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 364B334DB48; Thu, 20 Nov 2025 16:11:22 +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=1763655082; cv=none; b=G69n3XuZnPnLCOJ3HGO2JVaCUvScpqfAEoUr+2a5WIzwMlDC7tNhqXTkscb1K/pRCZiMhfnggOTJtGUBQFYbDUt0mg9tKRcX1jOr7GE9vIzXVSNXC8pok6d9jsf1z9gJOCBjHBf/Rt/9LiN9HQwzGFxZz48woeya3GKF58XAn00= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763655082; c=relaxed/simple; bh=BbjFmvnZpIAYJemMHM1v/+EA292tt6R+P8dHMuj7Xbo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=QDIUMhTfUbVvhr0XM1i/7RYf07JjFCUhsmnP1BYcX5uav6viwyi+Of0vhJva7IgBAATwQ5wEG+D7Q03ZyXy7DZRCfwxZ5VxflJS2H9Pb7ZmX7w/H3+xf0/RxeXNDFUoVXkGqB1KUsT+bvMPEnbe0XGjS3wPcfiCAmdI0iNBjZe8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=j6sZSIw/; 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="j6sZSIw/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7944BC16AAE; Thu, 20 Nov 2025 16:11:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763655081; bh=BbjFmvnZpIAYJemMHM1v/+EA292tt6R+P8dHMuj7Xbo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=j6sZSIw/JPOJ5KPAnyvMTDJJwbyriGW5UTQEbsjE6QELz2EfAY2mJp36zyAAt0b+y +vswlXRwsb0Sxxg8huowpVFhvSMiHekutXcQKmGpubePU5D60wuTCeWev9J/6Fu+op cCSRGK1ecV/0eAkS9q+wD2uL2rM/iY1F7eOaa/u0kGHEoe9bkUCWrAbKWPBad3dSJT N2euymlkYqScUvei7EX4PwXMWXXmS+KZjw9lh/5DnWGrDlxud6l/CIoB+5tVAJ2r48 Fnk6TPbYFHVm8R935wu3uLwRsCucySQuCtStJiF1UoblbTDE8eVGumiMuEoLObpe/g VTBQZGKbhUaKw== Date: Thu, 20 Nov 2025 10:11:19 -0600 From: "Rob Herring (Arm)" To: Matti Vaittinen Cc: Pavel Machek , Alexandre Belloni , Linus Walleij , devicetree@vger.kernel.org, Liam Girdwood , Sebastian Reichel , Mark Brown , linux-gpio@vger.kernel.org, Andreas Kemnade , Michael Turquette , linux-pm@vger.kernel.org, Krzysztof Kozlowski , linux-kernel@vger.kernel.org, Stephen Boyd , Matti Vaittinen , linux-clk@vger.kernel.org, Conor Dooley , Lee Jones , linux-rtc@vger.kernel.org, linux-leds@vger.kernel.org, Matti Vaittinen , Bartosz Golaszewski Subject: Re: [PATCH v5 04/16] dt-bindings: battery: Voltage drop properties Message-ID: <176365507949.1467967.14779548559679744817.robh@kernel.org> References: <93768cba6688714756fca49cc57d46a111885863.1763625920.git.mazziesaccount@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <93768cba6688714756fca49cc57d46a111885863.1763625920.git.mazziesaccount@gmail.com> On Thu, 20 Nov 2025 10:20:24 +0200, Matti Vaittinen wrote: > From: Matti Vaittinen > > ROHM has developed a so called "zero-correction" -algorithm to improve > the fuel-gauging accuracy close to the point where battery is depleted. > This relies on battery specific "VDR" (voltage drop rate) tables, which > are measured from the battery, and which describe the voltage drop rate. > More thorough explanation about the "zero correction" and "VDR" > parameters is here: > https://lore.kernel.org/all/676253b9-ff69-7891-1f26-a8b5bb5a421b@fi.rohmeurope.com/ > > Document the VDR zero-correction specific battery properties used by the > BD71815, BD71828, BD72720 and some other ROHM chargers. (Note, charger > drivers aren't upstream yet). > > Signed-off-by: Matti Vaittinen > > --- > > Revision history: > v4 => v5: > - Move volt-drop parameters from rohm,vdr-battry,yaml to the > battery.yaml > - drop rohm, -prefix from volt-drop-* properties > - Drop the rohm,vdr-battry,yaml > - Add comment clarifying what the rohm,volt-drop-* properties are for > because this may no longer be obvious as they were moved to common > battery.yaml > - Drop Linus Walleij's rb-tag because the concept was changed > > v3 => v4: > - No changes > > v2 => v3: > - Constrain VDR threshold voltage to 48V > - Use standard '-bp' -suffix for the rohm,volt-drop-soc > > RFCv1 => v2: > - Add units to rohm,volt-drop-soc (tenths of %) > - Give real temperatures matching the VDR tables, instead of vague > 'high', 'normal', 'low', 'very low'. (Add table of temperatures and > use number matching the right temperature index in the VDR table name). > - Fix typoed 'algorithm' in commit message. > > The parameters are describing the battery voltage drop rates - so they > are properties of the battery, not the charger. Thus they do not belong > in the charger node. > > The right place for them is the battery node, which is described by the > generic "battery.yaml". There were some discussion whether these > properties should be in their own file, or if they should be added to > battery.yaml. Discussion can be found from: > https://lore.kernel.org/all/52b99bf7-bfea-4cee-aa57-4c13e87eaa0d@gmail.com/ > This patch implements the volt-drop properties as generic (not vemdor > specific) properties in the battery.yaml. It's worth noting that these > properties are: > > - Meaningful only for those charger drivers which have the VDR > algorithm implemented. (And even though the algorithm is not charger > specific, AFAICS, it is currently only used by some ROHM PMIC > drivers). > - Technique of measuring the VDR tables for a battery is not widely > known. AFAICS, only folks at ROHM are measuring those for some > customer products. We do have those tables available for some of the > products, like Kobo e-readers though. > --- > .../bindings/power/supply/battery.yaml | 22 +++++++++++++++++++ > 1 file changed, 22 insertions(+) > Reviewed-by: Rob Herring (Arm)