Commit b1598f94 authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
Browse files

staging: comedi: skel: use comedi_subdevice 'readback' 



Use the new comedi_subdevice 'readback' member and the core provided
(*insn_read) for the readback of the analog output subdevice channels.

For aesthetics, rename the (*insn_write) function and tidy it up a bit.

Add a comment about the 'readback' member.

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 d2762066

drivers/staging/comedi/drivers/skel.c

+35 −31
Original line number Diff line number Diff line
@@ -114,11 +114,7 @@ static const struct skel_board skel_boards[] = { 
   feel free to suggest moving the variable to the struct comedi_device struct.

 */

struct skel_private {



	int data;



	/* Used for AO readback */

	unsigned int ao_readback[2];

};



/* This function doesn't require a particular form, this is just
@@ -305,38 +301,29 @@ static int skel_ai_cmdtest(struct comedi_device *dev, 
	return 0;

}



static int skel_ao_winsn(struct comedi_device *dev, struct comedi_subdevice *s,

			 struct comedi_insn *insn, unsigned int *data)

static int skel_ao_insn_write(struct comedi_device *dev,

			      struct comedi_subdevice *s,

			      struct comedi_insn *insn,

			      unsigned int *data)

{

	struct skel_private *devpriv = dev->private;

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

	unsigned int val = s->readback[chan];

	int i;

	int chan = CR_CHAN(insn->chanspec);



	/* Writing a list of values to an AO channel is probably not

	 * very useful, but that's how the interface is defined. */

	/*

	 * Writing a list of values to an AO channel is probably not

	 * very useful, but that's how the interface is defined.

	 */

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

		val = data[i];



		/* a typical programming sequence */

		/* outw(data[i], dev->iobase + SKEL_DA0 + chan); */

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

	}

	/* save the last value for readback */

	s->readback[chan] = val;



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

	return i;

}



/* AO subdevices should have a read insn as well as a write insn.

 * Usually this means copying a value stored in devpriv. */

static int skel_ao_rinsn(struct comedi_device *dev, struct comedi_subdevice *s,

			 struct comedi_insn *insn, unsigned int *data)

{

	struct skel_private *devpriv = dev->private;

	int i;

	int chan = CR_CHAN(insn->chanspec);



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

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



	return i;

	return insn->n;

}



/*
@@ -446,8 +433,25 @@ static int skel_common_attach(struct comedi_device *dev) 
	s->n_chan = 1;

	s->maxdata = 0xffff;

	s->range_table = &range_bipolar5;

	s->insn_write = skel_ao_winsn;

	s->insn_read = skel_ao_rinsn;

	s->insn_write = skel_ao_insn_write;

	/*

	 * AO subdevices should have a (*insn_read) as well. Usually the

	 * hardware is not readable so the channel values need to be stored

	 * somewhere for readback. The comedi_subdevice has a 'readback'

	 * member to handle this.

	 *

	 * The comedi_readback_insn_read() function provides the (*insn_read)

	 * to return the 'readback' values.

	 *

	 * The comedi_alloc_subdev_readback() function will allocate memory

	 * for s->n_chan 'readback' values. The core will kfree the memory

	 * when the driver is detached.

	 */

	s->insn_read = comedi_readback_insn_read;



	ret = comedi_alloc_subdev_readback(s);

	if (ret)

		return ret;



	s = &dev->subdevices[2];

	/* digital i/o subdevice */