From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DD4F0D132C0 for ; Mon, 4 Nov 2024 13:21:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:In-Reply-To:From:References:Cc:To:Subject:MIME-Version:Date: Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=LNU2JpZX/eVQkXUoGnr/S3jjls/U0OlNS3uYWAIOpxw=; b=g54nBdW6Wq1Ae8olYWV8pDvD6W qGkRyl/kd+tv/vOA/BKI0y6SyIhWdTA2120W6Lvld1IfxqCt7FS4lHSFE9pz9YBvdQgC8Fw/ksknx TWVhuZMi6yVdDekBmFbnDr3Ims1KMeuTgVrjpD0NOY9KjynNUEywqrBYRXpZVmPgk8qB3P1sDRH97 9iINPfhKrED9D68AgMwx4wikp/KzGVwSxXFR41h1LTxlrSidp5Fu89Frpcjn2OEoG+MZT2gI3yhCn WbavFdZ28XBDS5k8tidZkxJTE9dR56H2CwNC8omv/LvzJBZGPRazcFbOp495hWA0Drx2FBR6RySqY /kb3nyiA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1t7x0u-0000000DpO0-3CG6; Mon, 04 Nov 2024 13:21:00 +0000 Received: from bali.collaboradmins.com ([148.251.105.195]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1t7wz9-0000000Dorv-2ZOe; Mon, 04 Nov 2024 13:19:12 +0000 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 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 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20241104_051911_831516_D9325035 X-CRM114-Status: GOOD ( 18.47 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org 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 >>