docs: power: clean up power_supply_class.rst

Clean up grammar, punctuation, etc., in the power supply class
documentation.

Add article adjectives where needed.
Hyphenate some adjectives.
Fix punctuation.
Fix some verb usage (singular/plural).
Fix run-on sentences.
Add "is" in a few places.
Change "QA" to "Q&A".

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Dhruva Gole <d-gole@ti.com>
Link: https://patch.msgid.link/20251014182008.823980-1-rdunlap@infradead.org
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
This commit is contained in:
Randy Dunlap
2025-10-14 11:20:07 -07:00
committed by Sebastian Reichel
parent 446fcf4946
commit 06b54f2d74

View File

@@ -7,35 +7,35 @@ Synopsis
Power supply class used to represent battery, UPS, AC or DC power supply Power supply class used to represent battery, UPS, AC or DC power supply
properties to user-space. properties to user-space.
It defines core set of attributes, which should be applicable to (almost) It defines a core set of attributes which should be applicable to (almost)
every power supply out there. Attributes are available via sysfs and uevent every power supply out there. Attributes are available via sysfs and uevent
interfaces. interfaces.
Each attribute has well defined meaning, up to unit of measure used. While Each attribute has a well-defined meaning, up to the unit of measure used. While
the attributes provided are believed to be universally applicable to any the attributes provided are believed to be universally applicable to any
power supply, specific monitoring hardware may not be able to provide them power supply, specific monitoring hardware may not be able to provide them
all, so any of them may be skipped. all, so any of them may be skipped.
Power supply class is extensible, and allows to define drivers own attributes. The power supply class is extensible and allows drivers to define their own
The core attribute set is subject to the standard Linux evolution (i.e. attributes. The core attribute set is subject to the standard Linux evolution
if it will be found that some attribute is applicable to many power supply (i.e., if some attribute is found to be applicable to many power
types or their drivers, it can be added to the core set). supply types or their drivers, it can be added to the core set).
It also integrates with LED framework, for the purpose of providing It also integrates with the LED framework, for the purpose of providing
typically expected feedback of battery charging/fully charged status and typically expected feedback of battery charging/fully charged status and
AC/USB power supply online status. (Note that specific details of the AC/USB power supply online status. (Note that specific details of the
indication (including whether to use it at all) are fully controllable by indication (including whether to use it at all) are fully controllable by
user and/or specific machine defaults, per design principles of LED user and/or specific machine defaults, per design principles of the LED
framework). framework.)
Attributes/properties Attributes/properties
~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~
Power supply class has predefined set of attributes, this eliminates code The power supply class has a predefined set of attributes. This eliminates code
duplication across drivers. Power supply class insist on reusing its duplication across drivers. The power supply class insists on reusing its
predefined attributes *and* their units. predefined attributes *and* their units.
So, userspace gets predictable set of attributes and their units for any So, userspace gets a predictable set of attributes and their units for any
kind of power supply, and can process/present them to a user in consistent kind of power supply, and can process/present them to a user in consistent
manner. Results for different power supplies and machines are also directly manner. Results for different power supplies and machines are also directly
comparable. comparable.
@@ -61,7 +61,7 @@ Attributes/properties detailed
| **Charge/Energy/Capacity - how to not confuse** | | **Charge/Energy/Capacity - how to not confuse** |
+--------------------------------------------------------------------------+ +--------------------------------------------------------------------------+
| **Because both "charge" (µAh) and "energy" (µWh) represents "capacity" | | **Because both "charge" (µAh) and "energy" (µWh) represents "capacity" |
| of battery, this class distinguish these terms. Don't mix them!** | | of battery, this class distinguishes these terms. Don't mix them!** |
