From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 558EA302161; Wed, 29 Oct 2025 13:33:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761744826; cv=none; b=BBspC1ngBHAxsZ79Djil4H/CRYgMOf2diltm3E9skpwMVN+8qnzQTXO+nOTt9Eime1pxi/E5uOSb2cJw/VdCDofYoNIo125zZdM1j0ddHaN6bdAa8ZpTC3RoEi6CDwvgJhTyO02+B2yTgu8kddrY4drLEVCPqUCi5BCzN2icuIY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761744826; c=relaxed/simple; bh=ZHmNvpRE/27NOb0eEnH0tbeTut2ItrA5+TdUUFpGM7k=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=blT7SeGxknvoDOgCUWRw1MXmnYjAQPPeXzgTUU0nXX4/0hLbguuFLh/Wn56SI6jAXCRakPuTwh4HzbmDMEWQGe0IQtAtoiTcrvJ1KGr5Kj2hq9JooXH2vKIEOEi2ldh679ICRalEnqSE5AvxfCdykTNe1wwqAIZel9coKGDlFI8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ou1VjCWO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ou1VjCWO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 078FAC4CEFF; Wed, 29 Oct 2025 13:33:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1761744825; bh=ZHmNvpRE/27NOb0eEnH0tbeTut2ItrA5+TdUUFpGM7k=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ou1VjCWOsp1l3s9vFI6F5hFO11knjGvnOej6wvPkNlcz5O9trZBuWS6cxW8obzWkb bMx37vdpUgjTmxB1gh1eVoiWHzy9/LiGlSL5LwAwAnGCSci6axkvgrSmx3KVIvRbxQ IYMNOrwm9nD8i7eRIW/WLbIs7RFi0pynXPTtFmRhO0WpmqOi9pwHNWRfUkMcm59dDr 1DE6Df080zlVN+aRrOSPvvPx/0CyqeYw/EleSE9D7UKDMpMfH4tb3kBC/qRvroBooU LcYu8vzysBKt0so2mGg1SLT7NK+fR2PoP9EpZlRpeFx4hWkqjS/6m859KMB9Mj428o 8GPcdUi8cgYWQ== Message-ID: Date: Wed, 29 Oct 2025 14:33:39 +0100 Precedence: bulk X-Mailing-List: linux-gpio@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 02/15] dt-bindings: Add trickle-charge upper limit To: Linus Walleij , Matti Vaittinen Cc: Matti Vaittinen , Lee Jones , Pavel Machek , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Sebastian Reichel , Liam Girdwood , Mark Brown , Michael Turquette , Stephen Boyd , Bartosz Golaszewski , Andreas Kemnade , Alexandre Belloni , linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org, linux-clk@vger.kernel.org, linux-gpio@vger.kernel.org, linux-rtc@vger.kernel.org References: <20251029-adamant-mamba-of-patience-cddb65@kuoka> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 29/10/2025 14:26, Linus Walleij wrote: > On Wed, Oct 29, 2025 at 7:22 AM Matti Vaittinen > wrote: > >>> But I believe this is wrong. Trickle charging does not switch to >>> anything more, there is no fast charging after trickle. You have some >>> sort of pre-pre-charging, which is just pre-charging. >> >> There is trickle, pre and fast-charge phases. Furthermore, the >> fast-charge is further divided to CC and CV. Finally, if my memory >> serves me well, Linus W did explain me that some chargers use >> 'trickle-charging' as a _last_ charging phase for a full battery. Thus >> the term 'trickle-charging' is slightly confusing - but it is already >> used by the existing bindings... >> >> https://lore.kernel.org/all/20211116001755.2132036-1-linus.walleij@linaro.org/ > > I think we need to refer to a textbook or IEEE articles to get this > terminology right. > > As you say it appears "trickle-charging" is ambiguous. > > Maybe what Krzysztof suggest to use: "pre-pre-charging" or > "empty-battery-charging" or something like this is needed. > > But we really need a trustworthy academic source here. Trickle charging is accurate for both cases - pre-pre and top-off - because it just describes very small current. That's why I found it in many TI datasheets - mostly for Li-Ion batteries describing Matti's case, but also in at least one case for Ni-Mh describing top-off (or maintenance). I am fine with the naming, but I want to be clear that this property will describe trickle only in case of pre-pre charging. Termination voltage simply does not fit the top-off/maintenance mode. Best regards, Krzysztof