ds2760_battery.c revision 02d0d2758821c38b2601d34dac544140af09e651
1/* 2 * Driver for batteries with DS2760 chips inside. 3 * 4 * Copyright © 2007 Anton Vorontsov 5 * 2004-2007 Matt Reimer 6 * 2004 Szabolcs Gyurko 7 * 8 * Use consistent with the GNU GPL is permitted, 9 * provided that this copyright notice is 10 * preserved in its entirety in all copies and derived works. 11 * 12 * Author: Anton Vorontsov <cbou@mail.ru> 13 * February 2007 14 * 15 * Matt Reimer <mreimer@vpop.net> 16 * April 2004, 2005, 2007 17 * 18 * Szabolcs Gyurko <szabolcs.gyurko@tlt.hu> 19 * September 2004 20 */ 21 22#include <linux/module.h> 23#include <linux/param.h> 24#include <linux/jiffies.h> 25#include <linux/workqueue.h> 26#include <linux/pm.h> 27#include <linux/platform_device.h> 28#include <linux/power_supply.h> 29 30#include "../w1/w1.h" 31#include "../w1/slaves/w1_ds2760.h" 32 33struct ds2760_device_info { 34 struct device *dev; 35 36 /* DS2760 data, valid after calling ds2760_battery_read_status() */ 37 unsigned long update_time; /* jiffies when data read */ 38 char raw[DS2760_DATA_SIZE]; /* raw DS2760 data */ 39 int voltage_raw; /* units of 4.88 mV */ 40 int voltage_uV; /* units of µV */ 41 int current_raw; /* units of 0.625 mA */ 42 int current_uA; /* units of µA */ 43 int accum_current_raw; /* units of 0.25 mAh */ 44 int accum_current_uAh; /* units of µAh */ 45 int temp_raw; /* units of 0.125 °C */ 46 int temp_C; /* units of 0.1 °C */ 47 int rated_capacity; /* units of µAh */ 48 int rem_capacity; /* percentage */ 49 int full_active_uAh; /* units of µAh */ 50 int empty_uAh; /* units of µAh */ 51 int life_sec; /* units of seconds */ 52 int charge_status; /* POWER_SUPPLY_STATUS_* */ 53 54 int full_counter; 55 struct power_supply bat; 56 struct device *w1_dev; 57 struct workqueue_struct *monitor_wqueue; 58 struct delayed_work monitor_work; 59}; 60 61static unsigned int cache_time = 1000; 62module_param(cache_time, uint, 0644); 63MODULE_PARM_DESC(cache_time, "cache time in milliseconds"); 64 65static unsigned int pmod_enabled; 66module_param(pmod_enabled, bool, 0644); 67MODULE_PARM_DESC(pmod_enabled, "PMOD enable bit"); 68 69static unsigned int rated_capacity; 70module_param(rated_capacity, uint, 0644); 71MODULE_PARM_DESC(rated_capacity, "rated battery capacity, 10*mAh or index"); 72 73static unsigned int current_accum; 74module_param(current_accum, uint, 0644); 75MODULE_PARM_DESC(current_accum, "current accumulator value"); 76 77/* Some batteries have their rated capacity stored a N * 10 mAh, while 78 * others use an index into this table. */ 79static int rated_capacities[] = { 80 0, 81 920, /* Samsung */ 82 920, /* BYD */ 83 920, /* Lishen */ 84 920, /* NEC */ 85 1440, /* Samsung */ 86 1440, /* BYD */ 87 1440, /* Lishen */ 88 1440, /* NEC */ 89 2880, /* Samsung */ 90 2880, /* BYD */ 91 2880, /* Lishen */ 92 2880 /* NEC */ 93}; 94 95/* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C 96 * temp is in Celsius */ 97static int battery_interpolate(int array[], int temp) 98{ 99 int index, dt; 100 101 if (temp <= 0) 102 return array[0]; 103 if (temp >= 40) 104 return array[4]; 105 106 index = temp / 10; 107 dt = temp % 10; 108 109 return array[index] + (((array[index + 1] - array[index]) * dt) / 10); 110} 111 112static int ds2760_battery_read_status(struct ds2760_device_info *di) 113{ 114 int ret, i, start, count, scale[5]; 115 116 if (di->update_time && time_before(jiffies, di->update_time + 117 msecs_to_jiffies(cache_time))) 118 return 0; 119 120 /* The first time we read the entire contents of SRAM/EEPROM, 121 * but after that we just read the interesting bits that change. */ 122 if (di->update_time == 0) { 123 start = 0; 124 count = DS2760_DATA_SIZE; 125 } else { 126 start = DS2760_VOLTAGE_MSB; 127 count = DS2760_TEMP_LSB - start + 1; 128 } 129 130 ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count); 131 if (ret != count) { 132 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n", 133 di->w1_dev); 134 return 1; 135 } 136 137 di->update_time = jiffies; 138 139 /* DS2760 reports voltage in