1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * I2C client/driver for the Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC 4 * 5 * Copyright (C) 2009 Bluewater Systems Ltd 6 * 7 * Author: Ryan Mallon 8 * 9 * DS2786 added by Yulia Vilensky <vilensky@compulab.co.il> 10 * 11 * UEvent sending added by Evgeny Romanov <romanov@neurosoft.ru> 12 */ 13 14 #include <linux/kernel.h> 15 #include <linux/module.h> 16 #include <linux/types.h> 17 #include <linux/errno.h> 18 #include <linux/swab.h> 19 #include <linux/i2c.h> 20 #include <linux/delay.h> 21 #include <linux/idr.h> 22 #include <linux/power_supply.h> 23 #include <linux/slab.h> 24 #include <linux/ds2782_battery.h> 25 26 #define DS2782_REG_RARC 0x06 /* Remaining active relative capacity */ 27 28 #define DS278x_REG_VOLT_MSB 0x0c 29 #define DS278x_REG_TEMP_MSB 0x0a 30 #define DS278x_REG_CURRENT_MSB 0x0e 31 32 /* EEPROM Block */ 33 #define DS2782_REG_RSNSP 0x69 /* Sense resistor value */ 34 35 /* Current unit measurement in uA for a 1 milli-ohm sense resistor */ 36 #define DS2782_CURRENT_UNITS 1563 37 38 #define DS2786_REG_RARC 0x02 /* Remaining active relative capacity */ 39 40 #define DS2786_CURRENT_UNITS 25 41 42 #define DS278x_DELAY 1000 43 44 struct ds278x_info; 45 46 struct ds278x_battery_ops { 47 int (*get_battery_current)(struct ds278x_info *info, int *current_uA); 48 int (*get_battery_voltage)(struct ds278x_info *info, int *voltage_uV); 49 int (*get_battery_capacity)(struct ds278x_info *info, int *capacity); 50 }; 51 52 #define to_ds278x_info(x) power_supply_get_drvdata(x) 53 54 struct ds278x_info { 55 struct i2c_client *client; 56 struct power_supply *battery; 57 struct power_supply_desc battery_desc; 58 const struct ds278x_battery_ops *ops; 59 struct delayed_work bat_work; 60 int id; 61 int rsns; 62 int capacity; 63 int status; /* State Of Charge */ 64 }; 65 66 static DEFINE_IDR(battery_id); 67 static DEFINE_MUTEX(battery_lock); 68 69 static inline int ds278x_read_reg(struct ds278x_info *info, int reg, u8 *val) 70 { 71 int ret; 72 73 ret = i2c_smbus_read_byte_data(info->client, reg); 74 if (ret < 0) { 75 dev_err(&info->client->dev, "register read failed\n"); 76 return ret; 77 } 78 79 *val = ret; 80 return 0; 81 } 82 83 static inline int ds278x_read_reg16(struct ds278x_info *info, int reg_msb, 84 s16 *val) 85 { 86 int ret; 87 88 ret = i2c_smbus_read_word_data(info->client, reg_msb); 89 if (ret < 0) { 90 dev_err(&info->client->dev, "register read failed\n"); 91 return ret; 92 } 93 94 *val = swab16(ret); 95 return 0; 96 } 97 98 static int ds278x_get_temp(struct ds278x_info *info, int *temp) 99 { 100 s16 raw; 101 int err; 102 103 /* 104 * Temperature is measured in units of 0.125 degrees celcius, the 105 * power_supply class measures temperature in tenths of degrees 106 * celsius. The temperature value is stored as a 10 bit number, plus 107 * sign in the upper bits of a 16 bit register. 