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