From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752756AbdECNyq (ORCPT ); Wed, 3 May 2017 09:54:46 -0400 Received: from lelnx194.ext.ti.com ([198.47.27.80]:28973 "EHLO lelnx194.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752165AbdECNyj (ORCPT ); Wed, 3 May 2017 09:54:39 -0400 Subject: Re: [PATCH 1/1] ARM: dts: dra7: Reduce cpu thermal shutdown temperature To: "bcousson@baylibre.com" , "tony@atomide.com" References: <20170412062442.17736-1-rk@ti.com> CC: "robh+dt@kernel.org" , "mark.rutland@arm.com" , "linux-omap@vger.kernel.org" , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" From: Ravikumar Message-ID: Date: Wed, 3 May 2017 19:27:40 +0530 User-Agent: Mozilla/5.0 (X11; Linux i686; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <20170412062442.17736-1-rk@ti.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Wednesday 12 April 2017 11:54 AM, Kattekola, Ravikumar wrote: > On dra7, as per TRM, the HW shutdown (TSHUT) temperature is hardcoded > to 123C and cannot be modified by SW. This means when the temperature > reaches 123C HW asserts TSHUT output which signals a warm reset. > This reset is held until the temperature goes below the TSHUT low (105C). > > While in SW, the thermal driver continuously monitors current temperature > and takes decisions based on whether it reached an alert or a critical point. > The intention of setting a SW critical point is to prevent force reset by HW > and instead do an orderly_poweroff(). But if the SW critical temperature is > greater than or equal to that of HW then it defeats the purpose. To address > this and let SW take action before HW does keep the SW critical temperature > less than HW TSHUT value. > > The value for SW critical temperature was chosen as 120C just to ensure > we give SW sometime before HW catches up. > > Document reference > SPRUI30C – DRA75x, DRA74x Technical Reference Manual - November 2016 > SPRUHZ6H - AM572x Technical Reference Manual - November 2016 > > Tested on: > DRA75x PG 2.0 Rev H EVM > > Signed-off-by: Ravikumar Kattekola > --- > arch/arm/boot/dts/dra7.dtsi | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/arch/arm/boot/dts/dra7.dtsi b/arch/arm/boot/dts/dra7.dtsi > index 57892f2..e714466 100644 > --- a/arch/arm/boot/dts/dra7.dtsi > +++ b/arch/arm/boot/dts/dra7.dtsi > @@ -2017,4 +2017,8 @@ > coefficients = <0 2000>; > }; > > +&cpu_crit { > + temperature = <120000>; /* milli Celsius */ > +}; > + > /include/ "dra7xx-clocks.dtsi" Ping.. Any comments? Regards, RK