kernel/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/module.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@perex.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         if (snd_BUG_ON(!bus))
  54                 return -EINVAL;
  55         while (!list_empty(&bus->devices)) {
  56                 device = snd_i2c_device(bus->devices.next);
  57                 snd_i2c_device_free(device);
  58         }
  59         if (bus->master)
  60                 list_del(&bus->buses);
  61         else {
  62                 while (!list_empty(&bus->buses)) {
  63                         slave = snd_i2c_slave_bus(bus->buses.next);
  64                         snd_device_free(bus->card, slave);
  65                 }
  66         }
  67         if (bus->private_free)
  68                 bus->private_free(bus);
  69         kfree(bus);
  70         return 0;
  71 }
  72
  73 static int snd_i2c_bus_dev_free(struct snd_device *device)
  74 {
  75         struct snd_i2c_bus *bus = device->device_data;
  76         return snd_i2c_bus_free(bus);
  77 }
  78
  79 int snd_i2c_bus_create(struct snd_card *card, const char *name,
  80                        struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
  81 {
  82         struct snd_i2c_bus *bus;
  83         int err;
  84         static struct snd_device_ops ops = {
  85                 .dev_free =     snd_i2c_bus_dev_free,
  86         };
  87
  88         *ri2c = NULL;
  89         bus = kzalloc(sizeof(*bus), GFP_KERNEL);
  90         if (bus == NULL)
  91                 return -ENOMEM;
  92         mutex_init(&bus->lock_mutex);
  93         INIT_LIST_HEAD(&bus->devices);
  94         INIT_LIST_HEAD(&bus->buses);
  95         bus->card = card;
  96         bus->ops = &snd_i2c_bit_ops;
  97         if (master) {
  98                 list_add_tail(&bus->buses, &master->buses);
  99                 bus->master = master;
 100         }
 101         strlcpy(bus->name, name, sizeof(bus->name));
 102         err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
 103         if (err < 0) {
 104                 snd_i2c_bus_free(bus);
 105                 return err;
 106         }
 107         *ri2c = bus;
 108         return 0;
 109 }
 110
 111 EXPORT_SYMBOL(snd_i2c_bus_create);
 112
 113 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
 114                           unsigned char addr, struct snd_i2c_device **rdevice)
 115 {
 116         struct snd_i2c_device *device;
 117
 118         *rdevice = NULL;
 119         if (snd_BUG_ON(!bus))
 120                 return -EINVAL;
 121         device = kzalloc(sizeof(*device), GFP_KERNEL);
 122         if (device == NULL)
 123                 return -ENOMEM;
 124         device->addr = addr;
 125         strlcpy(device->name, name, sizeof(device->name));
 126         list_add_tail(&device->list, &bus->devices);
 127         device->bus = bus;
 128         *rdevice = device;
 129         return 0;
 130 }
 131
 132 EXPORT_SYMBOL(snd_i2c_device_create);
 133
 134 int snd_i2c_device_free(struct snd_i2c_device *device)
 135 {
 136         if (device->bus)
 137                 list_del(&device->list);
 138         if (device->private_free)
 139                 device->private_free(device);
 140         kfree(device);
 141         return 0;
 142 }
 143
 144 EXPORT_SYMBOL(snd_i2c_device_free);
 145
 146 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
 147 {
 148         return device->bus->ops->sendbytes(device, bytes, count);
 149 }
 150
 151 EXPORT_SYMBOL(snd_i2c_sendbytes);
 152
 153 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
 154 {
 155         return device->bus->ops->readbytes(device, bytes, count);
 156 }
 157
 158 EXPORT_SYMBOL(snd_i2c_readbytes);
 159
 160 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
 161 {
 162         return bus->ops->probeaddr(bus, addr);
 163 }
 164
 165 EXPORT_SYMBOL(snd_i2c_probeaddr);
 166
 167 /*
 168  *  bit-operations
 169  */
 170
 171 static inline void snd_i2c_bit_hw_start(struct snd_i2c_bus *bus)
 172 {
 173         if (bus->hw_ops.bit->start)
 174                 bus->hw_ops.bit->start(bus);
 175 }
 176
 177 static inline void snd_i2c_bit_hw_stop(struct snd_i2c_bus *bus)
 178 {
 179         if (bus->hw_ops.bit->stop)
 180                 bus->hw_ops.bit->stop(bus);
 181 }
 182
 183 static void snd_i2c_bit_direction(struct snd_i2c_bus *bus, int clock, int data)
 184 {
 185         if (bus->hw_ops.bit->direction)
 186                 bus->hw_ops.bit->direction(bus, clock, data);
 187 }
 188
 189 static void snd_i2c_bit_set(struct snd_i2c_bus *bus, int clock, int data)
 190 {
 191         bus->hw_ops.bit->setlines(bus, clock, data);
 192 }
 193
 194 #if 0
 195 static int snd_i2c_bit_clock(struct snd_i2c_bus *bus)
 196 {
 197         if (bus->hw_ops.bit->getclock)
 198                 return bus->hw_ops.bit->getclock(bus);
 199         return -ENXIO;
 200 }
 201 #endif
 202
 203 static int snd_i2c_bit_data(struct snd_i2c_bus *bus, int ack)
