include/linux/power_supply.h

1 /* SPDX-License-Identifier: GPL-2.0-only */
29  * For systems where the charger determines the maximum battery capacity
226 /* Run-time specific power supply configuration */
349 	int vbat_uv;	/* Battery voltage in microvolt */
354  * struct power_supply_maintenance_charge_table - setting for maintenace charging
356  *   the charge of the battery full as current is consumed after full charging.
371  *   for the battery.
378  * charger: instead they will at all times dissipate the battery a little, like
387  *  +-------------------------------------------------------------------> t
389  * Practically this means that the Li-ions are wandering back and forth in the
390  * battery and this causes degeneration of the battery anode and cathode.
391  * To prolong the life of the battery, maintenance charging is applied after
392  * reaching charge_term_current_ua to hold up the charge in the battery while
393  * consuming power, thus lowering the wear on the battery:
400  *  +-------------------------------------------------------------------> t
411  * As an example, a Samsung EB425161LA Lithium-Ion battery is CC/CV charged
420  * appropriately. These need to be determined from battery discharge curves
426  * the expected stand-by current. Also overvoltage protection will be applied
438  * struct power_supply_battery_info - information about batteries
444  * @voltage_min_design_uv: minimum voltage across the poles when the battery
446  *   level the battery will need precharging when using CC/CV charging.
447  * @voltage_max_design_uv: voltage across the poles when the battery is fully
449  *   printed on the label of the battery.
451  *   charging the battery in microamperes. This is the charging phase when the
452  *   battery is completely empty and we need to carefully trickle in some
462  *   terminate completely and not restart until the voltage over the battery
464  * @charge_restart_voltage_uv: when the battery has been fully charged by
475  *   constant into the battery the voltage slowly ascends to
484  * @alert_low_temp_charge_current_ua: The charging current to use if the battery
485  *   enters low alert temperature, i.e. if the internal temperature is between
491  *   battery enters high alert temperature, i.e. if the internal temperature is
497  * @factory_internal_resistance_uohm: the internal resistance of the battery
499  *   depending on the lifetime and charge of the battery, so this is just a
501  *   when the battery is discharging.
503  *   battery at fabrication time while charging, expressed in microohms.
504  *   The charging process will affect the internal resistance of the battery
507  *   battery, so this is just a nominal ballpark figure.
509  *   temperature indices. This is an array of temperatures in degrees Celsius
510  *   indicating which capacity table to use for a certain temperature, since
513  *   temperature is the first variable we determine.
514  * @temp_ambient_alert_min: the battery will go outside of operating conditions
515  *   when the ambient temperature goes below this temperature in degrees
517  * @temp_ambient_alert_max: the battery will go outside of operating conditions
518  *   when the ambient temperature goes above this temperature in degrees
520  * @temp_alert_min: the battery should issue an alert if the internal
521  *   temperature goes below this temperature in degrees Celsius.
522  * @temp_alert_max: the battery should issue an alert if the internal
523  *   temperature goes above this temperature in degrees Celsius.
524  * @temp_min: the battery will go outside of operating conditions when
525  *   the internal temperature goes below this temperature in degrees Celsius.
527  * @temp_max: the battery will go outside of operating conditions when
528  *   the internal temperature goes above this temperature in degrees Celsius.
533  *   at the indexed temperature.
536  * @resist_table: this is a table that correlates a battery temperature to the
537  *   expected internal resistance at this temperature. The resistance is given
539  *   resistance of the battery is usually necessary for calculating the open
541  *   the capacity of the battery. The resist_table must be ordered descending
542  *   by temperature: highest temperature with lowest resistance first, lowest
543  *   temperature with highest resistance last.
545  * @vbat2ri_discharging: this is a table that correlates Battery voltage (VBAT)
549  *   of the battery. These voltages to resistance tables apply when the battery
555  *   when the battery is charging. Being under charge changes the battery's
560  * @bti_resistance_ohm: The Battery Type Indicator (BIT) nominal resistance
561  *   in ohms for this battery, if an identification resistor is mounted
562  *   between a third battery terminal and ground. This scheme is used by a lot
565  *   for example 10 for +/- 10%, if the bti_resistance is set to 7000 and the
566  *   tolerance is 10% we will detect a proper battery if the BTI resistance
569  * This is the recommended struct to manage static battery parameters,
574  * The default field value is -EINVAL or NULL for pointers.
582  * ^ Battery voltage
583  * |                                               --- overvoltage_limit_uv
596  * +------------------------------------------------------------------> time
598  * ^ Current into the battery
613  * +-----------------------------------------------------------------> time
618  * With CC/CV charging commence over time like this for an empty battery:
620  * 1. When the battery is completely empty it may need to be charged with
624  * 2. Next a small initial pre-charge current (precharge_current_ua)
632  *    constant_charge_current_max_ua of current to flow into the battery.
633  *    The chemical reaction in the battery will make the voltage go up as
634  *    charge goes into the battery. This current is applied until we reach
638  *    means we allow current to go into the battery, but we keep the voltage
639  *    fixed. This current will continue to charge the battery while keeping
640  *    the voltage the same. A chemical reaction in the battery goes on
645  * After this the battery is fully charged, and if we do not support maintenance
661  * DETERMINING BATTERY CAPACITY:
664  * capacity in the battery, usually as a percentage of charge. In practice
665  * many chargers uses a so-called fuel gauge or coloumb counter that measure
666  * how much charge goes into the battery and how much goes out (+/- leak
668  * battery has to begin with, such as when it is first used or was taken out
670  * the open circuit voltage with a look-up table to determine the rough
671  * capacity of the battery. The open circuit voltage can be conceptualized
675  *      +-------> IBAT >----------------+
679  *      o <----------        |          |
681  *    .---.         |        |          |
683  *    '---'         |        |          |
685  *  GND +-------------------------------+
692  * temperature and how much capacity is left in the battery due to the
695  * In many practical applications we cannot just disconnect the battery from
697  * current out from the battery), estimate the Ri and thus calculate the
700  *   OCV = VBAT - (IBAT * Ri)
706  * the battery even under load. Using this method will also compensate for
707  * temperature changes in the environment: this will also make the internal
709  * VBAT to Ri takes both remaining capacity and temperature into consideration.
711  * Alternatively a manufacturer can specify how the capacity of the battery
712  * is dependent on the battery temperature which is the main factor affecting
716  * the purpose of the table resist_table: this will take a temperature and
717  * tell us how big percentage of Ri the specified temperature correlates to.
836 	return ((info->vbat2ri_discharging != NULL) &&  in power_supply_supports_vbat2ri()
837 		info->vbat2ri_discharging_size > 0);  in power_supply_supports_vbat2ri()
843 	return ((info->resist_table != NULL) &&  in power_supply_supports_temp2ri()
844 		info->resist_table_size > 0);  in power_supply_supports_temp2ri()
850 static inline int power_supply_is_system_supplied(void) { return -ENOSYS; }  in power_supply_is_system_supplied()
975 	return -EOPNOTSUPP;  in power_supply_charge_behaviour_show()
981 	return -EOPNOTSUPP;  in power_supply_charge_behaviour_parse()