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 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 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 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); 112 113 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); 133 134 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); 145 146 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); 152 153 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); 159 160 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 */ 170 171 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 } 176 177 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 } 182 183 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 } 188 189 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 202 203 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack) 204 { 205 return bus->hw_ops.bit->getdata(bus, ack); 206 } 207 208 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 } 216 217 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 } 224 225 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 } 231 232 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 } 244 245 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 } 256 257 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 } 274 275 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 } 300 301 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 } 327 328 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 } 341 342 343 static int __init alsa_i2c_init(void) 344 { 345 return 0; 346 } 347 348 static void __exit alsa_i2c_exit(void) 349 { 350 } 351 352 module_init(alsa_i2c_init) 353 module_exit(alsa_i2c_exit) 354