data.c

来自「最新rtlinux内核源码」· C语言 代码 · 共 89 行

/*
    kcomedilib/data.c
    implements comedi_data_*() functions

    COMEDI - Linux Control and Measurement Device Interface
    Copyright (C) 2000 David A. Schleef <[e-mail]>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

*/

#include <linux/comedi.h>
#include <linux/comedilib.h>
#include <linux/comedidev.h> /* for comedi_udelay() */

#include <linux/string.h>


int comedi_data_write(comedi_t *dev,unsigned int subdev,unsigned int chan,
	unsigned int range,unsigned int aref,lsampl_t data)
{
	comedi_insn insn;

	memset(&insn,0,sizeof(insn));
	insn.insn = INSN_WRITE;
	insn.n = 1;
	insn.data = &data;
	insn.subdev = subdev;
	insn.chanspec = CR_PACK(chan,range,aref);

	return comedi_do_insn(dev,&insn);
}

int comedi_data_read(comedi_t *dev,unsigned int subdev,unsigned int chan,
	unsigned int range,unsigned int aref,lsampl_t *data)
{
	comedi_insn insn;

	memset(&insn,0,sizeof(insn));
	insn.insn = INSN_READ;
	insn.n = 1;
	insn.data = data;
	insn.subdev = subdev;
	insn.chanspec = CR_PACK(chan,range,aref);

	return comedi_do_insn(dev,&insn);
}

int comedi_data_read_hint(comedi_t *dev,unsigned int subdev,unsigned int chan,
	unsigned int range,unsigned int aref)
{
	comedi_insn insn;
	lsampl_t dummy_data;
	
	memset(&insn,0,sizeof(insn));
	insn.insn = INSN_READ;
	insn.n = 0;
	insn.data = &dummy_data;
	insn.subdev = subdev;
	insn.chanspec = CR_PACK(chan,range,aref);

	return comedi_do_insn(dev,&insn);
}

int comedi_data_read_delayed(comedi_t *dev,unsigned int subdev,unsigned int chan,
	unsigned int range,unsigned int aref,lsampl_t *data, unsigned int nano_sec)
{
	int retval;

	retval = comedi_data_read_hint( dev, subdev, chan, range, aref );
	if( retval < 0 ) return retval;

	comedi_udelay( ( nano_sec + 999 ) / 1000 );

	return comedi_data_read( dev, subdev, chan, range, aref, data );
}