Commit 0c0eadad authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

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: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: default avatarIan Abbott <abbotti@mev.co.uk>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 933fca13

drivers/staging/comedi/drivers/dmm32at.c

+16 −24
Original line number Diff line number Diff line
@@ -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 &&