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Commit 8d9c93b4 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: c6xdigio: add readback of last pwm channel values 



Add and (*insn_read) for the PWM subdevice to allow reading back the
last value written to the channels.

There are only 2 PWM channels and they have a maxdata of 500. Pack
the last values in the subdevice 'state' instead of adding a private
data struct to this driver.

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 a7b31d39

drivers/staging/comedi/drivers/c6xdigio.c

+32 −3
Original line number Diff line number Diff line
@@ -162,13 +162,41 @@ static int c6xdigio_pwm_insn_write(struct comedi_device *dev, 
				   unsigned int *data)

{

	unsigned int chan = CR_CHAN(insn->chanspec);

	unsigned int val = (s->state >> (16 * chan)) & 0xffff;

	int i;



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

		c6xdigio_pwm_write(dev, chan, data[i]);

		/*    devpriv->ao_readback[chan] = data[i]; */

		val = data[i];

		c6xdigio_pwm_write(dev, chan, val);

	}

	return i;



	/*

	 * There are only 2 PWM channels and they have a maxdata of 500.

	 * Instead of allocating private data to save the values in for

	 * readback this driver just packs the values for the two channels

	 * in the s->state.

	 */

	s->state &= (0xffff << (16 * chan));

	s->state |= (val << (16 * chan));



	return insn->n;

}



static int c6xdigio_pwm_insn_read(struct comedi_device *dev,

				  struct comedi_subdevice *s,

				  struct comedi_insn *insn,

				  unsigned int *data)

{

	unsigned int chan = CR_CHAN(insn->chanspec);

	unsigned int val;

	int i;



	val = (s->state >> (16 * chan)) & 0xffff;



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

		data[i] = val;



	return insn->n;

}



static int c6xdigio_encoder_insn_read(struct comedi_device *dev,
@@ -243,6 +271,7 @@ static int c6xdigio_attach(struct comedi_device *dev, 
	s->maxdata	= 500;

	s->range_table	= &range_unknown;

	s->insn_write	= c6xdigio_pwm_insn_write;

	s->insn_read	= c6xdigio_pwm_insn_read;



	s = &dev->subdevices[1];

	/* encoder (counter) subdevice */