 204 {
 205         return bus->hw_ops.bit->getdata(bus, ack);
 206 }
 207
 208 static void snd_i2c_bit_start(struct snd_i2c_bus *bus)
 209 {
 210         snd_i2c_bit_hw_start(bus);
 211         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 212         snd_i2c_bit_set(bus, 1, 1);
 213         snd_i2c_bit_set(bus, 1, 0);
 214         snd_i2c_bit_set(bus, 0, 0);
 215 }
 216
 217 static void snd_i2c_bit_stop(struct snd_i2c_bus *bus)
 218 {
 219         snd_i2c_bit_set(bus, 0, 0);
 220         snd_i2c_bit_set(bus, 1, 0);
 221         snd_i2c_bit_set(bus, 1, 1);
 222         snd_i2c_bit_hw_stop(bus);
 223 }
 224
 225 static void snd_i2c_bit_send(struct snd_i2c_bus *bus, int data)
 226 {
 227         snd_i2c_bit_set(bus, 0, data);
 228         snd_i2c_bit_set(bus, 1, data);
 229         snd_i2c_bit_set(bus, 0, data);
 230 }
 231
 232 static int snd_i2c_bit_ack(struct snd_i2c_bus *bus)
 233 {
 234         int ack;
 235
 236         snd_i2c_bit_set(bus, 0, 1);
 237         snd_i2c_bit_set(bus, 1, 1);
 238         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 239         ack = snd_i2c_bit_data(bus, 1);
 240         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 241         snd_i2c_bit_set(bus, 0, 1);
 242         return ack ? -EIO : 0;
 243 }
 244
 245 static int snd_i2c_bit_sendbyte(struct snd_i2c_bus *bus, unsigned char data)
 246 {
 247         int i, err;
 248
 249         for (i = 7; i >= 0; i--)
 250                 snd_i2c_bit_send(bus, !!(data & (1 << i)));
 251         err = snd_i2c_bit_ack(bus);
 252         if (err < 0)
 253                 return err;
 254         return 0;
 255 }
 256
 257 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
 258 {
 259         int i;
 260         unsigned char data = 0;
 261
 262         snd_i2c_bit_set(bus, 0, 1);
 263         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 264         for (i = 7; i >= 0; i--) {
 265                 snd_i2c_bit_set(bus, 1, 1);
 266                 if (snd_i2c_bit_data(bus, 0))
 267                         data |= (1 << i);
 268                 snd_i2c_bit_set(bus, 0, 1);
 269         }
 270         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 271         snd_i2c_bit_send(bus, !!last);
 272         return data;
 273 }
 274
 275 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
 276                                  unsigned char *bytes, int count)
 277 {
 278         struct snd_i2c_bus *bus = device->bus;
 279         int err, res = 0;
 280
 281         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 282                 return -EIO;            /* not yet implemented */
 283         snd_i2c_bit_start(bus);
 284         err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
 285         if (err < 0) {
 286                 snd_i2c_bit_hw_stop(bus);
 287                 return err;
 288         }
 289         while (count-- > 0) {
 290                 err = snd_i2c_bit_sendbyte(bus, *bytes++);
 291                 if (err < 0) {
 292                         snd_i2c_bit_hw_stop(bus);
 293                         return err;
 294                 }
 295                 res++;
 296         }
 297         snd_i2c_bit_stop(bus);
 298         return res;
 299 }
 300
 301 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
 302                                  unsigned char *bytes, int count)
 303 {
 304         struct snd_i2c_bus *bus = device->bus;
 305         int err, res = 0;
 306
 307         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 308                 return -EIO;            /* not yet implemented */
 309         snd_i2c_bit_start(bus);
 310         err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
 311         if (err < 0) {
 312                 snd_i2c_bit_hw_stop(bus);
 313                 return err;
 314         }
 315         while (count-- > 0) {
 316                 err = snd_i2c_bit_readbyte(bus, count == 0);
 317                 if (err < 0) {
 318                         snd_i2c_bit_hw_stop(bus);
 319                         return err;
 320                 }
 321                 *bytes++ = (unsigned char)err;
 322                 res++;
 323         }
 324         snd_i2c_bit_stop(bus);
 325         return res;
 326 }
 327
 328 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
 329 {
 330         int err;
 331
 332         if (addr & 0x8000)      /* 10-bit address */
 333                 return -EIO;    /* not yet implemented */
 334         if (addr & 0x7f80)      /* invalid address */
 335                 return -EINVAL;
 336         snd_i2c_bit_start(bus);
 337         err = snd_i2c_bit_sendbyte(bus, addr << 1);
 338         snd_i2c_bit_stop(bus);
 339         return err;
 340 }
 341
 342
 343 static int __init alsa_i2c_init(void)
 344 {
 345         return 0;
 346 }
 347
 348 static void __exit alsa_i2c_exit(void)
 349 {
 350 }
 351
 352 module_init(alsa_i2c_init)
 353 module_exit(alsa_i2c_exit)