

	}

	das1800_setup_counters(dev, cmd);

	setup_dma(dev, cmd);

	outb(control_c, dev->iobase + DAS1800_CONTROL_C);

	/*  set conversion rate and length for burst mode */

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