Commit f5fbccb9 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

staging: comedi: mpc624: introduce mpc624_ai_get_sample() 



Introduce a helper function to read the analog sample from the serially
connected A/D converter and handle the munging of the data.

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 aa0cf376

drivers/staging/comedi/drivers/mpc624.c

+83 −89
Original line number Diff line number Diff line
@@ -115,78 +115,34 @@ static const struct comedi_lrange range_mpc624_bipolar10 = { 
	 }

};



static int mpc624_ai_eoc(struct comedi_device *dev,

			 struct comedi_subdevice *s,

			 struct comedi_insn *insn,

			 unsigned long context)

{

	unsigned char status;



	status = inb(dev->iobase + MPC624_ADC);

	if ((status & MPC624_ADBUSY) == 0)

		return 0;

	return -EBUSY;

}



static int mpc624_ai_insn_read(struct comedi_device *dev,

			       struct comedi_subdevice *s,

			       struct comedi_insn *insn,

			       unsigned int *data)

static unsigned int mpc624_ai_get_sample(struct comedi_device *dev,

					 struct comedi_subdevice *s)

{

	struct mpc624_private *devpriv = dev->private;

	int n, i;

	unsigned long int data_in, data_out;

	int ret;



	/*

	 *  WARNING:

	 *  We always write 0 to GNSWA bit, so the channel range is +-/10.1Vdc

	 */

	outb(insn->chanspec, dev->iobase + MPC624_GNMUXCH);



	for (n = 0; n < insn->n; n++) {

		/*  Trigger the conversion */

		outb(MPC624_ADSCK, dev->iobase + MPC624_ADC);

		udelay(1);

		outb(MPC624_ADCS | MPC624_ADSCK, dev->iobase + MPC624_ADC);

		udelay(1);

		outb(0, dev->iobase + MPC624_ADC);

		udelay(1);



		/*  Wait for the conversion to end */

		ret = comedi_timeout(dev, s, insn, mpc624_ai_eoc, 0);

		if (ret)

			return ret;

	unsigned int data_out = devpriv->ai_speed;

	unsigned int data_in = 0;

	unsigned int bit;

	int i;



	/* Start reading data */

		data_in = 0;

		data_out = devpriv->ai_speed;

	udelay(1);

	for (i = 0; i < 32; i++) {

		/* Set the clock low */

		outb(0, dev->iobase + MPC624_ADC);

		udelay(1);



			if (data_out & BIT(31)) { /*  the next bit is a 1 */

				/*  Set the ADSDI line (send to MPC624) */

				outb(MPC624_ADSDI, dev->iobase + MPC624_ADC);

		/* Set the ADSDI line for the next bit (send to MPC624) */

		bit = (data_out & BIT(31)) ? MPC624_ADSDI : 0;

		outb(bit, dev->iobase + MPC624_ADC);

		udelay(1);

				/*  Set the clock high */

				outb(MPC624_ADSCK | MPC624_ADSDI,

				     dev->iobase + MPC624_ADC);

			} else {	/*  the next bit is a 0 */



				/*  Set the ADSDI line (send to MPC624) */

				outb(0, dev->iobase + MPC624_ADC);

				udelay(1);

		/* Set the clock high */

				outb(MPC624_ADSCK, dev->iobase + MPC624_ADC);

			}

			/*  Read ADSDO on high clock (receive from MPC624) */

		outb(MPC624_ADSCK | bit, dev->iobase + MPC624_ADC);

		udelay(1);



		/* Read ADSDO on high clock (receive from MPC624) */

		data_in <<= 1;

			data_in |=

			    (inb(dev->iobase + MPC624_ADC) & MPC624_ADSDO) >> 4;

		data_in |= (inb(dev->iobase + MPC624_ADC) & MPC624_ADSDO) >> 4;

		udelay(1);



		data_out <<= 1;
@@ -194,57 +150,95 @@ static int mpc624_ai_insn_read(struct comedi_device *dev, 


	/*

	 * Received 32-bit long value consist of:

		 *    31: EOC -

		 *          (End Of Transmission) bit - should be 0

		 *    30: DMY

		 *          (Dummy) bit - should be 0

		 *    29: SIG

		 *          (Sign) bit- 1 if the voltage is positive,

		 *                      0 if negative

		 *    28: MSB

		 *          (Most Significant Bit) - the first bit of

		 *                                   the conversion result

	 *	31: EOC - (End Of Transmission) bit - should be 0

	 *	30: DMY - (Dummy) bit - should be 0

	 *	29: SIG - (Sign) bit - 1 if positive, 0 if negative

	 *	28: MSB - (Most Significant Bit) - the first bit of the

	 *					   conversion result

	 *	....

