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Commit c36d44ac authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcl816: tidy up pcl818_check() 



This function probes a number of the boards registers during the
(*attach) to verify that it is actually a PCL-816 compatible board.
For aesthetics, move the function closer to the (*attach).

To better match the pcl818 driver, allocate the private data before
calling pcl816_check().

Refactor the function to return an errno if fails. Change the errno
from -EIO to -ENODEV and remove the unnecessary dev_err() noise.

Make sure the CONTROL register is reset to a known state after the
check. The 0x18 value actually defines an invalid interrupt selection
and sets an undefined bit.

Add a couple comments to clarify the magic values.

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 f51eb4f4

drivers/staging/comedi/drivers/pcl816.c

+31 −27
Original line number Diff line number Diff line
@@ -614,25 +614,6 @@ static int pcl816_ai_cancel(struct comedi_device *dev, 
	return 0;

}



static int pcl816_check(unsigned long iobase)

{

	outb(0x00, iobase + PCL816_MUX);

	udelay(1);

	if (inb(iobase + PCL816_MUX) != 0x00)

		return 1;	/* there isn't card */

	outb(0x55, iobase + PCL816_MUX);

	udelay(1);

	if (inb(iobase + PCL816_MUX) != 0x55)

		return 1;	/* there isn't card */

	outb(0x00, iobase + PCL816_MUX);

	udelay(1);

	outb(0x18, iobase + PCL816_CONTROL);

	udelay(1);

	if (inb(iobase + PCL816_CONTROL) != 0x18)

		return 1;	/* there isn't card */

	return 0;		/*  ok, card exist */

}



static void pcl816_reset(struct comedi_device *dev)

{

	unsigned long timer_base = dev->iobase + PCL816_TIMER_BASE;
@@ -733,6 +714,30 @@ setup_channel_list(struct comedi_device *dev, 
	     dev->iobase + PCL816_MUX);

}



static int pcl816_check(struct comedi_device *dev)

{

	/* the MUX register should return the same value written */

	outb(0x00, dev->iobase + PCL816_MUX);

	if (inb(dev->iobase + PCL816_MUX) != 0x00)

		return -ENODEV;

	outb(0x55, dev->iobase + PCL816_MUX);

	if (inb(dev->iobase + PCL816_MUX) != 0x55)

		return -ENODEV;



	/* reset the MUX register to a known state */

	outb(0x00, dev->iobase + PCL816_MUX);



	/* the CONTROL register should return the same value written */

	outb(0x18, dev->iobase + PCL816_CONTROL);

	if (inb(dev->iobase + PCL816_CONTROL) != 0x18)

		return -ENODEV;



	/* reset the CONTROL register to a known state */

	outb(0x00, dev->iobase + PCL816_CONTROL);



	return 0;

}



static int pcl816_attach(struct comedi_device *dev, struct comedi_devconfig *it)

{

	const struct pcl816_board *board = comedi_board(dev);
@@ -741,18 +746,17 @@ static int pcl816_attach(struct comedi_device *dev, struct comedi_devconfig *it) 
	int ret;

	int i;



	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));

	if (!devpriv)

		return -ENOMEM;



	ret = comedi_request_region(dev, it->options[0], 0x10);

	if (ret)

		return ret;



	if (pcl816_check(dev->iobase)) {

		dev_err(dev->class_dev, "I can't detect board. FAIL!\n");

		return -EIO;

	}



	devpriv = comedi_alloc_devpriv(dev, sizeof(*devpriv));

	if (!devpriv)

		return -ENOMEM;

	ret = pcl816_check(dev);

	if (ret)

		return ret;



	/* we can use IRQ 2-7 for async command support */

	if (it->options[1] >= 2 && it->options[1] <= 7) {