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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * Generic i2c interface for ALSA
3 *
4 * (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
5 * Modified for the ALSA driver by Jaroslav Kysela <perex@suse.cz>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
21 */
22
23#include <sound/driver.h>
24#include <linux/init.h>
25#include <linux/slab.h>
26#include <linux/string.h>
27#include <linux/errno.h>
28#include <sound/core.h>
29#include <sound/i2c.h>
30
31MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
32MODULE_DESCRIPTION("Generic i2c interface for ALSA");
33MODULE_LICENSE("GPL");
34
35static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
36static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
37static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr);
38
39static snd_i2c_ops_t snd_i2c_bit_ops = {
40 .sendbytes = snd_i2c_bit_sendbytes,
41 .readbytes = snd_i2c_bit_readbytes,
42 .probeaddr = snd_i2c_bit_probeaddr,
43};
44
45static int snd_i2c_bus_free(snd_i2c_bus_t *bus)
46{
47 snd_i2c_bus_t *slave;
48 snd_i2c_device_t *device;
49
50 snd_assert(bus != NULL, return -EINVAL);
51 while (!list_empty(&bus->devices)) {
52 device = snd_i2c_device(bus->devices.next);
53 snd_i2c_device_free(device);
54 }
55 if (bus->master)
56 list_del(&bus->buses);
57 else {
58 while (!list_empty(&bus->buses)) {
59 slave = snd_i2c_slave_bus(bus->buses.next);
60 snd_device_free(bus->card, slave);
61 }
62 }
63 if (bus->private_free)
64 bus->private_free(bus);
65 kfree(bus);
66 return 0;
67}
68
69static int snd_i2c_bus_dev_free(snd_device_t *device)
70{
71 snd_i2c_bus_t *bus = device->device_data;
72 return snd_i2c_bus_free(bus);
73}
74
75int snd_i2c_bus_create(snd_card_t *card, const char *name, snd_i2c_bus_t *master, snd_i2c_bus_t **ri2c)
76{
77 snd_i2c_bus_t *bus;
78 int err;
79 static snd_device_ops_t ops = {
80 .dev_free = snd_i2c_bus_dev_free,
81 };
82
83 *ri2c = NULL;
Takashi Iwai561b2202005-09-09 14:22:34 +020084 bus = kzalloc(sizeof(*bus), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085 if (bus == NULL)
86 return -ENOMEM;
87 init_MUTEX(&bus->lock_mutex);
88 INIT_LIST_HEAD(&bus->devices);
89 INIT_LIST_HEAD(&bus->buses);
90 bus->card = card;
91 bus->ops = &snd_i2c_bit_ops;
92 if (master) {
93 list_add_tail(&bus->buses, &master->buses);
94 bus->master = master;
95 }
96 strlcpy(bus->name, name, sizeof(bus->name));
97 if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
98 snd_i2c_bus_free(bus);
99 return err;
100 }
101 *ri2c = bus;
102 return 0;
103}
104
105int snd_i2c_device_create(snd_i2c_bus_t *bus, const char *name, unsigned char addr, snd_i2c_device_t **rdevice)
106{
107 snd_i2c_device_t *device;
108
109 *rdevice = NULL;
110 snd_assert(bus != NULL, return -EINVAL);
Takashi Iwai561b2202005-09-09 14:22:34 +0200111 device = kzalloc(sizeof(*device), GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 if (device == NULL)
113 return -ENOMEM;
114 device->addr = addr;
115 strlcpy(device->name, name, sizeof(device->name));
116 list_add_tail(&device->list, &bus->devices);
117 device->bus = bus;
118 *rdevice = device;
119 return 0;
120}
121
122int snd_i2c_device_free(snd_i2c_device_t *device)
123{
124 if (device->bus)
125 list_del(&device->list);
126 if (device->private_free)
127 device->private_free(device);
128 kfree(device);
129 return 0;
130}
131
132int snd_i2c_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
133{
134 return device->bus->ops->sendbytes(device, bytes, count);
135}
136
137
138int snd_i2c_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
139{
140 return device->bus->ops->readbytes(device, bytes, count);
141}
142
143int snd_i2c_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
144{
145 return bus->ops->probeaddr(bus, addr);
146}
147
148/*
149 * bit-operations
150 */
151
152static inline void snd_i2c_bit_hw_start(snd_i2c_bus_t *bus)
153{
154 if (bus->hw_ops.bit->start)
155 bus->hw_ops.bit->start(bus);
156}
157
158static inline void snd_i2c_bit_hw_stop(snd_i2c_bus_t *bus)
159{
160 if (bus->hw_ops.bit->stop)
161 bus->hw_ops.bit->stop(bus);
162}
163
164static void snd_i2c_bit_direction(snd_i2c_bus_t *bus, int clock, int data)
165{
