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path: root/drivers/staging/comedi
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Diffstat (limited to 'drivers/staging/comedi')
-rw-r--r--drivers/staging/comedi/drivers/usbdux.c53
1 files changed, 19 insertions, 34 deletions
diff --git a/drivers/staging/comedi/drivers/usbdux.c b/drivers/staging/comedi/drivers/usbdux.c
index 0683c8e..72094d9 100644
--- a/drivers/staging/comedi/drivers/usbdux.c
+++ b/drivers/staging/comedi/drivers/usbdux.c
@@ -1396,45 +1396,30 @@ pwm_start_exit:
return ret;
}
-/* generates the bit pattern for PWM with the optional sign bit */
static int usbdux_pwm_pattern(struct comedi_device *dev,
- struct comedi_subdevice *s, int channel,
- unsigned int value, unsigned int sign)
+ struct comedi_subdevice *s,
+ unsigned int chan,
+ unsigned int value,
+ unsigned int sign)
{
- struct usbdux_private *this_usbduxsub = dev->private;
- int i, szbuf;
- char *p_buf;
- char pwm_mask;
- char sgn_mask;
- char c;
-
- if (!this_usbduxsub)
- return -EFAULT;
+ struct usbdux_private *devpriv = dev->private;
+ char pwm_mask = (1 << chan); /* DIO bit for the PWM data */
+ char sgn_mask = (16 << chan); /* DIO bit for the sign */
+ char *buf = (char *)(devpriv->pwm_urb->transfer_buffer);
+ int szbuf = devpriv->pwm_buf_sz;
+ int i;
- /* this is the DIO bit which carries the PWM data */
- pwm_mask = (1 << channel);
- /* this is the DIO bit which carries the optional direction bit */
- sgn_mask = (16 << channel);
- /* this is the buffer which will be filled with the with bit */
- /* pattern for one period */
- szbuf = this_usbduxsub->pwm_buf_sz;
- p_buf = (char *)(this_usbduxsub->pwm_urb->transfer_buffer);
for (i = 0; i < szbuf; i++) {
- c = *p_buf;
- /* reset bits */
- c = c & (~pwm_mask);
- /* set the bit as long as the index is lower than the value */
+ char c = *buf;
+
+ c &= ~pwm_mask;
if (i < value)
- c = c | pwm_mask;
- /* set the optional sign bit for a relay */
- if (!sign) {
- /* positive value */
- c = c & (~sgn_mask);
- } else {
- /* negative value */
- c = c | sgn_mask;
- }
- *(p_buf++) = c;
+ c |= pwm_mask;
+ if (!sign)
+ c &= ~sgn_mask;
+ else
+ c |= sgn_mask;
+ *buf++ = c;
}
return 1;
}