[PATCH v4] docs: ABI: sysfs-class-power: Documented cycle_count property

Commit c955fe8e0bdd ("POWER: Add support for cycle_count") added a
POWER_SUPPLY_PROP_CYCLE_COUNT "cycle_count" property to the set of
standard power-supply properties, but this was never documented,
document it now.

Link: https://gitlab.freedesktop.org/upower/upower/-/issues/152
Reported-by: Bastien Nocera <hadess@hadess.net>
Signed-off-by: Hans de Goede <redacted>
---
Changes in v4:
- Document that some drivers, such as e.g. the often used
  drivers/acpi/battery.c driver may return 0 when cycle_count information
  is not available

Changes in v3 (aka the really really typo free version)
- Fix typo in "cycle_count" in Subject

Changes in v2:
- s/Possitive/Positive/
---
 Documentation/ABI/testing/sysfs-class-power | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-class-power b/Documentation/ABI/testing/sysfs-class-power
index ca830c6cd809..f7904efc4cfa 100644
--- a/Documentation/ABI/testing/sysfs-class-power
+++ b/Documentation/ABI/testing/sysfs-class-power

@@ -480,6 +480,19 @@ Description:
 
 		Valid values: Represented in microvolts
 
+What:		/sys/class/power_supply/<supply_name>/cycle_count
+Date:		January 2010
+Contact:	linux-pm@vger.kernel.org
+Description:
+		Reports the number of full charge + discharge cycles the
+		battery has undergone.
+
+		Access: Read
+
+		Valid values:
+			Integer > 0: representing full cycles
+			Integer = 0: cycle_count info is not available
+
 **USB Properties**
 
 What:		/sys/class/power_supply/<supply_name>/input_current_limit

-- 
2.31.1