ds2760_battery.c revision ae9fb6e814ecede683bcd404910085cea3ab1260
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 65/* Some batteries have their rated capacity stored a N * 10 mAh, while 66 * others use an index into this table. */ 67static int rated_capacities[] = { 68 0, 69 920, /* Samsung */ 70 920, /* BYD */ 71 920, /* Lishen */ 72 920, /* NEC */ 73 1440, /* Samsung */ 74 1440, /* BYD */ 75 1440, /* Lishen */ 76 1440, /* NEC */ 77 2880, /* Samsung */ 78 2880, /* BYD */ 79 2880, /* Lishen */ 80 2880 /* NEC */ 81}; 82 83/* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C 84 * temp is in Celsius */ 85static int battery_interpolate(int array[], int temp) 86{ 87 int index, dt; 88 89 if (temp <= 0) 90 return array[0]; 91 if (temp >= 40) 92 return array[4]; 93 94 index = temp / 10; 95 dt = temp % 10; 96 97 return array[index] + (((array[index + 1] - array[index]) * dt) / 10); 98} 99 100static int ds2760_battery_read_status(struct ds2760_device_info *di) 101{ 102 int ret, i, start, count, scale[5]; 103 104 if (di->update_time && time_before(jiffies, di->update_time + 105 msecs_to_jiffies(cache_time))) 106 return 0; 107 108 /* The first time we read the entire contents of SRAM/EEPROM, 109 * but after that we just read the interesting bits that change. */ 110 if (di->update_time == 0) { 111 start = 0; 112 count = DS2760_DATA_SIZE; 113 } else { 114 start = DS2760_VOLTAGE_MSB; 115 count = DS2760_TEMP_LSB - start + 1; 116 } 117 118 ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count); 119 if (ret != count) { 120 dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n", 121 di->w1_dev); 122 return 1; 123 } 124 125 di->update_time = jiffies; 126 127 /* DS2760 reports voltage in units of 4.88mV, but the battery class 128 * reports in units of uV, so convert by multiplying by 4880. */ 129 di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) | 130 (di->raw[DS2760_VOLTAGE_LSB] >> 5); 131 di->voltage_uV = di->voltage_raw * 4880; 132 133 /* DS2760 reports current in signed units of 0.625mA, but the battery 134 * class reports in units of µA, so convert by multiplying by 625. */ 135 di->current_raw = 136 (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) | 137 (di->raw[DS2760_CURRENT_LSB] >> 3); 138 di->current_uA = di->current_raw * 625; 139 140 /* DS2760 reports accumulated current in signed units of 0.25mAh. */ 141 di->accum_current_raw = 142 (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) | 143 di->raw[DS2760_CURRENT_ACCUM_LSB]; 144 di->accum_current_uAh = di->accum_current_raw * 250; 145 146 /* DS2760 reports temperature in signed units of 0.125°C, but the 147 * battery class reports in units of 1/10 °C, so we convert by 148 * multiplying by .125 * 10 = 1.25. */ 149 di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) | 150 (di->raw[DS2760_TEMP_LSB] >> 5); 151 di->temp_C = di->temp_raw + (di->temp_raw / 4); 152 153 /* At least some battery monitors (e.g. HP iPAQ) store the battery's 154 * maximum rated capacity. */ 155 if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities)) 156 di->rated_capacity = rated_capacities[ 157 (unsigned int)di->raw[DS2760_RATED_CAPACITY]]; 158 else 159 di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10; 160 161 di->rated_capacity *= 1000; /* convert to µAh */ 162 163 /* Calculate the full level at the present temperature. */ 164 di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 | 165 di->raw[DS2760_ACTIVE_FULL + 1]; 166 167 scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 | 168 di->raw[DS2760_ACTIVE_FULL + 1]; 169 for (i = 1; i < 5; i++) 170 scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i]; 171 172 di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10); 173 di->full_active_uAh *= 1000; /* convert to µAh */ 174 175 /* Calculate the empty level at the present temperature. */ 176 scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4]; 177 for (i = 3; i >= 0; i--) 178 scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i]; 