units of 4.88mV, but the battery class 140 * reports in units of uV, so convert by multiplying by 4880. */ 141 di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) | 142 (di->raw[DS2760_VOLTAGE_LSB] >> 5); 143 di->voltage_uV = di->voltage_raw * 4880; 144 145 /* DS2760 reports current in signed units of 0.625mA, but the battery 146 * class reports in units of µA, so convert by multiplying by 625. */ 147 di->current_raw = 148 (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) | 149 (di->raw[DS2760_CURRENT_LSB] >> 3); 150 di->current_uA = di->current_raw * 625; 151 152 /* DS2760 reports accumulated current in signed units of 0.25mAh. */ 153 di->accum_current_raw = 154 (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) | 155 di->raw[DS2760_CURRENT_ACCUM_LSB]; 156 di->accum_current_uAh = di->accum_current_raw * 250; 157 158 /* DS2760 reports temperature in signed units of 0.125°C, but the 159 * battery class reports in units of 1/10 °C, so we convert by 160 * multiplying by .125 * 10 = 1.25. */ 161 di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) | 162 (di->raw[DS2760_TEMP_LSB] >> 5); 163 di->temp_C = di->temp_raw + (di->temp_raw / 4); 164 165 /* At least some battery monitors (e.g. HP iPAQ) store the battery's 166 * maximum rated capacity. */ 167 if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities)) 168 di->rated_capacity = rated_capacities[ 169 (unsigned int)di->raw[DS2760_RATED_CAPACITY]]; 170 else 171 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10; 172 173 di->rated_capacity *= 1000; /* convert to µAh */ 174 175 /* Calculate the full level at the present temperature. */ 176 di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 | 177 di->raw[DS2760_ACTIVE_FULL + 1]; 178 179 /* If the full_active_uAh value is not given, fall back to the rated 180 * capacity. This is likely to happen when chips are not part of the 181 * battery pack and is therefore not bootstrapped. */ 182 if (di->full_active_uAh == 0) 183 di->full_active_uAh = di->rated_capacity / 1000L; 184 185 scale[0] = di->full_active_uAh; 186 for (i = 1; i < 5; i++) 187 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i]; 188 189 di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10); 190 di->full_active_uAh *= 1000; /* convert to µAh */ 191 192 /* Calculate the empty level at the present temperature. */ 193 scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4]; 194 for (i = 3; i >= 0; i--) 195 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i]; 196 197 di->empty_uAh = battery_interpolate(scale, di->temp_C / 10); 198 di->empty_uAh *= 1000; /* convert to µAh */ 199 200 if (di->full_active_uAh == di->empty_uAh) 201 di->rem_capacity = 0; 202 else 203 /* From Maxim Application Note 131: remaining capacity = 204 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ 205 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / 206 (di->full_active_uAh - di->empty_uAh); 207 208 if (di->rem_capacity < 0) 209 di->rem_capacity = 0; 210 if (di->rem_capacity > 100) 211 di->rem_capacity = 100; 212 213 if (di->current_uA) 214 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 215 3600L) / di->current_uA; 216 else 217 di->life_sec = 0; 218 219 return 0; 220} 221 222static void ds2760_battery_set_current_accum(struct ds2760_device_info *di, 223 unsigned int acr_val) 224{ 225 unsigned char acr[2]; 226 227 /* acr is in units of 0.25 mAh */ 228 acr_val *= 4L; 229 acr_val /= 1000; 230 231 acr[0] = acr_val >> 8; 232 acr[1] = acr_val & 0xff; 233 234 if (w1_ds2760_write(di->w1_dev, acr, DS2760_CURRENT_ACCUM_MSB, 2) < 2) 235 dev_warn(di->dev, "ACR write failed\n"); 236} 237 238static void ds2760_battery_update_status(struct ds2760_device_info *di) 239{ 240 int old_charge_status = di->charge_status; 241 242 ds2760_battery_read_status(di); 243 244 if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN) 245 di->full_counter = 0; 246 247 if (power_supply_am_i_supplied(&di->bat)) { 248 if (di->current_uA > 10000) { 249 di->charge_status = POWER_SUPPLY_STATUS_CHARGING; 250 di->full_counter = 0; 251 } else if (di->current_uA < -5000) { 252 if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING) 253 dev_notice(di->dev, "not enough power to " 254 "charge\n"); 255 di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING; 256 di->full_counter = 0; 257 } else if (di->current_uA < 10000 && 258 di->charge_status != POWER_SUPPLY_STATUS_FULL) { 259 260 /* Don't consider the battery to be full unless 261 * we've seen the current < 10 mA at least two 262 * consecutive times. */ 263 264 di->full_counter++; 265 266 if (di->full_counter < 2) { 267 di->charge_status = POWER_SUPPLY_STATUS_CHARGING; 268 } else { 269 di->charge_status = POWER_SUPPLY_STATUS_FULL; 270 ds2760_battery_set_current_accum(di, 271 di->full_active_uAh); 272 } 273 } 274 } else { 275 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING; 276 di->full_counter = 0; 277 } 278 279 if (di->charge_status != old_charge_status) 280 power_supply_changed(&di->bat); 281} 282 283static void ds2760_battery_write_status(struct ds2760_device_info *di, 284 char status) 285{ 286 if (status == di->raw[DS2760_STATUS_REG]) 287 return; 288 289 w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1); 290 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 291 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 292} 293 294static void ds2760_battery_write_rated_capacity(struct ds2760_device_info *di, 295 unsigned char rated_capacity) 296{ 297 if (rated_capacity == di->raw[DS2760_RATED_CAPACITY]) 298 return; 299 300 w1_ds2760_write(di->w1_dev, &rated_capacity, DS2760_RATED_CAPACITY, 1); 301 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 302 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 303} 304 305static void ds2760_battery_work(struct work_struct *work) 306{ 307 struct ds2760_device_info *di = container_of(work, 308 struct ds2760_device_info, monitor_work.work); 309 const int interval = HZ * 60; 310 311 dev_dbg(di->dev, "%s\n", __func__); 312 313 ds2760_battery_update_status(di); 314 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval); 315} 316 317#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \ 318 bat); 319 320static void ds2760_battery_external_power_changed(struct power_supply *psy) 321{ 322 struct ds2760_device_info *di = to_ds2760_device_info(psy); 323 324 dev_dbg(di->dev, "%s\n", __func__); 325 326 cancel_delayed_work(&di->monitor_work); 327 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10); 328} 329 330static int ds2760_battery_get_property(struct power_supply *psy, 331 enum power_supply_property psp, 332 union power_supply_propval *val) 333{ 334 struct ds2760_device_info *di = to_ds2760_device_info(psy); 335 336 switch (psp) { 337 case POWER_SUPPLY_PROP_STATUS: 338 val->intval = di->charge_status; 339 return 0; 340 default: 341 break; 342 } 343 344 ds2760_battery_read_status(di); 345 346 switch (psp) { 347 case POWER_SUPPLY_PROP_VOLTAGE_NOW: 348 val->intval = di->voltage_uV; 349 break; 350 case POWER_SUPPLY_PROP_CURRENT_NOW: 351 val->intval = di->current_uA; 352 break; 353 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: 354 val->intval = di->rated_capacity; 355 break; 356 case POWER_SUPPLY_PROP_CHARGE_FULL: 357 val->intval = di->full_active_uAh; 358 break; 359 case POWER_SUPPLY_PROP_CHARGE_EMPTY: 360 val->intval = di->empty_uAh; 361 break; 362 case POWER_SUPPLY_PROP_CHARGE_NOW: 363 val->intval = di->accum_current_uAh; 364 break; 365 case POWER_SUPPLY_PROP_TEMP: 366 val->intval = di->temp_C; 367 break; 368 case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: 369 val->intval = di->life_sec; 370 break; 371 case POWER_SUPPLY_PROP_CAPACITY: 372 val->intval = di->rem_capacity; 373 break; 374 default: 375 return -EINVAL; 376 } 377 378 return 0; 379} 380 381static enum power_supply_property ds2760_battery_props[] = { 382 POWER_SUPPLY_PROP_STATUS, 383 POWER_SUPPLY_PROP_VOLTAGE_NOW, 384 POWER_SUPPLY_PROP_CURRENT_NOW, 385 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 386 POWER_SUPPLY_PROP_CHARGE_FULL, 387 POWER_SUPPLY_PROP_CHARGE_EMPTY, 388 POWER_SUPPLY_PROP_CHARGE_NOW, 389 