drivers/power/supply/ltc2941-battery-gauge.c

   1 /*
   2  * I2C client/driver for the Linear Technology LTC2941, LTC2942, LTC2943
   3  * and LTC2944 Battery Gas Gauge IC
   4  *
   5  * Copyright (C) 2014 Topic Embedded Systems
   6  *
   7  * Author: Auryn Verwegen
   8  * Author: Mike Looijmans
   9  */
  10 #include <linux/kernel.h>
  11 #include <linux/module.h>
  12 #include <linux/of_device.h>
  13 #include <linux/types.h>
  14 #include <linux/errno.h>
  15 #include <linux/swab.h>
  16 #include <linux/i2c.h>
  17 #include <linux/delay.h>
  18 #include <linux/power_supply.h>
  19 #include <linux/slab.h>
  20
  21 #define I16_MSB(x)                      ((x >> 8) & 0xFF)
  22 #define I16_LSB(x)                      (x & 0xFF)
  23
  24 #define LTC294X_WORK_DELAY              10      /* Update delay in seconds */
  25
  26 #define LTC294X_MAX_VALUE               0xFFFF
  27 #define LTC294X_MID_SUPPLY              0x7FFF
  28
  29 #define LTC2941_MAX_PRESCALER_EXP       7
  30 #define LTC2943_MAX_PRESCALER_EXP       6
  31
  32 enum ltc294x_reg {
  33         LTC294X_REG_STATUS              = 0x00,
  34         LTC294X_REG_CONTROL             = 0x01,
  35         LTC294X_REG_ACC_CHARGE_MSB      = 0x02,
  36         LTC294X_REG_ACC_CHARGE_LSB      = 0x03,
  37         LTC294X_REG_CHARGE_THR_HIGH_MSB = 0x04,
  38         LTC294X_REG_CHARGE_THR_HIGH_LSB = 0x05,
  39         LTC294X_REG_CHARGE_THR_LOW_MSB  = 0x06,
  40         LTC294X_REG_CHARGE_THR_LOW_LSB  = 0x07,
  41         LTC294X_REG_VOLTAGE_MSB         = 0x08,
  42         LTC294X_REG_VOLTAGE_LSB         = 0x09,
  43         LTC2942_REG_TEMPERATURE_MSB     = 0x0C,
  44         LTC2942_REG_TEMPERATURE_LSB     = 0x0D,
  45         LTC2943_REG_CURRENT_MSB         = 0x0E,
  46         LTC2943_REG_CURRENT_LSB         = 0x0F,
  47         LTC2943_REG_TEMPERATURE_MSB     = 0x14,
  48         LTC2943_REG_TEMPERATURE_LSB     = 0x15,
  49 };
  50
  51 enum ltc294x_id {
  52         LTC2941_ID,
  53         LTC2942_ID,
  54         LTC2943_ID,
  55         LTC2944_ID,
  56 };
  57
  58 #define LTC2941_REG_STATUS_CHIP_ID      BIT(7)
  59
  60 #define LTC2942_REG_CONTROL_MODE_SCAN   (BIT(7) | BIT(6))
  61 #define LTC2943_REG_CONTROL_MODE_SCAN   BIT(7)
  62 #define LTC294X_REG_CONTROL_PRESCALER_MASK      (BIT(5) | BIT(4) | BIT(3))
  63 #define LTC294X_REG_CONTROL_SHUTDOWN_MASK       (BIT(0))
  64 #define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
  65         ((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
  66 #define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED        0
  67 #define LTC294X_REG_CONTROL_ADC_DISABLE(x)      ((x) & ~(BIT(7) | BIT(6)))
  68
  69 struct ltc294x_info {
  70         struct i2c_client *client;      /* I2C Client pointer */
  71         struct power_supply *supply;    /* Supply pointer */
  72         struct power_supply_desc supply_desc;   /* Supply description */
  73         struct delayed_work work;       /* Work scheduler */
  74         enum ltc294x_id id;             /* Chip type */
  75         int charge;     /* Last charge register content */
  76         int r_sense;    /* mOhm */
  77         int Qlsb;       /* nAh */
  78 };
  79
  80 static inline int convert_bin_to_uAh(
  81         const struct ltc294x_info *info, int Q)
  82 {
  83         return ((Q * (info->Qlsb / 10))) / 100;
  84 }
  85
  86 static inline int convert_uAh_to_bin(
  87         const struct ltc294x_info *info, int uAh)
  88 {
  89         int Q;
  90
  91         Q = (uAh * 100) / (info->Qlsb/10);
  92         return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
  93 }
  94
  95 static int ltc294x_read_regs(struct i2c_client *client,
  96         enum ltc294x_reg reg, u8 *buf, int num_regs)
  97 {
  98         int ret;
  99         struct i2c_msg msgs[2] = { };
 100         u8 reg_start = reg;
 101
 102         msgs[0].addr    = client->addr;
 103         msgs[0].len     = 1;
 104         msgs[0].buf     = &reg_start;
 105
 106         msgs[1].addr    = client->addr;
 107         msgs[1].len     = num_regs;
 108         msgs[1].buf     = buf;
 109         msgs[1].flags   = I2C_M_RD;
 110
