i2c.c 8.3 KB

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  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@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. #include <sound/driver.h>
  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>
  29. MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
  30. MODULE_DESCRIPTION("Generic i2c interface for ALSA");
  31. MODULE_LICENSE("GPL");
  32. static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
  33. unsigned char *bytes, int count);
  34. static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
  35. unsigned char *bytes, int count);
  36. static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
  37. unsigned short addr);
  38. static struct snd_i2c_ops snd_i2c_bit_ops = {
  39. .sendbytes = snd_i2c_bit_sendbytes,
  40. .readbytes = snd_i2c_bit_readbytes,
  41. .probeaddr = snd_i2c_bit_probeaddr,
  42. };
  43. static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
  44. {
  45. struct snd_i2c_bus *slave;
  46. struct snd_i2c_device *device;
  47. snd_assert(bus != NULL, return -EINVAL);
  48. while (!list_empty(&bus->devices)) {
  49. device = snd_i2c_device(bus->devices.next);
  50. snd_i2c_device_free(device);
  51. }
  52. if (bus->master)
  53. list_del(&bus->buses);
  54. else {
  55. while (!list_empty(&bus->buses)) {
  56. slave = snd_i2c_slave_bus(bus->buses.next);
  57. snd_device_free(bus->card, slave);
  58. }
  59. }
  60. if (bus->private_free)
  61. bus->private_free(bus);
  62. kfree(bus);
  63. return 0;
  64. }
  65. static int snd_i2c_bus_dev_free(struct snd_device *device)
  66. {
  67. struct snd_i2c_bus *bus = device->device_data;
  68. return snd_i2c_bus_free(bus);
  69. }
  70. int snd_i2c_bus_create(struct snd_card *card, const char *name,
  71. struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
  72. {
  73. struct snd_i2c_bus *bus;
  74. int err;
  75. static struct snd_device_ops ops = {
  76. .dev_free = snd_i2c_bus_dev_free,
  77. };
  78. *ri2c = NULL;
  79. bus = kzalloc(sizeof(*bus), GFP_KERNEL);
  80. if (bus == NULL)
  81. return -ENOMEM;
  82. mutex_init(&bus->lock_mutex);
  83. INIT_LIST_HEAD(&bus->devices);
  84. INIT_LIST_HEAD(&bus->buses);
  85. bus->card = card;
  86. bus->ops = &snd_i2c_bit_ops;
  87. if (master) {
  88. list_add_tail(&bus->buses, &master->buses);
  89. bus->master = master;
  90. }
  91. strlcpy(bus->name, name, sizeof(bus->name));
  92. if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) {
  93. snd_i2c_bus_free(bus);
  94. return err;
  95. }
  96. *ri2c = bus;
  97. return 0;
  98. }
  99. EXPORT_SYMBOL(snd_i2c_bus_create);
  100. int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
  101. unsigned char addr, struct snd_i2c_device **rdevice)
  102. {
  103. struct snd_i2c_device *device;
  104. *rdevice = NULL;
  105. snd_assert(bus != NULL, return -EINVAL);
  106. device = kzalloc(sizeof(*device), GFP_KERNEL);
  107. if (device == NULL)
  108. return -ENOMEM;
  109. device->addr = addr;
  110. strlcpy(device->name, name, sizeof(device->name));
  111. list_add_tail(&device->list, &bus->devices);
  112. device->bus = bus;
  113. *rdevice = device;
  114. return 0;
  115. }
  116. EXPORT_SYMBOL(snd_i2c_device_create);
  117. int snd_i2c_device_free(struct snd_i2c_device *device)
  118. {
  119. if (device->bus)
  120. list_del(&device->list);
  121. if (device->private_free)
  122. device->private_free(device);
  123. kfree(device);
  124. return 0;
  125. }
  126. EXPORT_SYMBOL(snd_i2c_device_free);
  127. int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
  128. {
  129. return device->bus->ops->sendbytes(device, bytes, count);
  130. }
  131. EXPORT_SYMBOL(snd_i2c_sendbytes);
  132. int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
  133. {
  134. return device->bus->ops->readbytes(device, bytes, count);
  135. }
  136. EXPORT_SYMBOL(snd_i2c_readbytes);
  137. int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
  138. {
  139. return bus->ops->probeaddr(bus, addr);
  140. }
  141. EXPORT_SYMBOL(snd_i2c_probeaddr);
  142. /*
  143. * bit-operations
  144. */
  145. static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
  146. {
  147. if (bus->hw_ops.bit->start)
  148. bus->hw_ops.bit->start(bus);
  149. }
  150. static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
  151. {
  152. if (bus->hw_ops.bit->stop)
  153. bus->hw_ops.bit->stop(bus);
  154. }
