From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751459AbeEVSIm (ORCPT ); Tue, 22 May 2018 14:08:42 -0400 Received: from mail-yw0-f195.google.com ([209.85.161.195]:44035 "EHLO mail-yw0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751278AbeEVSIk (ORCPT ); Tue, 22 May 2018 14:08:40 -0400 X-Google-Smtp-Source: AB8JxZr1lhXK+XxTk7s0hAY13IF7Jo0uHJ7Woa/Qz94aqVOg37hXKCE0D8wxaL0qU2wJ+brUDlhvcg== Date: Tue, 22 May 2018 13:08:38 -0500 From: Rob Herring To: Saravana Kannan Cc: MyungJoo Ham , Kyungmin Park , Chanwoo Choi , Mark Rutland , Rajendra Nayak , Amit Kucheria , linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] PM / devfreq: Add support for QCOM devfreq firmware Message-ID: <20180522180838.GA13423@rob-hp-laptop> References: <1526629965-28729-1-git-send-email-skannan@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1526629965-28729-1-git-send-email-skannan@codeaurora.org> User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 18, 2018 at 12:52:40AM -0700, Saravana Kannan wrote: > The firmware present in some QCOM chipsets offloads the steps necessary for > changing the frequency of some devices (Eg: L3). This driver implements the > devfreq interface for this firmware so that various governors could be used > to scale the frequency of these devices. > > Each client (say cluster 0 and cluster 1) that wants to vote for a > particular device's frequency (say, L3 frequency) is represented as a > separate voter device (qcom,devfreq-fw-voter) that's a child of the > firmware device (qcom,devfreq-fw). > > Signed-off-by: Saravana Kannan > --- > .../bindings/devfreq/devfreq-qcom-fw.txt | 41 +++ > drivers/devfreq/Kconfig | 14 + > drivers/devfreq/Makefile | 1 + > drivers/devfreq/devfreq_qcom_fw.c | 330 +++++++++++++++++++++ > 4 files changed, 386 insertions(+) > create mode 100644 Documentation/devicetree/bindings/devfreq/devfreq-qcom-fw.txt > create mode 100644 drivers/devfreq/devfreq_qcom_fw.c > > diff --git a/Documentation/devicetree/bindings/devfreq/devfreq-qcom-fw.txt b/Documentation/devicetree/bindings/devfreq/devfreq-qcom-fw.txt > new file mode 100644 > index 0000000..f882a0b > --- /dev/null > +++ b/Documentation/devicetree/bindings/devfreq/devfreq-qcom-fw.txt > @@ -0,0 +1,41 @@ > +QCOM Devfreq firmware device > + > +Some Qualcomm Technologies, Inc. (QTI) chipsets have a firmware that > +offloads the steps for frequency switching. It provides a table of > +supported frequencies and a register to request one of the supported > +freqencies. > + > +The qcom,devfreq-fw represents this firmware as a device. Sometimes, > +multiple entities want to vote on the frequency request that is sent to the > +firmware. The qcom,devfreq-fw-voter represents these voters as child > +devices of the corresponding qcom,devfreq-fw device. > + > +Required properties: > +- compatible: Must be "qcom,devfreq-fw" or "qcom,devfreq-fw-voter" No versions of firmware? > +Only for qcom,devfreq-fw: > +- reg: Pairs of physical base addresses and region sizes of > + memory mapped registers. Registers? Is this firmware or h/w block? > +- reg-names: Names of the bases for the above registers. > + Required register regions are: > + - "en-base": address of register to check if the > + firmware is enabled. > + - "ftbl-base": address region for the frequency > + table. > + - "perf-base": address of register to request a > + frequency. > + > +Example: > + > + qcom,devfreq-l3 { > + compatible = "qcom,devfreq-fw"; > + reg-names = "en-base", "ftbl-base", "perf-base"; > + reg = <0x18321000 0x4>, <0x18321110 0x600>, <0x18321920 0x4>; > + > + qcom,cpu0-l3 { > + compatible = "qcom,devfreq-fw-voter"; There's no point in these nodes. They don't have any properties or resources. > + }; > + > + qcom,cpu4-l3 { > + compatible = "qcom,devfreq-fw-voter"; > + }; > + };