179 180 di->empty_uAh = battery_interpolate(scale, di->temp_C / 10); 181 di->empty_uAh *= 1000; /* convert to µAh */ 182 183 if (di->full_active_uAh == di->empty_uAh) 184 di->rem_capacity = 0; 185 else 186 /* From Maxim Application Note 131: remaining capacity = 187 * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ 188 di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / 189 (di->full_active_uAh - di->empty_uAh); 190 191 if (di->rem_capacity < 0) 192 di->rem_capacity = 0; 193 if (di->rem_capacity > 100) 194 di->rem_capacity = 100; 195 196 if (di->current_uA) 197 di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 198 3600L) / di->current_uA; 199 else 200 di->life_sec = 0; 201 202 return 0; 203} 204 205static void ds2760_battery_update_status(struct ds2760_device_info *di) 206{ 207 int old_charge_status = di->charge_status; 208 209 ds2760_battery_read_status(di); 210 211 if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN) 212 di->full_counter = 0; 213 214 if (power_supply_am_i_supplied(&di->bat)) { 215 if (di->current_uA > 10000) { 216 di->charge_status = POWER_SUPPLY_STATUS_CHARGING; 217 di->full_counter = 0; 218 } else if (di->current_uA < -5000) { 219 if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING) 220 dev_notice(di->dev, "not enough power to " 221 "charge\n"); 222 di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING; 223 di->full_counter = 0; 224 } else if (di->current_uA < 10000 && 225 di->charge_status != POWER_SUPPLY_STATUS_FULL) { 226 227 /* Don't consider the battery to be full unless 228 * we've seen the current < 10 mA at least two 229 * consecutive times. */ 230 231 di->full_counter++; 232 233 if (di->full_counter < 2) { 234 di->charge_status = POWER_SUPPLY_STATUS_CHARGING; 235 } else { 236 unsigned char acr[2]; 237 int acr_val; 238 239 /* acr is in units of 0.25 mAh */ 240 acr_val = di->full_active_uAh * 4L / 1000; 241 242 acr[0] = acr_val >> 8; 243 acr[1] = acr_val & 0xff; 244 245 if (w1_ds2760_write(di->w1_dev, acr, 246 DS2760_CURRENT_ACCUM_MSB, 2) < 2) 247 dev_warn(di->dev, 248 "ACR reset failed\n"); 249 250 di->charge_status = POWER_SUPPLY_STATUS_FULL; 251 } 252 } 253 } else { 254 di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING; 255 di->full_counter = 0; 256 } 257 258 if (di->charge_status != old_charge_status) 259 power_supply_changed(&di->bat); 260} 261 262static void ds2760_battery_work(struct work_struct *work) 263{ 264 struct ds2760_device_info *di = container_of(work, 265 struct ds2760_device_info, monitor_work.work); 266 const int interval = HZ * 60; 267 268 dev_dbg(di->dev, "%s\n", __func__); 269 270 ds2760_battery_update_status(di); 271 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval); 272} 273 274#define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \ 275 bat); 276 277static void ds2760_battery_external_power_changed(struct power_supply *psy) 278{ 279 struct ds2760_device_info *di = to_ds2760_device_info(psy); 280 281 dev_dbg(di->dev, "%s\n", __func__); 282 283 cancel_delayed_work(&di->monitor_work); 284 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10); 285} 286 287static int ds2760_battery_get_property(struct power_supply *psy, 288 enum power_supply_property psp, 289 union power_supply_propval *val) 290{ 291 struct ds2760_device_info *di = to_ds2760_device_info(psy); 292 293 switch (psp) { 294 case POWER_SUPPLY_PROP_STATUS: 295 val->intval = di->charge_status; 296 return 0; 297 default: 298 break; 299 } 300 301 ds2760_battery_read_status(di); 302 303 switch (psp) { 304 case POWER_SUPPLY_PROP_VOLTAGE_NOW: 305 val->intval = di->voltage_uV; 306 break; 307 case POWER_SUPPLY_PROP_CURRENT_NOW: 308 val->intval = di->current_uA; 309 break; 310 case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: 311 val->intval = di->rated_capacity; 312 break; 313 case POWER_SUPPLY_PROP_CHARGE_FULL: 314 val->intval = di->full_active_uAh; 315 break; 316 case POWER_SUPPLY_PROP_CHARGE_EMPTY: 317 