 111         ret = i2c_transfer(client->adapter, &msgs[0], 2);
 112         if (ret < 0) {
 113                 dev_err(&client->dev, "ltc2941 read_reg failed!\n");
 114                 return ret;
 115         }
 116
 117         dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
 118                 __func__, reg, num_regs, *buf);
 119
 120         return 0;
 121 }
 122
 123 static int ltc294x_write_regs(struct i2c_client *client,
 124         enum ltc294x_reg reg, const u8 *buf, int num_regs)
 125 {
 126         int ret;
 127         u8 reg_start = reg;
 128
 129         ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
 130         if (ret < 0) {
 131                 dev_err(&client->dev, "ltc2941 write_reg failed!\n");
 132                 return ret;
 133         }
 134
 135         dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
 136                 __func__, reg, num_regs, *buf);
 137
 138         return 0;
 139 }
 140
 141 static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
 142 {
 143         int ret;
 144         u8 value;
 145         u8 control;
 146
 147         /* Read status and control registers */
 148         ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
 149         if (ret < 0) {
 150                 dev_err(&info->client->dev,
 151                         "Could not read registers from device\n");
 152                 goto error_exit;
 153         }
 154
 155         control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
 156                                 LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
 157         /* Put device into "monitor" mode */
 158         switch (info->id) {
 159         case LTC2942_ID:        /* 2942 measures every 2 sec */
 160                 control |= LTC2942_REG_CONTROL_MODE_SCAN;
 161                 break;
 162         case LTC2943_ID:
 163         case LTC2944_ID:        /* 2943 and 2944 measure every 10 sec */
 164                 control |= LTC2943_REG_CONTROL_MODE_SCAN;
 165                 break;
 166         default:
 167                 break;
 168         }
 169
 170         if (value != control) {
 171                 ret = ltc294x_write_regs(info->client,
 172                         LTC294X_REG_CONTROL, &control, 1);
 173                 if (ret < 0) {
 174                         dev_err(&info->client->dev,
 175                                 "Could not write register\n");
 176                         goto error_exit;
 177                 }
 178         }
 179
 180         return 0;
 181
 182 error_exit:
 183         return ret;
 184 }
 185
 186 static int ltc294x_read_charge_register(const struct ltc294x_info *info,
 187                                         enum ltc294x_reg reg)
 188  {
 189         int ret;
 190         u8 datar[2];
 191
 192         ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
 193         if (ret < 0)
 194                 return ret;
 195         return (datar[0] << 8) + datar[1];
 196 }
 197
 198 static int ltc294x_get_charge(const struct ltc294x_info *info,
 199                                 enum ltc294x_reg reg, int *val)
 200 {
 201         int value = ltc294x_read_charge_register(info, reg);
 202
 203         if (value < 0)
 204                 return value;
 205         /* When r_sense < 0, this counts up when the battery discharges */
 206         if (info->Qlsb < 0)
 207                 value -= 0xFFFF;
 208         *val = convert_bin_to_uAh(info, value);
 209         return 0;
 210 }
 211
 212 static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
 213 {
 214         int ret;
 215         u8 dataw[2];
 216         u8 ctrl_reg;
 217         s32 value;
 218
 219         value = convert_uAh_to_bin(info, val);
 220         /* Direction depends on how sense+/- were connected */
 221         if (info->Qlsb < 0)
 222                 value += 0xFFFF;
 223         if ((value < 0) || (value > 0xFFFF)) /* input validation */
 224                 return -EINVAL;
 225
 226         /* Read control register */
 227         ret = ltc294x_read_regs(info->client,
 228                 LTC294X_REG_CONTROL, &ctrl_reg, 1);
 229         if (ret < 0)
 230                 return ret;
