sound/i2c/i2c.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *   Generic i2c interface for ALSA
   4  *
   5  *   (c) 1998 Gerd Knorr <kraxel@cs.tu-berlin.de>
   6  *   Modified for the ALSA driver by Jaroslav Kysela <perex@perex.cz>
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/slab.h>
  11 #include <linux/module.h>
  12 #include <linux/string.h>
  13 #include <linux/errno.h>
  14 #include <sound/core.h>
  15 #include <sound/i2c.h>
  16
  17 MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
  18 MODULE_DESCRIPTION("Generic i2c interface for ALSA");
  19 MODULE_LICENSE("GPL");
  20
  21 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
  22                                  unsigned char *bytes, int count);
  23 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
  24                                  unsigned char *bytes, int count);
  25 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus,
  26                                  unsigned short addr);
  27
  28 static const struct snd_i2c_ops snd_i2c_bit_ops = {
  29         .sendbytes = snd_i2c_bit_sendbytes,
  30         .readbytes = snd_i2c_bit_readbytes,
  31         .probeaddr = snd_i2c_bit_probeaddr,
  32 };
  33
  34 static int snd_i2c_bus_free(struct snd_i2c_bus *bus)
  35 {
  36         struct snd_i2c_bus *slave;
  37         struct snd_i2c_device *device;
  38
  39         if (snd_BUG_ON(!bus))
  40                 return -EINVAL;
  41         while (!list_empty(&bus->devices)) {
  42                 device = snd_i2c_device(bus->devices.next);
  43                 snd_i2c_device_free(device);
  44         }
  45         if (bus->master)
  46                 list_del(&bus->buses);
  47         else {
  48                 while (!list_empty(&bus->buses)) {
  49                         slave = snd_i2c_slave_bus(bus->buses.next);
  50                         snd_device_free(bus->card, slave);
  51                 }
  52         }
  53         if (bus->private_free)
  54                 bus->private_free(bus);
  55         kfree(bus);
  56         return 0;
  57 }
  58
  59 static int snd_i2c_bus_dev_free(struct snd_device *device)
  60 {
  61         struct snd_i2c_bus *bus = device->device_data;
  62         return snd_i2c_bus_free(bus);
  63 }
  64
  65 int snd_i2c_bus_create(struct snd_card *card, const char *name,
  66                        struct snd_i2c_bus *master, struct snd_i2c_bus **ri2c)
  67 {
  68         struct snd_i2c_bus *bus;
  69         int err;
  70         static struct snd_device_ops ops = {
  71                 .dev_free =     snd_i2c_bus_dev_free,
  72         };
  73
  74         *ri2c = NULL;
  75         bus = kzalloc(sizeof(*bus), GFP_KERNEL);
  76         if (bus == NULL)
  77                 return -ENOMEM;
  78         mutex_init(&bus->lock_mutex);
  79         INIT_LIST_HEAD(&bus->devices);
  80         INIT_LIST_HEAD(&bus->buses);
  81         bus->card = card;
  82         bus->ops = &snd_i2c_bit_ops;
  83         if (master) {
  84                 list_add_tail(&bus->buses, &master->buses);
  85                 bus->master = master;
  86         }
  87         strlcpy(bus->name, name, sizeof(bus->name));
  88         err = snd_device_new(card, SNDRV_DEV_BUS, bus, &ops);
  89         if (err < 0) {
  90                 snd_i2c_bus_free(bus);
  91                 return err;
  92         }
  93         *ri2c = bus;
  94         return 0;
  95 }
  96
  97 EXPORT_SYMBOL(snd_i2c_bus_create);
  98
  99 int snd_i2c_device_create(struct snd_i2c_bus *bus, const char *name,
 100                           unsigned char addr, struct snd_i2c_device **rdevice)
 101 {
 102         struct snd_i2c_device *device;
 103
 104         *rdevice = NULL;
 105         if (snd_BUG_ON(!bus))
 106                 return -EINVAL;
 107         device = kzalloc(sizeof(*device), GFP_KERNEL);
 108         if (device == NULL)
 109                 return -ENOMEM;
 110         device->addr = addr;
 111         strlcpy(device->name, name, sizeof(device->name));
 112         list_add_tail(&device->list, &bus->devices);
 113         device->bus = bus;
 114         *rdevice = device;
 115         return 0;
 116 }
 117
 118 EXPORT_SYMBOL(snd_i2c_device_create);
 119
 120 int snd_i2c_device_free(struct snd_i2c_device *device)
