ds2760_battery.c revision 2e83a5c5d2317c386de2880eb43ef0bef8eb1fa9
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 69/* Some batteries have their rated capacity stored a N * 10 mAh, while 70 * others use an index into this table. */ 71static int rated_capacities[] = { 72 0, 73 920, /* Samsung */ 74 920, /* BYD */ 75 920, /* Lishen */ 76 920, /* NEC */ 77 1440, /* Samsung */ 78 1440, /* BYD */ 79 1440, /* Lishen */ 80 1440, /* NEC */ 81 2880, /* Samsung */ 82 2880, /* BYD */ 83 2880, /* Lishen */ 84 2880 /* NEC */ 85}; 86 87/* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C 88 * temp is in Celsius */ 89static int battery_interpolate(int array[], int temp) 90{ 91 int index, dt; 92 93 if (temp <= 0) 94 return array[0]; 95 if (temp >= 40) 96 return array[4]; 97 98 index = temp / 10; 99 dt = temp % 10; 100 101 return array[index] + (((array[index + 1] - array[index]) * dt) / 10); 102} 103 104static int ds2760_battery_read_status(struct ds2760_device_info *di) 105{ 106 int ret, i, start, count, scale[5]; 107 108 if (di->update_time && time_before(jiffies, di->update_time + 109 msecs_to_jiffies(cache_time))) 110 return 0; 111 112 /* The first time we read the entire contents of SRAM/EEPROM, 113 * but after that we just read the interesting bits that change. */ 114 if (di->update_time == 0) { 115 start = 0; 116 count = DS2760_DATA_SIZE; 117 } else { 118 start = DS2760_VOLTAGE_MSB; 119 count = DS2760_TEMP_LSB - start + 1; 120 } 121 122 ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count); 123 if (ret != count) { 124 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n", 125 di->w1_dev); 126 return 1; 127 } 128 129 di->update_time = jiffies; 130 131 /* DS2760 reports voltage in units of 4.88mV, but the battery class 132 * reports in units of uV, so convert by multiplying by 4880. */ 133 di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) | 134 (di->raw[DS2760_VOLTAGE_LSB] >> 5); 135 di->voltage_uV = di->voltage_raw * 4880; 136 137 /* DS2760 reports current in signed units of 0.625mA, but the battery 138 * class reports in units of µA, so convert by multiplying by 625. */ 139 di->current_raw = 140 (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) | 141 (di->raw[DS2760_CURRENT_LSB] >> 3); 142 di->current_uA = di->current_raw * 625; 143 144 /* DS2760 reports accumulated current in signed units of 0.25mAh. */ 145 di->accum_current_raw = 146 (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) | 147 di->raw[DS2760_CURRENT_ACCUM_LSB]; 148 di->accum_current_uAh = di->accum_current_raw * 250; 149 150 /* DS2760 reports temperature in signed units of 0.125°C, but the 151 * battery class reports in units of 1/10 °C, so we convert by 152 * multiplying by .125 * 10 = 1.25. */ 153 di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) | 154 (di->raw[DS2760_TEMP_LSB] >> 5); 155 di->temp_C = di->temp_raw + (di->temp_raw / 4); 156 157 /* At least some battery monitors (e.g. HP iPAQ) store the battery's 158 * maximum rated capacity. */ 159 if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities)) 160 di->rated_capacity = rated_capacities[ 161 (unsigned int)di->raw[DS2760_RATED_CAPACITY]]; 162 else 163 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10; 164 165 di->rated_capacity *= 1000; /* convert to µAh */ 166 167 /* Calculate the full level at the present temperature. */ 168 di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 | 169 di->raw[DS2760_ACTIVE_FULL + 1]; 170 171 scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 | 172 di->raw[DS2760_ACTIVE_FULL + 1]; 173 for (i = 1; i < 5; i++) 174 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i]; 175 176 di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10); 177 di->full_active_uAh *= 1000; /* convert to µAh */ 178 179 /* Calculate the empty level at the present temperature. */ 180 scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4]; 181 for (i = 3; i >= 0; i--) 182 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i]; 183 184 di->empty_uAh = battery_interpolate(scale, di->temp_C / 10); 185 di->empty_uAh *= 1000; /* convert to µAh */ 186 187 if (di->full_active_uAh == di->empty_uAh) 188 di->rem_capacity = 0; 189 else 190 /* From Maxim Application Note 131: remaining capacity = 191 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ 192 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / 193 (di->full_active_uAh - di->empty_uAh); 194 195 if (di->rem_capacity < 0) 196 di->rem_capacity = 0; 197 if (di->rem_capacity > 100) 198 di->rem_capacity = 100; 199 200 if (di->current_uA) 201 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 202 3600L) / di->current_uA; 203 else 204 di->life_sec = 0; 205 206 return 0; 207} 208 209static void ds2760_battery_update_status(struct ds2760_device_info *di) 210{ 211 int old_charge_status = di->charge_status; 212 213 ds2760_battery_read_status(di); 214 215 if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN) 216 di->full_counter = 0; 217 218 if (power_supply_am_i_supplied(&di->bat)) { 219 if (di->current_uA > 10000) { 220 di->charge_status = POWER_SUPPLY_STATUS_CHARGING; 221 di->full_counter = 0; 222 } else if (di->current_uA < -5000) { 223 if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING) 224 dev_notice(di->dev, "not enough power to " 225 "charge\n"); 226 di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING; 227 di->full_counter = 0; 228 } else if (di->current_uA < 10000 && 229 di->charge_status != POWER_SUPPLY_STATUS_FULL) { 230 231 /* Don't consider the battery to be full unless 232 * we've seen the current < 10 mA at least two 233 * consecutive times. */ 234 235 di->full_counter++; 236 237 if (di->full_counter < 2) { 238 di->charge_status = POWER_SUPPLY_STATUS_CHARGING; 239 } else { 240 unsigned char acr[2]; 241 int acr_val; 242 243 /* acr is in units of 0.25 mAh */ 244 acr_val = di->full_active_uAh * 4L / 1000; 245 246 acr[0] = acr_val >> 8; 247 acr[1] = acr_val & 0xff; 248 249 if (w1_ds2760_write(di->w1_dev, acr, 250 DS2760_CURRENT_ACCUM_MSB, 2) < 2) 251 dev_warn(di->dev, 252 "ACR reset failed\n"); 253 254 di->charge_status = POWER_SUPPLY_STATUS_FULL; 255 } 256 } 257 } else { 258 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING; 259 di->full_counter = 0; 260 } 261 262 if (di->charge_status != old_charge_status) 263 power_supply_changed(&di->bat); 264} 265 266static void ds2760_battery_write_status(struct ds2760_device_info *di, 267 char status) 268{ 269 if (status == di->raw[DS2760_STATUS_REG]) 270 return; 271 272 w1_ds2760_write(di->w1_dev, &status, DS2760_STATUS_WRITE_REG, 1); 273 w1_ds2760_store_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 274 w1_ds2760_recall_eeprom(di->w1_dev, DS2760_EEPROM_BLOCK1); 275} 276 277static void ds2760_battery_work(struct work_struct *work) 278{ 279 struct ds2760_device_info *di = container_of(work, 280 struct ds2760_device_info, monitor_work.work); 281 const int interval = HZ * 60; 282 283 dev_dbg(di->dev, "%s\n", __func__); 284 285 ds2760_battery_update_status(di); 286 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval); 287} 288 289#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \ 290 bat); 291 292static void ds2760_battery_external_power_changed(struct power_supply *psy) 293{ 294 struct ds2760_device_info *di = to_ds2760_device_info(psy); 295 296 dev_dbg(di->dev, "%s\n", __func__); 297 298 cancel_delayed_work(&di->monitor_work); 299 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10); 300} 301 302static int ds2760_battery_get_property(struct power_supply *psy, 303 enum power_supply_property psp, 304 union power_supply_propval *val) 305{ 306 struct ds2760_device_info *di = to_ds2760_device_info(psy); 307 308 switch (psp) { 309 case POWER_SUPPLY_PROP_STATUS: 310 val->intval = di->charge_status; 311 return 0; 312 default: 313 break; 314 } 315 316 ds2760_battery_read_status(di); 317 318 switch (psp) { 319 case POWER_SUPPLY_PROP_VOLTAGE_NOW: 320 val->intval = di->voltage_uV; 321 break; 322 case POWER_SUPPLY_PROP_CURRENT_NOW: 323 val->intval = di->current_uA; 324 break; 325 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: 326 val->intval = di->rated_capacity; 327 break; 328 case POWER_SUPPLY_PROP_CHARGE_FULL: 329 val->intval = di->full_active_uAh; 330 break; 331 case POWER_SUPPLY_PROP_CHARGE_EMPTY: 332 val->intval = di->empty_uAh; 333 break; 334 case