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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * I2C client/driver for the Linear Technology LTC2941, LTC2942, LTC2943
   4  * and LTC2944 Battery Gas Gauge IC
   5  *
   6  * Copyright (C) 2014 Topic Embedded Systems
   7  *
   8  * Author: Auryn Verwegen
   9  * Author: Mike Looijmans
  10  */
  11 #include <linux/kernel.h>
  12 #include <linux/module.h>
  13 #include <linux/of_device.h>
  14 #include <linux/types.h>
  15 #include <linux/errno.h>
  16 #include <linux/swab.h>
  17 #include <linux/i2c.h>
  18 #include <linux/delay.h>
  19 #include <linux/power_supply.h>
  20 #include <linux/slab.h>
  21
  22 #define I16_MSB(x)                      ((x >> 8) & 0xFF)
  23 #define I16_LSB(x)                      (x & 0xFF)
  24
  25 #define LTC294X_WORK_DELAY              10      /* Update delay in seconds */
  26
  27 #define LTC294X_MAX_VALUE               0xFFFF
  28 #define LTC294X_MID_SUPPLY              0x7FFF
  29
  30 #define LTC2941_MAX_PRESCALER_EXP       7
  31 #define LTC2943_MAX_PRESCALER_EXP       6
  32
  33 enum ltc294x_reg {
  34         LTC294X_REG_STATUS              = 0x00,
  35         LTC294X_REG_CONTROL             = 0x01,
  36         LTC294X_REG_ACC_CHARGE_MSB      = 0x02,
  37         LTC294X_REG_ACC_CHARGE_LSB      = 0x03,
  38         LTC294X_REG_CHARGE_THR_HIGH_MSB = 0x04,
  39         LTC294X_REG_CHARGE_THR_HIGH_LSB = 0x05,
  40         LTC294X_REG_CHARGE_THR_LOW_MSB  = 0x06,
  41         LTC294X_REG_CHARGE_THR_LOW_LSB  = 0x07,
  42         LTC294X_REG_VOLTAGE_MSB         = 0x08,
  43         LTC294X_REG_VOLTAGE_LSB         = 0x09,
  44         LTC2942_REG_TEMPERATURE_MSB     = 0x0C,
  45         LTC2942_REG_TEMPERATURE_LSB     = 0x0D,
  46         LTC2943_REG_CURRENT_MSB         = 0x0E,
  47         LTC2943_REG_CURRENT_LSB         = 0x0F,
  48         LTC2943_REG_TEMPERATURE_MSB     = 0x14,
  49         LTC2943_REG_TEMPERATURE_LSB     = 0x15,
  50 };
  51
  52 enum ltc294x_id {
  53         LTC2941_ID,
  54         LTC2942_ID,
  55         LTC2943_ID,
  56         LTC2944_ID,
  57 };
  58
  59 #define LTC2941_REG_STATUS_CHIP_ID      BIT(7)
  60
  61 #define LTC2942_REG_CONTROL_MODE_SCAN   (BIT(7) | BIT(6))
  62 #define LTC2943_REG_CONTROL_MODE_SCAN   BIT(7)
  63 #define LTC294X_REG_CONTROL_PRESCALER_MASK      (BIT(5) | BIT(4) | BIT(3))
  64 #define LTC294X_REG_CONTROL_SHUTDOWN_MASK       (BIT(0))
  65 #define LTC294X_REG_CONTROL_PRESCALER_SET(x) \
  66         ((x << 3) & LTC294X_REG_CONTROL_PRESCALER_MASK)
  67 #define LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED        0
  68 #define LTC294X_REG_CONTROL_ADC_DISABLE(x)      ((x) & ~(BIT(7) | BIT(6)))
  69
  70 struct ltc294x_info {
  71         struct i2c_client *client;      /* I2C Client pointer */
  72         struct power_supply *supply;    /* Supply pointer */
  73         struct power_supply_desc supply_desc;   /* Supply description */
  74         struct delayed_work work;       /* Work scheduler */
  75         enum ltc294x_id id;             /* Chip type */
  76         int charge;     /* Last charge register content */
  77         int r_sense;    /* mOhm */
  78         int Qlsb;       /* nAh */
  79 };
  80
  81 static inline int convert_bin_to_uAh(
  82         const struct ltc294x_info *info, int Q)
  83 {
  84         return ((Q * (info->Qlsb / 10))) / 100;
  85 }
  86
  87 static inline int convert_uAh_to_bin(
  88         const struct ltc294x_info *info, int uAh)
  89 {
  90         int Q;
  91
  92         Q = (uAh * 100) / (info->Qlsb/10);
