/* SPDX-License-Identifier: GPL-2.0-only */ /* * Universal power supply monitor class * * Copyright © 2007 Anton Vorontsov <[email protected]> * Copyright © 2004 Szabolcs Gyurko * Copyright © 2003 Ian Molton <[email protected]> * * Modified: 2004, Oct Szabolcs Gyurko */ #ifndef __LINUX_POWER_SUPPLY_H__ #define __LINUX_POWER_SUPPLY_H__ #include <linux/device.h> #include <linux/workqueue.h> #include <linux/leds.h> #include <linux/spinlock.h> #include <linux/notifier.h> /* * All voltages, currents, charges, energies, time and temperatures in uV, * µA, µAh, µWh, seconds and tenths of degree Celsius unless otherwise * stated. It's driver's job to convert its raw values to units in which * this class operates. */ /* * For systems where the charger determines the maximum battery capacity * the min and max fields should be used to present these values to user * space. Unused/unknown fields will not appear in sysfs. */ enum { … }; /* What algorithm is the charger using? */ enum { … }; enum { … }; enum { … }; enum { … }; enum { … }; enum power_supply_property { … }; enum power_supply_type { … }; enum power_supply_usb_type { … }; enum power_supply_charge_behaviour { … }; enum power_supply_notifier_events { … }; power_supply_propval; struct device_node; struct power_supply; /* Run-time specific power supply configuration */ struct power_supply_config { … }; /* Description of power supply */ struct power_supply_desc { … }; struct power_supply { … }; /* * This is recommended structure to specify static power supply parameters. * Generic one, parametrizable for different power supplies. Power supply * class itself does not use it, but that's what implementing most platform * drivers, should try reuse for consistency. */ struct power_supply_info { … }; struct power_supply_battery_ocv_table { … }; struct power_supply_resistance_temp_table { … }; struct power_supply_vbat_ri_table { … }; /** * struct power_supply_maintenance_charge_table - setting for maintenace charging * @charge_current_max_ua: maintenance charging current that is used to keep * the charge of the battery full as current is consumed after full charging. * The corresponding charge_voltage_max_uv is used as a safeguard: when we * reach this voltage the maintenance charging current is turned off. It is * turned back on if we fall below this voltage. * @charge_voltage_max_uv: maintenance charging voltage that is usually a bit * lower than the constant_charge_voltage_max_uv. We can apply this settings * charge_current_max_ua until we get back up to this voltage. * @safety_timer_minutes: maintenance charging safety timer, with an expiry * time in minutes. We will only use maintenance charging in this setting * for a certain amount of time, then we will first move to the next * maintenance charge current and voltage pair in respective array and wait * for the next safety timer timeout, or, if we reached the last maintencance * charging setting, disable charging until we reach * charge_restart_voltage_uv and restart ordinary CC/CV charging from there. * These timers should be chosen to align with the typical discharge curve * for the battery. * * Ordinary CC/CV charging will stop charging when the charge current goes * below charge_term_current_ua, and then restart it (if the device is still * plugged into the charger) at charge_restart_voltage_uv. This happens in most * consumer products because the power usage while connected to a charger is * not zero, and devices are not manufactured to draw power directly from the * charger: instead they will at all times dissipate the battery a little, like * the power used in standby mode. This will over time give a charge graph * such as this: * * Energy * ^ ... ... ... ... ... ... ... * | . . . . . . . . . . . . . * | .. . .. . .. . .. . .. . .. . .. * |. .. .. .. .. .. .. * +-------------------------------------------------------------------> t * * Practically this means that the Li-ions are wandering back and forth in the * battery and this causes degeneration of the battery anode and cathode. * To prolong the life of the battery, maintenance charging is applied after * reaching charge_term_current_ua to hold up the charge in the battery while * consuming power, thus lowering the wear on the battery: * * Energy * ^ ....................................... * | . ...................... * | .. * |. * +-------------------------------------------------------------------> t * * Maintenance charging uses the voltages from this table: a table of settings * is