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 <sound/core.h>
  27 #include <sound/i2c.h>
  28
  29 MODULE_AUTHOR("Jaroslav Kysela <perex@suse.cz>");
  30 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
  31 MODULE_LICENSE("GPL");
  32
  33 static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
  34 static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count);
  35 static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr);
  36
  37 static snd_i2c_ops_t snd_i2c_bit_ops = {
  38         sendbytes: snd_i2c_bit_sendbytes,
  39         readbytes: snd_i2c_bit_readbytes,
  40         probeaddr: snd_i2c_bit_probeaddr,
  41 };
  42
  43 static int snd_i2c_bus_free(snd_i2c_bus_t *bus)
  44 {
  45         snd_i2c_bus_t *slave;
  46         snd_i2c_device_t *device;
  47
  48         snd_assert(bus != NULL, return -EINVAL);
  49         while (!list_empty(&bus->devices)) {
  50                 device = snd_i2c_device(bus->devices.next);
  51                 snd_i2c_device_free(device);
  52         }
  53         if (bus->master)
  54                 list_del(&bus->buses);
  55         else {
  56                 while (!list_empty(&bus->buses)) {
  57                         slave = snd_i2c_slave_bus(bus->buses.next);
  58                         snd_device_free(bus->card, slave);
  59                 }
  60         }
  61         if (bus->private_free)
  62                 bus->private_free(bus);
  63         snd_magic_kfree(bus);
  64         return 0;
  65 }
  66
  67 static int snd_i2c_bus_dev_free(snd_device_t *device)
  68 {
  69         snd_i2c_bus_t *bus = snd_magic_cast(snd_i2c_bus_t, device->device_data, return -ENXIO);
  70         return snd_i2c_bus_free(bus);
  71 }
  72
  73 int snd_i2c_bus_create(snd_card_t *card, const char *name, snd_i2c_bus_t *master, snd_i2c_bus_t **ri2c)
  74 {
  75         snd_i2c_bus_t *bus;
  76         int err;
  77         static snd_device_ops_t ops = {
  78                 dev_free:       snd_i2c_bus_dev_free,
  79         };
  80
  81         *ri2c = NULL;
  82         bus = (snd_i2c_bus_t *)snd_magic_kcalloc(snd_i2c_bus_t, 0, GFP_KERNEL);
  83         if (bus == NULL)
  84                 return -ENOMEM;
  85         spin_lock_init(&bus->lock);
  86         INIT_LIST_HEAD(&bus->devices);
  87         INIT_LIST_HEAD(&bus->buses);
  88         bus->card = card;
  89         bus->ops = &snd_i2c_bit_ops;
  90         if (master) {
  91                 list_add_tail(&bus->buses, &master->buses);
  92                 bus->master = master;
  93         }
  94         strncpy(bus->name, name, sizeof(bus->name) - 1);
  95         if ((err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, bus, &ops)) < 0) {
  96                 snd_i2c_bus_free(bus);
  97                 return err;
  98         }
  99         *ri2c = bus;
 100         return 0;
 101 }
 102
 103 int snd_i2c_device_create(snd_i2c_bus_t *bus, const char *name, unsigned char addr, snd_i2c_device_t **rdevice)
 104 {
 105         snd_i2c_device_t *device;
 106
 107         *rdevice = NULL;
 108         snd_assert(bus != NULL, return -EINVAL);
 109         device = (snd_i2c_device_t *)snd_magic_kcalloc(snd_i2c_device_t, 0, GFP_KERNEL);
 110         if (device == NULL)
 111                 return -ENOMEM;
 112         device->addr = addr;
 113         strncpy(device->name, name, sizeof(device->name)-1);
 114         list_add_tail(&device->list, &bus->devices);
 115         device->bus = bus;
 116         *rdevice = device;
 117         return 0;
 118 }
 119
 120 int snd_i2c_device_free(snd_i2c_device_t *device)
 121 {
 122         if (device->bus)
 123                 list_del(&device->list);
 124         if (device->private_free)
 125                 device->private_free(device);
 126         snd_magic_kfree(device);
 127         return 0;
 128 }
 129
 130 int snd_i2c_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
 131 {
 132         return device->bus->ops->sendbytes(device, bytes, count);
 133 }
 134
 135
 136 int snd_i2c_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
 137 {
 138         return device->bus->ops->readbytes(device, bytes, count);
 139 }
 140
 141 int snd_i2c_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
 142 {
 143         return bus->ops->probeaddr(bus, addr);
 144 }
 145
 146 /*
 147  *  bit-operations
 148  */
 149
 150 static inline void snd_i2c_bit_hw_start(snd_i2c_bus_t *bus)
 151 {
 152         if (bus->hw_ops.bit->start)
 153                 bus->hw_ops.bit->start(bus);
 154 }
 155
 156 static inline void snd_i2c_bit_hw_stop(snd_i2c_bus_t *bus)
 157 {
 158         if (bus->hw_ops.bit->stop)
 159                 bus->hw_ops.bit->stop(bus);
 160 }
 161
 162 static void snd_i2c_bit_direction(snd_i2c_bus_t *bus, int clock, int data)
 163 {
 164         if (bus->hw_ops.bit->direction)
 165                 bus->hw_ops.bit->direction(bus, clock, data);
 166 }
 167
 168 static void snd_i2c_bit_set(snd_i2c_bus_t *bus, int clock, int data)
 169 {
 170         bus->hw_ops.bit->setlines(bus, clock, data);
 171 }
 172
 173 #if 0
