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 X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D05AC55179 for ; Thu, 5 Nov 2020 11:13:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 176E120756 for ; Thu, 5 Nov 2020 11:13:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="u8YwcS6h" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729016AbgKELNH (ORCPT ); Thu, 5 Nov 2020 06:13:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42064 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730114AbgKELNF (ORCPT ); Thu, 5 Nov 2020 06:13:05 -0500 Received: from mail-pf1-x444.google.com (mail-pf1-x444.google.com [IPv6:2607:f8b0:4864:20::444]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 062FAC061A4A for ; Thu, 5 Nov 2020 03:13:05 -0800 (PST) Received: by mail-pf1-x444.google.com with SMTP id 10so1239845pfp.5 for ; Thu, 05 Nov 2020 03:13:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=BcYYFtNRltYDE4hy/KAkGjdjtprJ1Trm7OKV+MnN8cU=; b=u8YwcS6hVr8BwxXTTAlNESEmEgsS3lF6OTr1XaUbam4I/edC3qndBdjg6Uy8iz2Q4Q hYlNAs1/XTw3soHv/si3tXmCczuo3mNDte6nlbwM878k4WF91kDK1iYVRDtibkoROSKj yjfCZIqB3MO3ncbEJATqL58LXrnls4IqwABwbbGOdNIV9RGTDrMZptXqbnjj+V1N6WqI HBRHng10F8RPuKJ6CJ1uCINPNb6xUgsC8CsubJFIRFcKAf9XUt6Zu0y7tcW3MCJO9JyS huRJpus5BnMDQprBpyeMBR2Zh8O7Sqy9/tsu93YAUw3ok0YtILTEkI4ZmB3ZgeuvMkLC Ze4g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=BcYYFtNRltYDE4hy/KAkGjdjtprJ1Trm7OKV+MnN8cU=; b=GFBLC6yVLJaADpa/k0sifliJj29dI84U3O2lGpZHR4IpncMT5670mZLsMo3JZJZkPr ZWWH4lh3UoPaigOAdv1DyyhLPGp0cQ2ex0fg+O/IsOMtOFMZirSPVmzTbd6UEdK/ujf7 ZeAkUNVoKoPEL8Zs/8AjP0Aarq3+eBqeyJ6tAFNvmUUMGT6YXf80tAoprxPK3Yi5mQzK pS05BGUgazd3oWh4D+8FNfDh5JIGAvHmRCInFiLnH1JtdhKC3ZOeeyRpIQ7C8ckbv7Pw wNQZ9OBhTpHqDeKTSzEMvzHDL7vJHGmUfnO9BXPhozyKCt3jlUpuFwAEAzuVBYbesdsF E5/g== X-Gm-Message-State: AOAM530yB6w4Qui8pDsvL9EH7TM/Nl1u3UY64jgmYejSzxUx53C1oohM POP65ohTB5vpCq8RSXJ6jki2fw== X-Google-Smtp-Source: ABdhPJwnuuk4daHbZCdYn/aCWQKiS7cX8bO0eWv5v6ODss+cRR8E8lvUDPwS9VwogQBWTDgNXP1wow== X-Received: by 2002:a17:90a:e391:: with SMTP id b17mr1925329pjz.209.1604574784247; Thu, 05 Nov 2020 03:13:04 -0800 (PST) Received: from localhost ([122.172.12.172]) by smtp.gmail.com with ESMTPSA id f204sm2296698pfa.189.2020.11.05.03.13.02 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 05 Nov 2020 03:13:03 -0800 (PST) Date: Thu, 5 Nov 2020 16:43:01 +0530 From: Viresh Kumar To: Ulf Hansson Cc: Dmitry Osipenko , Thierry Reding , Jonathan Hunter , Alan Stern , Peter Chen , Mark Brown , Liam Girdwood , Adrian Hunter , Krzysztof Kozlowski , Greg Kroah-Hartman , Lee Jones , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , Mauro Carvalho Chehab , Rob Herring , Marek Szyprowski , Peter Geis , Nicolas Chauvet , linux-samsung-soc , driverdevel , Linux USB List , linux-pwm@vger.kernel.org, "linux-mmc@vger.kernel.org" , Linux Kernel Mailing List , DTML , dri-devel , Linux Media Mailing List , linux-tegra Subject: Re: [PATCH v1 00/30] Introduce core voltage scaling for NVIDIA Tegra20/30 SoCs Message-ID: <20201105111301.2hxfx2tnmf2saakp@vireshk-i7> References: <20201104234427.26477-1-digetx@gmail.com> <20201105100603.skrirm7uke4s2xyl@vireshk-i7> <20201105104009.oo4dc6a2gdcwduhk@vireshk-i7> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20180716-391-311a52 Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On 05-11-20, 11:56, Ulf Hansson wrote: > On Thu, 5 Nov 2020 at 11:40, Viresh Kumar wrote: > > Btw, how do we identify if it is a power domain or a regulator ? To be honest, I was a bit afraid and embarrassed to ask this question, and was hoping people to make fun of me in return :) > Good question. It's not a crystal clear line in between them, I think. And I was relieved after reading this :) > A power domain to me, means that some part of a silicon (a group of > controllers or just a single piece, for example) needs some kind of > resource (typically a power rail) to be enabled to be functional, to > start with. Isn't this what a part of regulator does as well ? i.e. enabling/disabling of the regulator or power to a group of controllers. Over that the regulator does voltage/current scaling as well, which normally the power domains don't do (though we did that in performance-state case). > If there are operating points involved, that's also a > clear indication to me, that it's not a regular regulator. Is there any example of that? I hope by OPP you meant both freq and voltage here. I am not sure if I know of a case where a power domain handles both of them. > Maybe we should try to specify this more exactly in some > documentation, somewhere. I think yes, it is very much required. And in absence of that I think, many (or most) of the platforms that also need to scale the voltage would have modeled their hardware as a regulator and not a PM domain. What I always thought was: - Module that can just enable/disable power to a block of SoC is a power domain. - Module that can enable/disable as well as scale voltage is a regulator. And so I thought that this patchset has done the right thing. This changed a bit with the qcom stuff where the IP to be configured was in control of RPM and not Linux and so we couldn't add it as a regulator. If it was controlled by Linux, it would have been a regulator in kernel for sure :) -- viresh