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@xxxxxxxxxxxxxxxxxxx>
Cc: Ian Abbott <abbotti@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/staging/comedi/drivers/dmm32at.c | 40 +++++++++++++-------------------
1 file changed, 16 insertions(+), 24 deletions(-)
diff --git a/drivers/staging/comedi/drivers/dmm32at.c b/drivers/staging/comedi/drivers/dmm32at.c
index fce3b85..b90f619 100644
--- a/drivers/staging/comedi/drivers/dmm32at.c
+++ b/drivers/staging/comedi/drivers/dmm32at.c
@@ -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 &&
--
2.0.3
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