openkylin
/
linux
mirror of https://gitee.com/openkylin/linux.git
9
0
Fork 0
Code Issues Projects Releases Wiki Activity

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: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2014-02-19 10:11:31 -07:00 committed by Greg Kroah-Hartman
parent f51eb4f4b9
commit c36d44ace6
1 changed files with 31 additions and 27 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

58
drivers/staging/comedi/drivers/pcl816.c
View File

@ -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) {