diff options
Diffstat (limited to 'drivers/staging/comedi/drivers/das16m1.c')
-rw-r--r-- | drivers/staging/comedi/drivers/das16m1.c | 41 |
1 files changed, 22 insertions, 19 deletions
diff --git a/drivers/staging/comedi/drivers/das16m1.c b/drivers/staging/comedi/drivers/das16m1.c index a18a8878bdb8..3a37373fbb6f 100644 --- a/drivers/staging/comedi/drivers/das16m1.c +++ b/drivers/staging/comedi/drivers/das16m1.c @@ -69,18 +69,18 @@ irq can be omitted, although the cmd interface will not work without it. "cio-das16/m1" - 0 a/d bits 0-3, mux start 12 bit - 1 a/d bits 4-11 unused - 2 status control - 3 di 4 bit do 4 bit - 4 unused clear interrupt - 5 interrupt, pacer - 6 channel/gain queue address - 7 channel/gain queue data - 89ab 8254 - cdef 8254 - 400 8255 - 404-407 8254 + 0 a/d bits 0-3, mux start 12 bit + 1 a/d bits 4-11 unused + 2 status control + 3 di 4 bit do 4 bit + 4 unused clear interrupt + 5 interrupt, pacer + 6 channel/gain queue address + 7 channel/gain queue data + 89ab 8254 + cdef 8254 + 400 8255 + 404-407 8254 */ @@ -411,15 +411,18 @@ static void das16m1_handler(struct comedi_device *dev, unsigned int status) hw_counter = comedi_8254_read(devpriv->counter, 1); /* make sure hardware counter reading is not bogus due to initial value * not having been loaded yet */ - if (devpriv->adc_count == 0 && hw_counter == devpriv->initial_hw_count) { + if (devpriv->adc_count == 0 && + hw_counter == devpriv->initial_hw_count) { num_samples = 0; } else { - /* The calculation of num_samples looks odd, but it uses the following facts. - * 16 bit hardware counter is initialized with value of zero (which really - * means 0x1000). The counter decrements by one on each conversion - * (when the counter decrements from zero it goes to 0xffff). num_samples - * is a 16 bit variable, so it will roll over in a similar fashion to the - * hardware counter. Work it out, and this is what you get. */ + /* The calculation of num_samples looks odd, but it uses the + * following facts. 16 bit hardware counter is initialized with + * value of zero (which really means 0x1000). The counter + * decrements by one on each conversion (when the counter + * decrements from zero it goes to 0xffff). num_samples is a + * 16 bit variable, so it will roll over in a similar fashion + * to the hardware counter. Work it out, and this is what you + * get. */ num_samples = -hw_counter - devpriv->adc_count; } /* check if we only need some of the points */ |