108 */ 109 err = ds278x_read_reg16(info, DS278x_REG_TEMP_MSB, &raw); 110 if (err) 111 return err; 112 *temp = ((raw / 32) * 125) / 100; 113 return 0; 114 } 115 116 static int ds2782_get_current(struct ds278x_info *info, int *current_uA) 117 { 118 int sense_res; 119 int err; 120 u8 sense_res_raw; 121 s16 raw; 122 123 /* 124 * The units of measurement for current are dependent on the value of 125 * the sense resistor. 126 */ 127 err = ds278x_read_reg(info, DS2782_REG_RSNSP, &sense_res_raw); 128 if (err) 129 return err; 130 if (sense_res_raw == 0) { 131 dev_err(&info->client->dev, "sense resistor value is 0\n"); 132 return -ENXIO; 133 } 134 sense_res = 1000 / sense_res_raw; 135 136 dev_dbg(&info->client->dev, "sense resistor = %d milli-ohms\n", 137 sense_res); 138 err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw); 139 if (err) 140 return err; 141 *current_uA = raw * (DS2782_CURRENT_UNITS / sense_res); 142 return 0; 143 } 144 145 static int ds2782_get_voltage(struct ds278x_info *info, int *voltage_uV) 146 { 147 s16 raw; 148 int err; 149 150 /* 151 * Voltage is measured in units of 4.88mV. The voltage is stored as 152 * a 10-bit number plus sign, in the upper bits of a 16-bit register 153 */ 154 err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw); 155 if (err) 156 return err; 157 *voltage_uV = (raw / 32) * 4800; 158 return 0; 159 } 160 161 static int ds2782_get_capacity(struct ds278x_info *info, int *capacity) 162 { 163 int err; 164 u8 raw; 165 166 err = ds278x_read_reg(info, DS2782_REG_RARC, &raw); 167 if (err) 168 return err; 169 *capacity = raw; 170 return 0; 171 } 172 173 static int ds2786_get_current(struct ds278x_info *info, int *current_uA) 174 { 175 int err; 176 s16 raw; 177 178 err = ds278x_read_reg16(info, DS278x_REG_CURRENT_MSB, &raw); 179 if (err) 180 return err; 181 *current_uA = (raw / 16) * (DS2786_CURRENT_UNITS / info->rsns); 182 return 0; 183 } 184 185 static int ds2786_get_voltage(struct ds278x_info *info, int *voltage_uV) 186 { 187 s16 raw; 188 int err; 189 190 /* 191 * Voltage is measured in units of 1.22mV. The voltage is stored as 192 * a 12-bit number plus sign, in the upper bits of a 16-bit register 193 */ 194 err = ds278x_read_reg16(info, DS278x_REG_VOLT_MSB, &raw); 195 if (err) 196 return err; 197 *voltage_uV = (raw / 8) * 1220; 198 return 0; 199 } 200 201 static int ds2786_get_capacity(struct ds278x_info *info, int *capacity) 202 { 203 int err; 204 u8 raw; 205 206 err = ds278x_read_reg(info, DS2786_REG_RARC, &raw); 207 if (err) 208 return err; 209 /* Relative capacity is displayed with resolution 0.5 % */ 210 *capacity = raw/2 ; 211 return 0; 212 } 213 214 static int ds278x_get_status(struct ds278x_info *info, int *status) 215 { 216 int err; 217 int current_uA; 218 int capacity; 219 220 err = info->ops->get_battery_current(info, ¤t_uA); 221 if (err) 222 return err; 223 224 err = info->ops->get_battery_capacity(info, &capacity); 225 if (err) 226 return err; 227 228 info->capacity = capacity; 229 230 if (capacity == 100) 231 *status = POWER_SUPPLY_STATUS_FULL; 232 else if (current_uA == 0) 233 *status = POWER_SUPPLY_STATUS_NOT_CHARGING; 234 else if (current_uA < 0) 235 *status = POWER_SUPPLY_STATUS_DISCHARGING; 236 else 237 *status = POWER_SUPPLY_STATUS_CHARGING; 238 239 return 0; 240 } 241 242 