1 /*
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@perex.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 <linux/init.h>
24 #include <linux/slab.h>
25 #include <linux/module.h>
26 #include <linux/string.h>
27 #include <linux/errno.h>
28 #include <sound/core.h>
29 #include <sound/i2c.h>
30
31 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
32 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
33 MODULE_LICENSE("GPL");
34
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,
40 unsigned short addr);
41
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,
46 };
47
snd_i2c_bus_free(struct snd_i2c_bus * bus)48 static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
49 {
50 struct snd_i2c_bus *slave;
51 struct snd_i2c_device *device;
52
53 if (snd_BUG_ON(!bus))
54 return -EINVAL;
55 while (!list_empty(&bus->devices)) {
56 device = snd_i2c_device(bus->devices.next);
57 snd_i2c_device_free(device);
58 }
59 if (bus->master)
60 list_del(&bus->buses);
61 else {
62 while (!list_empty(&bus->buses)) {
63 slave = snd_i2c_slave_bus(bus->buses.next);
64 snd_device_free(bus->card, slave);
65 }
66 }
67 if (bus->private_free)
68 bus->private_free(bus);
69 kfree(bus);
70 return 0;
71 }
72
snd_i2c_bus_dev_free(struct snd_device * device)73 static int snd_i2c_bus_dev_free(struct snd_device *device)
74 {
75 struct snd_i2c_bus *bus = device->device_data;
76 return snd_i2c_bus_free(bus);
77 }
78
snd_i2c_bus_create(struct snd_card * card,const char * name,struct snd_i2c_bus * master,struct snd_i2c_bus ** ri2c)79 int snd_i2c_bus_create(struct snd_card *card, const char *name,
80 struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
81 {
82 struct snd_i2c_bus *bus;
83 int err;
84 static struct snd_device_ops ops = {
85 .dev_free = snd_i2c_bus_dev_free,
86 };
87
88 *ri2c = NULL;
89 bus = kzalloc(sizeof(*bus), GFP_KERNEL);
90 if (bus == NULL)
91 return -ENOMEM;
92 mutex_init(&bus->lock_mutex);
93 INIT_LIST_HEAD(&bus->devices);
94 INIT_LIST_HEAD(&bus->buses);
95 bus->card = card;
96 bus->ops = &snd_i2c_bit_ops;
97 if (master) {
98 list_add_tail(&bus->buses, &master->buses);
99 bus->master = master;
100 }
101 strlcpy(bus->name, name, sizeof(bus->name));
102 err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
103 if (err < 0) {
104 snd_i2c_bus_free(bus);
105 return err;
106 }
107 *ri2c = bus;
108 return 0;
109 }
110
111 EXPORT_SYMBOL(snd_i2c_bus_create);
112
snd_i2c_device_create(struct snd_i2c_bus * bus,const char * name,unsigned char addr,struct snd_i2c_device ** rdevice)113 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
114 unsigned char addr, struct snd_i2c_device **rdevice)
115 {
116 struct snd_i2c_device *device;
117
118 *rdevice = NULL;
119 if (snd_BUG_ON(!bus))
120 return -EINVAL;
121 device = kzalloc(sizeof(*device), GFP_KERNEL);
122 if (device == NULL)
123 return -ENOMEM;
124 device->addr = addr;
125 strlcpy(device->name, name, sizeof(device->name));
126 list_add_tail(&device->list, &bus->devices);
127 device->bus = bus;
128 *rdevice = device;
129 return 0;
130 }
131
132 EXPORT_SYMBOL(snd_i2c_device_create);
133
snd_i2c_device_free(struct snd_i2c_device * device)134 int snd_i2c_device_free(struct snd_i2c_device *device)
135 {
136 if (device->bus)
137 list_del(&device->list);
138 if (device->private_free)
139 device->private_free(device);
140 kfree(device);
141 return 0;
142 }
143
144 EXPORT_SYMBOL(snd_i2c_device_free);
145
snd_i2c_sendbytes(struct snd_i2c_device * device,unsigned char * bytes,int count)146 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
147 {
148 return device->bus->ops->sendbytes(device, bytes, count);
149 }
150
151 EXPORT_SYMBOL(snd_i2c_sendbytes);
152
snd_i2c_readbytes(struct snd_i2c_device * device,unsigned char * bytes,int count)153 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
154 {
155 return device->bus->ops->readbytes(device, bytes, count);
156 }
157
158 EXPORT_SYMBOL(snd_i2c_readbytes);
159
snd_i2c_probeaddr(struct snd_i2c_bus * bus,unsigned short addr)160 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
161 {
162 return bus->ops->probeaddr(bus, addr);
163 }
164
165 EXPORT_SYMBOL(snd_i2c_probeaddr);
166
167 /*
168 * bit-operations
169 */
170
snd_i2c_bit_hw_start(struct snd_i2c_bus * bus)171 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
172 {
173 if (bus->hw_ops.bit->start)
174 bus->hw_ops.bit->start(bus);
175 }
176
snd_i2c_bit_hw_stop(struct snd_i2c_bus * bus)177 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
178 {
179 if (bus->hw_ops.bit->stop)
180 bus->hw_ops.bit->stop(bus);
181 }
182
snd_i2c_bit_direction(struct snd_i2c_bus * bus,int clock,int data)183 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
184 {
185 if (bus->hw_ops.bit->direction)
186 bus->hw_ops.bit->direction(bus, clock, data);
