/* * Driver for batteries with DS2760 chips inside. * * Copyright © 2007 Anton Vorontsov * 2004-2007 Matt Reimer * 2004 Szabolcs Gyurko * * Use consistent with the GNU GPL is permitted, * provided that this copyright notice is * preserved in its entirety in all copies and derived works. * * Author: Anton Vorontsov <cbou@mail.ru> * February 2007 * * Matt Reimer <mreimer@vpop.net> * April 2004, 2005, 2007 * * Szabolcs Gyurko <szabolcs.gyurko@tlt.hu> * September 2004 */ #include <linux/module.h> #include <linux/param.h> #include <linux/jiffies.h> #include <linux/workqueue.h> #include <linux/pm.h> #include <linux/platform_device.h> #include <linux/power_supply.h> #include "../w1/w1.h" #include "../w1/slaves/w1_ds2760.h" struct ds2760_device_info { struct device *dev; /* DS2760 data, valid after calling ds2760_battery_read_status() */ unsigned long update_time; /* jiffies when data read */ char raw[DS2760_DATA_SIZE]; /* raw DS2760 data */ int voltage_raw; /* units of 4.88 mV */ int voltage_uV; /* units of µV */ int current_raw; /* units of 0.625 mA */ int current_uA; /* units of µA */ int accum_current_raw; /* units of 0.25 mAh */ int accum_current_uAh; /* units of µAh */ int temp_raw; /* units of 0.125 °C */ int temp_C; /* units of 0.1 °C */ int rated_capacity; /* units of µAh */ int rem_capacity; /* percentage */ int full_active_uAh; /* units of µAh */ int empty_uAh; /* units of µAh */ int life_sec; /* units of seconds */ int charge_status; /* POWER_SUPPLY_STATUS_* */ int full_counter; struct power_supply bat; struct device *w1_dev; struct workqueue_struct *monitor_wqueue; struct delayed_work monitor_work; }; static unsigned int cache_time = 1000; module_param(cache_time, uint, 0644); MODULE_PARM_DESC(cache_time, "cache time in milliseconds"); /* Some batteries have their rated capacity stored a N * 10 mAh, while * others use an index into this table. */ static int rated_capacities[] = { 0, 920, /* Samsung */ 920, /* BYD */ 920, /* Lishen */ 920, /* NEC */ 1440, /* Samsung */ 1440, /* BYD */ 1440, /* Lishen */ 1440, /* NEC */ 2880, /* Samsung */ 2880, /* BYD */ 2880, /* Lishen */ 2880 /* NEC */ }; /* array is level at temps 0°C, 10°C, 20°C, 30°C, 40°C * temp is in Celsius */ static int battery_interpolate(int array[], int temp) { int index, dt; if (temp <= 0) return array[0]; if (temp >= 40) return array[4]; index = temp / 10; dt = temp % 10; return array[index] + (((array[index + 1] - array[index]) * dt) / 10); } static int ds2760_battery_read_status(struct ds2760_device_info *di) { int ret, i, start, count, scale[5]; if (di->update_time && time_before(jiffies, di->update_time + msecs_to_jiffies(cache_time))) return 0; /* The first time we read the entire contents of SRAM/EEPROM, * but after that we just read the interesting bits that change. */ if (di->update_time == 0) { start = 0; count = DS2760_DATA_SIZE; } else { start = DS2760_VOLTAGE_MSB; count = DS2760_TEMP_LSB - start + 1; } ret = w1_ds2760_read(di->w1_dev, di->raw + start, start, count); if (ret != count) { dev_warn(di->dev, "call to w1_ds2760_read failed (0x%p)\n", di->w1_dev); return 1; } di->update_time = jiffies; /* DS2760 reports voltage in units of 4.88mV, but the battery class * reports in units of uV, so convert by multiplying by 4880. */ di->voltage_raw = (di->raw[DS2760_VOLTAGE_MSB] << 3) | (di->raw[DS2760_VOLTAGE_LSB] >> 5); di->voltage_uV = di->voltage_raw * 4880; /* DS2760 reports current in signed units of 0.625mA, but the battery * class reports in units of µA, so convert by multiplying by 625. */ di->current_raw = (((signed char)di->raw[DS2760_CURRENT_MSB]) << 5) | (di->raw[DS2760_CURRENT_LSB] >> 3); di->current_uA = di->current_raw * 625; /* DS2760 reports accumulated current in signed units of 0.25mAh. */ di->accum_current_raw = (((signed char)di->raw[DS2760_CURRENT_ACCUM_MSB]) << 8) | di->raw[DS2760_CURRENT_ACCUM_LSB]; di->accum_current_uAh = di->accum_current_raw * 250; /* DS2760 reports temperature in signed units of 0.125°C, but the * battery class reports in