drivers/i2c/busses/i2c-scmi.c

   1 /*
   2  * SMBus driver for ACPI SMBus CMI
   3  *
   4  * Copyright (C) 2009 Crane Cai <crane.cai@amd.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation version 2.
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/slab.h>
  13 #include <linux/kernel.h>
  14 #include <linux/stddef.h>
  15 #include <linux/init.h>
  16 #include <linux/i2c.h>
  17 #include <linux/acpi.h>
  18
  19 #define ACPI_SMBUS_HC_CLASS             "smbus"
  20 #define ACPI_SMBUS_HC_DEVICE_NAME       "cmi"
  21
  22 ACPI_MODULE_NAME("smbus_cmi");
  23
  24 struct smbus_methods_t {
  25         char *mt_info;
  26         char *mt_sbr;
  27         char *mt_sbw;
  28 };
  29
  30 struct acpi_smbus_cmi {
  31         acpi_handle handle;
  32         struct i2c_adapter adapter;
  33         u8 cap_info:1;
  34         u8 cap_read:1;
  35         u8 cap_write:1;
  36 };
  37
  38 static const struct smbus_methods_t smbus_methods = {
  39         .mt_info = "_SBI",
  40         .mt_sbr  = "_SBR",
  41         .mt_sbw  = "_SBW",
  42 };
  43
  44 static const struct acpi_device_id acpi_smbus_cmi_ids[] = {
  45         {"SMBUS01", 0},
  46         {"", 0}
  47 };
  48
  49 #define ACPI_SMBUS_STATUS_OK                    0x00
  50 #define ACPI_SMBUS_STATUS_FAIL                  0x07
  51 #define ACPI_SMBUS_STATUS_DNAK                  0x10
  52 #define ACPI_SMBUS_STATUS_DERR                  0x11
  53 #define ACPI_SMBUS_STATUS_CMD_DENY              0x12
  54 #define ACPI_SMBUS_STATUS_UNKNOWN               0x13
  55 #define ACPI_SMBUS_STATUS_ACC_DENY              0x17
  56 #define ACPI_SMBUS_STATUS_TIMEOUT               0x18
  57 #define ACPI_SMBUS_STATUS_NOTSUP                0x19
  58 #define ACPI_SMBUS_STATUS_BUSY                  0x1a
  59 #define ACPI_SMBUS_STATUS_PEC                   0x1f
  60
  61 #define ACPI_SMBUS_PRTCL_WRITE                  0x00
  62 #define ACPI_SMBUS_PRTCL_READ                   0x01
  63 #define ACPI_SMBUS_PRTCL_QUICK                  0x02
  64 #define ACPI_SMBUS_PRTCL_BYTE                   0x04
  65 #define ACPI_SMBUS_PRTCL_BYTE_DATA              0x06
  66 #define ACPI_SMBUS_PRTCL_WORD_DATA              0x08
  67 #define ACPI_SMBUS_PRTCL_BLOCK_DATA             0x0a
  68
  69
  70 static int
  71 acpi_smbus_cmi_access(struct i2c_adapter *adap, u16 addr, unsigned short flags,
  72                    char read_write, u8 command, int size,
  73                    union i2c_smbus_data *data)
  74 {
  75         int result = 0;
  76         struct acpi_smbus_cmi *smbus_cmi = adap->algo_data;
  77         unsigned char protocol;
  78         acpi_status status = 0;
  79         struct acpi_object_list input;
  80         union acpi_object mt_params[5];
  81         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
  82         union acpi_object *obj;
  83         union acpi_object *pkg;
  84         char *method;
  85         int len = 0;
  86
  87         dev_dbg(&adap->dev, "access size: %d %s\n", size,
  88                 (read_write) ? "READ" : "WRITE");
  89         switch (size) {
  90         case I2C_SMBUS_QUICK:
  91                 protocol = ACPI_SMBUS_PRTCL_QUICK;
  92                 command = 0;
  93                 if (read_write == I2C_SMBUS_WRITE) {
  94                         mt_params[3].type = ACPI_TYPE_INTEGER;
  95                         mt_params[3].integer.value = 0;
  96                         mt_params[4].type = ACPI_TYPE_INTEGER;
  97                         mt_params[4].integer.value = 0;
  98                 }
  99                 break;
 100
 101         case I2C_SMBUS_BYTE:
 102                 protocol = ACPI_SMBUS_PRTCL_BYTE;
 103                 if (read_write == I2C_SMBUS_WRITE) {
 104                         mt_params[3].type = ACPI_TYPE_INTEGER;
 105                         mt_params[3].integer.value = 0;
 106                         mt_params[4].type = ACPI_TYPE_INTEGER;
 107                         mt_params[4].integer.value = 0;
 108                 } else {
 109                         command = 0;
 110                 }
 111                 break;
 112
 113         case I2C_SMBUS_BYTE_DATA:
