2 * Generic i2c interface for ALSA
4 * (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
5 * Modified for the ALSA driver by Jaroslav Kysela <perex@suse.cz>
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.
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.
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
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>
31 MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
32 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
33 MODULE_LICENSE("GPL");
35 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
36 unsigned char *bytes, int count);
37 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
38 unsigned char *bytes, int count);
39 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
42 static struct snd_i2c_ops snd_i2c_bit_ops = {
43 .sendbytes = snd_i2c_bit_sendbytes,
44 .readbytes = snd_i2c_bit_readbytes,
45 .probeaddr = snd_i2c_bit_probeaddr,
48 static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
50 struct snd_i2c_bus *slave;
51 struct snd_i2c_device *device;
53 snd_assert(bus != NULL, return -EINVAL);
54 while (!list_empty(&bus->devices)) {
55 device = snd_i2c_device(bus->devices.next);
56 snd_i2c_device_free(device);
59 list_del(&bus->buses);
61 while (!list_empty(&bus->buses)) {
62 slave = snd_i2c_slave_bus(bus->buses.next);
63 snd_device_free(bus->card, slave);
66 if (bus->private_free)
67 bus->private_free(bus);
72 static int snd_i2c_bus_dev_free(struct snd_device *device)
74 struct snd_i2c_bus *bus = device->device_data;
75 return snd_i2c_bus_free(bus);
78 int snd_i2c_bus_create(struct snd_card *card, const char *name,
79 struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
81 struct snd_i2c_bus *bus;
83 static struct snd_device_ops ops = {
84 .dev_free = snd_i2c_bus_dev_free,
88 bus = kzalloc(sizeof(*bus), GFP_KERNEL);
91 mutex_init(&bus->lock_mutex);
92 INIT_LIST_HEAD(&bus->devices);
93 INIT_LIST_HEAD(&bus->buses);
95 bus->ops = &snd_i2c_bit_ops;
97 list_add_tail(&bus->buses, &master->buses);
100 strlcpy(bus->name, name, sizeof(bus->name));
101 if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
102 snd_i2c_bus_free(bus);
109 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
110 unsigned char addr, struct snd_i2c_device **rdevice)
112 struct snd_i2c_device *device;
115 snd_assert(bus != NULL, return -EINVAL);
116 device = kzalloc(sizeof(*device), GFP_KERNEL);
120 strlcpy(device->name, name, sizeof(device->name));
121 list_add_tail(&device->list, &bus->devices);
127 int snd_i2c_device_free(struct snd_i2c_device *device)
130 list_del(&device->list);
131 if (device->private_free)
132 device->private_free(device);
137 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
139 return device->bus->ops->sendbytes(device, bytes, count);
143 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
145 return device->bus->ops->readbytes(device, bytes, count);
148 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
150 return bus->ops->probeaddr(bus, addr);
157 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
159 if (bus->hw_ops.bit->start)
160 bus->hw_ops.bit->start(bus);
163 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
165 if (bus->hw_ops.bit->stop)
166 bus->hw_ops.bit->stop(bus);
169 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
171 if (bus->hw_ops.bit->direction)
172 bus->hw_ops.bit->direction(bus, clock, data);
175 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
177 bus->hw_ops.bit->setlines(bus, clock, data);
181 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
183 if (bus->hw_ops.bit->getclock)
184 return bus->hw_ops.bit->getclock(bus);
189 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
191 return bus->hw_ops.bit->getdata(bus, ack);
194 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
196 snd_i2c_bit_hw_start(bus);
197 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
198 snd_i2c_bit_set(bus, 1, 1);
199 snd_i2c_bit_set(bus, 1, 0);
200 snd_i2c_bit_set(bus, 0, 0);
203 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
205 snd_i2c_bit_set(bus, 0, 0);
206 snd_i2c_bit_set(bus, 1, 0);
207 snd_i2c_bit_set(bus, 1, 1);
208 snd_i2c_bit_hw_stop(bus);
211 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
213 snd_i2c_bit_set(bus, 0, data);
214 snd_i2c_bit_set(bus, 1, data);
215 snd_i2c_bit_set(bus, 0, data);
218 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
222 snd_i2c_bit_set(bus, 0, 1);
223 snd_i2c_bit_set(bus, 1, 1);
224 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
225 ack = snd_i2c_bit_data(bus, 1);
226 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
227 snd_i2c_bit_set(bus, 0, 1);
228 return ack ? -EIO : 0;
231 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
235 for (i = 7; i >= 0; i--)
236 snd_i2c_bit_send(bus, !!(data & (1 << i)));
237 if ((err = snd_i2c_bit_ack(bus)) < 0)
242 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
245 unsigned char data = 0;
247 snd_i2c_bit_set(bus, 0, 1);
248 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
249 for (i = 7; i >= 0; i--) {
250 snd_i2c_bit_set(bus, 1, 1);
251 if (snd_i2c_bit_data(bus, 0))
253 snd_i2c_bit_set(bus, 0, 1);
255 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
256 snd_i2c_bit_send(bus, !!last);
260 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
261 unsigned char *bytes, int count)
263 struct snd_i2c_bus *bus = device->bus;
266 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
267 return -EIO; /* not yet implemented */
268 snd_i2c_bit_start(bus);
269 if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
270 snd_i2c_bit_hw_stop(bus);
273 while (count-- > 0) {
274 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
275 snd_i2c_bit_hw_stop(bus);
280 snd_i2c_bit_stop(bus);
284 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
285 unsigned char *bytes, int count)
287 struct snd_i2c_bus *bus = device->bus;
290 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
291 return -EIO; /* not yet implemented */
292 snd_i2c_bit_start(bus);
293 if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
294 snd_i2c_bit_hw_stop(bus);
297 while (count-- > 0) {
298 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
299 snd_i2c_bit_hw_stop(bus);
302 *bytes++ = (unsigned char)err;
305 snd_i2c_bit_stop(bus);
309 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
313 if (addr & 0x8000) /* 10-bit address */
314 return -EIO; /* not yet implemented */
315 if (addr & 0x7f80) /* invalid address */
317 snd_i2c_bit_start(bus);
318 err = snd_i2c_bit_sendbyte(bus, addr << 1);
319 snd_i2c_bit_stop(bus);
323 EXPORT_SYMBOL(snd_i2c_bus_create);
324 EXPORT_SYMBOL(snd_i2c_device_create);
325 EXPORT_SYMBOL(snd_i2c_device_free);
326 EXPORT_SYMBOL(snd_i2c_sendbytes);
327 EXPORT_SYMBOL(snd_i2c_readbytes);
328 EXPORT_SYMBOL(snd_i2c_probeaddr);
330 static int __init alsa_i2c_init(void)
335 static void __exit alsa_i2c_exit(void)
339 module_init(alsa_i2c_init)
340 module_exit(alsa_i2c_exit)