units of 1/10 °C, so we convert by * multiplying by .125 * 10 = 1.25. */ di->temp_raw = (((signed char)di->raw[DS2760_TEMP_MSB]) << 3) | (di->raw[DS2760_TEMP_LSB] >> 5); di->temp_C = di->temp_raw + (di->temp_raw / 4); /* At least some battery monitors (e.g. HP iPAQ) store the battery's * maximum rated capacity. */ if (di->raw[DS2760_RATED_CAPACITY] < ARRAY_SIZE(rated_capacities)) di->rated_capacity = rated_capacities[ (unsigned int)di->raw[DS2760_RATED_CAPACITY]]; else di->rated_capacity = di->raw[DS2760_RATED_CAPACITY] * 10; di->rated_capacity *= 1000; /* convert to µAh */ /* Calculate the full level at the present temperature. */ di->full_active_uAh = di->raw[DS2760_ACTIVE_FULL] << 8 | di->raw[DS2760_ACTIVE_FULL + 1]; scale[0] = di->raw[DS2760_ACTIVE_FULL] << 8 | di->raw[DS2760_ACTIVE_FULL + 1]; for (i = 1; i < 5; i++) scale[i] = scale[i - 1] + di->raw[DS2760_ACTIVE_FULL + 2 + i]; di->full_active_uAh = battery_interpolate(scale, di->temp_C / 10); di->full_active_uAh *= 1000; /* convert to µAh */ /* Calculate the empty level at the present temperature. */ scale[4] = di->raw[DS2760_ACTIVE_EMPTY + 4]; for (i = 3; i >= 0; i--) scale[i] = scale[i + 1] + di->raw[DS2760_ACTIVE_EMPTY + i]; di->empty_uAh = battery_interpolate(scale, di->temp_C / 10); di->empty_uAh *= 1000; /* convert to µAh */ /* From Maxim Application Note 131: remaining capacity = * ((ICA - Empty Value) / (Full Value - Empty Value)) x 100% */ di->rem_capacity = ((di->accum_current_uAh - di->empty_uAh) * 100L) / (di->full_active_uAh - di->empty_uAh); if (di->rem_capacity < 0) di->rem_capacity = 0; if (di->rem_capacity > 100) di->rem_capacity = 100; if (di->current_uA) di->life_sec = -((di->accum_current_uAh - di->empty_uAh) * 3600L) / di->current_uA; else di->life_sec = 0; return 0; } static void ds2760_battery_update_status(struct ds2760_device_info *di) { int old_charge_status = di->charge_status; ds2760_battery_read_status(di); if (di->charge_status == POWER_SUPPLY_STATUS_UNKNOWN) di->full_counter = 0; if (power_supply_am_i_supplied(&di->bat)) { if (di->current_uA > 10000) { di->charge_status = POWER_SUPPLY_STATUS_CHARGING; di->full_counter = 0; } else if (di->current_uA < -5000) { if (di->charge_status != POWER_SUPPLY_STATUS_NOT_CHARGING) dev_notice(di->dev, "not enough power to " "charge\n"); di->charge_status = POWER_SUPPLY_STATUS_NOT_CHARGING; di->full_counter = 0; } else if (di->current_uA < 10000 && di->charge_status != POWER_SUPPLY_STATUS_FULL) { /* Don't consider the battery to be full unless * we've seen the current < 10 mA at least two * consecutive times. */ di->full_counter++; if (di->full_counter < 2) { di->charge_status = POWER_SUPPLY_STATUS_CHARGING; } else { unsigned char acr[2]; int acr_val; /* acr is in units of 0.25 mAh */ acr_val = di->full_active_uAh * 4L / 1000; acr[0] = acr_val >> 8; acr[1] = acr_val & 0xff; if (w1_ds2760_write(di->w1_dev, acr, DS2760_CURRENT_ACCUM_MSB, 2) < 2) dev_warn(di->dev, "ACR reset failed\n"); di->charge_status = POWER_SUPPLY_STATUS_FULL; } } } else { di->charge_status = POWER_SUPPLY_STATUS_DISCHARGING; di->full_counter = 0; } if (di->charge_status != old_charge_status) power_supply_changed(&di->bat); } static void ds2760_battery_work(struct work_struct *work) { struct ds2760_device_info *di = container_of(work, struct ds2760_device_info, monitor_work.work); const int interval = HZ * 60; dev_dbg(di->dev, "%s\n", __FUNCTION__); ds2760_battery_update_status(di); queue_delayed_work(di->monitor_wqueue, &di->monitor_work, interval); } #define to_ds2760_device_info(x) container_of((x), struct ds2760_device_info, \ bat); static void ds2760_battery_external_power_changed(struct power_supply *psy) { struct ds2760_device_info *di = to_ds2760_device_info(psy); dev_dbg(di->dev, "%s\n", __FUNCTION__); cancel_delayed_work(&di->monitor_work); queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ/10); } static int ds2760_battery_get_property(struct power_supply *psy, enum power_supply_property psp, union power_supply_propval *val) { struct