  93         return (Q < LTC294X_MAX_VALUE) ? Q : LTC294X_MAX_VALUE;
  94 }
  95
  96 static int ltc294x_read_regs(struct i2c_client *client,
  97         enum ltc294x_reg reg, u8 *buf, int num_regs)
  98 {
  99         int ret;
 100         struct i2c_msg msgs[2] = { };
 101         u8 reg_start = reg;
 102
 103         msgs[0].addr    = client->addr;
 104         msgs[0].len     = 1;
 105         msgs[0].buf     = &reg_start;
 106
 107         msgs[1].addr    = client->addr;
 108         msgs[1].len     = num_regs;
 109         msgs[1].buf     = buf;
 110         msgs[1].flags   = I2C_M_RD;
 111
 112         ret = i2c_transfer(client->adapter, &msgs[0], 2);
 113         if (ret < 0) {
 114                 dev_err(&client->dev, "ltc2941 read_reg failed!\n");
 115                 return ret;
 116         }
 117
 118         dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
 119                 __func__, reg, num_regs, *buf);
 120
 121         return 0;
 122 }
 123
 124 static int ltc294x_write_regs(struct i2c_client *client,
 125         enum ltc294x_reg reg, const u8 *buf, int num_regs)
 126 {
 127         int ret;
 128         u8 reg_start = reg;
 129
 130         ret = i2c_smbus_write_i2c_block_data(client, reg_start, num_regs, buf);
 131         if (ret < 0) {
 132                 dev_err(&client->dev, "ltc2941 write_reg failed!\n");
 133                 return ret;
 134         }
 135
 136         dev_dbg(&client->dev, "%s (%#x, %d) -> %#x\n",
 137                 __func__, reg, num_regs, *buf);
 138
 139         return 0;
 140 }
 141
 142 static int ltc294x_reset(const struct ltc294x_info *info, int prescaler_exp)
 143 {
 144         int ret;
 145         u8 value;
 146         u8 control;
 147
 148         /* Read status and control registers */
 149         ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
 150         if (ret < 0) {
 151                 dev_err(&info->client->dev,
 152                         "Could not read registers from device\n");
 153                 goto error_exit;
 154         }
 155
 156         control = LTC294X_REG_CONTROL_PRESCALER_SET(prescaler_exp) |
 157                                 LTC294X_REG_CONTROL_ALCC_CONFIG_DISABLED;
 158         /* Put device into "monitor" mode */
 159         switch (info->id) {
 160         case LTC2942_ID:        /* 2942 measures every 2 sec */
 161                 control |= LTC2942_REG_CONTROL_MODE_SCAN;
 162                 break;
 163         case LTC2943_ID:
 164         case LTC2944_ID:        /* 2943 and 2944 measure every 10 sec */
 165                 control |= LTC2943_REG_CONTROL_MODE_SCAN;
 166                 break;
 167         default:
 168                 break;
 169         }
 170
 171         if (value != control) {
 172                 ret = ltc294x_write_regs(info->client,
 173                         LTC294X_REG_CONTROL, &control, 1);
 174                 if (ret < 0) {
 175                         dev_err(&info->client->dev,
 176                                 "Could not write register\n");
 177                         goto error_exit;
 178                 }
 179         }
 180
 181         return 0;
 182
 183 error_exit:
 184         return ret;
 185 }
 186
 187 static int ltc294x_read_charge_register(const struct ltc294x_info *info,
 188                                         enum ltc294x_reg reg)
 189  {
 190         int ret;
 191         u8 datar[2];
 192
 193         ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
 194         if (ret < 0)
 195                 return ret;
 196         return (datar[0] << 8) + datar[1];
