range.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * comedi/range.c
 * comedi routines for voltage ranges
 *
 * COMEDI - Linux Control and Measurement Device Interface
 * Copyright (C) 1997-8 David A. Schleef <[email protected]>
 */

#include <linux/uaccess.h>
#include <linux/comedi/comedidev.h>
#include "comedi_internal.h"

const struct comedi_lrange range_bipolar10 = { 1, {BIP_RANGE(10)} };
EXPORT_SYMBOL_GPL(range_bipolar10);
const struct comedi_lrange range_bipolar5 = { 1, {BIP_RANGE(5)} };
EXPORT_SYMBOL_GPL(range_bipolar5);
const struct comedi_lrange range_bipolar2_5 = { 1, {BIP_RANGE(2.5)} };
EXPORT_SYMBOL_GPL(range_bipolar2_5);
const struct comedi_lrange range_unipolar10 = { 1, {UNI_RANGE(10)} };
EXPORT_SYMBOL_GPL(range_unipolar10);
const struct comedi_lrange range_unipolar5 = { 1, {UNI_RANGE(5)} };
EXPORT_SYMBOL_GPL(range_unipolar5);
const struct comedi_lrange range_unipolar2_5 = { 1, {UNI_RANGE(2.5)} };
EXPORT_SYMBOL_GPL(range_unipolar2_5);
const struct comedi_lrange range_0_20mA = { 1, {RANGE_mA(0, 20)} };
EXPORT_SYMBOL_GPL(range_0_20mA);
const struct comedi_lrange range_4_20mA = { 1, {RANGE_mA(4, 20)} };
EXPORT_SYMBOL_GPL(range_4_20mA);
const struct comedi_lrange range_0_32mA = { 1, {RANGE_mA(0, 32)} };
EXPORT_SYMBOL_GPL(range_0_32mA);
const struct comedi_lrange range_unknown = { 1, {{0, 1000000, UNIT_none} } };
EXPORT_SYMBOL_GPL(range_unknown);

/*
 * COMEDI_RANGEINFO ioctl
 * range information
 *
 * arg:
 *	pointer to comedi_rangeinfo structure
 *
 * reads:
 *	comedi_rangeinfo structure
 *
 * writes:
 *	array of comedi_krange structures to rangeinfo->range_ptr pointer
 */
int do_rangeinfo_ioctl(struct comedi_device *dev,
		       struct comedi_rangeinfo *it)
{
	int subd, chan;
	const struct comedi_lrange *lr;
	struct comedi_subdevice *s;

	subd = (it->range_type >> 24) & 0xf;
	chan = (it->range_type >> 16) & 0xff;

	if (!dev->attached)
		return -EINVAL;
	if (subd >= dev->n_subdevices)
		return -EINVAL;
	s = &dev->subdevices[subd];
	if (s->range_table) {
		lr = s->range_table;
	} else if (s->range_table_list) {
		if (chan >= s->n_chan)
			return -EINVAL;
		lr = s->range_table_list[chan];
	} else {
		return -EINVAL;
	}

	if (RANGE_LENGTH(it->range_type) != lr->length) {
		dev_dbg(dev->class_dev,
			"wrong length %d should be %d (0x%08x)\n",
			RANGE_LENGTH(it->range_type),
			lr->length, it->range_type);
		return -EINVAL;
	}

	if (copy_to_user(it->range_ptr, lr->range,
			 sizeof(struct comedi_krange) * lr->length))
		return -EFAULT;

	return 0;
}

/**
 * comedi_check_chanlist() - Validate each element in a chanlist.
 * @s: comedi_subdevice struct
 * @n: number of elements in the chanlist
 * @chanlist: the chanlist to validate
 *
 * Each element consists of a channel number, a range index, an analog
 * reference type and some flags, all packed into an unsigned int.
 *
 * This checks that the channel number and range index are supported by
 * the comedi subdevice.  It does not check whether the analog reference
 * type and the flags are supported.  Drivers that care should check those
 * themselves.
 *
 * Return: %0 if all @chanlist elements are valid (success),
 *         %-EINVAL if one or more elements are invalid.
 */
int comedi_check_chanlist(struct comedi_subdevice *s, int n,
			  unsigned int *chanlist)
{
	struct comedi_device *dev = s->device;
	unsigned int chanspec;
	int chan, range_len, i;

	for (i = 0; i < n; i++) {
		chanspec = chanlist[i];
		chan = CR_CHAN(chanspec);
		if (s->range_table)
			range_len = s->range_table->length;
		else if (s->range_table_list && chan < s->n_chan)
			range_len = s->range_table_list[chan]->length;
		else
			range_len = 0;
		if (chan >= s->n_chan ||
		    CR_RANGE(chanspec) >= range_len) {
			dev_warn(dev->class_dev,
				 "bad chanlist[%d]=0x%08x chan=%d range length=%d\n",
				 i, chanspec, chan, range_len);
			return -EINVAL;
		}
	}
	return 0;
}
EXPORT_SYMBOL_GPL(comedi_check_chanlist);