static int ds278x_battery_get_property(struct power_supply *psy, 243 enum power_supply_property prop, 244 union power_supply_propval *val) 245 { 246 struct ds278x_info *info = to_ds278x_info(psy); 247 int ret; 248 249 switch (prop) { 250 case POWER_SUPPLY_PROP_STATUS: 251 ret = ds278x_get_status(info, &val->intval); 252 break; 253 254 case POWER_SUPPLY_PROP_CAPACITY: 255 ret = info->ops->get_battery_capacity(info, &val->intval); 256 break; 257 258 case POWER_SUPPLY_PROP_VOLTAGE_NOW: 259 ret = info->ops->get_battery_voltage(info, &val->intval); 260 break; 261 262 case POWER_SUPPLY_PROP_CURRENT_NOW: 263 ret = info->ops->get_battery_current(info, &val->intval); 264 break; 265 266 case POWER_SUPPLY_PROP_TEMP: 267 ret = ds278x_get_temp(info, &val->intval); 268 break; 269 270 default: 271 ret = -EINVAL; 272 } 273 274 return ret; 275 } 276 277 static void ds278x_bat_update(struct ds278x_info *info) 278 { 279 int old_status = info->status; 280 int old_capacity = info->capacity; 281 282 ds278x_get_status(info, &info->status); 283 284 if ((old_status != info->status) || (old_capacity != info->capacity)) 285 power_supply_changed(info->battery); 286 } 287 288 static void ds278x_bat_work(struct work_struct *work) 289 { 290 struct ds278x_info *info; 291 292 info = container_of(work, struct ds278x_info, bat_work.work); 293 ds278x_bat_update(info); 294 295 schedule_delayed_work(&info->bat_work, DS278x_DELAY); 296 } 297 298 static enum power_supply_property ds278x_battery_props[] = { 299 POWER_SUPPLY_PROP_STATUS, 300 POWER_SUPPLY_PROP_CAPACITY, 301 POWER_SUPPLY_PROP_VOLTAGE_NOW, 302 POWER_SUPPLY_PROP_CURRENT_NOW, 303 POWER_SUPPLY_PROP_TEMP, 304 }; 305 306 static void ds278x_power_supply_init(struct power_supply_desc *battery) 307 { 308 battery->type = POWER_SUPPLY_TYPE_BATTERY; 309 battery->properties = ds278x_battery_props; 310 battery->num_properties = ARRAY_SIZE(ds278x_battery_props); 311 battery->get_property = ds278x_battery_get_property; 312 battery->external_power_changed = NULL; 313 } 314 315 static void ds278x_battery_remove(struct i2c_client *client) 316 { 317 struct ds278x_info *info = i2c_get_clientdata(client); 318 int id = info->id; 319 320 power_supply_unregister(info->battery); 321 cancel_delayed_work_sync(&info->bat_work); 322 kfree(info->battery_desc.name); 323 kfree(info); 324 325 mutex_lock(&battery_lock); 326 idr_remove(&battery_id, id); 327 mutex_unlock(&battery_lock); 328 } 329 330 #ifdef CONFIG_PM_SLEEP 331 332 static int ds278x_suspend(struct device *dev) 333 { 334 struct i2c_client *client = to_i2c_client(dev); 335 struct ds278x_info *info = i2c_get_clientdata(client); 336 337 cancel_delayed_work(&info->bat_work); 338 return 0; 339 } 340 341 static int ds278x_resume(struct device *dev) 342 { 343 struct i2c_client *client = to_i2c_client(dev); 344 struct ds278x_info *info = i2c_get_clientdata(client); 345 346 schedule_delayed_work(&info->bat_work, DS278x_DELAY); 347 return 0; 348 } 349 #endif /* CONFIG_PM_SLEEP */ 350 351 static SIMPLE_DEV_PM_OPS(ds278x_battery_pm_ops, ds278x_suspend, ds278x_resume); 352 353 enum ds278x_num_id { 354 