Every ioctl for the acpi_battery driver takes a single integer value for the battery unit number as an
argument, and returns a specific structure for each request. A special unit number
ACPI_BATTERY_ALL_UNITS specifies all of the attached units and reports accumulated information.
ACPIIO_BATT_GET_UNITS int
Returns the number of battery units in the system. The unit number argument will be ignored.
ACPIIO_BATT_GET_BATTINFO structacpi_battinfo
Returns the following:
cap Battery capacity in percent,
min Remaining battery life in minutes,
state Current status of the battery encoded in the following:
ACPI_BATT_STAT_DISCHARG (0x0001)
Battery is discharging,
ACPI_BATT_STAT_CHARGING (0x0002)
Battery is being charged, or
ACPI_BATT_STAT_CRITICAL (0x0004)
Remaining battery life is critically low.
Note that the status bits of each battery will be consolidated when
ACPI_BATTERY_ALL_UNITS is specified.
rate Current battery discharging rate in mW. -1 means not discharging right now.
ACPIIO_BATT_GET_BIX structacpi_bix
Returns battery information given by the ACPI _BIX (Battery Information) object, which is the
static portion of the Control Method Battery information. In the case of a Smart Battery
attached to SMBus or a Control Method Battery with a _BIF object, this ioctl will build a structacpi_bix structure based on the obtained information and return it.
rev Revision number of the object. There are the following well-known values:
ACPI_BIX_REV_0 (0x0000)
A _BIX object in ACPI 4.0.
ACPI_BIX_REV_1 (0x0001)
A _BIX object in ACPI 6.0.
ACPI_BIX_REV_BIF (0xffff)
A _BIX object built from the _BIF object found on the system.
Note that this field should be checked by using ACPI_BIX_REV_MIN_CHECK(var, rev) macro
when checking the minimum revision number.
units Indicates the units used by the battery to report its capacity and charge rate encoded in
the following:
ACPI_BIX_UNITS_MW (0x00000000)
in mW (power)
ACPI_BIX_UNITS_MA (0x00000001)
in mA (current)
Note that capacity is expressed in mWh or mAh, and rate is expressed in mW or mA,
respectively.
dcap The Battery's design capacity, which is the nominal capacity of a new battery. This is
expressed as power or current depending on the value of units.
lfcap Predicted battery capacity when fully charged. Typically this will decrease every
charging cycle.
btech Battery technology:
0x00000000 Primary cell (non-rechargable)
0x00000001 Secondary cell (rechargable)
dvol Design voltage in mV, which is the nominal voltage of a new battery.
wcap Design capacity of warning. When a discharging battery device reaches this capacity,
notification is sent to the system.
lcap Design capacity of low.
cycles (rev 0 or newer) The number of cycles the battery has experienced. A cycle means an
amount of discharge occurred which was approximately equal to the value of Design
Capacity.
accuracy
(rev 0 or newer) The accuracy of the battery capacity measurement, in thousandth of a
percent.
stmax (rev 0 or newer) The Maximum Sampling Time of the battery in milliseconds. This is the
maximum duration between two consecutive measurements of the battery's capacities
specified in _BST. If two succeeding readings of _BST beyond this duration occur, two
different results can be returned.
stmin (rev 0 or newer) The Minimum Sampling Time of the battery in milliseconds.
aimax (rev 0 or newer) The Maximum Average Interval of the battery in milliseconds. This is
the length of time within which the battery averages the capacity measurements specified
in _BST. The Sampling Time specifies the frequency of measurements, and the Average
Interval specifies the width of the time window of every measurement.
aimin (rev 0 or newer) The Minimum Average Interval of the battery in milliseconds.
gra1 Battery capacity granularity between low and warning. This is expressed as power or
current depending on the value of units.
gra2 Battery capacity granularity between warning and full. This is expressed as power or
current depending on the value of units.
model Model number of the battery as a string.
serial Serial number of the battery as a string.
type Type identifier of the battery as a string.
oeminfo
OEM-specific information of the battery as a string.
scap (rev 1 or newer) Battery swapping capability encoded in the following:
ACPI_BIX_SCAP_NO (0x00000000)
Non-swappable
ACPI_BIX_SCAP_COLD (0x00000001)
Cold-swappable
ACPI_BIX_SCAP_HOT (0x00000010)
Hot-swappable
ACPIIO_BATT_GET_BIF structacpi_bif
(deprecated) Returns battery information given by the ACPI _BIF (Battery Information) object,
which was deprecated in ACPI 4.0 specification. The data structure is a subset of structacpi_bix.
Note that this ioctl will built a structacpi_bif structure based on the obtained information
even if this object is not available and a _BIX object is found.
ACPIIO_BATT_GET_BST structacpi_bst
Returns battery information given by the ACPI _BST (Battery Status) object, which is the present
battery status. In the case of a Smart Battery attached to SMBus, this ioctl will build a structacpi_bst structure based on the obtained information and return it.
state Battery state. The value is encoded in the same way as state of structacpi_battinfo.
rate Battery present rate of charging or discharging. The unit of the value depends on unit
of structacpi_bif.
cap Battery remaining capacity. The unit of this value depends on unit of structacpi_bif.
volt Battery present voltage.
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