 197 }
 198
 199 static int ltc294x_get_charge(const struct ltc294x_info *info,
 200                                 enum ltc294x_reg reg, int *val)
 201 {
 202         int value = ltc294x_read_charge_register(info, reg);
 203
 204         if (value < 0)
 205                 return value;
 206         /* When r_sense < 0, this counts up when the battery discharges */
 207         if (info->Qlsb < 0)
 208                 value -= 0xFFFF;
 209         *val = convert_bin_to_uAh(info, value);
 210         return 0;
 211 }
 212
 213 static int ltc294x_set_charge_now(const struct ltc294x_info *info, int val)
 214 {
 215         int ret;
 216         u8 dataw[2];
 217         u8 ctrl_reg;
 218         s32 value;
 219
 220         value = convert_uAh_to_bin(info, val);
 221         /* Direction depends on how sense+/- were connected */
 222         if (info->Qlsb < 0)
 223                 value += 0xFFFF;
 224         if ((value < 0) || (value > 0xFFFF)) /* input validation */
 225                 return -EINVAL;
 226
 227         /* Read control register */
 228         ret = ltc294x_read_regs(info->client,
 229                 LTC294X_REG_CONTROL, &ctrl_reg, 1);
 230         if (ret < 0)
 231                 return ret;
 232         /* Disable analog section */
 233         ctrl_reg |= LTC294X_REG_CONTROL_SHUTDOWN_MASK;
 234         ret = ltc294x_write_regs(info->client,
 235                 LTC294X_REG_CONTROL, &ctrl_reg, 1);
 236         if (ret < 0)
 237                 return ret;
 238         /* Set new charge value */
 239         dataw[0] = I16_MSB(value);
 240         dataw[1] = I16_LSB(value);
 241         ret = ltc294x_write_regs(info->client,
 242                 LTC294X_REG_ACC_CHARGE_MSB, &dataw[0], 2);
 243         if (ret < 0)
 244                 goto error_exit;
 245         /* Enable analog section */
 246 error_exit:
 247         ctrl_reg &= ~LTC294X_REG_CONTROL_SHUTDOWN_MASK;
 248         ret = ltc294x_write_regs(info->client,
 249                 LTC294X_REG_CONTROL, &ctrl_reg, 1);
 250
 251         return ret < 0 ? ret : 0;
 252 }
 253
 254 static int ltc294x_set_charge_thr(const struct ltc294x_info *info,
 255                                         enum ltc294x_reg reg, int val)
 256 {
 257         u8 dataw[2];
 258         s32 value;
 259
 260         value = convert_uAh_to_bin(info, val);
 261         /* Direction depends on how sense+/- were connected */
 262         if (info->Qlsb < 0)
 263                 value += 0xFFFF;
 264         if ((value < 0) || (value > 0xFFFF)) /* input validation */
 265                 return -EINVAL;
 266
 267         /* Set new charge value */
 268         dataw[0] = I16_MSB(value);
 269         dataw[1] = I16_LSB(value);
 270         return ltc294x_write_regs(info->client, reg, &dataw[0], 2);
 271 }
 272
 273 static int ltc294x_get_charge_counter(
 274         const struct ltc294x_info *info, int *val)
 275 {
 276         int value = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
 277
 278         if (value < 0)
 279                 return value;
 280         value -= LTC294X_MID_SUPPLY;
 281         *val = convert_bin_to_uAh(info, value);
 282         return 0;
 283 }
 284
 285 static int ltc294x_get_voltage(const struct ltc294x_info *info, int *val)
 286 {
 287         int ret;
 288         u8 datar[2];
 289         u32 value;
 290
 291         ret = ltc294x_read_regs(info->client,
 292                 LTC294X_REG_VOLTAGE_MSB, &datar[0], 2);
 293         value = (datar[0] << 8) | datar[1];
 294         switch (info->id) {
 295         case LTC2943_ID:
