From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Subject: Re: [RFC PATCH v2 09/17] ARM: dts: tegra20: harmony: Setup voltage regulators for DVFS Date: Mon, 22 Oct 2018 09:33:23 -0600 Message-ID: References: <20181021205501.23943-1-digetx@gmail.com> <20181021205501.23943-10-digetx@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20181021205501.23943-10-digetx@gmail.com> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org To: Dmitry Osipenko Cc: "Rafael J. Wysocki" , Viresh Kumar , Rob Herring , Thierry Reding , Jonathan Hunter , Nishanth Menon , Stephen Boyd , Marcel Ziswiler , linux-tegra@vger.kernel.org, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: devicetree@vger.kernel.org On 10/21/18 2:54 PM, Dmitry Osipenko wrote: > Set min/max regulators voltage and add CPU node that hooks up CPU with > voltage regulators. > diff --git a/arch/arm/boot/dts/tegra20-harmony.dts b/arch/arm/boot/dts/tegra20-harmony.dts > - sm0 { > + core_vdd_reg: sm0 { > regulator-name = "vdd_sm0,vdd_core"; > - regulator-min-microvolt = <1200000>; > - regulator-max-microvolt = <1200000>; > + regulator-min-microvolt = <1000000>; > + regulator-max-microvolt = <1300000>; > + regulator-coupled-with = <&rtc_vdd_reg>; > + regulator-coupled-max-spread = <150000>; > regulator-always-on; > }; How do you know for sure that these increased ranges are safe (high end) and stable (low end) for this particular board? IIRC the safe/legal range depends on the chip SKU, and to be honest I have no idea which SKU is present on Harmony... For public boards like Colibri I imagine there's enough information out there to tell what will work, but maybe not our internal boards like Harmony, unless you checked our ancient downstream kernels?