drivers/i2c/busses/i2c-powermac.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3     i2c Support for Apple SMU Controller
   4
   5     Copyright (c) 2005 Benjamin Herrenschmidt, IBM Corp.
   6                        <benh@kernel.crashing.org>
   7
   8
   9 */
  10
  11 #include <linux/module.h>
  12 #include <linux/kernel.h>
  13 #include <linux/types.h>
  14 #include <linux/i2c.h>
  15 #include <linux/device.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/of_irq.h>
  18
  19 #include <asm/pmac_low_i2c.h>
  20
  21 MODULE_AUTHOR("Benjamin Herrenschmidt <benh@kernel.crashing.org>");
  22 MODULE_DESCRIPTION("I2C driver for Apple PowerMac");
  23 MODULE_LICENSE("GPL");
  24
  25 /*
  26  * SMBUS-type transfer entrypoint
  27  */
  28 static s32 i2c_powermac_smbus_xfer(     struct i2c_adapter*     adap,
  29                                         u16                     addr,
  30                                         unsigned short          flags,
  31                                         char                    read_write,
  32                                         u8                      command,
  33                                         int                     size,
  34                                         union i2c_smbus_data*   data)
  35 {
  36         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
  37         int                     rc = 0;
  38         int                     read = (read_write == I2C_SMBUS_READ);
  39         int                     addrdir = (addr << 1) | read;
  40         int                     mode, subsize, len;
  41         u32                     subaddr;
  42         u8                      *buf;
  43         u8                      local[2];
  44
  45         if (size == I2C_SMBUS_QUICK || size == I2C_SMBUS_BYTE) {
  46                 mode = pmac_i2c_mode_std;
  47                 subsize = 0;
  48                 subaddr = 0;
  49         } else {
  50                 mode = read ? pmac_i2c_mode_combined : pmac_i2c_mode_stdsub;
  51                 subsize = 1;
  52                 subaddr = command;
  53         }
  54
  55         switch (size) {
  56         case I2C_SMBUS_QUICK:
  57                 buf = NULL;
  58                 len = 0;
  59                 break;
  60         case I2C_SMBUS_BYTE:
  61         case I2C_SMBUS_BYTE_DATA:
  62                 buf = &data->byte;
  63                 len = 1;
  64                 break;
  65         case I2C_SMBUS_WORD_DATA:
  66                 if (!read) {
  67                         local[0] = data->word & 0xff;
  68                         local[1] = (data->word >> 8) & 0xff;
  69                 }
  70                 buf = local;
  71                 len = 2;
  72                 break;
  73
  74         /* Note that these are broken vs. the expected smbus API where
  75          * on reads, the length is actually returned from the function,
  76          * but I think the current API makes no sense and I don't want
  77          * any driver that I haven't verified for correctness to go
  78          * anywhere near a pmac i2c bus anyway ...
  79          */
  80         case I2C_SMBUS_BLOCK_DATA:
  81                 buf = data->block;
  82                 len = data->block[0] + 1;
  83                 break;
  84         case I2C_SMBUS_I2C_BLOCK_DATA:
  85                 buf = &data->block[1];
  86                 len = data->block[0];
  87                 break;
  88
  89         default:
  90                 return -EINVAL;
  91         }
  92
  93         rc = pmac_i2c_open(bus, 0);
  94         if (rc) {
  95                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
  96                 return rc;
  97         }
  98
  99         rc = pmac_i2c_setmode(bus, mode);
 100         if (rc) {
 101                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
 102                         mode, rc);
 103                 goto bail;
 104         }
 105
 106         rc = pmac_i2c_xfer(bus, addrdir, subsize, subaddr, buf, len);
 107         if (rc) {
 108                 if (rc == -ENXIO)
 109                         dev_dbg(&adap->dev,
 110                                 "I2C transfer at 0x%02x failed, size %d, "
 111                                 "err %d\n", addrdir >> 1, size, rc);
 112                 else
 113                         dev_err(&adap->dev,
 114                                 "I2C transfer at 0x%02x failed, size %d, "
 115                                 "err %d\n", addrdir >> 1, size, rc);
