summaryrefslogtreecommitdiffstats
path: root/Documentation/power/charger-manager.txt
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation/power/charger-manager.txt')
-rw-r--r--Documentation/power/charger-manager.txt200
1 files changed, 0 insertions, 200 deletions
diff --git a/Documentation/power/charger-manager.txt b/Documentation/power/charger-manager.txt
deleted file mode 100644
index b4f7f4b..0000000
--- a/Documentation/power/charger-manager.txt
+++ /dev/null
@@ -1,200 +0,0 @@
-Charger Manager
- (C) 2011 MyungJoo Ham <myungjoo.ham@samsung.com>, GPL
-
-Charger Manager provides in-kernel battery charger management that
-requires temperature monitoring during suspend-to-RAM state
-and where each battery may have multiple chargers attached and the userland
-wants to look at the aggregated information of the multiple chargers.
-
-Charger Manager is a platform_driver with power-supply-class entries.
-An instance of Charger Manager (a platform-device created with Charger-Manager)
-represents an independent battery with chargers. If there are multiple
-batteries with their own chargers acting independently in a system,
-the system may need multiple instances of Charger Manager.
-
-1. Introduction
-===============
-
-Charger Manager supports the following:
-
-* Support for multiple chargers (e.g., a device with USB, AC, and solar panels)
- A system may have multiple chargers (or power sources) and some of
- they may be activated at the same time. Each charger may have its
- own power-supply-class and each power-supply-class can provide
- different information about the battery status. This framework
- aggregates charger-related information from multiple sources and
- shows combined information as a single power-supply-class.
-
-* Support for in suspend-to-RAM polling (with suspend_again callback)
- While the battery is being charged and the system is in suspend-to-RAM,
- we may need to monitor the battery health by looking at the ambient or
- battery temperature. We can accomplish this by waking up the system
- periodically. However, such a method wakes up devices unncessary for
- monitoring the battery health and tasks, and user processes that are
- supposed to be kept suspended. That, in turn, incurs unnecessary power
- consumption and slow down charging process. Or even, such peak power
- consumption can stop chargers in the middle of charging
- (external power input < device power consumption), which not
- only affects the charging time, but the lifespan of the battery.
-
- Charger Manager provides a function "cm_suspend_again" that can be
- used as suspend_again callback of platform_suspend_ops. If the platform
- requires tasks other than cm_suspend_again, it may implement its own
- suspend_again callback that calls cm_suspend_again in the middle.
- Normally, the platform will need to resume and suspend some devices
- that are used by Charger Manager.
-
-* Support for premature full-battery event handling
- If the battery voltage drops by "fullbatt_vchkdrop_uV" after
- "fullbatt_vchkdrop_ms" from the full-battery event, the framework
- restarts charging. This check is also performed while suspended by
- setting wakeup time accordingly and using suspend_again.
-
-* Support for uevent-notify
- With the charger-related events, the device sends
- notification to users with UEVENT.
-
-2. Global Charger-Manager Data related with suspend_again
-========================================================
-In order to setup Charger Manager with suspend-again feature
-(in-suspend monitoring), the user should provide charger_global_desc
-with setup_charger_manager(struct charger_global_desc *).
-This charger_global_desc data for in-suspend monitoring is global
-as the name suggests. Thus, the user needs to provide only once even
-if there are multiple batteries. If there are multiple batteries, the
-multiple instances of Charger Manager share the same charger_global_desc
-and it will manage in-suspend monitoring for all instances of Charger Manager.
-
-The user needs to provide all the three entries properly in order to activate
-in-suspend monitoring:
-
-struct charger_global_desc {
-
-char *rtc_name;
- : The name of rtc (e.g., "rtc0") used to wakeup the system from
- suspend for Charger Manager. The alarm interrupt (AIE) of the rtc
- should be able to wake up the system from suspend. Charger Manager
- saves and restores the alarm value and use the previously-defined
- alarm if it is going to go off earlier than Charger Manager so that
- Charger Manager does not interfere with previously-defined alarms.
-
-bool (*rtc_only_wakeup)(void);
- : This callback should let CM know whether
- the wakeup-from-suspend is caused only by the alarm of "rtc" in the
- same struct. If there is any other wakeup source triggered the
- wakeup, it should return false. If the "rtc" is the only wakeup
- reason, it should return true.
-
-bool assume_timer_stops_in_suspend;
- : if true, Charger Manager assumes that
- the timer (CM uses jiffies as timer) stops during suspend. Then, CM
- assumes that the suspend-duration is same as the alarm length.
-};
-
-3. How to setup suspend_again
-=============================
-Charger Manager provides a function "extern bool cm_suspend_again(void)".
