diff options
Diffstat (limited to 'include/linux/power_supply.h')
| -rw-r--r-- | include/linux/power_supply.h | 213 |
1 files changed, 209 insertions, 4 deletions
diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h index e218041cc000..cb380c1d9459 100644 --- a/include/linux/power_supply.h +++ b/include/linux/power_supply.h @@ -49,6 +49,7 @@ enum { POWER_SUPPLY_CHARGE_TYPE_ADAPTIVE, /* dynamically adjusted speed */ POWER_SUPPLY_CHARGE_TYPE_CUSTOM, /* use CHARGE_CONTROL_* props */ POWER_SUPPLY_CHARGE_TYPE_LONGLIFE, /* slow speed, longer life */ + POWER_SUPPLY_CHARGE_TYPE_BYPASS, /* bypassing the charger */ }; enum { @@ -348,6 +349,57 @@ struct power_supply_resistance_temp_table { int resistance; /* internal resistance percent */ }; +struct power_supply_vbat_ri_table { + int vbat_uv; /* Battery voltage in microvolt */ + int ri_uohm; /* Internal resistance in microohm */ +}; + +/** + * 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. + * + * When the main CC/CV charging is complete the battery can optionally be + * maintenance charged at 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 + * 60 hours, then maintenance charged at 600mA and 4100mV for 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. + */ +struct power_supply_maintenance_charge_table { + int charge_current_max_ua; + int charge_voltage_max_uv; + int charge_safety_timer_minutes; +}; + #define POWER_SUPPLY_OCV_TEMP_MAX 20 /** @@ -393,10 +445,34 @@ struct power_supply_resistance_temp_table { * @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. + * 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 @@ -434,13 +510,38 @@ struct power_supply_resistance_temp_table { * 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. + * 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 @@ -525,6 +626,66 @@ struct power_supply_resistance_temp_table { * 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. */ @@ -542,7 +703,14 @@ struct power_supply_battery_info { int overvoltage_limit_uv; int constant_charge_current_max_ua; int constant_charge_voltage_max_uv; + struct power_supply_maintenance_charge_table *maintenance_charge; + int maintenance_charge_size; + int alert_low_temp_charge_current_ua; + int alert_low_temp_charge_voltage_uv; + int alert_high_temp_charge_current_ua; + int alert_high_temp_charge_voltage_uv; int factory_internal_resistance_uohm; + int factory_internal_resistance_charging_uohm; int ocv_temp[POWER_SUPPLY_OCV_TEMP_MAX]; int temp_ambient_alert_min; int temp_ambient_alert_max; @@ -554,6 +722,12 @@ struct power_supply_battery_info { int ocv_table_size[POWER_SUPPLY_OCV_TEMP_MAX]; struct power_supply_resistance_temp_table *resist_table; int resist_table_size; + struct power_supply_vbat_ri_table *vbat2ri_discharging; + int vbat2ri_discharging_size; + struct power_supply_vbat_ri_table *vbat2ri_charging; + int vbat2ri_charging_size; + int bti_resistance_ohm; + int bti_resistance_tolerance; }; extern struct atomic_notifier_head power_supply_notifier; @@ -595,12 +769,43 @@ extern int power_supply_batinfo_ocv2cap(struct power_supply_battery_info *info, 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 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); -extern int power_supply_set_input_current_limit_from_supplier( - 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) +{ + struct power_supply_maintenance_charge_table *mt; + + mt = power_supply_get_maintenance_charging_setting(info, 0); + + return (mt != NULL); +} + +static inline bool +power_supply_supports_vbat2ri(struct power_supply_battery_info *info) +{ + return ((info->vbat2ri_discharging != NULL) && + info->vbat2ri_discharging_size > 0); +} + +static inline bool +power_supply_supports_temp2ri(struct power_supply_battery_info *info) +{ + return ((info->resist_table != NULL) && + info->resist_table_size > 0); +} + #ifdef CONFIG_POWER_SUPPLY extern int power_supply_is_system_supplied(void); #else |