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 init_MUTEX(&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 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name, 110 unsigned char addr, struct snd_i2c_device **rdevice) 111 { 112 struct snd_i2c_device *device; 113 114 *rdevice = NULL; 115 snd_assert(bus != NULL, return -EINVAL); 116 device = kzalloc(sizeof(*device), GFP_KERNEL); 117 if (device == NULL) 118 return -ENOMEM; 119 device->addr = addr; 120 strlcpy(device->name, name, sizeof(device->name)); 121 list_add_tail(&device->list, &bus->devices); 122 device->bus = bus; 123 *rdevice = device; 124 return 0; 125 } 126 127 int snd_i2c_device_free(struct snd_i2c_device *device) 128 { 129 if (device->bus) 130 list_del(&device->list); 131 if (device->private_free) 132 device->private_free(device); 133 kfree(device); 134 return 0; 135 } 136 137 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count) 138 { 139 return device->bus->ops->sendbytes(device, bytes, count); 140 } 141 142 143 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count) 144 { 145 return device->bus->ops->readbytes(device, bytes, count); 146 } 147 148 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr) 149 { 150 return bus->ops->probeaddr(bus, addr); 151 } 152 153 /* 154 * bit-operations 155 */ 156 157 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus) 158 { 159 if (bus->hw_ops.bit->start) 160 bus->hw_ops.bit->start(bus); 161 } 162 163 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus) 164 { 165 if (bus->hw_ops.bit->stop) 166 bus->hw_ops.bit->stop(bus); 167 } 168 169 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data) 170 { 171 if (bus->hw_ops.bit->direction) 172 bus->hw_ops.bit->direction(bus, clock, data); 173 } 174 175 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data) 176 { 177 bus->hw_ops.bit->setlines(bus, clock, data); 178 } 179 180 #if 0 181 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus) 182 { 183 if (bus->hw_ops.bit->getclock) 184 return bus->hw_ops.bit->getclock(bus); 185 return -ENXIO; 186 } 187 #endif 188 189 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack) 190 { 191 return bus->hw_ops.bit->getdata(bus, ack); 192 } 193 194 static void snd_i2c_bit_start(struct snd_i2c_bus *bus) 195 { 196 snd_i2c_bit_hw_start(bus); 197 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */ 198 snd_i2c_bit_set(bus, 1, 1); 199 snd_i2c_bit_set(bus, 1, 0); 200 snd_i2c_bit_set(bus, 0, 0); 201 } 202 203 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus) 204 { 205 snd_i2c_bit_set(bus, 0, 0); 206 snd_i2c_bit_set(bus, 1, 0); 207 snd_i2c_bit_set(bus, 1, 1); 208 snd_i2c_bit_hw_stop(bus); 209 } 210 211 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data) 212 { 213 snd_i2c_bit_set(bus, 0, data); 214 snd_i2c_bit_set(bus, 1, data); 215 snd_i2c_bit_set(bus, 0, data); 216 } 217 218 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus) 219 { 220 int ack; 221 222 snd_i2c_bit_set(bus, 0, 1); 223 snd_i2c_bit_set(bus, 1, 1); 224 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */ 225 ack = snd_i2c_bit_data(bus, 1); 226 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */ 227 snd_i2c_bit_set(bus, 0, 1); 228 return ack ? -EIO : 0; 229 } 230 231 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data) 232 { 233 int i, err; 234 235 for (i = 7; i >= 0; i--) 236 snd_i2c_bit_send(bus, !!(data & (1 << i))); 237 if ((err = snd_i2c_bit_ack(bus)) < 0) 238 return err; 239 return 0; 240 } 241 242 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last) 243 { 244 int i; 245 unsigned char data = 0; 246 247 snd_i2c_bit_set(bus, 0, 1); 248 snd_i2c_bit_direction(bus, 1, 0); /* SCL - wr, SDA - rd */ 249 for (i = 7; i >= 0; i--) { 250 snd_i2c_bit_set(bus, 1, 1); 251 if (snd_i2c_bit_data(bus, 0)) 252 data |= (1 << i); 253 snd_i2c_bit_set(bus, 0, 1); 254 } 255 snd_i2c_bit_direction(bus, 1, 1); /* SCL - wr, SDA - wr */ 256 snd_i2c_bit_send(bus, !!last); 257 return data; 258 } 259 260 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device, 261 unsigned char *bytes, int count) 262 { 263 struct snd_i2c_bus *bus = device->bus; 264 int err, res = 0; 265 266 if (device->flags & SND_I2C_DEVICE_ADDRTEN) 267 return -EIO; /* not yet implemented */ 268 snd_i2c_bit_start(bus); 269 if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) { 270 snd_i2c_bit_hw_stop(bus); 271 return err; 272 } 273 while (count-- > 0) { 274 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) { 275 snd_i2c_bit_hw_stop(bus); 276 return err; 277 } 278 res++; 279 } 280 snd_i2c_bit_stop(bus); 281 return res; 282 } 283 284 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device, 285 unsigned char *bytes, int count) 286 { 287 struct snd_i2c_bus *bus = device->bus; 288 int err, res = 0; 289 290 if (device->flags & SND_I2C_DEVICE_ADDRTEN) 291 return -EIO; /* not yet implemented */ 292 snd_i2c_bit_start(bus); 293 if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) { 294 snd_i2c_bit_hw_stop(bus); 295 return err; 296 } 297 while (count-- > 0) { 298 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) { 299 snd_i2c_bit_hw_stop(bus); 300 return err; 301 } 302 *bytes++ = (unsigned char)err; 303 res++; 304 } 305 snd_i2c_bit_stop(bus); 306 return res; 307 } 308 309 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr) 310 { 311 int err; 312 313 if (addr & 0x8000) /* 10-bit address */ 314 return -EIO; /* not yet implemented */ 315 if (addr & 0x7f80) /* invalid address */ 316 return -EINVAL; 317 snd_i2c_bit_start(bus); 318 err = snd_i2c_bit_sendbyte(bus, addr << 1); 319 snd_i2c_bit_stop(bus); 320 return err; 321 } 322 323 EXPORT_SYMBOL(snd_i2c_bus_create); 324 EXPORT_SYMBOL(snd_i2c_device_create); 325 EXPORT_SYMBOL(snd_i2c_device_free); 326 EXPORT_SYMBOL(snd_i2c_sendbytes); 327 EXPORT_SYMBOL(snd_i2c_readbytes); 328 EXPORT_SYMBOL(snd_i2c_probeaddr); 329 330 static int __init alsa_i2c_init(void) 331 { 332 return 0; 333 } 334 335 static void __exit alsa_i2c_exit(void) 336 { 337 } 338 339 module_init(alsa_i2c_init) 340 module_exit(alsa_i2c_exit) 341