/*
 * comedi_fc.h
 * This is a place for code driver writers wish to share between
 * two or more drivers. These functions are meant to be used only
 * by drivers, they are NOT part of the kcomedilib API!
 *
 * Author: Frank Mori Hess <fmhess@users.sourceforge.net>
 * Copyright (C) 2002 Frank Mori Hess
 *
 * 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.
 */

#ifndef _COMEDI_FC_H
#define _COMEDI_FC_H

#include "../comedidev.h"

/**
 * cfc_check_trigger_src() - trivially validate a comedi_cmd trigger source
 * @src: pointer to the trigger source to validate
 * @flags: bitmask of valid TRIG_* for the trigger
 *
 * This is used in "step 1" of the do_cmdtest functions of comedi drivers
 * to vaildate the comedi_cmd triggers. The mask of the @src against the
 * @flags allows the userspace comedilib to pass all the comedi_cmd
 * triggers as TRIG_ANY and get back a bitmask of the valid trigger sources.
 */
static inline int cfc_check_trigger_src(unsigned int *src, unsigned int flags)
{
	unsigned int orig_src = *src;

	*src = orig_src & flags;
	if (*src == TRIG_INVALID || *src != orig_src)
		return -EINVAL;
	return 0;
}

/**
 * cfc_check_trigger_is_unique() - make sure a trigger source is unique
 * @src: the trigger source to check
 */
static inline int cfc_check_trigger_is_unique(unsigned int src)
{
	/* this test is true if more than one _src bit is set */
	if ((src & (src - 1)) != 0)
		return -EINVAL;
	return 0;
}

/**
 * cfc_check_trigger_arg_is() - trivially validate a trigger argument
 * @arg: pointer to the trigger arg to validate
 * @val: the value the argument should be
 */
static inline int cfc_check_trigger_arg_is(unsigned int *arg, unsigned int val)
{
	if (*arg != val) {
		*arg = val;
		return -EINVAL;
	}
	return 0;
}

/**
 * cfc_check_trigger_arg_min() - trivially validate a trigger argument
 * @arg: pointer to the trigger arg to validate
 * @val: the minimum value the argument should be
 */
static inline int cfc_check_trigger_arg_min(unsigned int *arg,
					    unsigned int val)
{
	if (*arg < val) {
		*arg = val;
		return -EINVAL;
	}
	return 0;
}

/**
 * cfc_check_trigger_arg_max() - trivially validate a trigger argument
 * @arg: pointer to the trigger arg to validate
 * @val: the maximum value the argument should be
 */
static inline int cfc_check_trigger_arg_max(unsigned int *arg,
					    unsigned int val)
{
	if (*arg > val) {
		*arg = val;
		return -EINVAL;
	}
	return 0;
}

#endif /* _COMEDI_FC_H */