 231         /* Disable analog section */
 232         ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
 233         ret = ltc294x_write_regs(info->client,
 234                 LTC294X_REG_CONTROL, &ctrl_reg, 1);
 235         if (ret < 0)
 236                 return ret;
 237         /* Set new charge value */
 238         dataw[0] = I16_MSB(value);
 239         dataw[1] = I16_LSB(value);
 240         ret = ltc294x_write_regs(info->client,
 241                 LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
 242         if (ret < 0)
 243                 goto error_exit;
 244         /* Enable analog section */
 245 error_exit:
 246         ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
 247         ret = ltc294x_write_regs(info->client,
 248                 LTC294X_REG_CONTROL, &ctrl_reg, 1);
 249
 250         return ret < 0 ? ret : 0;
 251 }
 252
 253 static int ltc294x_set_charge_thr(const struct ltc294x_info *info,
 254                                         enum ltc294x_reg reg, int val)
 255 {
 256         u8 dataw[2];
 257         s32 value;
 258
 259         value = convert_uAh_to_bin(info, val);
 260         /* Direction depends on how sense+/- were connected */
 261         if (info->Qlsb < 0)
 262                 value += 0xFFFF;
 263         if ((value < 0) || (value > 0xFFFF)) /* input validation */
 264                 return -EINVAL;
 265
 266         /* Set new charge value */
 267         dataw[0] = I16_MSB(value);
 268         dataw[1] = I16_LSB(value);
 269         return ltc294x_write_regs(info->client, reg, &dataw[0], 2);
 270 }
 271
 272 static int ltc294x_get_charge_counter(
 273         const struct ltc294x_info *info, int *val)
 274 {
 275         int value = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
 276
 277         if (value < 0)
 278                 return value;
 279         value -= LTC294X_MID_SUPPLY;
 280         *val = convert_bin_to_uAh(info, value);
 281         return 0;
 282 }
 283
 284 static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
 285 {
 286         int ret;
 287         u8 datar[2];
 288         u32 value;
 289
 290         ret = ltc294x_read_regs(info->client,
 291                 LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
 292         value = (datar[0] << 8) | datar[1];
 293         switch (info->id) {
 294         case LTC2943_ID:
 295                 value *= 23600 * 2;
 296                 value /= 0xFFFF;
 297                 value *= 1000 / 2;
 298                 break;
 299         case LTC2944_ID:
 300                 value *= 70800 / 5*4;
 301                 value /= 0xFFFF;
 302                 value *= 1000 * 5/4;
 303                 break;
 304         default:
 305                 value *= 6000 * 10;
 306                 value /= 0xFFFF;
 307                 value *= 1000 / 10;
 308                 break;
 309         }
 310         *val = value;
 311         return ret;
 312 }
 313
 314 static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
 315 {
 316         int ret;
 317         u8 datar[2];
 318         s32 value;
 319
 320         ret = ltc294x_read_regs(info->client,
 321                 LTC2943_REG_CURRENT_MSB, &datar[0], 2);
 322         value = (datar[0] << 8) | datar[1];
 323         value -= 0x7FFF;
 324         if (info->id == LTC2944_ID)
 325                 value *= 64000;
 326         else
 327                 value *= 60000;
 328         /* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
 329          * the formula below keeps everything in s32 range while preserving
 330          * enough digits */
 331         *val = 1000 * (value / (info->r_sense * 0x7FFF)); /* in uA */
 332         return ret;
 333 }
 334
 335 static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
 336 {
 337         enum ltc294x_reg reg;
 338         int ret;
 339         u8 datar[2];
 340         u32 value;
 341
 342         if (info->id == LTC2942_ID) {
 343                 reg = LTC2942_REG_TEMPERATURE_MSB;
 344                 value = 6000;   /* Full-scale is 600 Kelvin */
 345         } else {
 346                 reg = LTC2943_REG_TEMPERATURE_MSB;