 174 static int snd_i2c_bit_clock(snd_i2c_bus_t *bus)
 175 {
 176         if (bus->hw_ops.bit->getclock)
 177                 return bus->hw_ops.bit->getclock(bus);
 178         return -ENXIO;
 179 }
 180 #endif
 181
 182 static int snd_i2c_bit_data(snd_i2c_bus_t *bus, int ack)
 183 {
 184         return bus->hw_ops.bit->getdata(bus, ack);
 185 }
 186
 187 static void snd_i2c_bit_start(snd_i2c_bus_t *bus)
 188 {
 189         snd_i2c_bit_hw_start(bus);
 190         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 191         snd_i2c_bit_set(bus, 1, 1);
 192         snd_i2c_bit_set(bus, 1, 0);
 193         snd_i2c_bit_set(bus, 0, 0);
 194 }
 195
 196 static void snd_i2c_bit_stop(snd_i2c_bus_t *bus)
 197 {
 198         snd_i2c_bit_set(bus, 0, 0);
 199         snd_i2c_bit_set(bus, 1, 0);
 200         snd_i2c_bit_set(bus, 1, 1);
 201         snd_i2c_bit_hw_stop(bus);
 202 }
 203
 204 static void snd_i2c_bit_send(snd_i2c_bus_t *bus, int data)
 205 {
 206         snd_i2c_bit_set(bus, 0, data);
 207         snd_i2c_bit_set(bus, 1, data);
 208         snd_i2c_bit_set(bus, 0, data);
 209 }
 210
 211 static int snd_i2c_bit_ack(snd_i2c_bus_t *bus)
 212 {
 213         int ack;
 214
 215         snd_i2c_bit_set(bus, 0, 1);
 216         snd_i2c_bit_set(bus, 1, 1);
 217         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 218         ack = snd_i2c_bit_data(bus, 1);
 219         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 220         snd_i2c_bit_set(bus, 0, 1);
 221         return ack ? -EREMOTEIO : 0;
 222 }
 223
 224 static int snd_i2c_bit_sendbyte(snd_i2c_bus_t *bus, unsigned char data)
 225 {
 226         int i, err;
 227
 228         for (i = 7; i >= 0; i--)
 229                 snd_i2c_bit_send(bus, !!(data & (1 << i)));
 230         if ((err = snd_i2c_bit_ack(bus)) < 0)
 231                 return err;
 232         return 0;
 233 }
 234
 235 static int snd_i2c_bit_readbyte(snd_i2c_bus_t *bus, int last)
 236 {
 237         int i;
 238         unsigned char data = 0;
 239
 240         snd_i2c_bit_set(bus, 0, 1);
 241         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 242         for (i = 7; i >= 0; i--) {
 243                 snd_i2c_bit_set(bus, 1, 1);
 244                 if (snd_i2c_bit_data(bus, 0))
 245                         data |= (1 << i);
 246                 snd_i2c_bit_set(bus, 0, 1);
 247         }
 248         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 249         snd_i2c_bit_send(bus, !!last);
 250         return data;
 251 }
 252
 253 static int snd_i2c_bit_sendbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
 254 {
 255         snd_i2c_bus_t *bus = device->bus;
 256         int err, res = 0;
 257
 258         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 259                 return -EIO;            /* not yet implemented */
 260         snd_i2c_bit_start(bus);
 261         if ((err = snd_i2c_bit_sendbyte(bus, device->addr << 1)) < 0)
 262                 return err;
 263         while (count-- > 0) {
 264                 if ((err = snd_i2c_bit_sendbyte(bus, *bytes++)) < 0)
 265                         return err;
 266                 res++;
 267         }
 268         snd_i2c_bit_stop(bus);
 269         return res;
 270 }
 271
 272 static int snd_i2c_bit_readbytes(snd_i2c_device_t *device, unsigned char *bytes, int count)
 273 {
 274         snd_i2c_bus_t *bus = device->bus;
 275         int err, res = 0;
 276
 277         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 278                 return -EIO;            /* not yet implemented */
 279         snd_i2c_bit_start(bus);
 280         if ((err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1)) < 0)
 281                 return err;
 282         while (count-- > 0) {
 283                 if ((err = snd_i2c_bit_readbyte(bus, count == 0)) < 0)
 284                         return err;
 285                 *bytes++ = (unsigned char)err;
 286                 res++;
 287         }
 288         snd_i2c_bit_stop(bus);
 289         return res;
 290 }
 291
 292 static int snd_i2c_bit_probeaddr(snd_i2c_bus_t *bus, unsigned short addr)
 293 {
 294         int err;
 295
 296         if (addr & 0x8000)      /* 10-bit address */
 297                 return -EIO;    /* not yet implemented */
 298         if (addr & 0x7f80)      /* invalid address */
 299                 return -EINVAL;
 300         snd_i2c_bit_start(bus);
 301         if ((err = snd_i2c_bit_sendbyte(bus, addr << 1)) < 0)
 302                 return err;
 303         snd_i2c_bit_stop(bus);
 304         return 1;               /* present */
 305 }
 306
 307 EXPORT_SYMBOL(snd_i2c_bus_create);
 308 EXPORT_SYMBOL(snd_i2c_device_create);
 309 EXPORT_SYMBOL(snd_i2c_device_free);
 310 EXPORT_SYMBOL(snd_i2c_sendbytes);
 311 EXPORT_SYMBOL(snd_i2c_readbytes);
 312 EXPORT_SYMBOL(snd_i2c_probeaddr);
 313
 314 static int __init alsa_i2c_init(void)
 315 {
 316         return 0;
 317 }
 318
 319 static void __exit alsa_i2c_exit(void)
 320 {
 321 }
 322
 323 module_init(alsa_i2c_init)
 324 module_exit(alsa_i2c_exit)