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/string.h> 26 #include <linux/errno.h> 27 #include <sound/core.h> 28 #include <sound/i2c.h> 29 30 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>"); 31 MODULE_DESCRIPTION("Generic i2c interface for ALSA"); 32 MODULE_LICENSE("GPL"); 33 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, 39 unsigned short addr); 40 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, 45 }; 46 47 static int snd_i2c_bus_free(struct snd_i2c_bus *bus) 48 { 49 struct snd_i2c_bus *slave; 50 struct snd_i2c_device *device; 51 52 if (snd_BUG_ON(!bus)) 53 return -EINVAL; 54 while (!list_empty(&bus->devices)) { 55 device = snd_i2c_device(bus->devices.next); 56 snd_i2c_device_free(device); 57 } 58 if (bus->master) 59 list_del(&bus->buses); 60 else { 61 while (!list_empty(&bus->buses)) { 62 slave = snd_i2c_slave_bus(bus->buses.next); 63 snd_device_free(bus->card, slave); 64 } 65 } 66 if (bus->private_free) 67 bus->private_free(bus); 68 kfree(bus); 69 return 0; 70 } 71 72 static int snd_i2c_bus_dev_free(struct snd_device *device) 73 { 74 struct snd_i2c_bus *bus = device->device_data; 75 return snd_i2c_bus_free(bus); 76 } 77 78 int snd_i2c_bus_create(struct snd_card *card, const char *name, 79 struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c) 80 { 81 struct snd_i2c_bus *bus; 82 int err; 83 static struct snd_device_ops ops = { 84 .dev_free = snd_i2c_bus_dev_free, 85 }; 86 87 *ri2c = NULL; 88 bus = kzalloc(sizeof(*bus), GFP_KERNEL); 89 if (bus == NULL) 90 return -ENOMEM; 91 mutex_init(&bus->lock_mutex); 92 INIT_LIST_HEAD(&bus->devices); 93 INIT_LIST_HEAD(&bus->buses); 94 bus->card = card; 95 bus->ops = &snd_i2c_bit_ops; 96 if (master) { 97 list_add_tail(&bus->buses, &master->buses); 98 bus->master = master; 99 } 100 strlcpy(bus->name, name, sizeof(bus->name)); 101 err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops); 102 if (err < 0) { 103 snd_i2c_bus_free(bus); 104 return err; 105 } 106 *ri2c = bus; 107 return 0; 108 } 109 110 EXPORT_SYMBOL(snd_i2c_bus_create); 111 112 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name, 113 unsigned char addr, struct snd_i2c_device **rdevice) 114 { 115 struct snd_i2c_device *device; 116 117 *rdevice = NULL; 118 if (snd_BUG_ON(!bus)) 119 return -EINVAL; 120 device = kzalloc(sizeof(*device), GFP_KERNEL); 121 if (device == NULL) 122 return -ENOMEM; 123 device->addr = addr; 124 strlcpy(device->name, name, sizeof(device->name)); 125 list_add_tail(&device->list, &bus->devices); 126 device->bus = bus; 127 *rdevice = device; 128 return 0; 129 } 130 131 EXPORT_SYMBOL(snd_i2c_device_create); 132 133 int snd_i2c_device_free(struct snd_i2c_device *device) 134 { 135 if (device->bus) 136 list_del(&device->list); 137 if (device->private_free) 138 device->private_free(device); 139 kfree(device); 140 return 0; 141 } 142 143 EXPORT_SYMBOL(snd_i2c_device_free); 144 145 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count) 146 { 147 return device->bus->ops->sendbytes(device, bytes, count); 148 } 149 150 EXPORT_SYMBOL(snd_i2c_sendbytes); 151 152 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count) 153 { 154 return device->bus->ops->readbytes(device, bytes, count); 155 } 156 157 EXPORT_SYMBOL(snd_i2c_readbytes); 158 159 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr) 160 { 161 return bus->ops->probeaddr(bus, addr); 162 } 163 164 EXPORT_SYMBOL(snd_i2c_probeaddr); 165 166 /* 167 * bit-operations 168 */ 169 170 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus) 171 { 172 if (bus->hw_ops.bit->start) 173 bus->hw_ops.bit->start(bus); 174 } 175 176 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus) 177 { 178 if (bus->hw_ops.bit->stop) 179 bus->hw_ops.bit->stop(bus); 180 } 181 182 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data) 183 { 184 if (bus->hw_ops.bit->direction) 185 bus->hw_ops.bit->direction(bus, clock, data); 186 } 187 188 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data) 189 { 190 