ds2760_device_info *di = to_ds2760_device_info(psy); switch (psp) { case POWER_SUPPLY_PROP_STATUS: val->intval = di->charge_status; return 0; default: break; } ds2760_battery_read_status(di); switch (psp) { case POWER_SUPPLY_PROP_VOLTAGE_NOW: val->intval = di->voltage_uV; break; case POWER_SUPPLY_PROP_CURRENT_NOW: val->intval = di->current_uA; break; case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN: val->intval = di->rated_capacity; break; case POWER_SUPPLY_PROP_CHARGE_FULL: val->intval = di->full_active_uAh; break; case POWER_SUPPLY_PROP_CHARGE_EMPTY: val->intval = di->empty_uAh; break; case POWER_SUPPLY_PROP_CHARGE_NOW: val->intval = di->accum_current_uAh; break; case POWER_SUPPLY_PROP_TEMP: val->intval = di->temp_C; break; default: return -EINVAL; } return 0; } static enum power_supply_property ds2760_battery_props[] = { POWER_SUPPLY_PROP_STATUS, POWER_SUPPLY_PROP_VOLTAGE_NOW, POWER_SUPPLY_PROP_CURRENT_NOW, POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN, POWER_SUPPLY_PROP_CHARGE_FULL, POWER_SUPPLY_PROP_CHARGE_EMPTY, POWER_SUPPLY_PROP_CHARGE_NOW, POWER_SUPPLY_PROP_TEMP, }; static int ds2760_battery_probe(struct platform_device *pdev) { int retval = 0; struct ds2760_device_info *di; struct ds2760_platform_data *pdata; di = kzalloc(sizeof(*di), GFP_KERNEL); if (!di) { retval = -ENOMEM; goto di_alloc_failed; } platform_set_drvdata(pdev, di); pdata = pdev->dev.platform_data; di->dev = &pdev->dev; di->w1_dev = pdev->dev.parent; di->bat.name = pdev->dev.bus_id; di->bat.type = POWER_SUPPLY_TYPE_BATTERY; di->bat.properties = ds2760_battery_props; di->bat.num_properties = ARRAY_SIZE(ds2760_battery_props); di->bat.get_property = ds2760_battery_get_property; di->bat.external_power_changed = ds2760_battery_external_power_changed; di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; retval = power_supply_register(&pdev->dev, &di->bat); if (retval) { dev_err(di->dev, "failed to register battery\n"); goto batt_failed; } INIT_DELAYED_WORK(&di->monitor_work, ds2760_battery_work); di->monitor_wqueue = create_singlethread_workqueue(pdev->dev.bus_id); if (!di->monitor_wqueue) { retval = -ESRCH; goto workqueue_failed; } queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ * 1); goto success; workqueue_failed: power_supply_unregister(&di->bat); batt_failed: kfree(di); di_alloc_failed: success: return retval; } static int ds2760_battery_remove(struct platform_device *pdev) { struct ds2760_device_info *di = platform_get_drvdata(pdev); cancel_rearming_delayed_workqueue(di->monitor_wqueue, &di->monitor_work); destroy_workqueue(di->monitor_wqueue); power_supply_unregister(&di->bat); return 0; } #ifdef CONFIG_PM static int ds2760_battery_suspend(struct platform_device *pdev, pm_message_t state) { struct ds2760_device_info *di = platform_get_drvdata(pdev); di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; return 0; } static int ds2760_battery_resume(struct platform_device *pdev) { struct ds2760_device_info *di = platform_get_drvdata(pdev); di->charge_status = POWER_SUPPLY_STATUS_UNKNOWN; power_supply_changed(&di->bat); cancel_delayed_work(&di->monitor_work); queue_delayed_work(di->monitor_wqueue, &di->monitor_work, HZ); return 0; } #else #define ds2760_battery_suspend NULL #define ds2760_battery_resume NULL #endif /* CONFIG_PM */ static struct platform_driver ds2760_battery_driver = { .driver = { .name = "ds2760-battery", }, .probe = ds2760_battery_probe, .remove = ds2760_battery_remove, .suspend = ds2760_battery_suspend, .resume = ds2760_battery_resume, }; static int __init ds2760_battery_init(void) { return platform_driver_register(&ds2760_battery_driver); } static void __exit ds2760_battery_exit(void) { platform_driver_unregister(&ds2760_battery_driver); } module_init(ds2760_battery_init); module_exit(ds2760_battery_exit); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Szabolcs Gyurko <szabolcs.gyurko@tlt.hu>, " "Matt Reimer <mreimer@vpop.net>, " "Anton Vorontsov <cbou@mail.ru>"); MODULE_DESCRIPTION("ds2760 battery driver");