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Commit f0dc084e authored by H Hartley Sweeten's avatar H Hartley Sweeten Committed by Greg Kroah-Hartman
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staging: comedi: pcmda12: cleanup pcmda12_ao_insn_write() 



Only the last value needs to be saved for readback.

Remove the LSB and MSB macros.

(*insn_write) functions should return an errno or the number of
samples actually read. Change the final return to insn->n to
make this clear.

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 cac10bf9

drivers/staging/comedi/drivers/pcmda12.c

+12 −20
Original line number Diff line number Diff line
@@ -51,8 +51,6 @@ Configuration Options: 


#define CHANS 8

#define IOSIZE 16

#define LSB(x) ((unsigned char)((x) & 0xff))

#define MSB(x) ((unsigned char)((((unsigned short)(x))>>8) & 0xff))

#define LSB_PORT(chan) (dev->iobase + (chan)*2)

#define MSB_PORT(chan) (LSB_PORT(chan)+1)
@@ -90,31 +88,25 @@ static int pcmda12_ao_insn_write(struct comedi_device *dev, 
				 unsigned int *data)

{

	struct pcmda12_private *devpriv = dev->private;

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

	unsigned int val = devpriv->ao_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. */

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

		val = data[i];

		outb(val & 0xff, LSB_PORT(chan));

		outb((val >> 8) & 0xff, MSB_PORT(chan));



/*      /\* do this as one instruction?? *\/ */

/*      outw(data[i], LSB_PORT(chan)); */



		/* Need to do this as two instructions due to 8-bit bus?? */

		/*  first, load the low byte */

		outb(LSB(data[i]), LSB_PORT(chan));

		/*  next, write the high byte */

		outb(MSB(data[i]), MSB_PORT(chan));



		/* save shadow register */

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



		/*

		 * Initiate transfer if not in simultaneaous xfer

		 * mode by reading one of the AO registers.

		 */

		if (!devpriv->simultaneous_xfer_mode)

			inb(LSB_PORT(chan));

	}

	devpriv->ao_readback[chan] = val;



	/* return the number of samples written */

	return i;

	return insn->n;

}



static int pcmda12_ao_insn_read(struct comedi_device *dev,