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staging: comedi: rti800: tidy up analog input 'muxgain'

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Refactor the code that determines the 'delay' after setting the muxgain
register to remove the BUG_ON().

Change the private data 'muxgain_bits' to an unsigned char, the muxgain
register is only 8-bits.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2013-04-08 18:20:02 -07:00 • committed by Greg Kroah-Hartman
parent ee35269665
commit 0546f77762
1 changed files with 15 additions and 11 deletions
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26
drivers/staging/comedi/drivers/rti800.c
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@ -156,24 +156,22 @@ struct rti800_private {
bool dac_2comp[2];
const struct comedi_lrange *ao_range_type_list[2];
unsigned int ao_readback[2];
int muxgain_bits;
unsigned char muxgain_bits;
};
#define RTI800_TIMEOUT 100
/* settling delay times in usec for different gains */
static const int gaindelay[] = { 10, 20, 40, 80 };
static int rti800_ai_insn_read(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn, unsigned int *data)
struct comedi_insn *insn,
unsigned int *data)
{
struct rti800_private *devpriv = dev->private;
unsigned int chan = CR_CHAN(insn->chanspec);
unsigned int gain = CR_RANGE(insn->chanspec);
unsigned char muxgain_bits;
int i, t;
int status;
unsigned muxgain_bits;
inb(dev->iobase + RTI800_ADCHI);
outb(0, dev->iobase + RTI800_CLRFLAGS);
@ -182,11 +180,16 @@ static int rti800_ai_insn_read(struct comedi_device *dev,
if (muxgain_bits != devpriv->muxgain_bits) {
devpriv->muxgain_bits = muxgain_bits;
outb(devpriv->muxgain_bits, dev->iobase + RTI800_MUXGAIN);
/* without a delay here, the RTI_OVERRUN bit
* gets set, and you will have an error. */
/*
* Without a delay here, the RTI_OVERRUN bit
* gets set, and you will have an error.
*/
if (insn->n > 0) {
BUG_ON(gain >= ARRAY_SIZE(gaindelay));
udelay(gaindelay[gain]);
int delay = (gain == 0) ? 10 :
(gain == 1) ? 20 :
(gain == 2) ? 40 : 80;
udelay(delay);
}
}
@ -330,7 +333,8 @@ static int rti800_attach(struct comedi_device *dev, struct comedi_devconfig *it)
devpriv->adc_coding = it->options[4];
devpriv->dac_2comp[0] = (it->options[6] == 0);
devpriv->dac_2comp[1] = (it->options[8] == 0);
devpriv->muxgain_bits = -1;
/* invalid, forces the MUXGAIN register to be set when first used */
devpriv->muxgain_bits = 0xff;
ret = comedi_alloc_subdevices(dev, 4);
if (ret)