From 0c0eadadcbe6ed9596568696f9c5b157707a7c8f Mon Sep 17 00:00:00 2001 From: H Hartley Sweeten Date: Tue, 11 Nov 2014 16:55:19 -0700 Subject: [PATCH] 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 Reviewed-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- 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 fce3b855fdbd..b90f61965396 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 && -- 2.34.1