 296                 value *= 23600 * 2;
 297                 value /= 0xFFFF;
 298                 value *= 1000 / 2;
 299                 break;
 300         case LTC2944_ID:
 301                 value *= 70800 / 5*4;
 302                 value /= 0xFFFF;
 303                 value *= 1000 * 5/4;
 304                 break;
 305         default:
 306                 value *= 6000 * 10;
 307                 value /= 0xFFFF;
 308                 value *= 1000 / 10;
 309                 break;
 310         }
 311         *val = value;
 312         return ret;
 313 }
 314
 315 static int ltc294x_get_current(const struct ltc294x_info *info, int *val)
 316 {
 317         int ret;
 318         u8 datar[2];
 319         s32 value;
 320
 321         ret = ltc294x_read_regs(info->client,
 322                 LTC2943_REG_CURRENT_MSB, &datar[0], 2);
 323         value = (datar[0] << 8) | datar[1];
 324         value -= 0x7FFF;
 325         if (info->id == LTC2944_ID)
 326                 value *= 64000;
 327         else
 328                 value *= 60000;
 329         /* Value is in range -32k..+32k, r_sense is usually 10..50 mOhm,
 330          * the formula below keeps everything in s32 range while preserving
 331          * enough digits */
 332         *val = 1000 * (value / (info->r_sense * 0x7FFF)); /* in uA */
 333         return ret;
 334 }
 335
 336 static int ltc294x_get_temperature(const struct ltc294x_info *info, int *val)
 337 {
 338         enum ltc294x_reg reg;
 339         int ret;
 340         u8 datar[2];
 341         u32 value;
 342
 343         if (info->id == LTC2942_ID) {
 344                 reg = LTC2942_REG_TEMPERATURE_MSB;
 345                 value = 6000;   /* Full-scale is 600 Kelvin */
 346         } else {
 347                 reg = LTC2943_REG_TEMPERATURE_MSB;
 348                 value = 5100;   /* Full-scale is 510 Kelvin */
 349         }
 350         ret = ltc294x_read_regs(info->client, reg, &datar[0], 2);
 351         value *= (datar[0] << 8) | datar[1];
 352         /* Convert to tenths of degree Celsius */
 353         *val = value / 0xFFFF - 2722;
 354         return ret;
 355 }
 356
 357 static int ltc294x_get_property(struct power_supply *psy,
 358                                 enum power_supply_property prop,
 359                                 union power_supply_propval *val)
 360 {
 361         struct ltc294x_info *info = power_supply_get_drvdata(psy);
 362
 363         switch (prop) {
 364         case POWER_SUPPLY_PROP_CHARGE_FULL:
 365                 return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_HIGH_MSB,
 366                                                 &val->intval);
 367         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 368                 return ltc294x_get_charge(info, LTC294X_REG_CHARGE_THR_LOW_MSB,
 369                                                 &val->intval);
 370         case POWER_SUPPLY_PROP_CHARGE_NOW:
 371                 return ltc294x_get_charge(info, LTC294X_REG_ACC_CHARGE_MSB,
 372                                                 &val->intval);
 373         case POWER_SUPPLY_PROP_CHARGE_COUNTER:
 374                 return ltc294x_get_charge_counter(info, &val->intval);
 375         case POWER_SUPPLY_PROP_VOLTAGE_NOW:
 376                 return ltc294x_get_voltage(info, &val->intval);
 377         case POWER_SUPPLY_PROP_CURRENT_NOW:
 378                 return ltc294x_get_current(info, &val->intval);
 379         case POWER_SUPPLY_PROP_TEMP:
 380                 return ltc294x_get_temperature(info, &val->intval);
 381         default:
 382                 return -EINVAL;
 383         }
 384 }
 385
 386 static int ltc294x_set_property(struct power_supply *psy,
 387         enum power_supply_property psp,
 388         const union power_supply_propval *val)
 389 {
 390         struct ltc294x_info *info = power_supply_get_drvdata(psy);
 391
 392         switch (psp) {
 393         case POWER_SUPPLY_PROP_CHARGE_FULL:
 394                 return ltc294x_set_charge_thr(info,
 395                         LTC294X_REG_CHARGE_THR_HIGH_MSB, val->intval);
 396         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 397                 return ltc294x_set_charge_thr(info,
 398                         LTC294X_REG_CHARGE_THR_LOW_MSB, val->intval);
 399         case POWER_SUPPLY_PROP_CHARGE_NOW:
 400                 return ltc294x_set_charge_now(info, val->intval);
 401         default:
 402                 return -EPERM;
 403         }
 404 }
 405
 406 static int ltc294x_property_is_writeable(
 407         struct power_supply *psy, enum power_supply_property psp)
 408 {
 409         switch (psp) {
 410         case POWER_SUPPLY_PROP_CHARGE_FULL:
 411         case POWER_SUPPLY_PROP_CHARGE_EMPTY:
 412         case POWER_SUPPLY_PROP_CHARGE_NOW:
 413                 return 1;
 414         default:
 415                 return 0;
 416         }
 417 }
 418
 419 static void ltc294x_update(struct ltc294x_info *info)
 420 {
 421         int charge = ltc294x_read_charge_register(info, LTC294X_REG_ACC_CHARGE_MSB);
 422
 423         if (charge != info->charge) {
 424                 info->charge = charge;
 425                 power_supply_changed(info->supply);
 426         }
 427 }
 428
 429 static void ltc294x_work(struct work_struct *work)
 430 {
 431         struct ltc294x_info *info;
 432
 433         info = container_of(work, struct ltc294x_info, work.work);
 434         ltc294x_update(info);
 435         schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
 436 }
 437
 438 static enum power_supply_property ltc294x_properties[] = {
 439         POWER_SUPPLY_PROP_CHARGE_COUNTER,
 440         POWER_SUPPLY_PROP_CHARGE_FULL,
 441         POWER_SUPPLY_PROP_CHARGE_EMPTY,
 442         POWER_SUPPLY_PROP_CHARGE_NOW,
 443         POWER_SUPPLY_PROP_VOLTAGE_NOW,
 444         POWER_SUPPLY_PROP_TEMP,
 445         POWER_SUPPLY_PROP_CURRENT_NOW,
 446 };
 447
 448 static int ltc294x_i2c_remove(struct i2c_client *client)
 449 {
 450         struct ltc294x_info *info = i2c_get_clientdata(client);
 451
 452         cancel_delayed_work_sync(&info->work);
 453         power_supply_unregister(info->supply);
 454         return 0;
 455 }
 456
 457 static int ltc294x_i2c_probe(struct i2c_client *client,
 458         const struct i2c_device_id *id)
 459 {
 460         struct power_supply_config psy_cfg = {};
 461         struct ltc294x_info *info;
 462         struct device_node *np;
 463         int ret;
 464         u32 prescaler_exp;
 465         s32 r_sense;
 466         u8 status;
 467
 468         info = devm_kzalloc(&client->dev, sizeof(*info), GFP_KERNEL);
 469         if (info == NULL)
 470                 return -ENOMEM;
 471
 472         i2c_set_clientdata(client, info);
 473
 474         np = of_node_get(client->dev.of_node);
 475
 476         info->id = (enum ltc294x_id)of_device_get_match_data(&client->dev);
 477         info->supply_desc.name = np->name;
 478
 479         /* r_sense can be negative, when sense+ is connected to the battery
 480          * instead of the sense-. This results in reversed measurements. */
 481         ret = of_property_read_u32(np, "lltc,resistor-sense", &r_sense);