  155. static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
  156. {
  157. if (bus->hw_ops.bit->direction)
  158. bus->hw_ops.bit->direction(bus, clock, data);
  159. }
  160. static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
  161. {
  162. bus->hw_ops.bit->setlines(bus, clock, data);
  163. }
  164. #if 0
  165. static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
  166. {
  167. if (bus->hw_ops.bit->getclock)
  168. return bus->hw_ops.bit->getclock(bus);
  169. return -ENXIO;
  170. }
  171. #endif
  172. static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
  173. {
  174. return bus->hw_ops.bit->getdata(bus, ack);
  175. }
  176. static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
  177. {
  178. snd_i2c_bit_hw_start(bus);
  179. snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
  180. snd_i2c_bit_set(bus, 1, 1);
  181. snd_i2c_bit_set(bus, 1, 0);
  182. snd_i2c_bit_set(bus, 0, 0);
  183. }
  184. static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
  185. {
  186. snd_i2c_bit_set(bus, 0, 0);
  187. snd_i2c_bit_set(bus, 1, 0);
  188. snd_i2c_bit_set(bus, 1, 1);
  189. snd_i2c_bit_hw_stop(bus);
  190. }
  191. static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
  192. {
  193. snd_i2c_bit_set(bus, 0, data);
  194. snd_i2c_bit_set(bus, 1, data);
  195. snd_i2c_bit_set(bus, 0, data);
  196. }
  197. static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
  198. {
  199. int ack;
  200. snd_i2c_bit_set(bus, 0, 1);
  201. snd_i2c_bit_set(bus, 1, 1);
  202. snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
  203. ack = snd_i2c_bit_data(bus, 1);
  204. snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
  205. snd_i2c_bit_set(bus, 0, 1);
  206. return ack ? -EIO : 0;
  207. }
  208. static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
  209. {
  210. int i, err;
  211. for (i = 7; i >= 0; i--)
  212. snd_i2c_bit_send(bus, !!(data & (1 << i)));
  213. if ((err = snd_i2c_bit_ack(bus)) < 0)
  214. return err;
  215. return 0;
  216. }
  217. static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
  218. {
  219. int i;
  220. unsigned char data = 0;
  221. snd_i2c_bit_set(bus, 0, 1);
  222. snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */
  223. for (i = 7; i >= 0; i--) {
  224. snd_i2c_bit_set(bus, 1, 1);
  225. if (snd_i2c_bit_data(bus, 0))
  226. data |= (1 << i);
  227. snd_i2c_bit_set(bus, 0, 1);
  228. }
  229. snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */
  230. snd_i2c_bit_send(bus, !!last);
  231. return data;
  232. }
  233. static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
  234. unsigned char *bytes, int count)
  235. {
  236. struct snd_i2c_bus *bus = device->bus;
  237. int err, res = 0;
  238. if (device->flags & SND_I2C_DEVICE_ADDRTEN)
  239. return -EIO; /* not yet implemented */
  240. snd_i2c_bit_start(bus);
  241. if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
  242. snd_i2c_bit_hw_stop(bus);
  243. return err;
  244. }
  245. while (count-- > 0) {
  246. if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
  247. snd_i2c_bit_hw_stop(bus);
  248. return err;
  249. }
  250. res++;
  251. }
  252. snd_i2c_bit_stop(bus);
  253. return res;
  254. }
  255. static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
  256. unsigned char *bytes, int count)
  257. {
  258. struct snd_i2c_bus *bus = device->bus;
  259. int err, res = 0;
  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) | 1)) < 0) {
  264. snd_i2c_bit_hw_stop(bus);
  265. return err;
  266. }
  267. while (count-- > 0) {
  268. if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
  269. snd_i2c_bit_hw_stop(bus);
  270. return err;
  271. }
  272. *bytes++ = (unsigned char)err;
  273. res++;
  274. }
  275. snd_i2c_bit_stop(bus);
  276. return res;
  277. }
  278. static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
  279. {
  280. int err;
  281. if (addr & 0x8000) /* 10-bit address */
  282. return -EIO; /* not yet implemented */
  283. if (addr & 0x7f80) /* invalid address */
  284. return -EINVAL;
  285. snd_i2c_bit_start(bus);
  286. err = snd_i2c_bit_sendbyte(bus, addr << 1);
  287. snd_i2c_bit_stop(bus);
  288. return err;
  289. }
  290. static int __init alsa_i2c_init(void)
  291. {
  292. return 0;
  293. }
  294. static void __exit alsa_i2c_exit(void)
  295. {
  296. }
  297. module_init(alsa_i2c_init)
  298. module_exit(alsa_i2c_exit)