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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * kcomedilib/kcomedilib.c
4 * a comedlib interface for kernel modules
5 *
6 * COMEDI - Linux Control and Measurement Device Interface
7 * Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
8 */
9
10#include <linux/module.h>
11
12#include <linux/errno.h>
13#include <linux/kernel.h>
14#include <linux/sched.h>
15#include <linux/fcntl.h>
16#include <linux/mm.h>
17#include <linux/io.h>
18
19#include <linux/comedi.h>
20#include <linux/comedi/comedidev.h>
21#include <linux/comedi/comedilib.h>
22
23MODULE_AUTHOR("David Schleef <ds@schleef.org>");
24MODULE_DESCRIPTION("Comedi kernel library");
25MODULE_LICENSE("GPL");
26
27struct comedi_device *comedi_open(const char *filename)
28{
29 struct comedi_device *dev, *retval = NULL;
30 unsigned int minor;
31
32 if (strncmp(filename, "/dev/comedi", 11) != 0)
33 return NULL;
34
35 if (kstrtouint(filename + 11, 0, &minor))
36 return NULL;
37
38 if (minor >= COMEDI_NUM_BOARD_MINORS)
39 return NULL;
40
41 dev = comedi_dev_get_from_minor(minor);
42 if (!dev)
43 return NULL;
44
45 down_read(&dev->attach_lock);
46 if (dev->attached)
47 retval = dev;
48 else
49 retval = NULL;
50 up_read(&dev->attach_lock);
51
52 if (!retval)
53 comedi_dev_put(dev);
54
55 return retval;
56}
57EXPORT_SYMBOL_GPL(comedi_open);
58
59int comedi_close(struct comedi_device *dev)
60{
61 comedi_dev_put(dev);
62 return 0;
63}
64EXPORT_SYMBOL_GPL(comedi_close);
65
66static int comedi_do_insn(struct comedi_device *dev,
67 struct comedi_insn *insn,
68 unsigned int *data)
69{
70 struct comedi_subdevice *s;
71 int ret;
72
73 mutex_lock(&dev->mutex);
74
75 if (!dev->attached) {
76 ret = -EINVAL;
77 goto error;
78 }
79
80 /* a subdevice instruction */
81 if (insn->subdev >= dev->n_subdevices) {
82 ret = -EINVAL;
83 goto error;
84 }
85 s = &dev->subdevices[insn->subdev];
86
87 if (s->type == COMEDI_SUBD_UNUSED) {
88 dev_err(dev->class_dev,
89 "%d not usable subdevice\n", insn->subdev);
90 ret = -EIO;
91 goto error;
92 }
93
94 /* XXX check lock */
95
96 ret = comedi_check_chanlist(s, 1, &insn->chanspec);
97 if (ret < 0) {
98 dev_err(dev->class_dev, "bad chanspec\n");
99 ret = -EINVAL;
100 goto error;
101 }
102
103 if (s->busy) {
104 ret = -EBUSY;
105 goto error;
106 }
107 s->busy = dev;
108
109 switch (insn->insn) {
110 case INSN_BITS:
111 ret = s->insn_bits(dev, s, insn, data);
112 break;
113 case INSN_CONFIG:
114 /* XXX should check instruction length */
115 ret = s->insn_config(dev, s, insn, data);
116 break;
117 default:
118 ret = -EINVAL;
119 break;
120 }
121
122 s->busy = NULL;
123error:
124
125 mutex_unlock(&dev->mutex);
126 return ret;
127}
128
129int comedi_dio_get_config(struct comedi_device *dev, unsigned int subdev,
130 unsigned int chan, unsigned int *io)
131{
132 struct comedi_insn insn;
133 unsigned int data[2];
134 int ret;
135
136 memset(&insn, 0, sizeof(insn));
137 insn.insn = INSN_CONFIG;
138 insn.n = 2;
139 insn.subdev = subdev;
140 insn.chanspec = CR_PACK(chan, 0, 0);
141 data[0] = INSN_CONFIG_DIO_QUERY;
142 data[1] = 0;
143 ret = comedi_do_insn(dev, &insn, data);
144 if (ret >= 0)
145 *io = data[1];
146 return ret;
147}
148EXPORT_SYMBOL_GPL(comedi_dio_get_config);
149
150int comedi_dio_config(struct comedi_device *dev, unsigned int subdev,
151 unsigned int chan, unsigned int io)
152{
153 struct comedi_insn insn;
154
155 memset(&insn, 0, sizeof(insn));
156 insn.insn = INSN_CONFIG;
157 insn.n = 1;
158 insn.subdev = subdev;
159 insn.chanspec = CR_PACK(chan, 0, 0);
160
161 return comedi_do_insn(dev, &insn, &io);
162}
163EXPORT_SYMBOL_GPL(comedi_dio_config);
164
165int comedi_dio_bitfield2(struct comedi_device *dev, unsigned int subdev,
166 unsigned int mask, unsigned int *bits,
167 unsigned int base_channel)
168{
169 struct comedi_insn insn;
170 unsigned int data[2];
171 unsigned int n_chan;
172 unsigned int shift;
173 int ret;
174
175 base_channel = CR_CHAN(base_channel);
176 n_chan = comedi_get_n_channels(dev, subdev);
177 if (base_channel >= n_chan)
178 return -EINVAL;
179
180 memset(&insn, 0, sizeof(insn));
181 insn.insn = INSN_BITS;
182 insn.chanspec = base_channel;
183 insn.n = 2;
184 insn.subdev = subdev;
185
186 data[0] = mask;
187 data[1] = *bits;
188
189 /*
190 * Most drivers ignore the base channel in insn->chanspec.
191 * Fix this here if the subdevice has <= 32 channels.
192 */
193 if (n_chan <= 32) {
194 shift = base_channel;
195 if (shift) {
196 insn.chanspec = 0;
197 data[0] <<= shift;
198 data[1] <<= shift;
199 }
200 } else {
201 shift = 0;
202 }
203
204 ret = comedi_do_insn(dev, &insn, data);
205 *bits = data[1] >> shift;
206 return ret;
207}
208EXPORT_SYMBOL_GPL(comedi_dio_bitfield2);
209
210int comedi_find_subdevice_by_type(struct comedi_device *dev, int type,
211 unsigned int subd)
212{
213 struct comedi_subdevice *s;
214 int ret = -ENODEV;
215
216 down_read(&dev->attach_lock);
217 if (dev->attached)
218 for (; subd < dev->n_subdevices; subd++) {
219 s = &dev->subdevices[subd];
220 if (s->type == type) {
221 ret = subd;
222 break;
223 }
224 }
225 up_read(&dev->attach_lock);
226 return ret;
227}
228EXPORT_SYMBOL_GPL(comedi_find_subdevice_by_type);
229
230int comedi_get_n_channels(struct comedi_device *dev, unsigned int subdevice)
231{
232 int n;
233
234 down_read(&dev->attach_lock);
235 if (!dev->attached || subdevice >= dev->n_subdevices)
236 n = 0;
237 else
238 n = dev->subdevices[subdevice].n_chan;
239 up_read(&dev->attach_lock);
240
241 return n;
242}
243EXPORT_SYMBOL_GPL(comedi_get_n_channels);
244
245static int __init kcomedilib_module_init(void)
246{
247 return 0;
248}
249
250static void __exit kcomedilib_module_exit(void)
251{
252}
253
254module_init(kcomedilib_module_init);
255module_exit(kcomedilib_module_exit);