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