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1/*
2    kcomedilib/kcomedilib.c
3    a comedlib interface for kernel modules
4
5    COMEDI - Linux Control and Measurement Device Interface
6    Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
7
8    This program is free software; you can redistribute it and/or modify
9    it under the terms of the GNU General Public License as published by
10    the Free Software Foundation; either version 2 of the License, or
11    (at your option) any later version.
12
13    This program is distributed in the hope that it will be useful,
14    but WITHOUT ANY WARRANTY; without even the implied warranty of
15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
16    GNU General Public License for more details.
17*/
18
19#include <linux/module.h>
20
21#include <linux/errno.h>
22#include <linux/kernel.h>
23#include <linux/sched.h>
24#include <linux/fcntl.h>
25#include <linux/mm.h>
26#include <linux/io.h>
27
28#include "../comedi.h"
29#include "../comedilib.h"
30#include "../comedidev.h"
31
32MODULE_AUTHOR("David Schleef <ds@schleef.org>");
33MODULE_DESCRIPTION("Comedi kernel library");
34MODULE_LICENSE("GPL");
35
36struct comedi_device *comedi_open(const char *filename)
37{
38	struct comedi_device *dev, *retval = NULL;
39	unsigned int minor;
40
41	if (strncmp(filename, "/dev/comedi", 11) != 0)
42		return NULL;
43
44	if (kstrtouint(filename + 11, 0, &minor))
45		return NULL;
46
47	if (minor >= COMEDI_NUM_BOARD_MINORS)
48		return NULL;
49
50	dev = comedi_dev_get_from_minor(minor);
51	if (!dev)
52		return NULL;
53
54	down_read(&dev->attach_lock);
55	if (dev->attached)
56		retval = dev;
57	else
58		retval = NULL;
59	up_read(&dev->attach_lock);
60
61	if (retval == NULL)
62		comedi_dev_put(dev);
63
64	return retval;
65}
66EXPORT_SYMBOL_GPL(comedi_open);
67
68int comedi_close(struct comedi_device *dev)
69{
70	comedi_dev_put(dev);
71	return 0;
72}
73EXPORT_SYMBOL_GPL(comedi_close);
74
75static int comedi_do_insn(struct comedi_device *dev,
76			  struct comedi_insn *insn,
77			  unsigned int *data)
78{
79	struct comedi_subdevice *s;
80	int ret;
81
82	mutex_lock(&dev->mutex);
83
84	if (!dev->attached) {
85		ret = -EINVAL;
86		goto error;
87	}
88
89	/* a subdevice instruction */
90	if (insn->subdev >= dev->n_subdevices) {
91		ret = -EINVAL;
92		goto error;
93	}
94	s = &dev->subdevices[insn->subdev];
95
96	if (s->type == COMEDI_SUBD_UNUSED) {
97		dev_err(dev->class_dev,
98			"%d not useable subdevice\n", insn->subdev);
99		ret = -EIO;
100		goto error;
101	}
102
103	/* XXX check lock */
104
105	ret = comedi_check_chanlist(s, 1, &insn->chanspec);
106	if (ret < 0) {
107		dev_err(dev->class_dev, "bad chanspec\n");
108		ret = -EINVAL;
109		goto error;
110	}
111
112	if (s->busy) {
113		ret = -EBUSY;
114		goto error;
115	}
116	s->busy = dev;
117
118	switch (insn->insn) {
119	case INSN_BITS:
120		ret = s->insn_bits(dev, s, insn, data);
121		break;
122	case INSN_CONFIG:
123		/* XXX should check instruction length */
124		ret = s->insn_config(dev, s, insn, data);
125		break;
126	default:
127		ret = -EINVAL;
128		break;
129	}
130
131	s->busy = NULL;
132error:
133
134	mutex_unlock(&dev->mutex);
135	return ret;
136}
137
138int comedi_dio_get_config(struct comedi_device *dev, unsigned int subdev,
139			  unsigned int chan, unsigned int *io)
140{
141	struct comedi_insn insn;
142	unsigned int data[2];
143	int ret;
144
145	memset(&insn, 0, sizeof(insn));
146	insn.insn = INSN_CONFIG;
147	insn.n = 2;
148	insn.subdev = subdev;
149	insn.chanspec = CR_PACK(chan, 0, 0);
150	data[0] = INSN_CONFIG_DIO_QUERY;
151	data[1] = 0;
152	ret = comedi_do_insn(dev, &insn, data);
153	if (ret >= 0)
154		*io = data[1];
155	return ret;
156}
157EXPORT_SYMBOL_GPL(comedi_dio_get_config);
158
159int comedi_dio_config(struct comedi_device *dev, unsigned int subdev,
160		      unsigned int chan, unsigned int io)
161{
162	struct comedi_insn insn;
163
164	memset(&insn, 0, sizeof(insn));
165	insn.insn = INSN_CONFIG;
166	insn.n = 1;
167	insn.subdev = subdev;
168	insn.chanspec = CR_PACK(chan, 0, 0);
169
170	return comedi_do_insn(dev, &insn, &io);
171}
172EXPORT_SYMBOL_GPL(comedi_dio_config);
173
174int comedi_dio_bitfield2(struct comedi_device *dev, unsigned int subdev,
175			 unsigned int mask, unsigned int *bits,
176			 unsigned int base_channel)
177{
178	struct comedi_insn insn;
179	unsigned int data[2];
180	unsigned int n_chan;
181	unsigned int shift;
182	int ret;
183
184	base_channel = CR_CHAN(base_channel);
185	n_chan = comedi_get_n_channels(dev, subdev);
186	if (base_channel >= n_chan)
187		return -EINVAL;
188
189	memset(&insn, 0, sizeof(insn));
190	insn.insn = INSN_BITS;
191	insn.chanspec = base_channel;
192	insn.n = 2;
193	insn.subdev = subdev;
194
195	data[0] = mask;
196	data[1] = *bits;
197
198	/*
199	 * Most drivers ignore the base channel in insn->chanspec.
200	 * Fix this here if the subdevice has <= 32 channels.
201	 */
202	if (n_chan <= 32) {
203		shift = base_channel;
204		if (shift) {
205			insn.chanspec = 0;
206			data[0] <<= shift;
207			data[1] <<= shift;
208		}
209	} else {
210		shift = 0;
211	}
212
213	ret = comedi_do_insn(dev, &insn, data);
214	*bits = data[1] >> shift;
215	return ret;
216}
217EXPORT_SYMBOL_GPL(comedi_dio_bitfield2);
218
219int comedi_find_subdevice_by_type(struct comedi_device *dev, int type,
220				  unsigned int subd)
221{
222	struct comedi_subdevice *s;
223	int ret = -ENODEV;
224
225	down_read(&dev->attach_lock);
226	if (dev->attached)
227		for (; subd < dev->n_subdevices; subd++) {
228			s = &dev->subdevices[subd];
229			if (s->type == type) {
230				ret = subd;
231				break;
232			}
233		}
234	up_read(&dev->attach_lock);
235	return ret;
236}
237EXPORT_SYMBOL_GPL(comedi_find_subdevice_by_type);
238
239int comedi_get_n_channels(struct comedi_device *dev, unsigned int subdevice)
240{
241	int n;
242
243	down_read(&dev->attach_lock);
244	if (!dev->attached || subdevice >= dev->n_subdevices)
245		n = 0;
246	else
247		n = dev->subdevices[subdevice].n_chan;
248	up_read(&dev->attach_lock);
249
250	return n;
251}
252EXPORT_SYMBOL_GPL(comedi_get_n_channels);
253