| 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) |