 114                 protocol = ACPI_SMBUS_PRTCL_BYTE_DATA;
 115                 if (read_write == I2C_SMBUS_WRITE) {
 116                         mt_params[3].type = ACPI_TYPE_INTEGER;
 117                         mt_params[3].integer.value = 1;
 118                         mt_params[4].type = ACPI_TYPE_INTEGER;
 119                         mt_params[4].integer.value = data->byte;
 120                 }
 121                 break;
 122
 123         case I2C_SMBUS_WORD_DATA:
 124                 protocol = ACPI_SMBUS_PRTCL_WORD_DATA;
 125                 if (read_write == I2C_SMBUS_WRITE) {
 126                         mt_params[3].type = ACPI_TYPE_INTEGER;
 127                         mt_params[3].integer.value = 2;
 128                         mt_params[4].type = ACPI_TYPE_INTEGER;
 129                         mt_params[4].integer.value = data->word;
 130                 }
 131                 break;
 132
 133         case I2C_SMBUS_BLOCK_DATA:
 134                 protocol = ACPI_SMBUS_PRTCL_BLOCK_DATA;
 135                 if (read_write == I2C_SMBUS_WRITE) {
 136                         len = data->block[0];
 137                         if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 138                                 return -EINVAL;
 139                         mt_params[3].type = ACPI_TYPE_INTEGER;
 140                         mt_params[3].integer.value = len;
 141                         mt_params[4].type = ACPI_TYPE_BUFFER;
 142                         mt_params[4].buffer.pointer = data->block + 1;
 143                 }
 144                 break;
 145
 146         default:
 147                 dev_warn(&adap->dev, "Unsupported transaction %d\n", size);
 148                 return -EOPNOTSUPP;
 149         }
 150
 151         if (read_write == I2C_SMBUS_READ) {
 152                 protocol |= ACPI_SMBUS_PRTCL_READ;
 153                 method = smbus_methods.mt_sbr;
 154                 input.count = 3;
 155         } else {
 156                 protocol |= ACPI_SMBUS_PRTCL_WRITE;
 157                 method = smbus_methods.mt_sbw;
 158                 input.count = 5;
 159         }
 160
 161         input.pointer = mt_params;
 162         mt_params[0].type = ACPI_TYPE_INTEGER;
 163         mt_params[0].integer.value = protocol;
 164         mt_params[1].type = ACPI_TYPE_INTEGER;
 165         mt_params[1].integer.value = addr;
 166         mt_params[2].type = ACPI_TYPE_INTEGER;
 167         mt_params[2].integer.value = command;
 168
 169         status = acpi_evaluate_object(smbus_cmi->handle, method, &input,
 170                                       &buffer);
 171         if (ACPI_FAILURE(status)) {
 172                 ACPI_ERROR((AE_INFO, "Evaluating %s: %i", method, status));
 173                 return -EIO;
 174         }
 175
 176         pkg = buffer.pointer;
 177         if (pkg && pkg->type == ACPI_TYPE_PACKAGE)
 178                 obj = pkg->package.elements;
 179         else {
 180                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 181                 result = -EIO;
 182                 goto out;
 183         }
 184         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 185                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 186                 result = -EIO;
 187                 goto out;
 188         }
 189
 190         result = obj->integer.value;
 191         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "%s return status: %i\n",
 192                           method, result));
 193
 194         switch (result) {
 195         case ACPI_SMBUS_STATUS_OK:
 196                 result = 0;
 197                 break;
 198         case ACPI_SMBUS_STATUS_BUSY:
 199                 result = -EBUSY;
 200                 goto out;
 201         case ACPI_SMBUS_STATUS_TIMEOUT:
 202                 result = -ETIMEDOUT;
 203                 goto out;
 204         case ACPI_SMBUS_STATUS_DNAK:
 205                 result = -ENXIO;
 206                 goto out;
 207         default:
 208                 result = -EIO;
 209                 goto out;
 210         }
 211
 212         if (read_write == I2C_SMBUS_WRITE || size == I2C_SMBUS_QUICK)
