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@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(snd_i2c_device_t *device, unsigned char *bytes, int count);
  36 static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
  37 static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr);
  38
  39 static snd_i2c_ops_t snd_i2c_bit_ops = {
  40         .sendbytes = snd_i2c_bit_sendbytes,
  41         .readbytes = snd_i2c_bit_readbytes,
  42         .probeaddr = snd_i2c_bit_probeaddr,
  43 };
  44
  45 static int snd_i2c_bus_free(snd_i2c_bus_t *bus)
  46 {
  47         snd_i2c_bus_t *slave;
  48         snd_i2c_device_t *device;
  49
  50         snd_assert(bus != NULL, return -EINVAL);
  51         while (!list_empty(&bus->devices)) {
  52                 device = snd_i2c_device(bus->devices.next);
  53                 snd_i2c_device_free(device);
  54         }
  55         if (bus->master)
  56                 list_del(&bus->buses);
  57         else {
  58                 while (!list_empty(&bus->buses)) {
  59                         slave = snd_i2c_slave_bus(bus->buses.next);
  60                         snd_device_free(bus->card, slave);
  61                 }
  62         }
  63         if (bus->private_free)
  64                 bus->private_free(bus);
  65         kfree(bus);
  66         return 0;
  67 }
  68
  69 static int snd_i2c_bus_dev_free(snd_device_t *device)
  70 {
  71         snd_i2c_bus_t *bus = device->device_data;
  72         return snd_i2c_bus_free(bus);
  73 }
  74
  75 int snd_i2c_bus_create(snd_card_t *card, const char *name, snd_i2c_bus_t *master, snd_i2c_bus_t **ri2c)
  76 {
  77         snd_i2c_bus_t *bus;
  78         int err;
  79         static snd_device_ops_t ops = {
  80                 .dev_free =     snd_i2c_bus_dev_free,
  81         };
  82
  83         *ri2c = NULL;
  84         bus = kcalloc(1, sizeof(*bus), GFP_KERNEL);
  85         if (bus == NULL)
  86                 return -ENOMEM;
  87         init_MUTEX(&bus->lock_mutex);
  88         INIT_LIST_HEAD(&bus->devices);
  89         INIT_LIST_HEAD(&bus->buses);
  90         bus->card = card;
  91         bus->ops = &snd_i2c_bit_ops;
  92         if (master) {
  93                 list_add_tail(&bus->buses, &master->buses);
  94                 bus->master = master;
  95         }
  96         strlcpy(bus->name, name, sizeof(bus->name));
  97         if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, bus, &ops)) < 0) {
  98                 snd_i2c_bus_free(bus);
  99                 return err;
 100         }
 101         *ri2c = bus;
 102         return 0;
 103 }
 104
 105 int snd_i2c_device_create(snd_i2c_bus_t *bus, const char *name, unsigned char addr, snd_i2c_device_t **rdevice)
 106 {
 107         snd_i2c_device_t *device;
 108
 109         *rdevice = NULL;
 110         snd_assert(bus != NULL, return -EINVAL);
 111         device = kcalloc(1, sizeof(*device), GFP_KERNEL);
 112         if (device == NULL)
 113                 return -ENOMEM;
 114         device->addr = addr;
 115         strlcpy(device->name, name, sizeof(device->name));
 116         list_add_tail(&device->list, &bus->devices);
 117         device->bus = bus;
 118         *rdevice = device;
 119         return 0;
 120 }
 121
 122 int snd_i2c_device_free(snd_i2c_device_t *device)
 123 {
 124         if (device->bus)
 125                 list_del(&device->list);
 126         if (device->private_free)
 127                 device->private_free(device);
 128         kfree(device);
 129         return 0;
 130 }
 131
 132 int snd_i2c_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
 133 {
 134         return device->bus->ops->sendbytes(device, bytes, count);
 135 }
 136
 137
 138 int snd_i2c_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
 139 {
 140         return device->bus->ops->readbytes(device, bytes, count);
 141 }
 142
 143 int snd_i2c_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
 144 {
 145         return bus->ops->probeaddr(bus, addr);
 146 }
 147
 148 /*
 149  *  bit-operations
 150  */
 151
 152 static inline void snd_i2c_bit_hw_start(snd_i2c_bus_t *bus)
 153 {
 154         if (bus->hw_ops.bit->start)
 155                 bus->hw_ops.bit->start(bus);
 156 }
 157
 158 static inline void snd_i2c_bit_hw_stop(snd_i2c_bus_t *bus)
 159 {
 160         if (bus->hw_ops.bit->stop)
 161                 bus->hw_ops.bit->stop(bus);
 162 }
 163
 164 static void snd_i2c_bit_direction(snd_i2c_bus_t *bus, int clock, int data)
 165 {
 166         if (bus->hw_ops.bit->direction)
 167                 bus->hw_ops.bit->direction(bus, clock, data);
 168 }
 169
 170 static void snd_i2c_bit_set(snd_i2c_bus_t *bus, int clock, int data)
 171 {
 172         bus->hw_ops.bit->setlines(bus, clock, data);
 173 }
 174
 175 #if 0
 176 static int snd_i2c_bit_clock(snd_i2c_bus_t *bus)
 177 {
 178         if (bus->hw_ops.bit->getclock)
 179                 return bus->hw_ops.bit->getclock(bus);
 180         return -ENXIO;
 181 }