 347                 value = 5100;   /* Full-scale is 510 Kelvin */
 348         }
 349         ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
 350         value *= (datar[0] << 8) | datar[1];
 351         /* Convert to tenths of degree Celsius */
 352         *val = value / 0xFFFF - 2722;
 353         return ret;
 354 }
 355
 356 static int ltc294x_get_property(struct power_supply *psy,
 357                                 enum power_supply_property prop,
 358                                 union power_supply_propval *val)
 359 {
 360         struct ltc294x_info *info = power_supply_get_drvdata(psy);
 361
 362         switch (prop) {
 363         case POWER_SUPPLY_PROP_CHARGE_FULL:
 364                 return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_HIGH_MSB,
 365                                                 &val->intval);
 366         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 367                 return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_LOW_MSB,
 368                                                 &val->intval);
 369         case POWER_SUPPLY_PROP_CHARGE_NOW:
 370                 return ltc294x_get_charge(info, LTC294X_REG_ACC_CHARGE_MSB,
 371                                                 &val->intval);
 372         case POWER_SUPPLY_PROP_CHARGE_COUNTER:
 373                 return ltc294x_get_charge_counter(info, &val->intval);
 374         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 375                 return ltc294x_get_voltage(info, &val->intval);
 376         case POWER_SUPPLY_PROP_CURRENT_NOW:
 377                 return ltc294x_get_current(info, &val->intval);
 378         case POWER_SUPPLY_PROP_TEMP:
 379                 return ltc294x_get_temperature(info, &val->intval);
 380         default:
 381                 return -EINVAL;
 382         }
 383 }
 384
 385 static int ltc294x_set_property(struct power_supply *psy,
 386         enum power_supply_property psp,
 387         const union power_supply_propval *val)
 388 {
 389         struct ltc294x_info *info = power_supply_get_drvdata(psy);
 390
 391         switch (psp) {
 392         case POWER_SUPPLY_PROP_CHARGE_FULL:
 393                 return ltc294x_set_charge_thr(info,
 394                         LTC294X_REG_CHARGE_THR_HIGH_MSB, val->intval);
 395         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 396                 return ltc294x_set_charge_thr(info,
 397                         LTC294X_REG_CHARGE_THR_LOW_MSB, val->intval);
 398         case POWER_SUPPLY_PROP_CHARGE_NOW:
 399                 return ltc294x_set_charge_now(info, val->intval);
 400         default:
 401                 return -EPERM;
 402         }
 403 }
 404
 405 static int ltc294x_property_is_writeable(
 406         struct power_supply *psy, enum power_supply_property psp)
 407 {
 408         switch (psp) {
 409         case POWER_SUPPLY_PROP_CHARGE_FULL:
 410         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 411         case POWER_SUPPLY_PROP_CHARGE_NOW:
 412                 return 1;
 413         default:
 414                 return 0;
 415         }
 416 }
 417
 418 static void ltc294x_update(struct ltc294x_info *info)
 419 {
 420         int charge = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
 421
 422         if (charge != info->charge) {
 423                 info->charge = charge;
 424                 power_supply_changed(info->supply);
 425         }
 426 }
 427
 428 static void ltc294x_work(struct work_struct *work)
 429 {
 430         struct ltc294x_info *info;
 431
 432         info = container_of(work, struct ltc294x_info, work.work);
 433         ltc294x_update(info);
 434         schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
 435 }
 436
 437 static enum power_supply_property ltc294x_properties[] = {
 438         POWER_SUPPLY_PROP_CHARGE_COUNTER,
 439         POWER_SUPPLY_PROP_CHARGE_FULL,
 440         POWER_SUPPLY_PROP_CHARGE_EMPTY,
 441         POWER_SUPPLY_PROP_CHARGE_NOW,
 442         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 443         POWER_SUPPLY_PROP_TEMP,
 444         POWER_SUPPLY_PROP_CURRENT_NOW,
 445 };
 446
 447 static int ltc294x_i2c_remove(struct i2c_client *client)