166 if (bus->hw_ops.bit->direction)
167 bus->hw_ops.bit->direction(bus, clock, data);
168}
169
170static void snd_i2c_bit_set(snd_i2c_bus_t *bus, int clock, int data)
171{
172 bus->hw_ops.bit->setlines(bus, clock, data);
173}
174
175#if 0
176static int snd_i2c_bit_clock(snd_i2c_bus_t *bus)
177{
178 if (bus->hw_ops.bit->getclock)
179 return bus->hw_ops.bit->getclock(bus);
180 return -ENXIO;
181}
182#endif
183
184static int snd_i2c_bit_data(snd_i2c_bus_t *bus, int ack)
185{
186 return bus->hw_ops.bit->getdata(bus, ack);
187}
188
189static void snd_i2c_bit_start(snd_i2c_bus_t *bus)
190{
191 snd_i2c_bit_hw_start(bus);
192 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
193 snd_i2c_bit_set(bus, 1, 1);
194 snd_i2c_bit_set(bus, 1, 0);
195 snd_i2c_bit_set(bus, 0, 0);
196}
197
198static void snd_i2c_bit_stop(snd_i2c_bus_t *bus)
199{
200 snd_i2c_bit_set(bus, 0, 0);
201 snd_i2c_bit_set(bus, 1, 0);
202 snd_i2c_bit_set(bus, 1, 1);
203 snd_i2c_bit_hw_stop(bus);
204}
205
206static void snd_i2c_bit_send(snd_i2c_bus_t *bus, int data)
207{
208 snd_i2c_bit_set(bus, 0, data);
209 snd_i2c_bit_set(bus, 1, data);
210 snd_i2c_bit_set(bus, 0, data);
211}
212
213static int snd_i2c_bit_ack(snd_i2c_bus_t *bus)
214{
215 int ack;
216
217 snd_i2c_bit_set(bus, 0, 1);
218 snd_i2c_bit_set(bus, 1, 1);
219 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
220 ack = snd_i2c_bit_data(bus, 1);
221 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
222 snd_i2c_bit_set(bus, 0, 1);
223 return ack ? -EIO : 0;
224}
225
226static int snd_i2c_bit_sendbyte(snd_i2c_bus_t *bus, unsigned char data)
227{
228 int i, err;
229
230 for (i = 7; i >= 0; i--)
231 snd_i2c_bit_send(bus, !!(data & (1 << i)));
232 if ((err = snd_i2c_bit_ack(bus)) < 0)
233 return err;
234 return 0;
235}
236
237static int snd_i2c_bit_readbyte(snd_i2c_bus_t *bus, int last)
238{
239 int i;
240 unsigned char data = 0;
241
242 snd_i2c_bit_set(bus, 0, 1);
243 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
244 for (i = 7; i >= 0; i--) {
245 snd_i2c_bit_set(bus, 1, 1);
246 if (snd_i2c_bit_data(bus, 0))
247 data |= (1 << i);
248 snd_i2c_bit_set(bus, 0, 1);
249 }
250 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
251 snd_i2c_bit_send(bus, !!last);
252 return data;
253}
254
255static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
256{
257 snd_i2c_bus_t *bus = device->bus;
258 int err, res = 0;
259
260 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
261 return -EIO; /* not yet implemented */
262 snd_i2c_bit_start(bus);
263 if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
264 snd_i2c_bit_hw_stop(bus);
265 return err;
266 }
267 while (count-- > 0) {
268 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
269 snd_i2c_bit_hw_stop(bus);
270 return err;
271 }
272 res++;
273 }
274 snd_i2c_bit_stop(bus);
275 return res;
276}
277
278static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
279{
280 snd_i2c_bus_t *bus = device->bus;
281 int err, res = 0;
282
283 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
284 return -EIO; /* not yet implemented */
285 snd_i2c_bit_start(bus);
286 if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
287 snd_i2c_bit_hw_stop(bus);
288 return err;
289 }
290 while (count-- > 0) {
291 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
292 snd_i2c_bit_hw_stop(bus);
293 return err;
294 }
295 *bytes++ = (unsigned char)err;
296 res++;
297 }
298 snd_i2c_bit_stop(bus);
299 return res;
300}
301
302static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
303{
304 int err;
305
306 if (addr & 0x8000) /* 10-bit address */
307 return -EIO; /* not yet implemented */
308 if (addr & 0x7f80) /* invalid address */
309 return -EINVAL;
310 snd_i2c_bit_start(bus);
311 err = snd_i2c_bit_sendbyte(bus, addr << 1);
312 snd_i2c_bit_stop(bus);
313 return err;
314}
315
316EXPORT_SYMBOL(snd_i2c_bus_create);
317EXPORT_SYMBOL(snd_i2c_device_create);
318EXPORT_SYMBOL(snd_i2c_device_free);
319EXPORT_SYMBOL(snd_i2c_sendbytes);
320EXPORT_SYMBOL(snd_i2c_readbytes);
321EXPORT_SYMBOL(snd_i2c_probeaddr);
322
323static int __init alsa_i2c_init(void)
324{
325 return 0;
326}
327
328static void __exit alsa_i2c_exit(void)
329{
330}
331
332module_init(alsa_i2c_init)
333module_exit(alsa_i2c_exit)