POWER_SUPPLY_PROP_CHARGE_NOW: 335 val->intval = di->accum_current_uAh; 336 break; 337 case POWER_SUPPLY_PROP_TEMP: 338 val->intval = di->temp_C; 339 break; 340 default: 341 return -EINVAL; 342 } 343 344 return 0; 345} 346 347static enum power_supply_property ds2760_battery_props[] = { 348 POWER_SUPPLY_PROP_STATUS, 349 POWER_SUPPLY_PROP_VOLTAGE_NOW, 350 POWER_SUPPLY_PROP_CURRENT_NOW, 351 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 352 POWER_SUPPLY_PROP_CHARGE_FULL, 353 POWER_SUPPLY_PROP_CHARGE_EMPTY, 354 POWER_SUPPLY_PROP_CHARGE_NOW, 355 POWER_SUPPLY_PROP_TEMP, 356}; 357 358static int ds2760_battery_probe(struct platform_device *pdev) 359{ 360 char status; 361 int retval = 0; 362 struct ds2760_device_info *di; 363 364 di = kzalloc(sizeof(*di), GFP_KERNEL); 365 if (!di) { 366 retval = -ENOMEM; 367 goto di_alloc_failed; 368 } 369 370 platform_set_drvdata(pdev, di); 371 372 di->dev = &pdev->dev; 373 di->w1_dev = pdev->dev.parent; 374 di->bat.name = dev_name(&pdev->dev); 375 di->bat.type = POWER_SUPPLY_TYPE_BATTERY; 376 di->bat.properties = ds2760_battery_props; 377 di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props); 378 di->bat.get_property = ds2760_battery_get_property; 379 di->bat.external_power_changed = 380 ds2760_battery_external_power_changed; 381 382 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 383 384 /* enable sleep mode feature */ 385 ds2760_battery_read_status(di); 386 status = di->raw[DS2760_STATUS_REG]; 387 if (pmod_enabled) 388 status |= DS2760_STATUS_PMOD; 389 else 390 status &= ~DS2760_STATUS_PMOD; 391 392 ds2760_battery_write_status(di, status); 393 394 retval = power_supply_register(&pdev->dev, &di->bat); 395 if (retval) { 396 dev_err(di->dev, "failed to register battery\n"); 397 goto batt_failed; 398 } 399 400 INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work); 401 di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev)); 402 if (!di->monitor_wqueue) { 403 retval = -ESRCH; 404 goto workqueue_failed; 405 } 406 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1); 407 408 goto success; 409 410workqueue_failed: 411 power_supply_unregister(&di->bat); 412batt_failed: 413 kfree(di); 414di_alloc_failed: 415success: 416 return retval; 417} 418 419static int ds2760_battery_remove(struct platform_device *pdev) 420{ 421 struct ds2760_device_info *di = platform_get_drvdata(pdev); 422 423 cancel_rearming_delayed_workqueue(di->monitor_wqueue, 424 &di->monitor_work); 425 destroy_workqueue(di->monitor_wqueue); 426 power_supply_unregister(&di->bat); 427 428 return 0; 429} 430 431#ifdef CONFIG_PM 432 433static int ds2760_battery_suspend(struct platform_device *pdev, 434 pm_message_t state) 435{ 436 struct ds2760_device_info *di = platform_get_drvdata(pdev); 437 438 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 439 440 return 0; 441} 442 443static int ds2760_battery_resume(struct platform_device *pdev) 444{ 445 struct ds2760_device_info *di = platform_get_drvdata(pdev); 446 447 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 448 power_supply_changed(&di->bat); 449 450 cancel_delayed_work(&di->monitor_work); 451 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ); 452 453 return 0; 454} 455 456#else 457 458#define ds2760_battery_suspend NULL 459#define ds2760_battery_resume NULL 460 461#endif /* CONFIG_PM */ 462 463MODULE_ALIAS("platform:ds2760-battery"); 464 465static struct platform_driver ds2760_battery_driver = { 466 .driver = { 467 .name = "ds2760-battery", 468 }, 469 .probe = ds2760_battery_probe, 470 .remove = ds2760_battery_remove, 471 .suspend = ds2760_battery_suspend, 472 .resume = ds2760_battery_resume, 473}; 474 475static int __init ds2760_battery_init(void) 476{ 477 return platform_driver_register(&ds2760_battery_driver); 478} 479 480static void __exit ds2760_battery_exit(void) 481{ 482 platform_driver_unregister(&ds2760_battery_driver); 483} 484 485module_init(ds2760_battery_init); 486module_exit(ds2760_battery_exit); 487 488MODULE_LICENSE("GPL"); 489MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, " 490 "Matt Reimer <mreimer@vpop.net>, " 491 "Anton Vorontsov <cbou@mail.ru>"); 492MODULE_DESCRIPTION("ds2760 battery driver"); 493