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staging: comedi: dmm32at: introduce dmm32_ai_get_sample() 

Introduce a helper function to read the two's complement analog input
sample from the hardware and munge it to the offset binary (unsigned)
format that comedi expects. Use the comedi_offset_munge() helper to
munge the data.

Use the new helper in the analog input (*insn_read) and in the interrupt
handler for the async command.

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 2014-11-11 16:55:19 -07:00 committed by Greg Kroah-Hartman
parent 933fca13a0
commit 0c0eadadcb
1 changed files with 16 additions and 24 deletions
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40
drivers/staging/comedi/drivers/dmm32at.c
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@ -156,6 +156,18 @@ struct dmm32at_private {
unsigned char dio_config;
};
static unsigned int dmm32at_ai_get_sample(struct comedi_device *dev,
struct comedi_subdevice *s)
{
unsigned int val;
val = inb(dev->iobase + DMM32AT_AILSB);
val |= (inb(dev->iobase + DMM32AT_AIMSB) << 8);
/* munge two's complement value to offset binary */
return comedi_offset_munge(s, val);
}
static int dmm32at_ai_status(struct comedi_device *dev,
struct comedi_subdevice *s,
struct comedi_insn *insn,
@ -174,8 +186,6 @@ static int dmm32at_ai_rinsn(struct comedi_device *dev,
struct comedi_insn *insn, unsigned int *data)
{
int n;
unsigned int d;
unsigned short msb, lsb;
unsigned char chan;
int range;
int ret;
@ -210,19 +220,7 @@ static int dmm32at_ai_rinsn(struct comedi_device *dev,
if (ret)
return ret;
/* read data */
lsb = inb(dev->iobase + DMM32AT_AILSB);
msb = inb(dev->iobase + DMM32AT_AIMSB);
/* invert sign bit to make range unsigned, this is an
idiosyncrasy of the diamond board, it return
conversions as a signed value, i.e. -32768 to
32767, flipping the bit and interpreting it as
signed gives you a range of 0 to 65535 which is
used by comedi */
d = ((msb ^ 0x0080) << 8) + lsb;
data[n] = d;
data[n] = dmm32at_ai_get_sample(dev, s);
}
/* return the number of samples read/written */
@ -465,8 +463,7 @@ static irqreturn_t dmm32at_isr(int irq, void *d)
{
struct comedi_device *dev = d;
unsigned char intstat;
unsigned int samp;
unsigned short msb, lsb;
unsigned int val;
int i;
if (!dev->attached) {
@ -481,13 +478,8 @@ static irqreturn_t dmm32at_isr(int irq, void *d)
struct comedi_cmd *cmd = &s->async->cmd;
for (i = 0; i < cmd->chanlist_len; i++) {
/* read data */
lsb = inb(dev->iobase + DMM32AT_AILSB);
msb = inb(dev->iobase + DMM32AT_AIMSB);
/* invert sign bit to make range unsigned */
samp = ((msb ^ 0x0080) << 8) + lsb;
comedi_buf_write_samples(s, &samp, 1);
val = dmm32at_ai_get_sample(dev, s);
comedi_buf_write_samples(s, &val, 1);
}
if (cmd->stop_src == TRIG_COUNT &&