187 }
188
snd_i2c_bit_set(struct snd_i2c_bus * bus,int clock,int data)189 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
190 {
191 bus->hw_ops.bit->setlines(bus, clock, data);
192 }
193
194 #if 0
195 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
196 {
197 if (bus->hw_ops.bit->getclock)
198 return bus->hw_ops.bit->getclock(bus);
199 return -ENXIO;
200 }
201 #endif
202
snd_i2c_bit_data(struct snd_i2c_bus * bus,int ack)203 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
204 {
205 return bus->hw_ops.bit->getdata(bus, ack);
206 }
207
snd_i2c_bit_start(struct snd_i2c_bus * bus)208 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
209 {
210 snd_i2c_bit_hw_start(bus);
211 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
212 snd_i2c_bit_set(bus, 1, 1);
213 snd_i2c_bit_set(bus, 1, 0);
214 snd_i2c_bit_set(bus, 0, 0);
215 }
216
snd_i2c_bit_stop(struct snd_i2c_bus * bus)217 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
218 {
219 snd_i2c_bit_set(bus, 0, 0);
220 snd_i2c_bit_set(bus, 1, 0);
221 snd_i2c_bit_set(bus, 1, 1);
222 snd_i2c_bit_hw_stop(bus);
223 }
224
snd_i2c_bit_send(struct snd_i2c_bus * bus,int data)225 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
226 {
227 snd_i2c_bit_set(bus, 0, data);
228 snd_i2c_bit_set(bus, 1, data);
229 snd_i2c_bit_set(bus, 0, data);
230 }
231
snd_i2c_bit_ack(struct snd_i2c_bus * bus)232 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
233 {
234 int ack;
235
236 snd_i2c_bit_set(bus, 0, 1);
237 snd_i2c_bit_set(bus, 1, 1);
238 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
239 ack = snd_i2c_bit_data(bus, 1);
240 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
241 snd_i2c_bit_set(bus, 0, 1);
242 return ack ? -EIO : 0;
243 }
244
snd_i2c_bit_sendbyte(struct snd_i2c_bus * bus,unsigned char data)245 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
246 {
247 int i, err;
248
249 for (i = 7; i >= 0; i--)
250 snd_i2c_bit_send(bus, !!(data & (1 << i)));
251 err = snd_i2c_bit_ack(bus);
252 if (err < 0)
253 return err;
254 return 0;
255 }
256
snd_i2c_bit_readbyte(struct snd_i2c_bus * bus,int last)257 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
258 {
259 int i;
260 unsigned char data = 0;
261
262 snd_i2c_bit_set(bus, 0, 1);
263 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
264 for (i = 7; i >= 0; i--) {
265 snd_i2c_bit_set(bus, 1, 1);
266 if (snd_i2c_bit_data(bus, 0))
267 data |= (1 << i);
268 snd_i2c_bit_set(bus, 0, 1);
269 }
270 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
271 snd_i2c_bit_send(bus, !!last);
272 return data;
273 }
274
snd_i2c_bit_sendbytes(struct snd_i2c_device * device,unsigned char * bytes,int count)275 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
276 unsigned char *bytes, int count)
277 {
278 struct snd_i2c_bus *bus = device->bus;
279 int err, res = 0;
280
281 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
282 return -EIO; /* not yet implemented */
283 snd_i2c_bit_start(bus);
284 err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
285 if (err < 0) {
286 snd_i2c_bit_hw_stop(bus);
287 return err;
288 }
289 while (count-- > 0) {
290 err = snd_i2c_bit_sendbyte(bus, *bytes++);
291 if (err < 0) {
292 snd_i2c_bit_hw_stop(bus);
293 return err;
294 }
295 res++;
296 }
297 snd_i2c_bit_stop(bus);
298 return res;
299 }
300
snd_i2c_bit_readbytes(struct snd_i2c_device * device,unsigned char * bytes,int count)301 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
302 unsigned char *bytes, int count)
303 {
304 struct snd_i2c_bus *bus = device->bus;
305 int err, res = 0;
306
307 if (device->flags & SND_I2C_DEVICE_ADDRTEN)
308 return -EIO; /* not yet implemented */
309 snd_i2c_bit_start(bus);
310 err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
311 if (err < 0) {
312 snd_i2c_bit_hw_stop(bus);
313 return err;
314 }
315 while (count-- > 0) {
316 err = snd_i2c_bit_readbyte(bus, count == 0);
317 if (err < 0) {
318 snd_i2c_bit_hw_stop(bus);
319 return err;
320 }
321 *bytes++ = (unsigned char)err;
322 res++;
323 }
324 snd_i2c_bit_stop(bus);
325 return res;
326 }
327
snd_i2c_bit_probeaddr(struct snd_i2c_bus * bus,unsigned short addr)328 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
329 {
330 int err;
331
332 if (addr & 0x8000) /* 10-bit address */
333 return -EIO; /* not yet implemented */
334 if (addr & 0x7f80) /* invalid address */
335 return -EINVAL;
336 snd_i2c_bit_start(bus);
337 err = snd_i2c_bit_sendbyte(bus, addr << 1);
338 snd_i2c_bit_stop(bus);
339 return err;
340 }
341
342
alsa_i2c_init(void)343 static int __init alsa_i2c_init(void)
344 {
345 return 0;
346 }
347
alsa_i2c_exit(void)348 static void __exit alsa_i2c_exit(void)
349 {
350 }
351
352 module_init(alsa_i2c_init)
353 module_exit(alsa_i2c_exit)
354