From mboxrd@z Thu Jan 1 00:00:00 1970 From: Lina Iyer Subject: Re: [PATCH RFC 02/27] PM / Domains: Allow domain power states to be read from DT Date: Tue, 15 Dec 2015 15:14:28 -0700 Message-ID: <20151215221428.GF992@linaro.org> References: <1447799871-56374-1-git-send-email-lina.iyer@linaro.org> <1447799871-56374-3-git-send-email-lina.iyer@linaro.org> <566FE652.1030602@baylibre.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Return-path: Received: from mail-pa0-f49.google.com ([209.85.220.49]:34482 "EHLO mail-pa0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752144AbbLOWOc (ORCPT ); Tue, 15 Dec 2015 17:14:32 -0500 Received: by mail-pa0-f49.google.com with SMTP id wq6so12061990pac.1 for ; Tue, 15 Dec 2015 14:14:31 -0800 (PST) Content-Disposition: inline In-Reply-To: <566FE652.1030602@baylibre.com> Sender: linux-arm-msm-owner@vger.kernel.org List-Id: linux-arm-msm@vger.kernel.org To: Marc Titinger Cc: Ulf Hansson , Kevin Hilman , "linux-pm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Geert Uytterhoeven , Krzysztof =?utf-8?Q?Koz=C5=82owski?= , msivasub@codeaurora.org, Andy Gross , Stephen Boyd , "linux-arm-msm@vger.kernel.org" , Lorenzo Pieralisi , Axel Haslam , Marc Titinger On Tue, Dec 15 2015 at 03:07 -0700, Marc Titinger wrote: >On 10/12/2015 17:53, Ulf Hansson wrote: >>On 17 November 2015 at 23:37, Lina Iyer wrote: >>>diff --git a/Documentation/devicetree/bindings/power/power_domain.txt b/Documentation/devicetree/bindings/power/power_domain.txt >>>index 025b5e7..e2f542e 100644 >>>--- a/Documentation/devicetree/bindings/power/power_domain.txt >>>+++ b/Documentation/devicetree/bindings/power/power_domain.txt >>>@@ -29,6 +29,44 @@ Optional properties: >>> specified by this binding. More details about power domain specifier are >>> available in the next section. >>> >>>+- power-states : A phandle of an idle-state that shall be soaked into a >>>+ generic domain power state. The power-state shall be >>>+ compatible with "linux,domain-state". >> >>Why mention the Linux specific "generic power domain" here? >> >>Let's instead try to describe this without using specific terminology >>from Linux. > >Hmm, I will need Lina's help to answer this one. >Following a previous review actually I dropped this power-states >compatible, to stick with idle-states. > I didnt want this to be ARM specific. An arm,idle-state is too specific to be reused for generic PM domains, hence this compatible. We dont need a compatible property, but I thought it would be nice to have the property to give structure to the power state node. >> >>>+ >>>+==Power state== >>>+ >>>+A PM domain power state describes an idle state of a domain and must be >>>+have the following properties - >>>+ >>>+ - compatible >>>+ Usage: Required >>>+ Value type: >>>+ Definition: Must be "linux,domain-state" >> >>Why do you need a compatible string? >> >>You already have the phandle available, I suppose you can use that >>instead of parsing for a new compatible string. >> Hmm.. okay. >>>+ >>>+ - entry-latency-us >>>+ Usage: Not required if wakeup-latency-us is provided. >>>+ Value type: >>>+ Definition: u32 value representing worst case latency in >>>+ microseconds required to enter the idle state. >>>+ The exit-latency-us duration may be guaranteed >>>+ only after entry-latency-us has passed. >>>+ >>>+ - exit-latency-us >>>+ Usage: Not required if wakeup-latency-us is provided. >>>+ Value type: >>>+ Definition: u32 value representing worst case latency >>>+ in microseconds required to exit the idle state. >>>+ >>>+ - wakeup-latency-us: >>>+ Usage: Not required if entry-latency-us and exit-latency-us >>>+ are provided. >>>+ Value type: >>>+ Definition: u32 value representing maximum delay between the >>>+ signaling the wakeup of the domain and the domain resuming >>>+ regular operation. >>>+ If omitted, this is assumed to be equal to: >>>+ entry-latency-us + exit-latency-us >> >>I think we should decide which of the two alternatives to use, we >>shouldn't make it more complicated than needed. > >Agreed. > I like the entry + exit option. Thanks, Lina