Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753688AbdCMO3d convert rfc822-to-8bit (ORCPT ); Mon, 13 Mar 2017 10:29:33 -0400 Received: from hqemgate16.nvidia.com ([216.228.121.65]:12191 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753580AbdCMO3C (ORCPT ); Mon, 13 Mar 2017 10:29:02 -0400 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Mon, 13 Mar 2017 07:26:21 -0700 Subject: Re: [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains To: Geert Uytterhoeven References: <1474367287-10402-1-git-send-email-jonathanh@nvidia.com> <52493231-71f4-1b62-b325-8532e63e4229@nvidia.com> <3e88692d-613b-9c25-2554-7d399c45637a@nvidia.com> CC: Ulf Hansson , "Rafael J. Wysocki" , Kevin Hilman , Rajendra Nayak , Stanimir Varbanov , Stephen Boyd , Marek Szyprowski , Linux PM list , "linux-kernel@vger.kernel.org" , "linux-tegra@vger.kernel.org" , Bjorn Andersson From: Jon Hunter Message-ID: <161ee6b9-7a76-c7b4-3cb4-06259fef4898@nvidia.com> Date: Mon, 13 Mar 2017 14:27:59 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: X-Originating-IP: [10.26.11.107] X-ClientProxiedBy: DRUKMAIL101.nvidia.com (10.25.59.19) To UKMAIL101.nvidia.com (10.26.138.13) Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2588 Lines: 65 Hi Geert, On 13/03/17 14:19, Geert Uytterhoeven wrote: > Hi Jon, > > On Mon, Mar 13, 2017 at 3:09 PM, Jon Hunter wrote: >> On 13/03/17 11:45, Ulf Hansson wrote: >>> +Björn >>> >>> On 13 March 2017 at 10:37, Jon Hunter wrote: >>>> Looks like there is still some interest/needs in/for this. Any thoughts >>>> on how we can move this forward? >>> >>> At the Linaro Connect last week, I was talking to Björn, Rajendra and >>> Stephen more about these related issues. >>> >>> It definitely seems like we need to progress with this somehow, >>> meaning we need a solution for being able to associate a device with >>> more than one PM domain. In that context, I don't think genpd based on >>> its current design, is a good fit to solve the problem. >>> >>> Instead I think we need something entirely new (perhaps some code can >>> be borrowed from genpd), which is more similar to the clock/regulator >>> framework. In other words, what you also were suggesting in a earlier >>> reply. >>> In this way, the driver/subsystem gains full flexibility of managing >>> its device's PM domains, which seems like the best future-proof >>> solution. >> >> I agree, I think that that would give us the most flexibility to handle >> whatever scenario. However, I was thinking that we could still use the >> genpd core to register pm-domains with and control. My thought was to >> allow devices to have a bindings with multiple pm-domains ... >> >> dev-xyz { >> ... >> power-domains = <&domain-a>, <&domain-b>; >> }; >> >> Then in the genpd core we do having something like ... >> >> diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c >> index e697dec9d25b..d1ae6ddf4903 100644 >> --- a/drivers/base/power/domain.c >> +++ b/drivers/base/power/domain.c >> @@ -2026,6 +2026,15 @@ int genpd_dev_pm_attach(struct device *dev) >> "samsung,power-domain", 0); >> if (!pd_args.np) >> return -ENOENT; >> + } else if (ret > 1) { >> + /* >> + * If there are more than one PM domain defined for a device, >> + * then these need to be manually controlled by the device >> + * driver because the genpd core cannot bind a device with > > Which device driver? > The driver for the device that belongs to multiple PM domains? Yes, exactly. So maybe I would need to say ... "manually controlled by the driver for *this* device ..." Jon -- nvpublic