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 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> 30 31 MODULE_AUTHOR("Jaroslav Kysela <perex@suse.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 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); 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 if ((err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops)) < 0) { 102 snd_i2c_bus_free(bus); 103 return err; 104 } 105 *ri2c = bus; 106 return 0; 107 } 108 109 EXPORT_SYMBOL(snd_i2c_bus_create); 110 111 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name, 112 unsigned char addr, struct snd_i2c_device **rdevice) 113 { 114 struct snd_i2c_device *device; 115 116 *rdevice = NULL; 117 snd_assert(bus != NULL, return -EINVAL); 118 device = kzalloc(sizeof(*device), GFP_KERNEL); 119 if (device == NULL) 120 return -ENOMEM; 121 device->addr = addr; 122 strlcpy(device->name, name, sizeof(device->name)); 123 list_add_tail(&device->list, &bus->devices); 124 device->bus = bus; 125 *rdevice = device; 126 return 0; 127 } 128 129 EXPORT_SYMBOL(snd_i2c_device_create); 130 131 int snd_i2c_device_free(struct snd_i2c_device *device) 132 { 133 if (device->bus) 134 list_del(&device->list); 135 if (device->private_free) 136 device->private_free(device); 137 kfree(device); 138 return 0; 139 } 140 141 EXPORT_SYMBOL(snd_i2c_device_free); 142 143 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count) 144 { 145 return device->bus->ops->sendbytes(device, bytes, count); 146 } 147 148 EXPORT_SYMBOL(snd_i2c_sendbytes); 149 150 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count) 151 { 152 return device->bus->ops->readbytes(device, bytes, count); 153 } 154 155 EXPORT_SYMBOL(snd_i2c_readbytes); 156 157 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr) 158 { 159 return bus->ops->probeaddr(bus, addr); 160 } 161 162 EXPORT_SYMBOL(snd_i2c_probeaddr); 163 164 /* 165 * bit-operations 166 */ 167 168 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus) 169 { 170 if (bus->hw_ops.bit->start) 171 bus->hw_ops.bit->start(bus); 172 } 173 174 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus) 175 { 176 if (bus->hw_ops.bit->stop) 177 bus->hw_ops.bit->stop(bus); 178 } 179 180 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data) 181 { 182 if (bus->hw_ops.bit->direction) 183 bus->hw_ops.bit->direction(bus, clock, data); 184 } 185 186 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data) 187 { 188 bus->hw_ops.bit->setlines(bus, clock, data); 189 } 190 191 #if 0 192 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus) 193 { 194 if (bus->hw_ops.bit->getclock) 195 return bus->hw_ops.bit->getclock(bus); 196 return -ENXIO; 197 } 198 #endif 199 200 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack) 201 { 202 return bus->hw_ops.bit->getdata(bus, ack); 203 } 204 205 static void snd_i2c_bit_start(struct snd_i2c_bus *bus) 206 { 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); 212 } 213 214 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus) 215 { 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); 220 } 221 222 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data) 223 { 224 snd_i2c_bit_set(bus, 0, data); 225 snd_i2c_bit_set(bus, 1, data); 226 snd_i2c_bit_set(bus, 0, data); 227 } 228 229 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus) 230 { 231 int ack; 232 233 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; 240 } 241 242 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data) 243 { 244 int i, err; 245 246 for (i = 7; i >= 0; i--) 247 snd_i2c_bit_send(bus, !!(data & (1 << i))); 248 if ((err = snd_i2c_bit_ack(bus)) < 0) 249 return err; 250 return 0; 251 } 252 253 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last) 254 { 255 int i; 256 unsigned char data = 0; 257 258 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)) 263 data |= (1 << i); 264 snd_i2c_bit_set(bus, 0, 1); 265 } 266 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */ 267 snd_i2c_bit_send(bus, !!last); 268 return data; 269 } 270 271 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device, 272 unsigned char *bytes, int count) 273 { 274 struct snd_i2c_bus *bus = device->bus; 275 int err, res = 0; 276 277 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); 282 return err; 283 } 284 while (count-- > 0) { 285 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) { 286 snd_i2c_bit_hw_stop(bus); 287 return err; 288 } 289 res++; 290 } 291 snd_i2c_bit_stop(bus); 292 return res; 293 } 294 295 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device, 296 unsigned char *bytes, int count) 297 { 298 struct snd_i2c_bus *bus = device->bus; 299 int err, res = 0; 300 301 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); 306 return err; 307 } 308 while (count-- > 0) { 309 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) { 310 snd_i2c_bit_hw_stop(bus); 311 return err; 312 } 313 *bytes++ = (unsigned char)err; 314 res++; 315 } 316 snd_i2c_bit_stop(bus); 317 return res; 318 } 319 320 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr) 321 { 322 int err; 323 324 if (addr & 0x8000) /* 10-bit address */ 325 return -EIO; /* not yet implemented */ 326 if (addr & 0x7f80) /* invalid address */ 327 return -EINVAL; 328 snd_i2c_bit_start(bus); 329 err = snd_i2c_bit_sendbyte(bus, addr << 1); 330 snd_i2c_bit_stop(bus); 331 return err; 332 } 333 334 335 static int __init alsa_i2c_init(void) 336 { 337 return 0; 338 } 339 340 static void __exit alsa_i2c_exit(void) 341 { 342 } 343 344 module_init(alsa_i2c_init) 345 module_exit(alsa_i2c_exit) 346