 116                 goto bail;
 117         }
 118
 119         if (size == I2C_SMBUS_WORD_DATA && read) {
 120                 data->word = ((u16)local[1]) << 8;
 121                 data->word |= local[0];
 122         }
 123
 124  bail:
 125         pmac_i2c_close(bus);
 126         return rc;
 127 }
 128
 129 /*
 130  * Generic i2c transfer entrypoint. This driver only supports single
 131  * messages (for "lame i2c" transfers). Anything else should use the smbus
 132  * entry point
 133  */
 134 static int i2c_powermac_xfer(struct i2c_adapter *adap,
 135                              struct i2c_msg *msgs,
 136                              int num)
 137 {
 138         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
 139         int                     rc = 0;
 140         int                     addrdir;
 141
 142         if (msgs->flags & I2C_M_TEN)
 143                 return -EINVAL;
 144         addrdir = i2c_8bit_addr_from_msg(msgs);
 145
 146         rc = pmac_i2c_open(bus, 0);
 147         if (rc) {
 148                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
 149                 return rc;
 150         }
 151         rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
 152         if (rc) {
 153                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
 154                         pmac_i2c_mode_std, rc);
 155                 goto bail;
 156         }
 157         rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
 158         if (rc < 0) {
 159                 if (rc == -ENXIO)
 160                         dev_dbg(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
 161                                 addrdir & 1 ? "read from" : "write to",
 162                                 addrdir >> 1, rc);
 163                 else
 164                         dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
 165                                 addrdir & 1 ? "read from" : "write to",
 166                                 addrdir >> 1, rc);
 167         }
 168  bail:
 169         pmac_i2c_close(bus);
 170         return rc < 0 ? rc : 1;
 171 }
 172
 173 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
 174 {
 175         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 176                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 177                 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
 178 }
 179
 180 /* For now, we only handle smbus */
 181 static const struct i2c_algorithm i2c_powermac_algorithm = {
 182         .smbus_xfer = i2c_powermac_smbus_xfer,
 183         .xfer = i2c_powermac_xfer,
 184         .functionality = i2c_powermac_func,
 185 };
 186
 187 static const struct i2c_adapter_quirks i2c_powermac_quirks = {
 188         .max_num_msgs = 1,
 189 };
 190
 191 static void i2c_powermac_remove(struct platform_device *dev)
 192 {
 193         struct i2c_adapter      *adapter = platform_get_drvdata(dev);
 194
 195         i2c_del_adapter(adapter);
 196         memset(adapter, 0, sizeof(*adapter));
 197 }
 198
 199 static u32 i2c_powermac_get_addr(struct i2c_adapter *adap,
 200                                            struct pmac_i2c_bus *bus,
 201                                            struct device_node *node)
 202 {
 203         u32 prop;
 204         int ret;
 205
 206         /* First check for valid "reg" */
 207         ret = of_property_read_u32(node, "reg", &prop);
 208         if (ret == 0)
 209                 return (prop & 0xff) >> 1;
 210
 211         /* Then check old-style "i2c-address" */
 212         ret = of_property_read_u32(node, "i2c-address", &prop);
 213         if (ret == 0)
 214                 return (prop & 0xff) >> 1;
 215
 216         /* Now handle some devices with missing "reg" properties */
 217         if (of_node_name_eq(node, "cereal"))
 218                 return 0x60;
 219         else if (of_node_name_eq(node, "deq"))
 220                 return 0x34;
 221
 222         dev_warn(&adap->dev, "No i2c address for %pOF\n", node);
 223
 224         return 0xffffffff;
 225 }
 226
 227 static void i2c_powermac_create_one(struct i2c_adapter *adap,
 228                                               const char *type,
 229                                               u32 addr)
 230 {
 231         struct i2c_board_info info = {};
 232         struct i2c_client *newdev;
 233
 234         strscpy(info.type, type, sizeof(info.type));
 235         info.addr = addr;
