root/drivers/i2c/busses/i2c-powermac.c

DEFINITIONS

1. i2c_powermac_smbus_xfer
2. i2c_powermac_master_xfer
3. i2c_powermac_func
4. i2c_powermac_remove
5. i2c_powermac_get_addr
6. i2c_powermac_create_one
7. i2c_powermac_add_missing
8. i2c_powermac_get_type
9. i2c_powermac_register_devices
10. i2c_powermac_probe

   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 #include <asm/prom.h>
  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          * I'm also not completely sure what kind of phases to do between
  81          * the actual command and the data (what I am _supposed_ to do that
  82          * is). For now, I assume writes are a single stream and reads have
  83          * a repeat start/addr phase (but not stop in between)
  84          */
  85         case I2C_SMBUS_BLOCK_DATA:
  86                 buf = data->block;
  87                 len = data->block[0] + 1;
  88                 break;
  89         case I2C_SMBUS_I2C_BLOCK_DATA:
  90                 buf = &data->block[1];
  91                 len = data->block[0];
  92                 break;
  93 
  94         default:
  95                 return -EINVAL;
  96         }
  97 
  98         rc = pmac_i2c_open(bus, 0);
  99         if (rc) {
 100                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
 101                 return rc;
 102         }
 103 
 104         rc = pmac_i2c_setmode(bus, mode);
 105         if (rc) {
 106                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
 107                         mode, rc);
 108                 goto bail;
 109         }
 110 
 111         rc = pmac_i2c_xfer(bus, addrdir, subsize, subaddr, buf, len);
 112         if (rc) {
 113                 if (rc == -ENXIO)
 114                         dev_dbg(&adap->dev,
 115                                 "I2C transfer at 0x%02x failed, size %d, "
 116                                 "err %d\n", addrdir >> 1, size, rc);
 117                 else
 118                         dev_err(&adap->dev,
 119                                 "I2C transfer at 0x%02x failed, size %d, "
 120                                 "err %d\n", addrdir >> 1, size, rc);
 121                 goto bail;
 122         }
 123 
 124         if (size == I2C_SMBUS_WORD_DATA && read) {
 125                 data->word = ((u16)local[1]) << 8;
 126                 data->word |= local[0];
 127         }
 128 
 129  bail:
 130         pmac_i2c_close(bus);
 131         return rc;
 132 }
 133 
 134 /*
 135  * Generic i2c master transfer entrypoint. This driver only support single
 136  * messages (for "lame i2c" transfers). Anything else should use the smbus
 137  * entry point
 138  */
 139 static int i2c_powermac_master_xfer(    struct i2c_adapter *adap,
 140                                         struct i2c_msg *msgs,
 141                                         int num)
 142 {
 143         struct pmac_i2c_bus     *bus = i2c_get_adapdata(adap);
 144         int                     rc = 0;
 145         int                     addrdir;
 146 
 147         if (msgs->flags & I2C_M_TEN)
 148                 return -EINVAL;
 149         addrdir = i2c_8bit_addr_from_msg(msgs);
 150 
 151         rc = pmac_i2c_open(bus, 0);
 152         if (rc) {
 153                 dev_err(&adap->dev, "Failed to open I2C, err %d\n", rc);
 154                 return rc;
 155         }
 156         rc = pmac_i2c_setmode(bus, pmac_i2c_mode_std);
 157         if (rc) {
 158                 dev_err(&adap->dev, "Failed to set I2C mode %d, err %d\n",
 159                         pmac_i2c_mode_std, rc);
 160                 goto bail;
 161         }
 162         rc = pmac_i2c_xfer(bus, addrdir, 0, 0, msgs->buf, msgs->len);
 163         if (rc < 0) {
 164                 if (rc == -ENXIO)
 165                         dev_dbg(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
 166                                 addrdir & 1 ? "read from" : "write to",
 167                                 addrdir >> 1, rc);
 168                 else
 169                         dev_err(&adap->dev, "I2C %s 0x%02x failed, err %d\n",
 170                                 addrdir & 1 ? "read from" : "write to",
 171                                 addrdir >> 1, rc);
 172         }
 173  bail:
 174         pmac_i2c_close(bus);
 175         return rc < 0 ? rc : 1;
 176 }
 177 
 178 static u32 i2c_powermac_func(struct i2c_adapter * adapter)
 179 {
 180         return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE |
 181                 I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA |
 182                 I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_I2C;
 183 }
 184 
 185 /* For now, we only handle smbus */
 186 static const struct i2c_algorithm i2c_powermac_algorithm = {
 187         .smbus_xfer     = i2c_powermac_smbus_xfer,
 188         .master_xfer    = i2c_powermac_master_xfer,
 189         .functionality  = i2c_powermac_func,
 190 };
 191 
 192 static const struct i2c_adapter_quirks i2c_powermac_quirks = {
 193         .max_num_msgs = 1,
 194 };
 195 
 196 static int i2c_powermac_remove(struct platform_device *dev)
 197 {
 198         struct i2c_adapter      *adapter = platform_get_drvdata(dev);
 199 
 200         i2c_del_adapter(adapter);