 482         if (ret < 0) {
 483                 dev_err(&client->dev,
 484                         "Could not find lltc,resistor-sense in devicetree\n");
 485                 return ret;
 486         }
 487         info->r_sense = r_sense;
 488
 489         ret = of_property_read_u32(np, "lltc,prescaler-exponent",
 490                 &prescaler_exp);
 491         if (ret < 0) {
 492                 dev_warn(&client->dev,
 493                         "lltc,prescaler-exponent not in devicetree\n");
 494                 prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
 495         }
 496
 497         if (info->id == LTC2943_ID) {
 498                 if (prescaler_exp > LTC2943_MAX_PRESCALER_EXP)
 499                         prescaler_exp = LTC2943_MAX_PRESCALER_EXP;
 500                 info->Qlsb = ((340 * 50000) / r_sense) /
 501                                 (4096 / (1 << (2*prescaler_exp)));
 502         } else {
 503                 if (prescaler_exp > LTC2941_MAX_PRESCALER_EXP)
 504                         prescaler_exp = LTC2941_MAX_PRESCALER_EXP;
 505                 info->Qlsb = ((85 * 50000) / r_sense) /
 506                                 (128 / (1 << prescaler_exp));
 507         }
 508
 509         /* Read status register to check for LTC2942 */
 510         if (info->id == LTC2941_ID || info->id == LTC2942_ID) {
 511                 ret = ltc294x_read_regs(client, LTC294X_REG_STATUS, &status, 1);
 512                 if (ret < 0) {
 513                         dev_err(&client->dev,
 514                                 "Could not read status register\n");
 515                         return ret;
 516                 }
 517                 if (status & LTC2941_REG_STATUS_CHIP_ID)
 518                         info->id = LTC2941_ID;
 519                 else
 520                         info->id = LTC2942_ID;
 521         }
 522
 523         info->client = client;
 524         info->supply_desc.type = POWER_SUPPLY_TYPE_BATTERY;
 525         info->supply_desc.properties = ltc294x_properties;
 526         switch (info->id) {
 527         case LTC2944_ID:
 528         case LTC2943_ID:
 529                 info->supply_desc.num_properties =
 530                         ARRAY_SIZE(ltc294x_properties);
 531                 break;
 532         case LTC2942_ID:
 533                 info->supply_desc.num_properties =
 534                         ARRAY_SIZE(ltc294x_properties) - 1;
 535                 break;
 536         case LTC2941_ID:
 537         default:
 538                 info->supply_desc.num_properties =
 539                         ARRAY_SIZE(ltc294x_properties) - 3;
 540                 break;
 541         }
 542         info->supply_desc.get_property = ltc294x_get_property;
 543         info->supply_desc.set_property = ltc294x_set_property;
 544         info->supply_desc.property_is_writeable = ltc294x_property_is_writeable;
 545         info->supply_desc.external_power_changed        = NULL;
 546
 547         psy_cfg.drv_data = info;
 548
 549         INIT_DELAYED_WORK(&info->work, ltc294x_work);
 550
 551         ret = ltc294x_reset(info, prescaler_exp);
 552         if (ret < 0) {
 553                 dev_err(&client->dev, "Communication with chip failed\n");
 554                 return ret;
 555         }
 556
 557         info->supply = power_supply_register(&client->dev, &info->supply_desc,
 558                                              &psy_cfg);
 559         if (IS_ERR(info->supply)) {
 560                 dev_err(&client->dev, "failed to register ltc2941\n");