traversed using a slightly lower current and voltage than what is used for * CC/CV charging. The maintenance charging will for safety reasons not go on * indefinately: we lower the current and voltage with successive maintenance * settings, then disable charging completely after we reach the last one, * and after that we do not restart charging until we reach * charge_restart_voltage_uv (see struct power_supply_battery_info) and restart * ordinary CC/CV charging from there. * * As an example, a Samsung EB425161LA Lithium-Ion battery is CC/CV charged * at 900mA to 4340mV, then maintenance charged at 600mA and 4150mV for up to * 60 hours, then maintenance charged at 600mA and 4100mV for up to 200 hours. * After this the charge cycle is restarted waiting for * charge_restart_voltage_uv. * * For most mobile electronics this type of maintenance charging is enough for * the user to disconnect the device and make use of it before both maintenance * charging cycles are complete, if the current and voltage has been chosen * appropriately. These need to be determined from battery discharge curves * and expected standby current. * * If the voltage anyway drops to charge_restart_voltage_uv during maintenance * charging, ordinary CC/CV charging is restarted. This can happen if the * device is e.g. actively used during charging, so more current is drawn than * the expected stand-by current. Also overvoltage protection will be applied * as usual. */ struct power_supply_maintenance_charge_table { … }; #define POWER_SUPPLY_OCV_TEMP_MAX … /** * struct power_supply_battery_info - information about batteries * @technology: from the POWER_SUPPLY_TECHNOLOGY_* enum * @energy_full_design_uwh: energy content when fully charged in microwatt * hours * @charge_full_design_uah: charge content when fully charged in microampere * hours * @voltage_min_design_uv: minimum voltage across the poles when the battery * is at minimum voltage level in microvolts. If the voltage drops below this * level the battery will need precharging when using CC/CV charging. * @voltage_max_design_uv: voltage across the poles when the battery is fully * charged in microvolts. This is the "nominal voltage" i.e. the voltage * printed on the label of the battery. * @tricklecharge_current_ua: the tricklecharge current used when trickle * charging the battery in microamperes. This is the charging phase when the * battery is completely empty and we need to carefully trickle in some * charge until we reach the precharging voltage. * @precharge_current_ua: current to use in the precharge phase in microamperes, * the precharge rate is limited by limiting the current to this value. * @precharge_voltage_max_uv: the maximum voltage allowed when precharging in * microvolts. When we pass this voltage we will nominally switch over to the * CC (constant current) charging phase defined by constant_charge_current_ua * and constant_charge_voltage_max_uv. * @charge_term_current_ua: when the current in the CV (constant voltage) * charging phase drops below this value in microamperes the charging will * terminate completely and not restart until the voltage over the battery * poles reach charge_restart_voltage_uv unless we use maintenance charging. * @charge_restart_voltage_uv: when the battery has been fully charged by * CC/CV charging and charging has been disabled, and the voltage subsequently * drops below this value in microvolts, the charging will be restarted * (typically using CV charging). * @overvoltage_limit_uv: If the voltage exceeds the nominal voltage * voltage_max_design_uv and we reach this voltage level, all charging must * stop and emergency procedures take place, such as shutting down the system * in some cases. * @constant_charge_current_max_ua: current in microamperes to use in the CC * (constant current) charging phase. The charging rate is limited * by this current. This is the main charging phase and as the current is * constant into the battery the voltage slowly ascends to * constant_charge_voltage_max_uv. * @constant_charge_voltage_max_uv: voltage in microvolts signifying the end of * the CC (constant current) charging phase and the beginning of the CV * (constant voltage) charging phase. * @maintenance_charge: an array of maintenance charging settings to be used * after the main CC/CV charging phase is complete. * @maintenance_charge_size: the number of maintenance charging settings in * maintenance_charge. * @alert_low_temp_charge_current_ua: The charging current to use if the battery * enters low alert temperature, i.e. if the internal temperature is between * temp_alert_min and temp_min. No matter the charging phase, this * and alert_high_temp_charge_voltage_uv will be applied. * @alert_low_temp_charge_voltage_uv: Same as alert_low_temp_charge_current_ua, * but for the charging voltage. * @alert_high_temp_charge_current_ua: The charging current to use if the * battery enters high alert temperature, i.e. if the internal temperature is * between temp_alert_max and temp_max. No matter the charging phase, this * and alert_high_temp_charge_voltage_uv will be applied, usually lowering * the charging current as an evasive manouver. * @alert_high_temp_charge_voltage_uv: Same as * alert_high_temp_charge_current_ua, but for the charging voltage. * @factory_internal_resistance_uohm: the internal resistance of the battery * at fabrication time, expressed in microohms. This resistance will vary * depending on the lifetime and charge of the battery, so this is just a * nominal ballpark figure. This internal resistance is given for the state * when the battery is discharging. * @factory_internal_resistance_charging_uohm: the internal resistance of the * battery at fabrication time while charging, expressed in microohms. * The charging process will affect the internal resistance of the battery * so this value provides a better resistance under these circumstances. * This resistance will vary depending on the lifetime and charge of the * battery, so this is just a nominal ballpark figure. * @ocv_temp: array indicating the open circuit voltage (OCV) capacity * temperature indices. This is an array of temperatures in degrees Celsius * indicating which capacity table to use for a certain temperature, since * the capacity for reasons of chemistry will be different at different * temperatures. Determining capacity is a multivariate problem and the * temperature is the first variable we determine. * @temp_ambient_alert_min: the battery will go outside of operating conditions * when the ambient temperature goes below this temperature in degrees * Celsius. * @temp_ambient_alert_max: the battery will go outside of operating conditions * when the ambient temperature goes above this temperature in degrees * Celsius. * @temp_alert_min: the battery should issue an alert if the internal * temperature goes below this temperature in degrees Celsius. * @temp_alert_max: the battery should issue an alert if the internal * temperature goes above this temperature in degrees Celsius. * @temp_min: the battery will go outside of operating conditions when * the internal temperature goes below this temperature in degrees Celsius. * Normally this means the system should shut down. * @temp_max: the battery will go outside of operating conditions when * the internal temperature goes above this temperature in degrees Celsius. * Normally this means the system should shut down. * @ocv_table: for each entry in ocv_temp there is a corresponding entry in * ocv_table and a size for each entry in ocv_table_size. These arrays * determine the capacity in percent in relation to the voltage in microvolts * at the indexed temperature. * @ocv_table_size: for each entry in ocv_temp this array is giving the size of * each entry in the array of capacity arrays in ocv_table. * @resist_table: this is a table that correlates a battery temperature to the * expected internal resistance at this temperature. The resistance is given * as a percentage of factory_internal_resistance_uohm. Knowing the * resistance of the battery is usually necessary for calculating the open * circuit voltage (OCV) that is then used with the ocv_table to calculate * the capacity of the battery. The resist_table must be ordered descending * by temperature: highest temperature with lowest resistance first, lowest * temperature with highest resistance last. * @resist_table_size: the number of items in the resist_table. * @vbat2ri_discharging: this is a table that correlates Battery voltage (VBAT) * to internal resistance (Ri). The resistance is given in microohm for the * corresponding voltage in microvolts. The internal resistance is used to * determine the open circuit voltage so that we can determine the capacity * of the battery. These voltages to resistance tables apply when the battery * is discharging. The table must be ordered descending by voltage: highest * voltage first. * @vbat2ri_discharging_size: the number of items in the vbat2ri_discharging * table. * @vbat2ri_charging: same function as vbat2ri_discharging but for the state * when the battery is charging. Being under charge changes the battery's * internal resistance characteristics so a separate table is needed.