From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bali.collaboradmins.com (bali.collaboradmins.com [148.251.105.195]) (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 85A62AD5E; Mon, 4 Nov 2024 13:19:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=148.251.105.195 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730726353; cv=none; b=TH28NDzazq+6g9qly3/YZQNjldyeQutBQS0oWZ2O5qWt6ApqymKM3rS0wmwj9Zwx+TXUOzbfAuLWYJFQO2fF811mh0kOdXzlQXjFutH5e+zZqzBYyxB9mJPefnH8X72Wdi7taJ4wAGaTYUs3J+Q/fAA4iO0/df7e/LYX9uHF5Lk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1730726353; c=relaxed/simple; bh=1PkamZZykZ77sMp0GI5lTUolLioO7jIOn5iTrhpoK+g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tVXW993pPk4ayay2Gh/rrrryt7tXlUqxJiuEEZZIaJRZDI8zYanS6KfdKtoESjkPZbNphHfDeWq71ROn1gb/iAOLIydSUdxVMad2/M+cB7pJ0S5KILV6gZ+aKAs5SKCYN9h8aGM0NUHLIWJgaxu99aDbtQZXF2m9jCmD7B65y0Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com; spf=pass smtp.mailfrom=collabora.com; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b=jdqx5P3z; arc=none smtp.client-ip=148.251.105.195 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=collabora.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=collabora.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=collabora.com header.i=@collabora.com header.b="jdqx5P3z" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=collabora.com; s=mail; t=1730726349; bh=1PkamZZykZ77sMp0GI5lTUolLioO7jIOn5iTrhpoK+g=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=jdqx5P3z8eit/2sxGG3RKvQuELfZyqNVAmJ7fow9TZRN9AIX0RMG/E9y64pnky2kz H9BPYhVUzu9yxTT9gD0Mmwi7kFvfSBVmHjFSYn/A5MaLdiwybosLQkNEPRVfiEvNSC R0LJ9BmPla8JVosjXDLfoPIi+Z/sODWMcmZNYyHsb5llDoYdWITCoihpyGtafxo4yD mKOA1yMsivY5G9X4wOiOcfCui9dtRPGalZn2aMYXUiuw2I+WHbyZRRmye9/QCWIS15 /C7ijWHXG/e6+mPTti8Zqy+EGF+pW3lzQYumh8S8GgojldzfQr1LRVEPf1RAHYPgn8 vhJFq/8IKXUlQ== Received: from [192.168.1.100] (2-237-20-237.ip236.fastwebnet.it [2.237.20.237]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (No client certificate requested) (Authenticated sender: kholk11) by bali.collaboradmins.com (Postfix) with ESMTPSA id 642C217E3620; Mon, 4 Nov 2024 14:19:09 +0100 (CET) Message-ID: Date: Mon, 4 Nov 2024 14:19:09 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] arm64: dts: mediatek: mt8183-kukui-jacuzzi: Drop pp3300_panel voltage settings To: Chen-Yu Tsai , Matthias Brugger Cc: devicetree@vger.kernel.org, linux-mediatek@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20241030070224.1006331-1-wenst@chromium.org> <20241030070224.1006331-2-wenst@chromium.org> From: AngeloGioacchino Del Regno Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Il 04/11/24 14:00, Chen-Yu Tsai ha scritto: > On Wed, Oct 30, 2024 at 3:02 PM Chen-Yu Tsai wrote: >> >> The pp3300_panel fixed regulator is just a load switch. It does not have >> any regulating capabilities. Thus having voltage constraints on it is >> wrong. >> >> Remove the voltage constraints. >> >> Fixes: cabc71b08eb5 ("arm64: dts: mt8183: Add kukui-jacuzzi-damu board") >> Signed-off-by: Chen-Yu Tsai > > I see that the other three patches were merged and included in the pull > request, but not this one. Were there any concerns? > Sorry I forgot to actually provide an explanation for that - yes, I do have some comment about this one. Despite this being a load switch, it's still switching power from regulator A to target device X, so this is technically still providing 3.3V to device X. Think about how a "regular" full-fledged regulator works: you can (sometimes) set a voltage, and then you can ENABLE the VOUT for said regulator (/rail): this kind of "load switch" does exactly the same as the ENABLE switch for a full-fledged regulator. So, this is switching on and off a power rail that is derived from a source rail, practically creating... well, a "new" rail, with... VIN=somewhere-3.3v, VOUT=somewhere-still-3.3v Any objections/doubts/etc? :-) P.S.: I'm writing fast, sorry if anything appears unclear, feel free to shoot more questions in case :-) Cheers, Angelo > > ChenYu > >> --- >> arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi | 2 -- >> 1 file changed, 2 deletions(-) >> >> diff --git a/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi b/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi >> index 783c333107bc..7bbafe926558 100644 >> --- a/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi >> +++ b/arch/arm64/boot/dts/mediatek/mt8183-kukui-jacuzzi.dtsi >> @@ -35,8 +35,6 @@ pp1800_mipibrdg: pp1800-mipibrdg { >> pp3300_panel: pp3300-panel { >> compatible = "regulator-fixed"; >> regulator-name = "pp3300_panel"; >> - regulator-min-microvolt = <3300000>; >> - regulator-max-microvolt = <3300000>; >> pinctrl-names = "default"; >> pinctrl-0 = <&pp3300_panel_pins>; >> >> -- >> 2.47.0.163.g1226f6d8fa-goog >>