bus->hw_ops.bit->setlines(bus, clock, data); 191 } 192 193 #if 0 194 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus) 195 { 196 if (bus->hw_ops.bit->getclock) 197 return bus->hw_ops.bit->getclock(bus); 198 return -ENXIO; 199 } 200 #endif 201 202 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack) 203 { 204 return bus->hw_ops.bit->getdata(bus, ack); 205 } 206 207 static void snd_i2c_bit_start(struct snd_i2c_bus *bus) 208 { 209 snd_i2c_bit_hw_start(bus); 210 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */ 211 snd_i2c_bit_set(bus, 1, 1); 212 snd_i2c_bit_set(bus, 1, 0); 213 snd_i2c_bit_set(bus, 0, 0); 214 } 215 216 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus) 217 { 218 snd_i2c_bit_set(bus, 0, 0); 219 snd_i2c_bit_set(bus, 1, 0); 220 snd_i2c_bit_set(bus, 1, 1); 221 snd_i2c_bit_hw_stop(bus); 222 } 223 224 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data) 225 { 226 snd_i2c_bit_set(bus, 0, data); 227 snd_i2c_bit_set(bus, 1, data); 228 snd_i2c_bit_set(bus, 0, data); 229 } 230 231 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus) 232 { 233 int ack; 234 235 snd_i2c_bit_set(bus, 0, 1); 236 snd_i2c_bit_set(bus, 1, 1); 237 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */ 238 ack = snd_i2c_bit_data(bus, 1); 239 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */ 240 snd_i2c_bit_set(bus, 0, 1); 241 return ack ? -EIO : 0; 242 } 243 244 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data) 245 { 246 int i, err; 247 248 for (i = 7; i >= 0; i--) 249 snd_i2c_bit_send(bus, !!(data & (1 << i))); 250 err = snd_i2c_bit_ack(bus); 251 if (err < 0) 252 return err; 253 return 0; 254 } 255 256 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last) 257 { 258 int i; 259 unsigned char data = 0; 260 261 snd_i2c_bit_set(bus, 0, 1); 262 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */ 263 for (i = 7; i >= 0; i--) { 264 snd_i2c_bit_set(bus, 1, 1); 265 if (snd_i2c_bit_data(bus, 0)) 266 data |= (1 << i); 267 snd_i2c_bit_set(bus, 0, 1); 268 } 269 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */ 270 snd_i2c_bit_send(bus, !!last); 271 return data; 272 } 273 274 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device, 275 unsigned char *bytes, int count) 276 { 277 struct snd_i2c_bus *bus = device->bus; 278 int err, res = 0; 279 280 if (device->flags & SND_I2C_DEVICE_ADDRTEN) 281 return -EIO; /* not yet implemented */ 282 snd_i2c_bit_start(bus); 283 err = snd_i2c_bit_sendbyte(bus, device->addr << 1); 284 if (err < 0) { 285 snd_i2c_bit_hw_stop(bus); 286 return err; 287 } 288 while (count-- > 0) { 289 err = snd_i2c_bit_sendbyte(bus, *bytes++); 290 if (err < 0) { 291 snd_i2c_bit_hw_stop(bus); 292 return err; 293 } 294 res++; 295 } 296 snd_i2c_bit_stop(bus); 297 return res; 298 } 299 300 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device, 301 unsigned char *bytes, int count) 302 { 303 struct snd_i2c_bus *bus = device->bus; 304 int err, res = 0; 305 306 if (device->flags & SND_I2C_DEVICE_ADDRTEN) 307 return -EIO; /* not yet implemented */ 308 snd_i2c_bit_start(bus); 309 err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1); 310 if (err < 0) { 311 snd_i2c_bit_hw_stop(bus); 312 return err; 313 } 314 while (count-- > 0) { 315 err = snd_i2c_bit_readbyte(bus, count == 0); 316 if (err < 0) { 317 snd_i2c_bit_hw_stop(bus); 318 return err; 319 } 320 *bytes++ = (unsigned char)err; 321 res++; 322 } 323 snd_i2c_bit_stop(bus); 324 return res; 325 } 326 327 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr) 328 { 329 int err; 330 331 if (addr & 0x8000) /* 10-bit address */ 332 return -EIO; /* not yet implemented */ 333 if (addr & 0x7f80) /* invalid address */ 334 return -EINVAL; 335 snd_i2c_bit_start(bus); 336 err = snd_i2c_bit_sendbyte(bus, addr << 1); 337 snd_i2c_bit_stop(bus); 338 return err; 339 } 340 341 342 static int __init alsa_i2c_init(void) 343 { 344 return 0; 345 } 346 347 static void __exit alsa_i2c_exit(void) 348 { 349 } 350 351 module_init(alsa_i2c_init) 352 module_exit(alsa_i2c_exit) 353