From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757135Ab3JKH1H (ORCPT ); Fri, 11 Oct 2013 03:27:07 -0400 Received: from mail-wg0-f49.google.com ([74.125.82.49]:62137 "EHLO mail-wg0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756351Ab3JKH1E convert rfc822-to-8bit (ORCPT ); Fri, 11 Oct 2013 03:27:04 -0400 MIME-Version: 1.0 In-Reply-To: <5257A0C0.8000701@ti.com> References: <1381402195-29257-1-git-send-email-kishon@ti.com> <20131010141949.GA13277@kahuna> <52579723.6080209@ti.com> <5257A05B.2070906@ti.com> <5257A0C0.8000701@ti.com> Date: Fri, 11 Oct 2013 02:27:02 -0500 X-Google-Sender-Auth: TJn5X7kQu56yLIA42sdRGAI5KrQ Message-ID: Subject: Re: [PATCH 1/2] ARM: dts: omap5-uevm: remove always_on, boot_on from smps10_out1 From: Nishanth Menon To: Kishon Vijay Abraham I Cc: Mark Rutland , dt list , Russell King - ARM Linux , Pawel Moll , "ijc+devicetree@hellion.org.uk" , Tony Lindgren , Stephen Warren , lkml , Rob Herring , Benoit Cousson , linux-omap , "linux-arm-kernel@lists.infradead.org" Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 11, 2013 at 1:54 AM, Kishon Vijay Abraham I wrote: > On Friday 11 October 2013 12:23 PM, Kishon Vijay Abraham I wrote: >> Hi, >> >> On Friday 11 October 2013 12:00 PM, Nishanth Menon wrote: >>> On Fri, Oct 11, 2013 at 1:13 AM, Kishon Vijay Abraham I wrote: >>>> >>>>> regulator-boot-on indicates that PMIC enables it by default as part of >>>>> OTP or some internal behavior -> Looking at the measurements done on >>>>> uEVM and OTP information -> regulator-boot-on should be kept here. >>>> >>>> No. Actually I don’t want PMIC to enable it by default. I want the palmas-usb >>>> driver to handle it. >>>> Enabling it by default makes palmas-usb to detect VBUS interrupt. This should >>>> ideally be detected only when you connect a host cable. >>>> Btw I didn't exactly get why you want regulator-boot-on should be kept here. >>> >>> binding description states: >>> - regulator-boot-on: bootloader/firmware enabled regulator >>> Further info: include/linux/regulator/machine.h >>> * @boot_on: Set if the regulator is enabled when the system is initially >>> * started. If the regulator is not enabled by the hardware or >>> * bootloader then it will be enabled when the constraints are >>> * applied. >>> >>> What that means is that it is enabled by firmware/bootloader (in our >>> case One Time Program {OTP} inside Palmas) when the system switches on >>> even before the kernel starts. and we know SMPS10 is autoenabled by >>> Palmas OTP configuration even before first instruction in A15 >>> executes. >> >> Not sure about that. Please note SMPS10 has two outputs OUT1 and OUT2 and I >> tend to think that it might be OUT2 that's getting enabled by the OTP. >>> >>> I think you misunderstand this to mean that you'd like the regulator >>> to be *switched on* automatically at kernel boot by regulator >>> framework - there is no reasoning why we'd want such a binding since >>> we'd expect drivers to do their job of requesting and enabling >>> regulators on need.. >> >> The comment you just quoted tells it enables the regulator if its not enabled >> by hardware. "If the regulator is not enabled by the hardware or bootloader >> then it will be enabled when the constraints are applied." At-least that's what >> I understood from that comment. >> >> Also from our experiments it doesn't look like SMPS10_OUT1 is enabled by the >> OTP and it gets enabled when we have *regulator-boot-on* constraints. > > btw.. I think this is the code in regulator fw that's responsible for enabling.. > > /* If the constraints say the regulator should be on at this point > * and we have control then make sure it is enabled. > */ > if ((rdev->constraints->always_on || rdev->constraints->boot_on) && > ops->enable) { > ret = ops->enable(rdev); > if (ret < 0) { > rdev_err(rdev, "failed to enable\n"); > goto out; > } > } Drat, you are right, I did not really dig deep. thanks for correcting my understanding here. I propose the following change in binding as it seems completely misleading to me. diff --git a/Documentation/devicetree/bindings/regulator/regulator.txt b/Documentation/devicetree/bindings/regulator/regulator.txt index 2bd8f09..d999f096 100644 --- a/Documentation/devicetree/bindings/regulator/regulator.txt +++ b/Documentation/devicetree/bindings/regulator/regulator.txt @@ -8,7 +8,9 @@ Optional properties: - regulator-min-microamp: smallest current consumers may set - regulator-max-microamp: largest current consumers may set - regulator-always-on: boolean, regulator should never be disabled -- regulator-boot-on: bootloader/firmware enabled regulator +- regulator-boot-on: regulator is enabled when the system is initially started. + If the regulator is not enabled by the hardware or bootloader then it will be + enabled when the constraints are applied. - regulator-allow-bypass: allow the regulator to go into bypass mode - -supply: phandle to the parent supply/regulator node - regulator-ramp-delay: ramp delay for regulator(in uV/uS)