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Commit 532a411e authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: cb_pcimdas: fix analog input channel configuration 



The hardware uses a switch on the board to set the number of analog
input channels to either 16 single-ended or 8 differential channels.
Currently the switch setting is checked for every (*insn_read) operation
to validate the channel number.

Check the switch setting during the driver attach and initialize the
subdevice accordingly. This allows the core to handle the validation.

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 bca3a6d1

drivers/staging/comedi/drivers/cb_pcimdas.c

+22 −12
Original line number Diff line number Diff line
@@ -109,20 +109,10 @@ static int cb_pcimdas_ai_rinsn(struct comedi_device *dev, 
	unsigned int d;

	int chan = CR_CHAN(insn->chanspec);

	unsigned short chanlims;

	int maxchans;

	int ret;



	/*  only support sw initiated reads from a single channel */



	/* check channel number */

	if ((inb(devpriv->BADR3 + 2) & 0x20) == 0)	/* differential mode */

		maxchans = s->n_chan / 2;

	else

		maxchans = s->n_chan;



	if (chan > (maxchans - 1))

		return -ETIMEDOUT;	/* *** Wrong error code. Fixme. */



	/* configure for sw initiated read */

	d = inb(devpriv->BADR3 + 5);

	if ((d & 0x03) > 0) {	/* only reset if needed. */
@@ -181,6 +171,20 @@ static int cb_pcimdas_ao_insn_write(struct comedi_device *dev, 
	return insn->n;

}



static bool cb_pcimdas_is_ai_se(struct comedi_device *dev)

{

	struct cb_pcimdas_private *devpriv = dev->private;

	unsigned int status;



	/*

	 * The number of Analog Input channels is set with the

	 * Analog Input Mode Switch on the board. The board can

	 * have 16 single-ended or 8 differential channels.

	 */

	status = inb(devpriv->BADR3 + 2);

	return status & 0x20;

}



static int cb_pcimdas_auto_attach(struct comedi_device *dev,

					    unsigned long context_unused)

{
@@ -209,8 +213,14 @@ static int cb_pcimdas_auto_attach(struct comedi_device *dev, 
	/* dev->read_subdev=s; */

	/*  analog input subdevice */

	s->type = COMEDI_SUBD_AI;

	s->subdev_flags = SDF_READABLE | SDF_GROUND;

	s->subdev_flags	= SDF_READABLE;

	if (cb_pcimdas_is_ai_se(dev)) {

		s->subdev_flags	|= SDF_GROUND;

		s->n_chan	= 16;

	} else {

		s->subdev_flags	|= SDF_DIFF;

		s->n_chan	= 8;

	}

	s->maxdata = 0xffff;

	s->range_table = &range_unknown;

	s->len_chanlist = 1;	/*  This is the maximum chanlist length that */