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