 448 {
 449         struct ltc294x_info *info = i2c_get_clientdata(client);
 450
 451         cancel_delayed_work(&info->work);
 452         power_supply_unregister(info->supply);
 453         return 0;
 454 }
 455
 456 static int ltc294x_i2c_probe(struct i2c_client *client,
 457         const struct i2c_device_id *id)
 458 {
 459         struct power_supply_config psy_cfg = {};
 460         struct ltc294x_info *info;
 461         struct device_node *np;
 462         int ret;
 463         u32 prescaler_exp;
 464         s32 r_sense;
 465         u8 status;
 466
 467         info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
 468         if (info == NULL)
 469                 return -ENOMEM;
 470
 471         i2c_set_clientdata(client, info);
 472
 473         np = of_node_get(client->dev.of_node);
 474
 475         info->id = (enum ltc294x_id)of_device_get_match_data(&client->dev);
 476         info->supply_desc.name = np->name;
 477
 478         /* r_sense can be negative, when sense+ is connected to the battery
 479          * instead of the sense-. This results in reversed measurements. */
 480         ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
 481         if (ret < 0) {
 482                 dev_err(&client->dev,
 483                         "Could not find lltc,resistor-sense in devicetree\n");
 484                 return ret;
 485         }
 486         info->r_sense = r_sense;
 487
 488         ret = of_property_read_u32(np, "lltc,prescaler-exponent",
 489                 &prescaler_exp);
 490         if (ret < 0) {
 491                 dev_warn(&client->dev,
 492                         "lltc,prescaler-exponent not in devicetree\n");
 493                 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
 494         }
 495
 496         if (info->id == LTC2943_ID) {
 497                 if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
 498                         prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
 499                 info->Qlsb = ((340 * 50000) / r_sense) /
 500                                 (4096 / (1 << (2*prescaler_exp)));
 501         } else {
 502                 if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
 503                         prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
 504                 info->Qlsb = ((85 * 50000) / r_sense) /
 505                                 (128 / (1 << prescaler_exp));
 506         }
 507
 508         /* Read status register to check for LTC2942 */
 509         if (info->id == LTC2941_ID || info->id == LTC2942_ID) {
 510                 ret = ltc294x_read_regs(client, LTC294X_REG_STATUS, &status, 1);
 511                 if (ret < 0) {
 512                         dev_err(&client->dev,
 513                                 "Could not read status register\n");
 514                         return ret;
 515                 }
 516                 if (status & LTC2941_REG_STATUS_CHIP_ID)
 517                         info->id = LTC2941_ID;
 518                 else
 519                         info->id = LTC2942_ID;
 520         }
 521
 522         info->client = client;
 523         info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
 524         info->supply_desc.properties = ltc294x_properties;
 525         switch (info->id) {
 526         case LTC2944_ID:
 527         case LTC2943_ID:
 528                 info->supply_desc.num_properties =
 529                         ARRAY_SIZE(ltc294x_properties);
 530                 break;
 531         case LTC2942_ID:
 532                 info->supply_desc.num_properties =
 533                         ARRAY_SIZE(ltc294x_properties) - 1;
 534                 break;
 535         case LTC2941_ID:
 536         default:
 537                 info->supply_desc.num_properties =
 538                         ARRAY_SIZE(ltc294x_properties) - 3;
 539                 break;
 540         }
 541         info->supply_desc.get_property = ltc294x_get_property;
 542         info->supply_desc.set_property = ltc294x_set_property;
 543         info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