 182 #endif
 183
 184 static int snd_i2c_bit_data(snd_i2c_bus_t *bus, int ack)
 185 {
 186         return bus->hw_ops.bit->getdata(bus, ack);
 187 }
 188
 189 static void snd_i2c_bit_start(snd_i2c_bus_t *bus)
 190 {
 191         snd_i2c_bit_hw_start(bus);
 192         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 193         snd_i2c_bit_set(bus, 1, 1);
 194         snd_i2c_bit_set(bus, 1, 0);
 195         snd_i2c_bit_set(bus, 0, 0);
 196 }
 197
 198 static void snd_i2c_bit_stop(snd_i2c_bus_t *bus)
 199 {
 200         snd_i2c_bit_set(bus, 0, 0);
 201         snd_i2c_bit_set(bus, 1, 0);
 202         snd_i2c_bit_set(bus, 1, 1);
 203         snd_i2c_bit_hw_stop(bus);
 204 }
 205
 206 static void snd_i2c_bit_send(snd_i2c_bus_t *bus, int data)
 207 {
 208         snd_i2c_bit_set(bus, 0, data);
 209         snd_i2c_bit_set(bus, 1, data);
 210         snd_i2c_bit_set(bus, 0, data);
 211 }
 212
 213 static int snd_i2c_bit_ack(snd_i2c_bus_t *bus)
 214 {
 215         int ack;
 216
 217         snd_i2c_bit_set(bus, 0, 1);
 218         snd_i2c_bit_set(bus, 1, 1);
 219         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 220         ack = snd_i2c_bit_data(bus, 1);
 221         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 222         snd_i2c_bit_set(bus, 0, 1);
 223         return ack ? -EIO : 0;
 224 }
 225
 226 static int snd_i2c_bit_sendbyte(snd_i2c_bus_t *bus, unsigned char data)
 227 {
 228         int i, err;
 229
 230         for (i = 7; i >= 0; i--)
 231                 snd_i2c_bit_send(bus, !!(data & (1 << i)));
 232         if ((err = snd_i2c_bit_ack(bus)) < 0)
 233                 return err;
 234         return 0;
 235 }
 236
 237 static int snd_i2c_bit_readbyte(snd_i2c_bus_t *bus, int last)
 238 {
 239         int i;
 240         unsigned char data = 0;
 241
 242         snd_i2c_bit_set(bus, 0, 1);
 243         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 244         for (i = 7; i >= 0; i--) {
 245                 snd_i2c_bit_set(bus, 1, 1);
 246                 if (snd_i2c_bit_data(bus, 0))
 247                         data |= (1 << i);
 248                 snd_i2c_bit_set(bus, 0, 1);
 249         }
 250         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 251         snd_i2c_bit_send(bus, !!last);
 252         return data;
 253 }
 254
 255 static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
 256 {
 257         snd_i2c_bus_t *bus = device->bus;
 258         int err, res = 0;
 259
 260         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 261                 return -EIO;            /* not yet implemented */
 262         snd_i2c_bit_start(bus);
 263         if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0) {
 264                 snd_i2c_bit_hw_stop(bus);
 265                 return err;
 266         }
 267         while (count-- > 0) {
 268                 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0) {
 269                         snd_i2c_bit_hw_stop(bus);
 270                         return err;
 271                 }
 272                 res++;
 273         }
 274         snd_i2c_bit_stop(bus);
 275         return res;
 276 }
 277
 278 static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
 279 {
 280         snd_i2c_bus_t *bus = device->bus;
 281         int err, res = 0;
 282
 283         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 284                 return -EIO;            /* not yet implemented */
 285         snd_i2c_bit_start(bus);
 286         if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0) {
 287                 snd_i2c_bit_hw_stop(bus);
 288                 return err;
 289         }
 290         while (count-- > 0) {
 291                 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0) {
 292                         snd_i2c_bit_hw_stop(bus);
 293                         return err;
 294                 }
 295                 *bytes++ = (unsigned char)err;
 296                 res++;
 297         }
 298         snd_i2c_bit_stop(bus);
 299         return res;
 300 }
 301
 302 static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
 303 {
 304         int err;
 305
 306         if (addr & 0x8000)      /* 10-bit address */
 307                 return -EIO;    /* not yet implemented */
 308         if (addr & 0x7f80)      /* invalid address */
 309                 return -EINVAL;
 310         snd_i2c_bit_start(bus);
 311         err = snd_i2c_bit_sendbyte(bus, addr << 1);
 312         snd_i2c_bit_stop(bus);
 313         return err;
 314 }
 315
 316 EXPORT_SYMBOL(snd_i2c_bus_create);
 317 EXPORT_SYMBOL(snd_i2c_device_create);
 318 EXPORT_SYMBOL(snd_i2c_device_free);
 319 EXPORT_SYMBOL(snd_i2c_sendbytes);
 320 EXPORT_SYMBOL(snd_i2c_readbytes);
 321 EXPORT_SYMBOL(snd_i2c_probeaddr);
 322
 323 static int __init alsa_i2c_init(void)
 324 {
 325         return 0;
 326 }
 327
 328 static void __exit alsa_i2c_exit(void)
 329 {
 330 }
 331
 332 module_init(alsa_i2c_init)
 333 module_exit(alsa_i2c_exit)