* * The table must be ordered descending by voltage: highest voltage first. * @vbat2ri_charging_size: the number of items in the vbat2ri_charging * table. * @bti_resistance_ohm: The Battery Type Indicator (BIT) nominal resistance * in ohms for this battery, if an identification resistor is mounted * between a third battery terminal and ground. This scheme is used by a lot * of mobile device batteries. * @bti_resistance_tolerance: The tolerance in percent of the BTI resistance, * for example 10 for +/- 10%, if the bti_resistance is set to 7000 and the * tolerance is 10% we will detect a proper battery if the BTI resistance * is between 6300 and 7700 Ohm. * * This is the recommended struct to manage static battery parameters, * populated by power_supply_get_battery_info(). Most platform drivers should * use these for consistency. * * Its field names must correspond to elements in enum power_supply_property. * The default field value is -EINVAL or NULL for pointers. * * CC/CV CHARGING: * * The charging parameters here assume a CC/CV charging scheme. This method * is most common with Lithium Ion batteries (other methods are possible) and * looks as follows: * * ^ Battery voltage * | --- overvoltage_limit_uv * | * | ................................................... * | .. constant_charge_voltage_max_uv * | .. * | . * | . * | . * | . * | . * | .. precharge_voltage_max_uv * | .. * |. (trickle charging) * +------------------------------------------------------------------> time * * ^ Current into the battery * | * | ............. constant_charge_current_max_ua * | . . * | . . * | . . * | . . * | . .. * | . .... * | . ..... * | ... precharge_current_ua ....... charge_term_current_ua * | . . * | . . * |.... tricklecharge_current_ua . * | . * +-----------------------------------------------------------------> time * * These diagrams are synchronized on time and the voltage and current * follow each other. * * With CC/CV charging commence over time like this for an empty battery: * * 1. When the battery is completely empty it may need to be charged with * an especially small current so that electrons just "trickle in", * this is the tricklecharge_current_ua. * * 2. Next a small initial pre-charge current (precharge_current_ua) * is applied if the voltage is below precharge_voltage_max_uv until we * reach precharge_voltage_max_uv. CAUTION: in some texts this is referred * to as "trickle charging" but the use in the Linux kernel is different * see below! * * 3. Then the main charging current is applied, which is called the constant * current (CC) phase. A current regulator is set up to allow * constant_charge_current_max_ua of current to flow into the battery. * The chemical reaction in the battery will make the voltage go up as * charge goes into the battery. This current is applied until we reach * the constant_charge_voltage_max_uv voltage. * * 4. At this voltage we switch over to the constant voltage (CV) phase. This * means we allow current to go into the battery, but we keep the voltage * fixed. This current will continue to charge the battery while keeping * the voltage the same. A chemical reaction in the battery goes on * storing energy without affecting the voltage. Over time the current * will slowly drop and when we reach charge_term_current_ua we will * end the constant voltage phase. * * After this the battery is fully charged, and if we do not support maintenance * charging, the charging will not restart until power dissipation makes the * voltage fall so that we reach charge_restart_voltage_uv and at this point * we restart charging at the appropriate phase, usually this will be inside * the CV phase. * * If we support maintenance charging the voltage is however kept high after * the CV phase with a very low current. This is meant to let the same charge * go in for usage while the charger is still connected, mainly for * dissipation for the power consuming entity while connected to the * charger. * * All charging MUST terminate if the overvoltage_limit_uv is ever reached. * Overcharging Lithium Ion cells can be DANGEROUS and lead to fire or * explosions. * * DETERMINING BATTERY CAPACITY: * * Several members of the struct deal with trying to determine the remaining * capacity in the battery, usually as a percentage of charge. In practice * many chargers uses a