| | | |
| - `CHARGE_*` | | - `CHARGE_*` |
| attributes represents capacity in µAh only. | | attributes represents capacity in µAh only. |
@@ -81,7 +81,7 @@ _NOW
STATUS STATUS
this attribute represents operating status (charging, full, this attribute represents operating status (charging, full,
discharging (i.e. powering a load), etc.). This corresponds to discharging (i.e., powering a load), etc.). This corresponds to
`BATTERY_STATUS_*` values, as defined in battery.h. `BATTERY_STATUS_*` values, as defined in battery.h.
CHARGE_TYPE CHARGE_TYPE
@@ -92,10 +92,10 @@ CHARGE_TYPE
AUTHENTIC AUTHENTIC
indicates the power supply (battery or charger) connected indicates the power supply (battery or charger) connected
to the platform is authentic(1) or non authentic(0). to the platform is authentic(1) or non-authentic(0).
HEALTH HEALTH
represents health of the battery, values corresponds to represents health of the battery. Values corresponds to
POWER_SUPPLY_HEALTH_*, defined in battery.h. POWER_SUPPLY_HEALTH_*, defined in battery.h.
VOLTAGE_OCV VOLTAGE_OCV
@@ -103,11 +103,11 @@ VOLTAGE_OCV
VOLTAGE_MAX_DESIGN, VOLTAGE_MIN_DESIGN VOLTAGE_MAX_DESIGN, VOLTAGE_MIN_DESIGN
design values for maximal and minimal power supply voltages. design values for maximal and minimal power supply voltages.
Maximal/minimal means values of voltages when battery considered Maximal/minimal means values of voltages when battery is considered
"full"/"empty" at normal conditions. Yes, there is no direct relation "full"/"empty" at normal conditions. Yes, there is no direct relation
between voltage and battery capacity, but some dumb between voltage and battery capacity, but some dumb
batteries use voltage for very approximated calculation of capacity. batteries use voltage for very approximated calculation of capacity.
Battery driver also can use this attribute just to inform userspace A battery driver also can use this attribute just to inform userspace
about maximal and minimal voltage thresholds of a given battery. about maximal and minimal voltage thresholds of a given battery.
VOLTAGE_MAX, VOLTAGE_MIN VOLTAGE_MAX, VOLTAGE_MIN
@@ -122,16 +122,16 @@ CURRENT_BOOT
Reports the current measured during boot Reports the current measured during boot
CHARGE_FULL_DESIGN, CHARGE_EMPTY_DESIGN CHARGE_FULL_DESIGN, CHARGE_EMPTY_DESIGN
design charge values, when battery considered full/empty. design charge values, when battery is considered full/empty.
ENERGY_FULL_DESIGN, ENERGY_EMPTY_DESIGN ENERGY_FULL_DESIGN, ENERGY_EMPTY_DESIGN
same as above but for energy. same as above but for energy.
CHARGE_FULL, CHARGE_EMPTY CHARGE_FULL, CHARGE_EMPTY
These attributes means "last remembered value of charge when battery These attributes mean "last remembered value of charge when battery
became full/empty". It also could mean "value of charge when battery became full/empty". They also could mean "value of charge when battery is
considered full/empty at given conditions (temperature, age)". considered full/empty at given conditions (temperature, age)".
I.e. these attributes represents real thresholds, not design values. I.e., these attributes represents real thresholds, not design values.
ENERGY_FULL, ENERGY_EMPTY ENERGY_FULL, ENERGY_EMPTY
same as above but for energy. same as above but for energy.
@@ -153,12 +153,12 @@ CHARGE_TERM_CURRENT
CONSTANT_CHARGE_CURRENT CONSTANT_CHARGE_CURRENT
constant charge current programmed by charger. constant charge current programmed by charger.
CONSTANT_CHARGE_CURRENT_MAX CONSTANT_CHARGE_CURRENT_MAX
maximum charge current supported by the power supply object. maximum charge current supported by the power supply object.
CONSTANT_CHARGE_VOLTAGE CONSTANT_CHARGE_VOLTAGE
constant charge voltage programmed by charger. constant charge voltage programmed by charger.
CONSTANT_CHARGE_VOLTAGE_MAX CONSTANT_CHARGE_VOLTAGE_MAX
maximum charge voltage supported by the power supply object. maximum charge voltage supported by the power supply object.
@@ -208,10 +208,10 @@ TEMP_MAX
TIME_TO_EMPTY TIME_TO_EMPTY
seconds left for battery to be considered empty seconds left for battery to be considered empty
(i.e. while battery powers a load) (i.e., while battery powers a load)
TIME_TO_FULL TIME_TO_FULL
seconds left for battery to be considered full seconds left for battery to be considered full
(i.e. while battery is charging) (i.e., while battery is charging)
Battery <-> external power supply interaction Battery <-> external power supply interaction
@@ -220,13 +220,13 @@ Often power supplies are acting as supplies and supplicants at the same