DS2782 = 0, 355 DS2786, 356 }; 357 358 static const struct ds278x_battery_ops ds278x_ops[] = { 359 [DS2782] = { 360 .get_battery_current = ds2782_get_current, 361 .get_battery_voltage = ds2782_get_voltage, 362 .get_battery_capacity = ds2782_get_capacity, 363 }, 364 [DS2786] = { 365 .get_battery_current = ds2786_get_current, 366 .get_battery_voltage = ds2786_get_voltage, 367 .get_battery_capacity = ds2786_get_capacity, 368 } 369 }; 370 371 static int ds278x_battery_probe(struct i2c_client *client) 372 { 373 const struct i2c_device_id *id = i2c_client_get_device_id(client); 374 struct ds278x_platform_data *pdata = client->dev.platform_data; 375 struct power_supply_config psy_cfg = {}; 376 struct ds278x_info *info; 377 int ret; 378 int num; 379 380 /* 381 * ds2786 should have the sense resistor value set 382 * in the platform data 383 */ 384 if (id->driver_data == DS2786 && !pdata) { 385 dev_err(&client->dev, "missing platform data for ds2786\n"); 386 return -EINVAL; 387 } 388 389 /* Get an ID for this battery */ 390 mutex_lock(&battery_lock); 391 ret = idr_alloc(&battery_id, client, 0, 0, GFP_KERNEL); 392 mutex_unlock(&battery_lock); 393 if (ret < 0) 394 goto fail_id; 395 num = ret; 396 397 info = kzalloc(sizeof(*info), GFP_KERNEL); 398 if (!info) { 399 ret = -ENOMEM; 400 goto fail_info; 401 } 402 403 info->battery_desc.name = kasprintf(GFP_KERNEL, "%s-%d", 404 client->name, num); 405 if (!info->battery_desc.name) { 406 ret = -ENOMEM; 407 goto fail_name; 408 } 409 410 if (id->driver_data == DS2786) 411 info->rsns = pdata->rsns; 412 413 i2c_set_clientdata(client, info); 414 info->client = client; 415 info->id = num; 416 info->ops = &ds278x_ops[id->driver_data]; 417 ds278x_power_supply_init(&info->battery_desc); 418 psy_cfg.drv_data = info; 419 420 info->capacity = 100; 421 info->status = POWER_SUPPLY_STATUS_FULL; 422 423 INIT_DELAYED_WORK(&info->bat_work, ds278x_bat_work); 424 425 info->battery = power_supply_register(&client->dev, 426 &info->battery_desc, &psy_cfg); 427 if (IS_ERR(info->battery)) { 428 dev_err(&client->dev, "failed to register battery\n"); 429 ret = PTR_ERR(info->battery); 430 goto fail_register; 431 } else { 432 schedule_delayed_work(&info->bat_work, DS278x_DELAY); 433 } 434 435 return 0; 436 437 fail_register: 438 kfree(info->battery_desc.name); 439 fail_name: 440 kfree(info); 441 fail_info: 442 mutex_lock(&battery_lock); 443 idr_remove(&battery_id, num); 444 mutex_unlock(&battery_lock); 445 fail_id: 446 return ret; 447 } 448 449 static const struct i2c_device_id ds278x_id[] = { 450 {"ds2782", DS2782}, 451 {"ds2786", DS2786}, 452 {}, 453 }; 454 MODULE_DEVICE_TABLE(i2c, ds278x_id); 455 456 static struct i2c_driver ds278x_battery_driver = { 457 .driver = { 458 .name = "ds2782-battery", 459 .pm = &ds278x_battery_pm_ops, 460 }, 461 .probe_new = ds278x_battery_probe, 462 .remove = ds278x_battery_remove, 463 .id_table = ds278x_id, 464 }; 465 module_i2c_driver(ds278x_battery_driver); 466 467 MODULE_AUTHOR("Ryan Mallon"); 468 MODULE_DESCRIPTION("Maxim/Dallas DS2782 Stand-Alone Fuel Gauge IC driver"); 469 MODULE_LICENSE("GPL"); 470