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 #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)