 236         newdev = i2c_new_client_device(adap, &info);
 237         if (IS_ERR(newdev))
 238                 dev_err(&adap->dev,
 239                         "i2c-powermac: Failure to register missing %s\n",
 240                         type);
 241 }
 242
 243 static void i2c_powermac_add_missing(struct i2c_adapter *adap,
 244                                                struct pmac_i2c_bus *bus,
 245                                                bool found_onyx)
 246 {
 247         struct device_node *busnode = pmac_i2c_get_bus_node(bus);
 248         int rc;
 249
 250         /* Check for the onyx audio codec */
 251 #define ONYX_REG_CONTROL                67
 252         if (of_device_is_compatible(busnode, "k2-i2c") && !found_onyx) {
 253                 union i2c_smbus_data data;
 254
 255                 rc = i2c_smbus_xfer(adap, 0x46, 0, I2C_SMBUS_READ,
 256                                     ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
 257                                     &data);
 258                 if (rc >= 0)
 259                         i2c_powermac_create_one(adap, "MAC,pcm3052", 0x46);
 260
 261                 rc = i2c_smbus_xfer(adap, 0x47, 0, I2C_SMBUS_READ,
 262                                     ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
 263                                     &data);
 264                 if (rc >= 0)
 265                         i2c_powermac_create_one(adap, "MAC,pcm3052", 0x47);
 266         }
 267 }
 268
 269 static bool i2c_powermac_get_type(struct i2c_adapter *adap,
 270                                             struct device_node *node,
 271                                             u32 addr, char *type, int type_size)
 272 {
 273         char tmp[16];
 274
 275         /*
 276          * Note: we do _NOT_ want the standard i2c drivers to match with any of
 277          * our powermac stuff unless they have been specifically modified to
 278          * handle it on a case by case basis. For example, for thermal control,
 279          * things like lm75 etc... shall match with their corresponding
 280          * windfarm drivers, _NOT_ the generic ones, so we force a prefix of
 281          * 'MAC', onto the modalias to make that happen
 282          */
 283
 284         /* First try proper modalias */
 285         if (of_alias_from_compatible(node, tmp, sizeof(tmp)) >= 0) {
 286                 snprintf(type, type_size, "MAC,%s", tmp);
 287                 return true;
 288         }
 289
 290         /* Now look for known workarounds */
 291         if (of_node_name_eq(node, "deq")) {
 292                 /* Apple uses address 0x34 for TAS3001 and 0x35 for TAS3004 */
 293                 if (addr == 0x34) {
 294                         snprintf(type, type_size, "MAC,tas3001");
 295                         return true;
 296                 } else if (addr == 0x35) {
 297                         snprintf(type, type_size, "MAC,tas3004");
 298                         return true;
 299                 }
 300         }
 301
 302         dev_err(&adap->dev, "i2c-powermac: modalias failure on %pOF\n", node);
 303         return false;
 304 }
 305
 306 static void i2c_powermac_register_devices(struct i2c_adapter *adap,
 307                                                     struct pmac_i2c_bus *bus)
 308 {
 309         struct i2c_client *newdev;
 310         struct device_node *node;
 311         bool found_onyx = false;
 312
 313         /*
 314          * In some cases we end up with the via-pmu node itself, in this
 315          * case we skip this function completely as the device-tree will
 316          * not contain anything useful.
 317          */
 318         if (of_node_name_eq(adap->dev.of_node, "via-pmu"))
 319                 return;
 320
 321         for_each_child_of_node(adap->dev.of_node, node) {
 322                 struct i2c_board_info info = {};
 323                 u32 addr;
 324
 325                 /* Get address & channel */
 326                 addr = i2c_powermac_get_addr(adap, bus, node);
 327                 if (addr == 0xffffffff)
 328                         continue;
 329
 330                 /* Multibus setup, check channel */
 331                 if (!pmac_i2c_match_adapter(node, adap))
 332                         continue;
 333
 334                 dev_dbg(&adap->dev, "i2c-powermac: register %pOF\n", node);
 335
 336                 /*
 337                  * Keep track of some device existence to handle
 338                  * workarounds later.