so-called fuel gauge or coloumb counter that measure * how much charge goes into the battery and how much goes out (+/- leak * consumption). This does not help if we do not know how much capacity the * battery has to begin with, such as when it is first used or was taken out * and charged in a separate charger. Therefore many capacity algorithms use * the open circuit voltage with a look-up table to determine the rough * capacity of the battery. The open circuit voltage can be conceptualized * with an ideal voltage source (V) in series with an internal resistance (Ri) * like this: * * +-------> IBAT >----------------+ * | ^ | * [ ] Ri | | * | | VBAT | * o <---------- | | * +| ^ | [ ] Rload * .---. | | | * | V | | OCV | | * '---' | | | * | | | | * GND +-------------------------------+ * * If we disconnect the load (here simplified as a fixed resistance Rload) * and measure VBAT with a infinite impedance voltage meter we will get * VBAT = OCV and this assumption is sometimes made even under load, assuming * Rload is insignificant. However this will be of dubious quality because the * load is rarely that small and Ri is strongly nonlinear depending on * temperature and how much capacity is left in the battery due to the * chemistry involved. * * In many practical applications we cannot just disconnect the battery from * the load, so instead we often try to measure the instantaneous IBAT (the * current out from the battery), estimate the Ri and thus calculate the * voltage drop over Ri and compensate like this: * * OCV = VBAT - (IBAT * Ri) * * The tables vbat2ri_discharging and vbat2ri_charging are used to determine * (by interpolation) the Ri from the VBAT under load. These curves are highly * nonlinear and may need many datapoints but can be found in datasheets for * some batteries. This gives the compensated open circuit voltage (OCV) for * the battery even under load. Using this method will also compensate for * temperature changes in the environment: this will also make the internal * resistance change, and it will affect the VBAT under load, so correlating * VBAT to Ri takes both remaining capacity and temperature into consideration. * * Alternatively a manufacturer can specify how the capacity of the battery * is dependent on the battery temperature which is the main factor affecting * Ri. As we know all checmical reactions are faster when it is warm and slower * when it is cold. You can put in 1500mAh and only get 800mAh out before the * voltage drops too low for example. This effect is also highly nonlinear and * the purpose of the table resist_table: this will take a temperature and * tell us how big percentage of Ri the specified temperature correlates to. * Usually we have 100% of the factory_internal_resistance_uohm at 25 degrees * Celsius. * * The power supply class itself doesn't use this struct as of now. */ struct power_supply_battery_info { … }; extern int power_supply_reg_notifier(struct notifier_block *nb); extern void power_supply_unreg_notifier(struct notifier_block *nb); #if IS_ENABLED(CONFIG_POWER_SUPPLY) extern struct power_supply *power_supply_get_by_name(const char *name); extern void power_supply_put(struct power_supply *psy); #else static inline void power_supply_put(struct power_supply *psy) {} static inline struct power_supply *power_supply_get_by_name(const char *name) { return NULL; } #endif #ifdef CONFIG_OF extern struct power_supply *power_supply_get_by_phandle(struct device_node *np, const char *property); extern struct power_supply *devm_power_supply_get_by_phandle( struct device *dev, const char *property); #else /* !CONFIG_OF */ static inline struct power_supply * power_supply_get_by_phandle(struct device_node *np, const char *property) { return NULL; } static inline struct power_supply * devm_power_supply_get_by_phandle(struct device *dev, const char *property) { return NULL; } #endif /* CONFIG_OF */ extern const enum power_supply_property power_supply_battery_info_properties[]; extern const size_t power_supply_battery_info_properties_size; extern int power_supply_get_battery_info(struct power_supply *psy, struct power_supply_battery_info **info_out); extern void power_supply_put_battery_info(struct power_supply *psy, struct power_supply_battery_info *info); extern bool power_supply_battery_info_has_prop(struct power_supply_battery_info *info, enum power_supply_property psp); extern int power_supply_battery_info_get_prop(struct power_supply_battery_info *info, enum power_supply_property psp, union