 213                 goto out;
 214
 215         obj = pkg->package.elements + 1;
 216         if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 217                 ACPI_ERROR((AE_INFO, "Invalid argument type"));
 218                 result = -EIO;
 219                 goto out;
 220         }
 221
 222         len = obj->integer.value;
 223         obj = pkg->package.elements + 2;
 224         switch (size) {
 225         case I2C_SMBUS_BYTE:
 226         case I2C_SMBUS_BYTE_DATA:
 227         case I2C_SMBUS_WORD_DATA:
 228                 if (obj == NULL || obj->type != ACPI_TYPE_INTEGER) {
 229                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 230                         result = -EIO;
 231                         goto out;
 232                 }
 233                 if (len == 2)
 234                         data->word = obj->integer.value;
 235                 else
 236                         data->byte = obj->integer.value;
 237                 break;
 238         case I2C_SMBUS_BLOCK_DATA:
 239                 if (obj == NULL || obj->type != ACPI_TYPE_BUFFER) {
 240                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 241                         result = -EIO;
 242                         goto out;
 243                 }
 244                 if (len == 0 || len > I2C_SMBUS_BLOCK_MAX)
 245                         return -EPROTO;
 246                 data->block[0] = len;
 247                 memcpy(data->block + 1, obj->buffer.pointer, len);
 248                 break;
 249         }
 250
 251 out:
 252         kfree(buffer.pointer);
 253         dev_dbg(&adap->dev, "Transaction status: %i\n", result);
 254         return result;
 255 }
 256
 257 static u32 acpi_smbus_cmi_func(struct i2c_adapter *adapter)
 258 {
 259         struct acpi_smbus_cmi *smbus_cmi = adapter->algo_data;
 260         u32 ret;
 261
 262         ret = smbus_cmi->cap_read | smbus_cmi->cap_write ?
 263                 I2C_FUNC_SMBUS_QUICK : 0;
 264
 265         ret |= smbus_cmi->cap_read ?
 266                 (I2C_FUNC_SMBUS_READ_BYTE |
 267                 I2C_FUNC_SMBUS_READ_BYTE_DATA |
 268                 I2C_FUNC_SMBUS_READ_WORD_DATA |
 269                 I2C_FUNC_SMBUS_READ_BLOCK_DATA) : 0;
 270
 271         ret |= smbus_cmi->cap_write ?
 272                 (I2C_FUNC_SMBUS_WRITE_BYTE |
 273                 I2C_FUNC_SMBUS_WRITE_BYTE_DATA |
 274                 I2C_FUNC_SMBUS_WRITE_WORD_DATA |
 275                 I2C_FUNC_SMBUS_WRITE_BLOCK_DATA) : 0;
 276
 277         return ret;
 278 }
 279
 280 static const struct i2c_algorithm acpi_smbus_cmi_algorithm = {
 281         .smbus_xfer = acpi_smbus_cmi_access,
 282         .functionality = acpi_smbus_cmi_func,
 283 };
 284
 285
 286 static int acpi_smbus_cmi_add_cap(struct acpi_smbus_cmi *smbus_cmi,
 287                                   const char *name)
 288 {
 289         struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
 290         union acpi_object *obj;
 291         acpi_status status;
 292
 293         if (!strcmp(name, smbus_methods.mt_info)) {
 294                 status = acpi_evaluate_object(smbus_cmi->handle,
 295                                         smbus_methods.mt_info,
 296                                         NULL, &buffer);
 297                 if (ACPI_FAILURE(status)) {
 298                         ACPI_ERROR((AE_INFO, "Evaluating %s: %i",
 299                                    smbus_methods.mt_info, status));
 300                         return -EIO;
 301                 }
 302
 303                 obj = buffer.pointer;
 304                 if (obj && obj->type == ACPI_TYPE_PACKAGE)
 305                         obj = obj->package.elements;
 306                 else {
 307                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 308                         kfree(buffer.pointer);
 309                         return -EIO;
 310                 }
 311
 312                 if (obj->type != ACPI_TYPE_INTEGER) {
 313                         ACPI_ERROR((AE_INFO, "Invalid argument type"));
 314                         kfree(buffer.pointer);
