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@perex.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 <linux/init.h>
24 #include <linux/slab.h>
25 #include <linux/string.h>
26 #include <linux/errno.h>
27 #include <sound/core.h>
28 #include <sound/i2c.h>
30 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
31 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
32 MODULE_LICENSE("GPL");
34 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
35 unsigned char *bytes, int count);
36 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
37 unsigned char *bytes, int count);
38 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
41 static struct snd_i2c_ops snd_i2c_bit_ops = {
42 .sendbytes = snd_i2c_bit_sendbytes,
43 .readbytes = snd_i2c_bit_readbytes,
44 .probeaddr = snd_i2c_bit_probeaddr,
47 static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
49 struct snd_i2c_bus *slave;
50 struct snd_i2c_device *device;
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 EXPORT_SYMBOL(snd_i2c_bus_create);
111 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
112 unsigned char addr, struct snd_i2c_device **rdevice)
114 struct snd_i2c_device *device;
117 if (snd_BUG_ON(!bus))
119 device = kzalloc(sizeof(*device), GFP_KERNEL);
123 strlcpy(device->name, name, sizeof(device->name));
124 list_add_tail(&device->list, &bus->devices);
130 EXPORT_SYMBOL(snd_i2c_device_create);
132 int snd_i2c_device_free(struct snd_i2c_device *device)
135 list_del(&device->list);
136 if (device->private_free)
137 device->private_free(device);
142 EXPORT_SYMBOL(snd_i2c_device_free);
144 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
146 return device->bus->ops->sendbytes(device, bytes, count);
149 EXPORT_SYMBOL(snd_i2c_sendbytes);
151 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
153 return device->bus->ops->readbytes(device, bytes, count);
156 EXPORT_SYMBOL(snd_i2c_readbytes);
158 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
160 return bus->ops->probeaddr(bus, addr);
163 EXPORT_SYMBOL(snd_i2c_probeaddr);
169 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
171 if (bus->hw_ops.bit->start)
172 bus->hw_ops.bit->start(bus);
175 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
177 if (bus->hw_ops.bit->stop)
178 bus->hw_ops.bit->stop(bus);
181 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
183 if (bus->hw_ops.bit->direction)
184 bus->hw_ops.bit->direction(bus, clock, data);
187 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
189 bus->hw_ops.bit->setlines(bus, clock, data);
193 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
195 if (bus->hw_ops.bit->getclock)
196 return bus->hw_ops.bit->getclock(bus);
201 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
203 return bus->hw_ops.bit->getdata(bus, ack);
206 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
208 snd_i2c_bit_hw_start(bus);
209 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
210 snd_i2c_bit_set(bus, 1, 1);
211 snd_i2c_bit_set(bus, 1, 0);
212 snd_i2c_bit_set(bus, 0, 0);
215 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
217 snd_i2c_bit_set(bus, 0, 0);
218 snd_i2c_bit_set(bus, 1, 0);
219 snd_i2c_bit_set(bus, 1, 1);
220 snd_i2c_bit_hw_stop(bus);
223 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
225 snd_i2c_bit_set(bus, 0, data);
226 snd_i2c_bit_set(bus, 1, data);
227 snd_i2c_bit_set(bus, 0, data);
230 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
234 snd_i2c_bit_set(bus, 0, 1);
235 snd_i2c_bit_set(bus, 1, 1);
236 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
237 ack = snd_i2c_bit_data(bus, 1);
238 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
239 snd_i2c_bit_set(bus, 0, 1);
240 return ack ? -EIO : 0;
243 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
247 for (i = 7; i >= 0; i--)
248 snd_i2c_bit_send(bus, !!(data & (1 << i)));
249 if ((err = snd_i2c_bit_ack(bus)) < 0)
254 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
257 unsigned char data = 0;
259 snd_i2c_bit_set(bus, 0, 1);
260 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
261 for (i = 7; i >= 0; i--) {
262 snd_i2c_bit_set(bus, 1, 1);
263 if (snd_i2c_bit_data(bus, 0))
265 snd_i2c_bit_set(bus, 0, 1);
267 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
268 snd_i2c_bit_send(bus, !!last);
272 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
273 unsigned char *bytes, int count)
275 struct snd_i2c_bus *bus = device->bus;
278 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
279 return -EIO; /* not yet implemented */
280 snd_i2c_bit_start(bus);
281 if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
282 snd_i2c_bit_hw_stop(bus);
285 while (count-- > 0) {
286 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
287 snd_i2c_bit_hw_stop(bus);
292 snd_i2c_bit_stop(bus);
296 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
297 unsigned char *bytes, int count)
299 struct snd_i2c_bus *bus = device->bus;
302 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
303 return -EIO; /* not yet implemented */
304 snd_i2c_bit_start(bus);
305 if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
306 snd_i2c_bit_hw_stop(bus);
309 while (count-- > 0) {
310 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
311 snd_i2c_bit_hw_stop(bus);
314 *bytes++ = (unsigned char)err;
317 snd_i2c_bit_stop(bus);
321 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
325 if (addr & 0x8000) /* 10-bit address */
326 return -EIO; /* not yet implemented */
327 if (addr & 0x7f80) /* invalid address */
329 snd_i2c_bit_start(bus);
330 err = snd_i2c_bit_sendbyte(bus, addr << 1);
331 snd_i2c_bit_stop(bus);
336 static int __init alsa_i2c_init(void)
341 static void __exit alsa_i2c_exit(void)
345 module_init(alsa_i2c_init)
346 module_exit(alsa_i2c_exit)