 339                  */
 340                 if (of_device_is_compatible(node, "pcm3052"))
 341                         found_onyx = true;
 342
 343                 /* Make up a modalias */
 344                 if (!i2c_powermac_get_type(adap, node, addr,
 345                                            info.type, sizeof(info.type))) {
 346                         continue;
 347                 }
 348
 349                 /* Fill out the rest of the info structure */
 350                 info.addr = addr;
 351                 info.irq = irq_of_parse_and_map(node, 0);
 352                 info.of_node = of_node_get(node);
 353
 354                 newdev = i2c_new_client_device(adap, &info);
 355                 if (IS_ERR(newdev)) {
 356                         dev_err(&adap->dev, "i2c-powermac: Failure to register"
 357                                 " %pOF\n", node);
 358                         of_node_put(node);
 359                         /* We do not dispose of the interrupt mapping on
 360                          * purpose. It's not necessary (interrupt cannot be
 361                          * re-used) and somebody else might have grabbed it
 362                          * via direct DT lookup so let's not bother
 363                          */
 364                         continue;
 365                 }
 366         }
 367
 368         /* Additional workarounds */
 369         i2c_powermac_add_missing(adap, bus, found_onyx);
 370 }
 371
 372 static int i2c_powermac_probe(struct platform_device *dev)
 373 {
 374         struct pmac_i2c_bus *bus = dev_get_platdata(&dev->dev);
 375         struct device_node *parent;
 376         struct i2c_adapter *adapter;
 377         int rc;
 378
 379         if (bus == NULL)
 380                 return -EINVAL;
 381         adapter = pmac_i2c_get_adapter(bus);
 382
 383         /* Ok, now we need to make up a name for the interface that will
 384          * match what we used to do in the past, that is basically the
 385          * controller's parent device node for keywest. PMU didn't have a
 386          * naming convention and SMU has a different one
 387          */
 388         switch(pmac_i2c_get_type(bus)) {
 389         case pmac_i2c_bus_keywest:
 390                 parent = of_get_parent(pmac_i2c_get_controller(bus));
 391                 if (parent == NULL)
 392                         return -EINVAL;
 393                 snprintf(adapter->name, sizeof(adapter->name), "%pOFn %d",
 394                          parent,
 395                          pmac_i2c_get_channel(bus));
 396                 of_node_put(parent);
 397                 break;
 398         case pmac_i2c_bus_pmu:
 399                 snprintf(adapter->name, sizeof(adapter->name), "pmu %d",
 400                          pmac_i2c_get_channel(bus));
 401                 break;
 402         case pmac_i2c_bus_smu:
 403                 /* This is not what we used to do but I'm fixing drivers at
 404                  * the same time as this change
 405                  */
 406                 snprintf(adapter->name, sizeof(adapter->name), "smu %d",
 407                          pmac_i2c_get_channel(bus));
 408                 break;
 409         default:
 410                 return -EINVAL;
 411         }
 412
 413         platform_set_drvdata(dev, adapter);
 414         adapter->algo = &i2c_powermac_algorithm;
 415         adapter->quirks = &i2c_powermac_quirks;
 416         i2c_set_adapdata(adapter, bus);
 417         adapter->dev.parent = &dev->dev;
 418
 419         /* Clear of_node to skip automatic registration of i2c child nodes */
 420         adapter->dev.of_node = NULL;
 421         rc = i2c_add_adapter(adapter);
 422         if (rc) {
 423                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
 424                        "failed\n", adapter->name);
 425                 memset(adapter, 0, sizeof(*adapter));
 426                 return rc;
 427         }
 428
 429         printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
 430
 431         /* Use custom child registration due to Apple device-tree funkyness */
 432         adapter->dev.of_node = dev->dev.of_node;
 433         i2c_powermac_register_devices(adapter, bus);
 434
 435         return 0;
 436 }
 437
 438 static struct platform_driver i2c_powermac_driver = {
 439         .probe = i2c_powermac_probe,
 440         .remove = i2c_powermac_remove,
 441         .driver = {
 442                 .name = "i2c-powermac",
 443                 .bus = &platform_bus_type,
 444         },
 445 };
 446
 447 module_platform_driver(i2c_powermac_driver);
 448
 449 MODULE_ALIAS("platform:i2c-powermac");