 201         memset(adapter, 0, sizeof(*adapter));
 202 
 203         return 0;
 204 }
 205 
 206 static u32 i2c_powermac_get_addr(struct i2c_adapter *adap,
 207                                            struct pmac_i2c_bus *bus,
 208                                            struct device_node *node)
 209 {
 210         const __be32 *prop;
 211         int len;
 212 
 213         /* First check for valid "reg" */
 214         prop = of_get_property(node, "reg", &len);
 215         if (prop && (len >= sizeof(int)))
 216                 return (be32_to_cpup(prop) & 0xff) >> 1;
 217 
 218         /* Then check old-style "i2c-address" */
 219         prop = of_get_property(node, "i2c-address", &len);
 220         if (prop && (len >= sizeof(int)))
 221                 return (be32_to_cpup(prop) & 0xff) >> 1;
 222 
 223         /* Now handle some devices with missing "reg" properties */
 224         if (of_node_name_eq(node, "cereal"))
 225                 return 0x60;
 226         else if (of_node_name_eq(node, "deq"))
 227                 return 0x34;
 228 
 229         dev_warn(&adap->dev, "No i2c address for %pOF\n", node);
 230 
 231         return 0xffffffff;
 232 }
 233 
 234 static void i2c_powermac_create_one(struct i2c_adapter *adap,
 235                                               const char *type,
 236                                               u32 addr)
 237 {
 238         struct i2c_board_info info = {};
 239         struct i2c_client *newdev;
 240 
 241         strncpy(info.type, type, sizeof(info.type));
 242         info.addr = addr;
 243         newdev = i2c_new_device(adap, &info);
 244         if (!newdev)
 245                 dev_err(&adap->dev,
 246                         "i2c-powermac: Failure to register missing %s\n",
 247                         type);
 248 }
 249 
 250 static void i2c_powermac_add_missing(struct i2c_adapter *adap,
 251                                                struct pmac_i2c_bus *bus,
 252                                                bool found_onyx)
 253 {
 254         struct device_node *busnode = pmac_i2c_get_bus_node(bus);
 255         int rc;
 256 
 257         /* Check for the onyx audio codec */
 258 #define ONYX_REG_CONTROL                67
 259         if (of_device_is_compatible(busnode, "k2-i2c") && !found_onyx) {
 260                 union i2c_smbus_data data;
 261 
 262                 rc = i2c_smbus_xfer(adap, 0x46, 0, I2C_SMBUS_READ,
 263                                     ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
 264                                     &data);
 265                 if (rc >= 0)
 266                         i2c_powermac_create_one(adap, "MAC,pcm3052", 0x46);
 267 
 268                 rc = i2c_smbus_xfer(adap, 0x47, 0, I2C_SMBUS_READ,
 269                                     ONYX_REG_CONTROL, I2C_SMBUS_BYTE_DATA,
 270                                     &data);
 271                 if (rc >= 0)
 272                         i2c_powermac_create_one(adap, "MAC,pcm3052", 0x47);
 273         }
 274 }
 275 
 276 static bool i2c_powermac_get_type(struct i2c_adapter *adap,
 277                                             struct device_node *node,
 278                                             u32 addr, char *type, int type_size)
 279 {
 280         char tmp[16];
 281 
 282         /* Note: we to _NOT_ want the standard
 283          * i2c drivers to match with any of our powermac stuff
 284          * unless they have been specifically modified to handle
 285          * it on a case by case basis. For example, for thermal
 286          * control, things like lm75 etc... shall match with their
 287          * corresponding windfarm drivers, _NOT_ the generic ones,
 288          * so we force a prefix of AAPL, onto the modalias to
 289          * make that happen
 290          */
 291 
 292         /* First try proper modalias */
 293         if (of_modalias_node(node, tmp, sizeof(tmp)) >= 0) {
 294                 snprintf(type, type_size, "MAC,%s", tmp);
 295                 return true;
 296         }
 297 
 298         /* Now look for known workarounds */
 299         if (of_node_name_eq(node, "deq")) {
 300                 /* Apple uses address 0x34 for TAS3001 and 0x35 for TAS3004 */
 301                 if (addr == 0x34) {
 302                         snprintf(type, type_size, "MAC,tas3001");
 303                         return true;
 304                 } else if (addr == 0x35) {
 305                         snprintf(type, type_size, "MAC,tas3004");
 306                         return true;
 307                 }
 308         }
 309 
 310         dev_err(&adap->dev, "i2c-powermac: modalias failure on %pOF\n", node);
 311         return false;
 312 }
 313 
 314 static void i2c_powermac_register_devices(struct i2c_adapter *adap,
 315                                                     struct pmac_i2c_bus *bus)
 316 {
 317         struct i2c_client *newdev;
 318         struct device_node *node;
 319         bool found_onyx = 0;
 320 
 321         /*
 322          * In some cases we end up with the via-pmu node itself, in this
 323          * case we skip this function completely as the device-tree will
 324          * not contain anything useful.