		 *    05: LSB

		 *          (Least Significant Bit)- the last bit of the

	 *	05: LSB - (Least Significant Bit)- the last bit of the

	 *					   conversion result

		 *    04-00: sub-LSB

		 *          - sub-LSBs are basically noise, but when

		 *            averaged properly, they can increase conversion

		 *            precision up to 29 bits; they can be discarded

		 *            without loss of resolution.

	 *	04-00: sub-LSB - sub-LSBs are basically noise, but when

	 *			 averaged properly, they can increase

	 *			 conversion precision up to 29 bits;

	 *			 they can be discarded without loss of

	 *			 resolution.

	 */



	if (data_in & MPC624_EOC_BIT)

			dev_dbg(dev->class_dev,

				"EOC bit is set (data_in=%lu)!", data_in);

		dev_dbg(dev->class_dev, "EOC bit is set!");

	if (data_in & MPC624_DMY_BIT)

			dev_dbg(dev->class_dev,

				"DMY bit is set (data_in=%lu)!", data_in);

		if (data_in & MPC624_SGN_BIT) {	/* Volatge is positive */

		dev_dbg(dev->class_dev, "DMY bit is set!");



	if (data_in & MPC624_SGN_BIT) {

		/*

		 * Voltage is positive

		 *

		 * comedi operates on unsigned numbers, so mask off EOC

		 * and DMY and don't clear the SGN bit

		 */

			data_in &= 0x3FFFFFFF;

			data[n] = data_in;

		} else { /*  The voltage is negative */

		data_in &= 0x3fffffff;

	} else {

		/*

		 * The voltage is negative

		 *

		 * data_in contains a number in 30-bit two's complement

		 * code and we must deal with it

		 */

		data_in |= MPC624_SGN_BIT;

		data_in = ~data_in;

		data_in += 1;

			data_in &= ~(MPC624_EOC_BIT | MPC624_DMY_BIT);

		/* clear EOC and DMY bits */

		data_in &= ~(MPC624_EOC_BIT | MPC624_DMY_BIT);

		data_in = 0x20000000 - data_in;

			data[n] = data_in;

	}

	return data_in;

}



static int mpc624_ai_eoc(struct comedi_device *dev,

			 struct comedi_subdevice *s,

			 struct comedi_insn *insn,

			 unsigned long context)

{

	unsigned char status;



	status = inb(dev->iobase + MPC624_ADC);

	if ((status & MPC624_ADBUSY) == 0)

		return 0;

	return -EBUSY;

}



static int mpc624_ai_insn_read(struct comedi_device *dev,

			       struct comedi_subdevice *s,

			       struct comedi_insn *insn,

			       unsigned int *data)

{

	int ret;

	int i;



	/*

	 *  WARNING:

	 *  We always write 0 to GNSWA bit, so the channel range is +-/10.1Vdc

	 */

	outb(insn->chanspec, dev->iobase + MPC624_GNMUXCH);



	for (i = 0; i < insn->n; i++) {

		/*  Trigger the conversion */

		outb(MPC624_ADSCK, dev->iobase + MPC624_ADC);

		udelay(1);

		outb(MPC624_ADCS | MPC624_ADSCK, dev->iobase + MPC624_ADC);

		udelay(1);

		outb(0, dev->iobase + MPC624_ADC);

		udelay(1);



		/*  Wait for the conversion to end */

		ret = comedi_timeout(dev, s, insn, mpc624_ai_eoc, 0);

		if (ret)

			return ret;



		data[i] = mpc624_ai_get_sample(dev, s);

	}



	/*  Return the number of samples read/written */

	return n;

	return insn->n;

}



static int mpc624_attach(struct comedi_device *dev, struct comedi_devconfig *it)

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