-When cm_suspend_again is called, it monitors every battery. The suspend_ops
-callback of the system's platform_suspend_ops can call cm_suspend_again
-function to know whether Charger Manager wants to suspend again or not.
-If there are no other devices or tasks that want to use suspend_again
-feature, the platform_suspend_ops may directly refer to cm_suspend_again
-for its suspend_again callback.
-
-The cm_suspend_again() returns true (meaning "I want to suspend again")
-if the system was woken up by Charger Manager and the polling
-(in-suspend monitoring) results in "normal".
-
-4. Charger-Manager Data (struct charger_desc)
-=============================================
-For each battery charged independently from other batteries (if a series of
-batteries are charged by a single charger, they are counted as one independent
-battery), an instance of Charger Manager is attached to it.
-
-struct charger_desc {
-
-char *psy_name;
- : The power-supply-class name of the battery. Default is
- "battery" if psy_name is NULL. Users can access the psy entries
- at "/sys/class/power_supply/[psy_name]/".
-
-enum polling_modes polling_mode;
- : CM_POLL_DISABLE: do not poll this battery.
- CM_POLL_ALWAYS: always poll this battery.
- CM_POLL_EXTERNAL_POWER_ONLY: poll this battery if and only if
- an external power source is attached.
- CM_POLL_CHARGING_ONLY: poll this battery if and only if the
- battery is being charged.
-
-unsigned int fullbatt_vchkdrop_ms;
-unsigned int fullbatt_vchkdrop_uV;
- : If both have non-zero values, Charger Manager will check the
- battery voltage drop fullbatt_vchkdrop_ms after the battery is fully
- charged. If the voltage drop is over fullbatt_vchkdrop_uV, Charger
- Manager will try to recharge the battery by disabling and enabling
- chargers. Recharge with voltage drop condition only (without delay
- condition) is needed to be implemented with hardware interrupts from
- fuel gauges or charger devices/chips.
-
-unsigned int fullbatt_uV;
- : If specified with a non-zero value, Charger Manager assumes
- that the battery is full (capacity = 100) if the battery is not being
- charged and the battery voltage is equal to or greater than
- fullbatt_uV.
-
-unsigned int polling_interval_ms;
- : Required polling interval in ms. Charger Manager will poll
- this battery every polling_interval_ms or more frequently.
-
-enum data_source battery_present;
- : CM_BATTERY_PRESENT: assume that the battery exists.
- CM_NO_BATTERY: assume that the battery does not exists.
- CM_FUEL_GAUGE: get battery presence information from fuel gauge.
- CM_CHARGER_STAT: get battery presence from chargers.
-
-char **psy_charger_stat;
- : An array ending with NULL that has power-supply-class names of
- chargers. Each power-supply-class should provide "PRESENT" (if
- battery_present is "CM_CHARGER_STAT"), "ONLINE" (shows whether an
- external power source is attached or not), and "STATUS" (shows whether
- the battery is {"FULL" or not FULL} or {"FULL", "Charging",
- "Discharging", "NotCharging"}).
-
-int num_charger_regulators;
-struct regulator_bulk_data *charger_regulators;
- : Regulators representing the chargers in the form for
- regulator framework's bulk functions.
-
-char *psy_fuel_gauge;
- : Power-supply-class name of the fuel gauge.
-
-int (*temperature_out_of_range)(int *mC);
-bool measure_battery_temp;
- : This callback returns 0 if the temperature is safe for charging,
- a positive number if it is too hot to charge, and a negative number
- if it is too cold to charge. With the variable mC, the callback returns
- the temperature in 1/1000 of centigrade.
- The source of temperature can be battery or ambient one according to
- the value of measure_battery_temp.
-};
-
-5. Notify Charger-Manager of charger events: cm_notify_event()
-=========================================================
-If there is an charger event is required to notify
-Charger Manager, a charger device driver that triggers the event can call
-cm_notify_event(psy, type, msg) to notify the corresponding Charger Manager.
-In the function, psy is the charger driver's power_supply pointer, which is
-associated with Charger-Manager. The parameter "type"
-is the same as irq's type (enum cm_event_types). The event message "msg" is
-optional and is effective only if the event type is "UNDESCRIBED" or "OTHERS".
-
-6. Other Considerations
-=======================
-
-At the charger/battery-related events such as battery-pulled-out,
-charger-pulled-out, charger-inserted, DCIN-over/under-voltage, charger-stopped,
-and others critical to chargers, the system should be configured to wake up.
-At least the following should wake up the system from a suspend:
-a) charger-on/off b) external-power-in/out c) battery-in/out (while charging)
-
-It is usually accomplished by configuring the PMIC as a wakeup source.