 315                         return -EIO;
 316                 } else
 317                         ACPI_DEBUG_PRINT((ACPI_DB_INFO, "SMBus CMI Version %x"
 318                                           "\n", (int)obj->integer.value));
 319
 320                 kfree(buffer.pointer);
 321                 smbus_cmi->cap_info = 1;
 322         } else if (!strcmp(name, smbus_methods.mt_sbr))
 323                 smbus_cmi->cap_read = 1;
 324         else if (!strcmp(name, smbus_methods.mt_sbw))
 325                 smbus_cmi->cap_write = 1;
 326         else
 327                 ACPI_DEBUG_PRINT((ACPI_DB_INFO, "Unsupported CMI method: %s\n",
 328                                  name));
 329
 330         return 0;
 331 }
 332
 333 static acpi_status acpi_smbus_cmi_query_methods(acpi_handle handle, u32 level,
 334                         void *context, void **return_value)
 335 {
 336         char node_name[5];
 337         struct acpi_buffer buffer = { sizeof(node_name), node_name };
 338         struct acpi_smbus_cmi *smbus_cmi = context;
 339         acpi_status status;
 340
 341         status = acpi_get_name(handle, ACPI_SINGLE_NAME, &buffer);
 342
 343         if (ACPI_SUCCESS(status))
 344                 acpi_smbus_cmi_add_cap(smbus_cmi, node_name);
 345
 346         return AE_OK;
 347 }
 348
 349 static int acpi_smbus_cmi_add(struct acpi_device *device)
 350 {
 351         struct acpi_smbus_cmi *smbus_cmi;
 352
 353         smbus_cmi = kzalloc(sizeof(struct acpi_smbus_cmi), GFP_KERNEL);
 354         if (!smbus_cmi)
 355                 return -ENOMEM;
 356
 357         smbus_cmi->handle = device->handle;
 358         strcpy(acpi_device_name(device), ACPI_SMBUS_HC_DEVICE_NAME);
 359         strcpy(acpi_device_class(device), ACPI_SMBUS_HC_CLASS);
 360         device->driver_data = smbus_cmi;
 361         smbus_cmi->cap_info = 0;
 362         smbus_cmi->cap_read = 0;
 363         smbus_cmi->cap_write = 0;
 364
 365         acpi_walk_namespace(ACPI_TYPE_METHOD, smbus_cmi->handle, 1,
 366                             acpi_smbus_cmi_query_methods, smbus_cmi, NULL);
 367
 368         if (smbus_cmi->cap_info == 0)
 369                 goto err;
 370
 371         snprintf(smbus_cmi->adapter.name, sizeof(smbus_cmi->adapter.name),
 372                 "SMBus CMI adapter %s",
 373                 acpi_device_name(device));
 374         smbus_cmi->adapter.owner = THIS_MODULE;
 375         smbus_cmi->adapter.algo = &acpi_smbus_cmi_algorithm;
 376         smbus_cmi->adapter.algo_data = smbus_cmi;
 377         smbus_cmi->adapter.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
 378         smbus_cmi->adapter.dev.parent = &device->dev;
 379
 380         if (i2c_add_adapter(&smbus_cmi->adapter)) {
 381                 dev_err(&device->dev, "Couldn't register adapter!\n");
 382                 goto err;
 383         }
 384
 385         return 0;
 386
 387 err:
 388         kfree(smbus_cmi);
 389         device->driver_data = NULL;
 390         return -EIO;
 391 }
 392
 393 static int acpi_smbus_cmi_remove(struct acpi_device *device, int type)
 394 {
 395         struct acpi_smbus_cmi *smbus_cmi = acpi_driver_data(device);
 396
 397         i2c_del_adapter(&smbus_cmi->adapter);
 398         kfree(smbus_cmi);
 399         device->driver_data = NULL;
 400
 401         return 0;
 402 }
 403
 404 static struct acpi_driver acpi_smbus_cmi_driver = {
 405         .name = ACPI_SMBUS_HC_DEVICE_NAME,
 406         .class = ACPI_SMBUS_HC_CLASS,
 407         .ids = acpi_smbus_cmi_ids,
 408         .ops = {
 409                 .add = acpi_smbus_cmi_add,
 410                 .remove = acpi_smbus_cmi_remove,
 411         },
 412 };
 413
 414 static int __init acpi_smbus_cmi_init(void)
 415 {
 416         return acpi_bus_register_driver(&acpi_smbus_cmi_driver);
 417 }
 418
 419 static void __exit acpi_smbus_cmi_exit(void)
 420 {
 421         acpi_bus_unregister_driver(&acpi_smbus_cmi_driver);
 422 }
 423
 424 module_init(acpi_smbus_cmi_init);
 425 module_exit(acpi_smbus_cmi_exit);
 426
 427 MODULE_LICENSE("GPL");
 428 MODULE_AUTHOR("Crane Cai <crane.cai@amd.com>");
 429 MODULE_DESCRIPTION("ACPI SMBus CMI driver");