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author | H Hartley Sweeten <hsweeten@visionengravers.com> | 2013-04-23 01:37:03 (GMT) |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-04-23 17:41:51 (GMT) |
commit | b4780a3afb944765f4b94d79463e570e4472ccb6 (patch) | |
tree | 3774db3ff7da245953406a5e47351a56d120d722 /drivers/staging | |
parent | e245b6d12691c1e178a6a075ac3cd1b7cd0d2e0e (diff) | |
download | linux-fsl-qoriq-b4780a3afb944765f4b94d79463e570e4472ccb6.tar.xz |
staging: comedi: das800: tidy up das800_ai_insn_read()
Introduce a couple helper functions to read the 16-bit analog input
sample and to wait for the analog conversion to complete.
Tidy up the das800_ai_insn_read() function by using the new helpers.
Also, remove the need for 'thisboard' in the function by checking the
subdevice 'maxdata' variable to determine the analog input resolution.
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>
Diffstat (limited to 'drivers/staging')
-rw-r--r-- | drivers/staging/comedi/drivers/das800.c | 63 |
1 files changed, 35 insertions, 28 deletions
diff --git a/drivers/staging/comedi/drivers/das800.c b/drivers/staging/comedi/drivers/das800.c index cc4202e..c30309c 100644 --- a/drivers/staging/comedi/drivers/das800.c +++ b/drivers/staging/comedi/drivers/das800.c @@ -473,6 +473,14 @@ static int das800_ai_do_cmd(struct comedi_device *dev, return 0; } +static unsigned int das800_ai_get_sample(struct comedi_device *dev) +{ + unsigned int lsb = inb(dev->iobase + DAS800_LSB); + unsigned int msb = inb(dev->iobase + DAS800_MSB); + + return (msb << 8) | lsb; +} + static irqreturn_t das800_interrupt(int irq, void *d) { short i; /* loop index */ @@ -570,61 +578,60 @@ static irqreturn_t das800_interrupt(int irq, void *d) return IRQ_HANDLED; } +static int das800_wait_for_conv(struct comedi_device *dev, int timeout) +{ + int i; + + for (i = 0; i < timeout; i++) { + if (!(inb(dev->iobase + DAS800_STATUS) & BUSY)) + return 0; + } + return -ETIME; +} + static int das800_ai_insn_read(struct comedi_device *dev, struct comedi_subdevice *s, struct comedi_insn *insn, unsigned int *data) { - const struct das800_board *thisboard = comedi_board(dev); struct das800_private *devpriv = dev->private; - int i, n; - int chan; - int range; - int lsb, msb; - int timeout = 1000; + unsigned int chan = CR_CHAN(insn->chanspec); + unsigned int range = CR_RANGE(insn->chanspec); unsigned long irq_flags; + unsigned int val; + int ret; + int i; das800_disable(dev); /* set multiplexer */ - chan = CR_CHAN(insn->chanspec); - spin_lock_irqsave(&dev->spinlock, irq_flags); das800_ind_write(dev, chan | devpriv->do_bits, CONTROL1); spin_unlock_irqrestore(&dev->spinlock, irq_flags); /* set gain / range */ - range = CR_RANGE(insn->chanspec); - if (thisboard->resolution == 12 && range) + if (s->maxdata == 0x0fff && range) range += 0x7; range &= 0xf; outb(range, dev->iobase + DAS800_GAIN); udelay(5); - for (n = 0; n < insn->n; n++) { + for (i = 0; i < insn->n; i++) { /* trigger conversion */ outb_p(0, dev->iobase + DAS800_MSB); - for (i = 0; i < timeout; i++) { - if (!(inb(dev->iobase + DAS800_STATUS) & BUSY)) - break; - } - if (i == timeout) { - comedi_error(dev, "timeout"); - return -ETIME; - } - lsb = inb(dev->iobase + DAS800_LSB); - msb = inb(dev->iobase + DAS800_MSB); - if (thisboard->resolution == 12) { - data[n] = (lsb >> 4) & 0xff; - data[n] |= (msb << 4); - } else { - data[n] = (msb << 8) | lsb; - } + ret = das800_wait_for_conv(dev, 1000); + if (ret) + return ret; + + val = das800_ai_get_sample(dev); + if (s->maxdata == 0x0fff) + val >>= 4; /* 12-bit sample */ + data[i] = val & s->maxdata; } - return n; + return insn->n; } static int das800_di_insn_bits(struct comedi_device *dev, |