[PATCH RESEND v6 02/17] dt-bindings: battery: Clarify trickle-charge

Matti Vaittinen
2025-12-15T13:17:58Z

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From: Matti Vaittinen <mazziesaccount@gmail.com>

The term 'trickle-charging' is used to describe a very slow charging
phase, where electrons "trickle-in" the battery.

There are two different use-cases for this type of charging. At least
some Li-Ion batteries can benefit from very slow, constant current,
pre-pre phase 'trickle-charging', if a battery is very empty.

Some other batteries use top-off phase 'trickle-charging', which is
different from the above case.

The battery bindings use the term 'trickle-charge' without specifying
which of the use-cases properties are addressing. This has already
caused some confusion.

Clarify that the 'trickle-charge-current-microamp' refers to the first
one, the "pre-pre" -charging use-case.

Suggested-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

---
Revision history:
v3 => :
- No changes

v2 => v3:
- New patch
---
.../devicetree/bindings/power/supply/battery.yaml | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/power/supply/battery.yaml b/Documentation/devicetree/bindings/power/supply/battery.yaml
index 491488e7b970..bfb7b716ae13 100644
--- a/Documentation/devicetree/bindings/power/supply/battery.yaml
+++ b/Documentation/devicetree/bindings/power/supply/battery.yaml
@@ -64,7 +64,12 @@ properties:
description: battery design capacity

trickle-charge-current-microamp:
- description: current for trickle-charge phase
+ description: current for trickle-charge phase.
+ Please note that the trickle-charging here, refers "wake-up" or
+ "pre-pre" -charging, for very empty batteries. Similar term is also
+ used for "maintenance" or "top-off" -charging of batteries (like
+ NiMh bq24400) - that is different and not controlled by this
+ property.

precharge-current-microamp:
description: current for pre-charge phase