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 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 snd_assert(bus != NULL, return -EINVAL);
118 device = kzalloc(sizeof(*device), GFP_KERNEL);
122 strlcpy(device->name, name, sizeof(device->name));
123 list_add_tail(&device->list, &bus->devices);
129 EXPORT_SYMBOL(snd_i2c_device_create);
131 int snd_i2c_device_free(struct snd_i2c_device *device)
134 list_del(&device->list);
135 if (device->private_free)
136 device->private_free(device);
141 EXPORT_SYMBOL(snd_i2c_device_free);
143 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
145 return device->bus->ops->sendbytes(device, bytes, count);
148 EXPORT_SYMBOL(snd_i2c_sendbytes);
150 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
152 return device->bus->ops->readbytes(device, bytes, count);
155 EXPORT_SYMBOL(snd_i2c_readbytes);
157 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
159 return bus->ops->probeaddr(bus, addr);
162 EXPORT_SYMBOL(snd_i2c_probeaddr);
168 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
170 if (bus->hw_ops.bit->start)
171 bus->hw_ops.bit->start(bus);
174 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
176 if (bus->hw_ops.bit->stop)
177 bus->hw_ops.bit->stop(bus);
180 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
182 if (bus->hw_ops.bit->direction)
183 bus->hw_ops.bit->direction(bus, clock, data);
186 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
188 bus->hw_ops.bit->setlines(bus, clock, data);
192 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
194 if (bus->hw_ops.bit->getclock)
195 return bus->hw_ops.bit->getclock(bus);
200 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
202 return bus->hw_ops.bit->getdata(bus, ack);
205 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
207 snd_i2c_bit_hw_start(bus);
208 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
209 snd_i2c_bit_set(bus, 1, 1);
210 snd_i2c_bit_set(bus, 1, 0);
211 snd_i2c_bit_set(bus, 0, 0);
214 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
216 snd_i2c_bit_set(bus, 0, 0);
217 snd_i2c_bit_set(bus, 1, 0);
218 snd_i2c_bit_set(bus, 1, 1);
219 snd_i2c_bit_hw_stop(bus);
222 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
224 snd_i2c_bit_set(bus, 0, data);
225 snd_i2c_bit_set(bus, 1, data);
226 snd_i2c_bit_set(bus, 0, data);
229 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
233 snd_i2c_bit_set(bus, 0, 1);
234 snd_i2c_bit_set(bus, 1, 1);
235 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
236 ack = snd_i2c_bit_data(bus, 1);
237 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
238 snd_i2c_bit_set(bus, 0, 1);
239 return ack ? -EIO : 0;
242 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
246 for (i = 7; i >= 0; i--)
247 snd_i2c_bit_send(bus, !!(data & (1 << i)));
248 if ((err = snd_i2c_bit_ack(bus)) < 0)
253 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
256 unsigned char data = 0;
258 snd_i2c_bit_set(bus, 0, 1);
259 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
260 for (i = 7; i >= 0; i--) {
261 snd_i2c_bit_set(bus, 1, 1);
262 if (snd_i2c_bit_data(bus, 0))
264 snd_i2c_bit_set(bus, 0, 1);
266 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
267 snd_i2c_bit_send(bus, !!last);
271 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
272 unsigned char *bytes, int count)
274 struct snd_i2c_bus *bus = device->bus;
277 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
278 return -EIO; /* not yet implemented */
279 snd_i2c_bit_start(bus);
280 if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
281 snd_i2c_bit_hw_stop(bus);
284 while (count-- > 0) {
285 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
286 snd_i2c_bit_hw_stop(bus);
291 snd_i2c_bit_stop(bus);
295 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
296 unsigned char *bytes, int count)
298 struct snd_i2c_bus *bus = device->bus;
301 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
302 return -EIO; /* not yet implemented */
303 snd_i2c_bit_start(bus);
304 if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
305 snd_i2c_bit_hw_stop(bus);
308 while (count-- > 0) {
309 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
310 snd_i2c_bit_hw_stop(bus);
313 *bytes++ = (unsigned char)err;
316 snd_i2c_bit_stop(bus);
320 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
324 if (addr & 0x8000) /* 10-bit address */
325 return -EIO; /* not yet implemented */
326 if (addr & 0x7f80) /* invalid address */
328 snd_i2c_bit_start(bus);
329 err = snd_i2c_bit_sendbyte(bus, addr << 1);
330 snd_i2c_bit_stop(bus);
335 static int __init alsa_i2c_init(void)
340 static void __exit alsa_i2c_exit(void)
344 module_init(alsa_i2c_init)
345 module_exit(alsa_i2c_exit)