 561                 return PTR_ERR(info->supply);
 562         } else {
 563                 schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
 564         }
 565
 566         return 0;
 567 }
 568
 569 static void ltc294x_i2c_shutdown(struct i2c_client *client)
 570 {
 571         struct ltc294x_info *info = i2c_get_clientdata(client);
 572         int ret;
 573         u8 value;
 574         u8 control;
 575
 576         /* The LTC2941 does not need any special handling */
 577         if (info->id == LTC2941_ID)
 578                 return;
 579
 580         /* Read control register */
 581         ret = ltc294x_read_regs(info->client, LTC294X_REG_CONTROL, &value, 1);
 582         if (ret < 0)
 583                 return;
 584
 585         /* Disable continuous ADC conversion as this drains the battery */
 586         control = LTC294X_REG_CONTROL_ADC_DISABLE(value);
 587         if (control != value)
 588                 ltc294x_write_regs(info->client, LTC294X_REG_CONTROL,
 589                         &control, 1);
 590 }
 591
 592 #ifdef CONFIG_PM_SLEEP
 593
 594 static int ltc294x_suspend(struct device *dev)
 595 {
 596         struct i2c_client *client = to_i2c_client(dev);
 597         struct ltc294x_info *info = i2c_get_clientdata(client);
 598
 599         cancel_delayed_work(&info->work);
 600         return 0;
 601 }
 602
 603 static int ltc294x_resume(struct device *dev)
 604 {
 605         struct i2c_client *client = to_i2c_client(dev);
 606         struct ltc294x_info *info = i2c_get_clientdata(client);
 607
 608         schedule_delayed_work(&info->work, LTC294X_WORK_DELAY * HZ);
 609         return 0;
 610 }
 611
 612 static SIMPLE_DEV_PM_OPS(ltc294x_pm_ops, ltc294x_suspend, ltc294x_resume);
 613 #define LTC294X_PM_OPS (&ltc294x_pm_ops)
 614
 615 #else
 616 #define LTC294X_PM_OPS NULL
 617 #endif /* CONFIG_PM_SLEEP */
 618
 619
 620 static const struct i2c_device_id ltc294x_i2c_id[] = {
 621         { "ltc2941", LTC2941_ID, },
 622         { "ltc2942", LTC2942_ID, },
 623         { "ltc2943", LTC2943_ID, },
 624         { "ltc2944", LTC2944_ID, },
 625         { },
 626 };
 627 MODULE_DEVICE_TABLE(i2c, ltc294x_i2c_id);
 628
 629 static const struct of_device_id ltc294x_i2c_of_match[] = {
 630         {
 631                 .compatible = "lltc,ltc2941",
 632                 .data = (void *)LTC2941_ID,
 633         },
 634         {
 635                 .compatible = "lltc,ltc2942",
 636                 .data = (void *)LTC2942_ID,
 637         },
 638         {
 639                 .compatible = "lltc,ltc2943",
 640                 .data = (void *)LTC2943_ID,
 641         },
 642         {
 643                 .compatible = "lltc,ltc2944",
 644                 .data = (void *)LTC2944_ID,
 645         },
 646         { },
 647 };
 648 MODULE_DEVICE_TABLE(of, ltc294x_i2c_of_match);
 649
 650 static struct i2c_driver ltc294x_driver = {
 651         .driver = {
 652                 .name   = "LTC2941",
 653                 .of_match_table = ltc294x_i2c_of_match,
 654                 .pm     = LTC294X_PM_OPS,
 655         },
 656         .probe          = ltc294x_i2c_probe,
 657         .remove         = ltc294x_i2c_remove,
 658         .shutdown       = ltc294x_i2c_shutdown,
 659         .id_table       = ltc294x_i2c_id,
 660 };
 661 module_i2c_driver(ltc294x_driver);
 662
 663 MODULE_AUTHOR("Auryn Verwegen, Topic Embedded Systems");
 664 MODULE_AUTHOR("Mike Looijmans, Topic Embedded Products");
 665 MODULE_DESCRIPTION("LTC2941/LTC2942/LTC2943/LTC2944 Battery Gas Gauge IC driver");
 666 MODULE_LICENSE("GPL");