 121 {
 122         if (device->bus)
 123                 list_del(&device->list);
 124         if (device->private_free)
 125                 device->private_free(device);
 126         kfree(device);
 127         return 0;
 128 }
 129
 130 EXPORT_SYMBOL(snd_i2c_device_free);
 131
 132 int snd_i2c_sendbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
 133 {
 134         return device->bus->ops->sendbytes(device, bytes, count);
 135 }
 136
 137 EXPORT_SYMBOL(snd_i2c_sendbytes);
 138
 139 int snd_i2c_readbytes(struct snd_i2c_device *device, unsigned char *bytes, int count)
 140 {
 141         return device->bus->ops->readbytes(device, bytes, count);
 142 }
 143
 144 EXPORT_SYMBOL(snd_i2c_readbytes);
 145
 146 int snd_i2c_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
 147 {
 148         return bus->ops->probeaddr(bus, addr);
 149 }
 150
 151 EXPORT_SYMBOL(snd_i2c_probeaddr);
 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         err = snd_i2c_bit_ack(bus);
 238         if (err < 0)
 239                 return err;
 240         return 0;
 241 }
 242
 243 static int snd_i2c_bit_readbyte(struct snd_i2c_bus *bus, int last)
 244 {
 245         int i;
 246         unsigned char data = 0;
 247
 248         snd_i2c_bit_set(bus, 0, 1);
 249         snd_i2c_bit_direction(bus, 1, 0);       /* SCL - wr, SDA - rd */
 250         for (i = 7; i >= 0; i--) {
 251                 snd_i2c_bit_set(bus, 1, 1);
 252                 if (snd_i2c_bit_data(bus, 0))
 253                         data |= (1 << i);
 254                 snd_i2c_bit_set(bus, 0, 1);
 255         }
 256         snd_i2c_bit_direction(bus, 1, 1);       /* SCL - wr, SDA - wr */
 257         snd_i2c_bit_send(bus, !!last);
 258         return data;
 259 }
 260
 261 static int snd_i2c_bit_sendbytes(struct snd_i2c_device *device,
 262                                  unsigned char *bytes, int count)
 263 {
 264         struct snd_i2c_bus *bus = device->bus;
 265         int err, res = 0;
 266
 267         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 268                 return -EIO;            /* not yet implemented */
 269         snd_i2c_bit_start(bus);
 270         err = snd_i2c_bit_sendbyte(bus, device->addr << 1);
 271         if (err < 0) {
 272                 snd_i2c_bit_hw_stop(bus);
 273                 return err;
 274         }
 275         while (count-- > 0) {
 276                 err = snd_i2c_bit_sendbyte(bus, *bytes++);
 277                 if (err < 0) {
 278                         snd_i2c_bit_hw_stop(bus);
 279                         return err;
 280                 }
 281                 res++;
 282         }
 283         snd_i2c_bit_stop(bus);
 284         return res;
 285 }
 286
 287 static int snd_i2c_bit_readbytes(struct snd_i2c_device *device,
 288                                  unsigned char *bytes, int count)
 289 {
 290         struct snd_i2c_bus *bus = device->bus;
 291         int err, res = 0;
 292
 293         if (device->flags & SND_I2C_DEVICE_ADDRTEN)
 294                 return -EIO;            /* not yet implemented */
 295         snd_i2c_bit_start(bus);
 296         err = snd_i2c_bit_sendbyte(bus, (device->addr << 1) | 1);
 297         if (err < 0) {
 298                 snd_i2c_bit_hw_stop(bus);
 299                 return err;
 300         }
 301         while (count-- > 0) {
 302                 err = snd_i2c_bit_readbyte(bus, count == 0);
 303                 if (err < 0) {
 304                         snd_i2c_bit_hw_stop(bus);
 305                         return err;
 306                 }
 307                 *bytes++ = (unsigned char)err;
 308                 res++;
 309         }
 310         snd_i2c_bit_stop(bus);
 311         return res;
 312 }
 313
 314 static int snd_i2c_bit_probeaddr(struct snd_i2c_bus *bus, unsigned short addr)
 315 {
 316         int err;
 317
 318         if (addr & 0x8000)      /* 10-bit address */
 319                 return -EIO;    /* not yet implemented */
 320         if (addr & 0x7f80)      /* invalid address */
 321                 return -EINVAL;
 322         snd_i2c_bit_start(bus);
 323         err = snd_i2c_bit_sendbyte(bus, addr << 1);
 324         snd_i2c_bit_stop(bus);
 325         return err;
 326 }