release/src-rt-6.x.4708/linux/linux-2.6.36/sound/i2c/i2c.c

   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
 194 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
 195 {
 196         return bus->hw_ops.bit->getdata(bus, ack);
 197 }
 198
 199 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
 200 {
 201         snd_i2c_bit_hw_start(bus);
 202         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 203         snd_i2c_bit_set(bus, 1, 1);
 204         snd_i2c_bit_set(bus, 1, 0);
 205         snd_i2c_bit_set(bus, 0, 0);
 206 }
 207
 208 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
 209 {
 210         snd_i2c_bit_set(bus, 0, 0);
 211         snd_i2c_bit_set(bus, 1, 0);
 212         snd_i2c_bit_set(bus, 1, 1);
 213         snd_i2c_bit_hw_stop(bus);
 214 }
 215
 216 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
 217 {
 218         snd_i2c_bit_set(bus, 0, data);
 219         snd_i2c_bit_set(bus, 1, data);
 220         snd_i2c_bit_set(bus, 0, data);
 221 }
 222
 223 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
 224 {
 225         int ack;
 226
 227         snd_i2c_bit_set(bus, 0, 1);
 228         snd_i2c_bit_set(bus, 1, 1);
 229         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 230         ack = snd_i2c_bit_data(bus, 1);
 231         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 232         snd_i2c_bit_set(bus, 0, 1);
 233         return ack ? -EIO : 0;
 234 }
 235
 236 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
 237 {
 238         int i, err;
 239
 240         for (i = 7; i >= 0; i--)
 241                 snd_i2c_bit_send(bus, !!(data & (1 << i)));
 242         err = snd_i2c_bit_ack(bus);
 243         if (err < 0)
 244                 return err;
 245         return 0;
 246 }
 247
 248 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
 249 {
 250         int i;
 251         unsigned char data = 0;
 252
 253         snd_i2c_bit_set(bus, 0, 1);
 254         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 255         for (i = 7; i >= 0; i--) {
 256                 snd_i2c_bit_set(bus, 1, 1);
 257                 if (snd_i2c_bit_data(bus, 0))
 258                         data |= (1 << i);
 259                 snd_i2c_bit_set(bus, 0, 1);
 260         }
 261         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 262         snd_i2c_bit_send(bus, !!last);
 263         return data;
 264 }
 265
 266 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
 267                                  unsigned char *bytes, int count)
 268 {
 269         struct snd_i2c_bus *bus = device->bus;
 270         int err, res = 0;
 271
 272         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 273                 return -EIO;            /* not yet implemented */
 274         snd_i2c_bit_start(bus);
 275         err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
 276         if (err < 0) {
 277                 snd_i2c_bit_hw_stop(bus);
 278                 return err;
 279         }
 280         while (count-- > 0) {
 281                 err = snd_i2c_bit_sendbyte(bus, *bytes++);
 282                 if (err < 0) {
 283                         snd_i2c_bit_hw_stop(bus);
 284                         return err;
 285                 }
 286                 res++;
 287         }
 288         snd_i2c_bit_stop(bus);
 289         return res;
 290 }
 291
 292 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
 293                                  unsigned char *bytes, int count)
 294 {
 295         struct snd_i2c_bus *bus = device->bus;
 296         int err, res = 0;
 297
 298         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 299                 return -EIO;            /* not yet implemented */
 300         snd_i2c_bit_start(bus);
 301         err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
 302         if (err < 0) {
 303                 snd_i2c_bit_hw_stop(bus);
 304                 return err;
 305         }
 306         while (count-- > 0) {
 307                 err = snd_i2c_bit_readbyte(bus, count == 0);
 308                 if (err < 0) {
 309                         snd_i2c_bit_hw_stop(bus);
 310                         return err;
 311                 }
 312                 *bytes++ = (unsigned char)err;
 313                 res++;
 314         }
 315         snd_i2c_bit_stop(bus);
 316         return res;
 317 }
 318
 319 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
 320 {
 321         int err;
 322
 323         if (addr & 0x8000)      /* 10-bit address */
 324                 return -EIO;    /* not yet implemented */
 325         if (addr & 0x7f80)      /* invalid address */
 326                 return -EINVAL;
 327         snd_i2c_bit_start(bus);
 328         err = snd_i2c_bit_sendbyte(bus, addr << 1);
 329         snd_i2c_bit_stop(bus);
 330         return err;
 331 }
 332
 333
 334 static int __init alsa_i2c_init(void)
 335 {
 336         return 0;
 337 }
 338
 339 static void __exit alsa_i2c_exit(void)
 340 {
 341 }
 342
 343 module_init(alsa_i2c_init)
 344 module_exit(alsa_i2c_exit)