POWER_SUPPLY_PROP_TEMP, 390 POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW, 391 POWER_SUPPLY_PROP_CAPACITY, 392}; 393 394static int ds2760_battery_probe(struct platform_device *pdev) 395{ 396 char status; 397 int retval = 0; 398 struct ds2760_device_info *di; 399 400 di = kzalloc(sizeof(*di), GFP_KERNEL); 401 if (!di) { 402 retval = -ENOMEM; 403 goto di_alloc_failed; 404 } 405 406 platform_set_drvdata(pdev, di); 407 408 di->dev = &pdev->dev; 409 di->w1_dev = pdev->dev.parent; 410 di->bat.name = dev_name(&pdev->dev); 411 di->bat.type = POWER_SUPPLY_TYPE_BATTERY; 412 di->bat.properties = ds2760_battery_props; 413 di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props); 414 di->bat.get_property = ds2760_battery_get_property; 415 di->bat.external_power_changed = 416 ds2760_battery_external_power_changed; 417 418 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 419 420 /* enable sleep mode feature */ 421 ds2760_battery_read_status(di); 422 status = di->raw[DS2760_STATUS_REG]; 423 if (pmod_enabled) 424 status |= DS2760_STATUS_PMOD; 425 else 426 status &= ~DS2760_STATUS_PMOD; 427 428 ds2760_battery_write_status(di, status); 429 430 /* set rated capacity from module param */ 431 if (rated_capacity) 432 ds2760_battery_write_rated_capacity(di, rated_capacity); 433 434 /* set current accumulator if given as parameter. 435 * this should only be done for bootstrapping the value */ 436 if (current_accum) 437 ds2760_battery_set_current_accum(di, current_accum); 438 439 retval = power_supply_register(&pdev->dev, &di->bat); 440 if (retval) { 441 dev_err(di->dev, "failed to register battery\n"); 442 goto batt_failed; 443 } 444 445 INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work); 446 di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev)); 447 if (!di->monitor_wqueue) { 448 retval = -ESRCH; 449 goto workqueue_failed; 450 } 451 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1); 452 453 goto success; 454 455workqueue_failed: 456 power_supply_unregister(&di->bat); 457batt_failed: 458 kfree(di); 459di_alloc_failed: 460success: 461 return retval; 462} 463 464static int ds2760_battery_remove(struct platform_device *pdev) 465{ 466 struct ds2760_device_info *di = platform_get_drvdata(pdev); 467 468 cancel_rearming_delayed_workqueue(di->monitor_wqueue, 469 &di->monitor_work); 470 destroy_workqueue(di->monitor_wqueue); 471 power_supply_unregister(&di->bat); 472 473 return 0; 474} 475 476#ifdef CONFIG_PM 477 478static int ds2760_battery_suspend(struct platform_device *pdev, 479 pm_message_t state) 480{ 481 struct ds2760_device_info *di = platform_get_drvdata(pdev); 482 483 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 484 485 return 0; 486} 487 488static int ds2760_battery_resume(struct platform_device *pdev) 489{ 490 struct ds2760_device_info *di = platform_get_drvdata(pdev); 491 492 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 493 power_supply_changed(&di->bat); 494 495 cancel_delayed_work(&di->monitor_work); 496 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ); 497 498 return 0; 499} 500 501#else 502 503#define ds2760_battery_suspend NULL 504#define ds2760_battery_resume NULL 505 506#endif /* CONFIG_PM */ 507 508MODULE_ALIAS("platform:ds2760-battery"); 509 510static struct platform_driver ds2760_battery_driver = { 511 .driver = { 512 .name = "ds2760-battery", 513 }, 514 .probe = ds2760_battery_probe, 515 .remove = ds2760_battery_remove, 516 .suspend = ds2760_battery_suspend, 517 .resume = ds2760_battery_resume, 518}; 519 520static int __init ds2760_battery_init(void) 521{ 522 return platform_driver_register(&ds2760_battery_driver); 523} 524 525static void __exit ds2760_battery_exit(void) 526{ 527 platform_driver_unregister(&ds2760_battery_driver); 528} 529 530module_init(ds2760_battery_init); 531module_exit(ds2760_battery_exit); 532 533MODULE_LICENSE("GPL"); 534MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, " 535 "Matt Reimer <mreimer@vpop.net>, " 536 "Anton Vorontsov <cbou@mail.ru>"); 537MODULE_DESCRIPTION("ds2760 battery driver"); 538