 325          */
 326         if (of_node_name_eq(adap->dev.of_node, "via-pmu"))
 327                 return;
 328 
 329         for_each_child_of_node(adap->dev.of_node, node) {
 330                 struct i2c_board_info info = {};
 331                 u32 addr;
 332 
 333                 /* Get address & channel */
 334                 addr = i2c_powermac_get_addr(adap, bus, node);
 335                 if (addr == 0xffffffff)
 336                         continue;
 337 
 338                 /* Multibus setup, check channel */
 339                 if (!pmac_i2c_match_adapter(node, adap))
 340                         continue;
 341 
 342                 dev_dbg(&adap->dev, "i2c-powermac: register %pOF\n", node);
 343 
 344                 /*
 345                  * Keep track of some device existence to handle
 346                  * workarounds later.
 347                  */
 348                 if (of_device_is_compatible(node, "pcm3052"))
 349                         found_onyx = true;
 350 
 351                 /* Make up a modalias */
 352                 if (!i2c_powermac_get_type(adap, node, addr,
 353                                            info.type, sizeof(info.type))) {
 354                         continue;
 355                 }
 356 
 357                 /* Fill out the rest of the info structure */
 358                 info.addr = addr;
 359                 info.irq = irq_of_parse_and_map(node, 0);
 360                 info.of_node = of_node_get(node);
 361 
 362                 newdev = i2c_new_device(adap, &info);
 363                 if (!newdev) {
 364                         dev_err(&adap->dev, "i2c-powermac: Failure to register"
 365                                 " %pOF\n", node);
 366                         of_node_put(node);
 367                         /* We do not dispose of the interrupt mapping on
 368                          * purpose. It's not necessary (interrupt cannot be
 369                          * re-used) and somebody else might have grabbed it
 370                          * via direct DT lookup so let's not bother
 371                          */
 372                         continue;
 373                 }
 374         }
 375 
 376         /* Additional workarounds */
 377         i2c_powermac_add_missing(adap, bus, found_onyx);
 378 }
 379 
 380 static int i2c_powermac_probe(struct platform_device *dev)
 381 {
 382         struct pmac_i2c_bus *bus = dev_get_platdata(&dev->dev);
 383         struct device_node *parent;
 384         struct i2c_adapter *adapter;
 385         int rc;
 386 
 387         if (bus == NULL)
 388                 return -EINVAL;
 389         adapter = pmac_i2c_get_adapter(bus);
 390 
 391         /* Ok, now we need to make up a name for the interface that will
 392          * match what we used to do in the past, that is basically the
 393          * controller's parent device node for keywest. PMU didn't have a
 394          * naming convention and SMU has a different one
 395          */
 396         switch(pmac_i2c_get_type(bus)) {
 397         case pmac_i2c_bus_keywest:
 398                 parent = of_get_parent(pmac_i2c_get_controller(bus));
 399                 if (parent == NULL)
 400                         return -EINVAL;
 401                 snprintf(adapter->name, sizeof(adapter->name), "%pOFn %d",
 402                          parent,
 403                          pmac_i2c_get_channel(bus));
 404                 of_node_put(parent);
 405                 break;
 406         case pmac_i2c_bus_pmu:
 407                 snprintf(adapter->name, sizeof(adapter->name), "pmu %d",
 408                          pmac_i2c_get_channel(bus));
 409                 break;
 410         case pmac_i2c_bus_smu:
 411                 /* This is not what we used to do but I'm fixing drivers at
 412                  * the same time as this change
 413                  */
 414                 snprintf(adapter->name, sizeof(adapter->name), "smu %d",
 415                          pmac_i2c_get_channel(bus));
 416                 break;
 417         default:
 418                 return -EINVAL;
 419         }
 420 
 421         platform_set_drvdata(dev, adapter);
 422         adapter->algo = &i2c_powermac_algorithm;
 423         adapter->quirks = &i2c_powermac_quirks;
 424         i2c_set_adapdata(adapter, bus);
 425         adapter->dev.parent = &dev->dev;
 426 
 427         /* Clear of_node to skip automatic registration of i2c child nodes */
 428         adapter->dev.of_node = NULL;
 429         rc = i2c_add_adapter(adapter);
 430         if (rc) {
 431                 printk(KERN_ERR "i2c-powermac: Adapter %s registration "
 432                        "failed\n", adapter->name);
 433                 memset(adapter, 0, sizeof(*adapter));
 434                 return rc;
 435         }
 436 
 437         printk(KERN_INFO "PowerMac i2c bus %s registered\n", adapter->name);
 438 
 439         /* Use custom child registration due to Apple device-tree funkyness */
 440         adapter->dev.of_node = dev->dev.of_node;
 441         i2c_powermac_register_devices(adapter, bus);
 442 
 443         return 0;
 444 }
 445 
 446 static struct platform_driver i2c_powermac_driver = {
 447         .probe = i2c_powermac_probe,
 448         .remove = i2c_powermac_remove,
 449         .driver = {
 450                 .name = "i2c-powermac",
 451                 .bus = &platform_bus_type,
 452         },
 453 };
 454 
 455 module_platform_driver(i2c_powermac_driver);
 456 
 457 MODULE_ALIAS("platform:i2c-powermac");