From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752381AbdB1P0O (ORCPT ); Tue, 28 Feb 2017 10:26:14 -0500 Received: from hqemgate16.nvidia.com ([216.228.121.65]:19081 "EHLO hqemgate16.nvidia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751135AbdB1P0J (ORCPT ); Tue, 28 Feb 2017 10:26:09 -0500 X-PGP-Universal: processed; by hqnvupgp08.nvidia.com on Tue, 28 Feb 2017 07:21:15 -0800 Subject: Re: [RFC PATCH 0/3] PM / Domains: Add support for devices that require multiple domains To: "Rafael J. Wysocki" , Kevin Hilman , Ulf Hansson , , , , , Marek Szyprowski References: <1474367287-10402-1-git-send-email-jonathanh@nvidia.com> CC: , , From: Jon Hunter Message-ID: <52493231-71f4-1b62-b325-8532e63e4229@nvidia.com> Date: Tue, 28 Feb 2017 15:18:47 +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: <1474367287-10402-1-git-send-email-jonathanh@nvidia.com> X-Originating-IP: [10.21.132.151] X-ClientProxiedBy: DRUKMAIL102.nvidia.com (10.25.59.20) To UKMAIL101.nvidia.com (10.26.138.13) Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi all, On 20/09/16 11:28, Jon Hunter wrote: > The Tegra124/210 XUSB subsystem (that consists of both host and device > controllers) is partitioned across 3 PM domains which are: > - XUSBA: Superspeed logic (for USB 3.0) > - XUSBB: Device controller > - XUSBC: Host controller > > These power domains are not nested and can be powered-up and down > independently of one another. In practice different scenarios require > different combinations of the power domains, for example: > - Superspeed host: XUSBA and XUSBC > - Superspeed device: XUSBA and XUSBB > > Although it could be possible to logically nest both the XUSBB and XUSBC > domains under the XUSBA, superspeed may not always be used/required and > so this would keep it on unnecessarily. > > Given that Tegra uses device-tree for describing the hardware, it would > be ideal that the device-tree 'power-domains' property for generic PM > domains could be extended to allow more than one PM domain to be > specified. For example, define the following the Tegra210 xHCI device ... > > usb@70090000 { > compatible = "nvidia,tegra210-xusb"; > ... > power-domains = <&pd_xusbhost>, <&pd_xusbss>; > }; > > This RFC extends the generic PM domain framework to allow a device to > define more than one PM domain in the device-tree 'power-domains' > property. I wanted to kick this thread again now in the new year and see if there is still some interest in pursuing this? There is still very much a need from a Tegra perspective. I have put all those who responded on TO. I know that a lot of time has passed since we discuss this and so if you are scratching your head wondering what I am harping on about, essentially with this RFC I was looking for a way to support devices that require multiple power domains where the domains do not have a parent-child relationship and so not are nested in anyway. If you need me to elaborate on the need for this, I am happy to do this. My take away from when we discussed this last year, was that there was a need for this. Cheers Jon -- nvpublic