power_supply_propval *val); extern int power_supply_ocv2cap_simple(struct power_supply_battery_ocv_table *table, int table_len, int ocv); extern struct power_supply_battery_ocv_table * power_supply_find_ocv2cap_table(struct power_supply_battery_info *info, int temp, int *table_len); extern int power_supply_batinfo_ocv2cap(struct power_supply_battery_info *info, int ocv, int temp); extern int power_supply_temp2resist_simple(struct power_supply_resistance_temp_table *table, int table_len, int temp); extern int power_supply_vbat2ri(struct power_supply_battery_info *info, int vbat_uv, bool charging); extern const struct power_supply_maintenance_charge_table * power_supply_get_maintenance_charging_setting(struct power_supply_battery_info *info, int index); extern bool power_supply_battery_bti_in_range(struct power_supply_battery_info *info, int resistance); extern void power_supply_changed(struct power_supply *psy); extern int power_supply_am_i_supplied(struct power_supply *psy); int power_supply_get_property_from_supplier(struct power_supply *psy, enum power_supply_property psp, union power_supply_propval *val); extern int power_supply_set_battery_charged(struct power_supply *psy); static inline bool power_supply_supports_maintenance_charging(struct power_supply_battery_info *info) { … } static inline bool power_supply_supports_vbat2ri(struct power_supply_battery_info *info) { … } static inline bool power_supply_supports_temp2ri(struct power_supply_battery_info *info) { … } #ifdef CONFIG_POWER_SUPPLY extern int power_supply_is_system_supplied(void); #else static inline int power_supply_is_system_supplied(void) { return -ENOSYS; } #endif extern int power_supply_get_property(struct power_supply *psy, enum power_supply_property psp, union power_supply_propval *val); #if IS_ENABLED(CONFIG_POWER_SUPPLY) extern int power_supply_set_property(struct power_supply *psy, enum power_supply_property psp, const union power_supply_propval *val); #else static inline int power_supply_set_property(struct power_supply *psy, enum power_supply_property psp, const union power_supply_propval *val) { return 0; } #endif extern int power_supply_property_is_writeable(struct power_supply *psy, enum power_supply_property psp); extern void power_supply_external_power_changed(struct power_supply *psy); extern struct power_supply *__must_check power_supply_register(struct device *parent, const struct power_supply_desc *desc, const struct power_supply_config *cfg); extern struct power_supply *__must_check power_supply_register_no_ws(struct device *parent, const struct power_supply_desc *desc, const struct power_supply_config *cfg); extern struct power_supply *__must_check devm_power_supply_register(struct device *parent, const struct power_supply_desc *desc, const struct power_supply_config *cfg); extern struct power_supply *__must_check devm_power_supply_register_no_ws(struct device *parent, const struct power_supply_desc *desc, const struct power_supply_config *cfg); extern void power_supply_unregister(struct power_supply *psy); extern int power_supply_powers(struct power_supply *psy, struct device *dev); #define to_power_supply(device) … extern void *power_supply_get_drvdata(struct power_supply *psy); extern int power_supply_for_each_device(void *data, int (*fn)(struct device *dev, void *data)); static inline bool power_supply_is_amp_property(enum power_supply_property psp) { … } static inline bool power_supply_is_watt_property(enum power_supply_property psp) { … } #ifdef CONFIG_POWER_SUPPLY_HWMON int power_supply_add_hwmon_sysfs(struct power_supply *psy); void power_supply_remove_hwmon_sysfs(struct power_supply *psy); #else static inline int power_supply_add_hwmon_sysfs(struct power_supply *psy) { return 0; } static inline void power_supply_remove_hwmon_sysfs(struct power_supply *psy) {} #endif #ifdef CONFIG_SYSFS ssize_t power_supply_charge_behaviour_show(struct device *dev, unsigned int available_behaviours, enum power_supply_charge_behaviour behaviour, char *buf); int power_supply_charge_behaviour_parse(unsigned int available_behaviours, const char *buf); #else static inline ssize_t power_supply_charge_behaviour_show(struct device *dev, unsigned int available_behaviours, enum power_supply_charge_behaviour behaviour, char *buf) { return -EOPNOTSUPP; } static inline int power_supply_charge_behaviour_parse(unsigned int available_behaviours, const char *buf) { return -EOPNOTSUPP; } #endif #endif /* __LINUX_POWER_SUPPLY_H__ */
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