time. Batteries are good example. So, batteries usually care if they're time. Batteries are good example. So, batteries usually care if they're
externally powered or not. externally powered or not.
For that case, power supply class implements notification mechanism for For that case, the power supply class implements a notification mechanism for
batteries. batteries.
External power supply (AC) lists supplicants (batteries) names in An external power supply (AC) lists supplicants (batteries) names in
"supplied_to" struct member, and each power_supply_changed() call "supplied_to" struct member, and each power_supply_changed() call
issued by external power supply will notify supplicants via issued by an external power supply will notify supplicants via
external_power_changed callback. the external_power_changed callback.
Devicetree battery characteristics Devicetree battery characteristics
@@ -241,14 +241,14 @@ battery node have names corresponding to elements in enum power_supply_property,
for naming consistency between sysfs attributes and battery node properties. for naming consistency between sysfs attributes and battery node properties.
QA Q&A
~~ ~~~
Q: Q:
Where is POWER_SUPPLY_PROP_XYZ attribute? Where is POWER_SUPPLY_PROP_XYZ attribute?
A: A:
If you cannot find attribute suitable for your driver needs, feel free If you cannot find an attribute suitable for your driver needs, feel free
to add it and send patch along with your driver. to add it and send a patch along with your driver.
The attributes available currently are the ones currently provided by the The attributes available currently are the ones currently provided by the
drivers written. drivers written.
@@ -258,18 +258,18 @@ A:
Q: Q:
I have some very specific attribute (e.g. battery color), should I add I have some very specific attribute (e.g., battery color). Should I add
this attribute to standard ones? this attribute to standard ones?
A: A:
Most likely, no. Such attribute can be placed in the driver itself, if Most likely, no. Such attribute can be placed in the driver itself, if
it is useful. Of course, if the attribute in question applicable to it is useful. Of course, if the attribute in question is applicable to
large set of batteries, provided by many drivers, and/or comes from a large set of batteries, provided by many drivers, and/or comes from
some general battery specification/standard, it may be a candidate to some general battery specification/standard, it may be a candidate to
be added to the core attribute set. be added to the core attribute set.
Q: Q:
Suppose, my battery monitoring chip/firmware does not provides capacity Suppose my battery monitoring chip/firmware does not provide capacity
in percents, but provides charge_{now,full,empty}. Should I calculate in percents, but provides charge_{now,full,empty}. Should I calculate
percentage capacity manually, inside the driver, and register CAPACITY percentage capacity manually, inside the driver, and register CAPACITY
attribute? The same question about time_to_empty/time_to_full. attribute? The same question about time_to_empty/time_to_full.
@@ -278,11 +278,11 @@ A:
directly measurable by the specific hardware available. directly measurable by the specific hardware available.
Inferring not available properties using some heuristics or mathematical Inferring not available properties using some heuristics or mathematical
model is not subject of work for a battery driver. Such functionality model is not a subject of work for a battery driver. Such functionality
should be factored out, and in fact, apm_power, the driver to serve should be factored out, and in fact, apm_power, the driver to serve
legacy APM API on top of power supply class, uses a simple heuristic of legacy APM API on top of the power supply class, uses a simple heuristic of
approximating remaining battery capacity based on its charge, current, approximating remaining battery capacity based on its charge, current,
voltage and so on. But full-fledged battery model is likely not subject voltage and so on. But a full-fledged battery model is likely not a subject
for kernel at all, as it would require floating point calculation to deal for the kernel at all, as it would require floating point calculations to
with things like differential equations and Kalman filters. This is deal with things like differential equations and Kalman filters. This is
better be handled by batteryd/libbattery, yet to be written. better be handled by batteryd/libbattery, yet to be written.