 544         info->supply_desc.external_power_changed        = NULL;
 545
 546         psy_cfg.drv_data = info;
 547
 548         INIT_DELAYED_WORK(&info->work, ltc294x_work);
 549
 550         ret = ltc294x_reset(info, prescaler_exp);
 551         if (ret < 0) {
 552                 dev_err(&client->dev, "Communication with chip failed\n");
 553                 return ret;
 554         }
 555
 556         info->supply = power_supply_register(&client->dev, &info->supply_desc,
 557                                              &psy_cfg);
 558         if (IS_ERR(info->supply)) {
 559                 dev_err(&client->dev, "failed to register ltc2941\n");
 560                 return PTR_ERR(info->supply);
 561         } else {
 562                 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
 563         }
 564
 565         return 0;
 566 }
 567
 568 static void ltc294x_i2c_shutdown(struct i2c_client *client)
 569 {
 570         struct ltc294x_info *info = i2c_get_clientdata(client);
 571         int ret;
 572         u8 value;
 573         u8 control;
 574
 575         /* The LTC2941 does not need any special handling */
 576         if (info->id == LTC2941_ID)
 577                 return;
 578
 579         /* Read control register */
 580         ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
 581         if (ret < 0)
 582                 return;
 583
 584         /* Disable continuous ADC conversion as this drains the battery */
 585         control = LTC294X_REG_CONTROL_ADC_DISABLE(value);
 586         if (control != value)
 587                 ltc294x_write_regs(info->client, LTC294X_REG_CONTROL,
 588                         &control, 1);
 589 }
 590
 591 #ifdef CONFIG_PM_SLEEP
 592
 593 static int ltc294x_suspend(struct device *dev)
 594 {
 595         struct i2c_client *client = to_i2c_client(dev);
 596         struct ltc294x_info *info = i2c_get_clientdata(client);
 597
 598         cancel_delayed_work(&info->work);
 599         return 0;
 600 }
 601
 602 static int ltc294x_resume(struct device *dev)
 603 {
 604         struct i2c_client *client = to_i2c_client(dev);
 605         struct ltc294x_info *info = i2c_get_clientdata(client);
 606
 607         schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
 608         return 0;
 609 }
 610
 611 static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
 612 #define LTC294X_PM_OPS (&ltc294x_pm_ops)
 613
 614 #else
 615 #define LTC294X_PM_OPS NULL
 616 #endif /* CONFIG_PM_SLEEP */
 617
 618
 619 static const struct i2c_device_id ltc294x_i2c_id[] = {
 620         { "ltc2941", LTC2941_ID, },
 621         { "ltc2942", LTC2942_ID, },
 622         { "ltc2943", LTC2943_ID, },
 623         { "ltc2944", LTC2944_ID, },
 624         { },
 625 };
 626 MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
 627
 628 static const struct of_device_id ltc294x_i2c_of_match[] = {
 629         {
 630                 .compatible = "lltc,ltc2941",
 631                 .data = (void *)LTC2941_ID,
 632         },
 633         {
 634                 .compatible = "lltc,ltc2942",
 635                 .data = (void *)LTC2942_ID,
 636         },
 637         {
 638                 .compatible = "lltc,ltc2943",
 639                 .data = (void *)LTC2943_ID,
 640         },
 641         {
 642                 .compatible = "lltc,ltc2944",
 643                 .data = (void *)LTC2944_ID,
 644         },
 645         { },
 646 };
 647 MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
 648
 649 static struct i2c_driver ltc294x_driver = {
 650         .driver = {
 651                 .name   = "LTC2941",
 652                 .of_match_table = ltc294x_i2c_of_match,
 653                 .pm     = LTC294X_PM_OPS,
 654         },
 655         .probe          = ltc294x_i2c_probe,
 656         .remove         = ltc294x_i2c_remove,
 657         .shutdown       = ltc294x_i2c_shutdown,
 658         .id_table       = ltc294x_i2c_id,
 659 };
 660 module_i2c_driver(ltc294x_driver);
 661
 662 MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
 663 MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
 664 MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
 665 MODULE_LICENSE("GPL");