val->intval = di->empty_uAh; 318 break; 319 case POWER_SUPPLY_PROP_CHARGE_NOW: 320 val->intval = di->accum_current_uAh; 321 break; 322 case POWER_SUPPLY_PROP_TEMP: 323 val->intval = di->temp_C; 324 break; 325 default: 326 return -EINVAL; 327 } 328 329 return 0; 330} 331 332static enum power_supply_property ds2760_battery_props[] = { 333 POWER_SUPPLY_PROP_STATUS, 334 POWER_SUPPLY_PROP_VOLTAGE_NOW, 335 POWER_SUPPLY_PROP_CURRENT_NOW, 336 POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, 337 POWER_SUPPLY_PROP_CHARGE_FULL, 338 POWER_SUPPLY_PROP_CHARGE_EMPTY, 339 POWER_SUPPLY_PROP_CHARGE_NOW, 340 POWER_SUPPLY_PROP_TEMP, 341}; 342 343static int ds2760_battery_probe(struct platform_device *pdev) 344{ 345 int retval = 0; 346 struct ds2760_device_info *di; 347 348 di = kzalloc(sizeof(*di), GFP_KERNEL); 349 if (!di) { 350 retval = -ENOMEM; 351 goto di_alloc_failed; 352 } 353 354 platform_set_drvdata(pdev, di); 355 356 di->dev = &pdev->dev; 357 di->w1_dev = pdev->dev.parent; 358 di->bat.name = dev_name(&pdev->dev); 359 di->bat.type = POWER_SUPPLY_TYPE_BATTERY; 360 di->bat.properties = ds2760_battery_props; 361 di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props); 362 di->bat.get_property = ds2760_battery_get_property; 363 di->bat.external_power_changed = 364 ds2760_battery_external_power_changed; 365 366 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 367 368 retval = power_supply_register(&pdev->dev, &di->bat); 369 if (retval) { 370 dev_err(di->dev, "failed to register battery\n"); 371 goto batt_failed; 372 } 373 374 INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work); 375 di->monitor_wqueue = create_singlethread_workqueue(dev_name(&pdev->dev)); 376 if (!di->monitor_wqueue) { 377 retval = -ESRCH; 378 goto workqueue_failed; 379 } 380 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1); 381 382 goto success; 383 384workqueue_failed: 385 power_supply_unregister(&di->bat); 386batt_failed: 387 kfree(di); 388di_alloc_failed: 389success: 390 return retval; 391} 392 393static int ds2760_battery_remove(struct platform_device *pdev) 394{ 395 struct ds2760_device_info *di = platform_get_drvdata(pdev); 396 397 cancel_rearming_delayed_workqueue(di->monitor_wqueue, 398 &di->monitor_work); 399 destroy_workqueue(di->monitor_wqueue); 400 power_supply_unregister(&di->bat); 401 402 return 0; 403} 404 405#ifdef CONFIG_PM 406 407static int ds2760_battery_suspend(struct platform_device *pdev, 408 pm_message_t state) 409{ 410 struct ds2760_device_info *di = platform_get_drvdata(pdev); 411 412 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 413 414 return 0; 415} 416 417static int ds2760_battery_resume(struct platform_device *pdev) 418{ 419 struct ds2760_device_info *di = platform_get_drvdata(pdev); 420 421 di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; 422 power_supply_changed(&di->bat); 423 424 cancel_delayed_work(&di->monitor_work); 425 queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ); 426 427 return 0; 428} 429 430#else 431 432#define ds2760_battery_suspend NULL 433#define ds2760_battery_resume NULL 434 435#endif /* CONFIG_PM */ 436 437MODULE_ALIAS("platform:ds2760-battery"); 438 439static struct platform_driver ds2760_battery_driver = { 440 .driver = { 441 .name = "ds2760-battery", 442 }, 443 .probe = ds2760_battery_probe, 444 .remove = ds2760_battery_remove, 445 .suspend = ds2760_battery_suspend, 446 .resume = ds2760_battery_resume, 447}; 448 449static int __init ds2760_battery_init(void) 450{ 451 return platform_driver_register(&ds2760_battery_driver); 452} 453 454static void __exit ds2760_battery_exit(void) 455{ 456 platform_driver_unregister(&ds2760_battery_driver); 457} 458 459module_init(ds2760_battery_init); 460module_exit(ds2760_battery_exit); 461 462MODULE_LICENSE("GPL"); 463MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, " 464 "Matt Reimer <mreimer@vpop.net>, " 465 "Anton Vorontsov <cbou@mail.ru>"); 466MODULE_DESCRIPTION("ds2760 battery driver"); 467