From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.3 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C8A01C433E0 for ; Mon, 27 Jul 2020 09:46:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A03E42074F for ; Mon, 27 Jul 2020 09:46:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="bmiSU3rf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726196AbgG0JqD (ORCPT ); Mon, 27 Jul 2020 05:46:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50486 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726140AbgG0JqD (ORCPT ); Mon, 27 Jul 2020 05:46:03 -0400 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9CC07C061794; Mon, 27 Jul 2020 02:46:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=ICcPARetP40zUorjS7dcYCqx0YJx8qUK4R318qaC2G4=; b=bmiSU3rfKiA+hjvdrfEZbldwW 5o7JEI+ATlaX78/5TW8fpGu0LNJ+qrq8e0gLOjeveOBJFNPTW+En2OI8jcR7tn74XRZOtTxPZq1v/ r/lq0lubttsxW+uEBNMX8IN2w9/bzzld/gcjAeGhTWtq1E2BeaOJcieMKeXlg4QgL2fSmlJbf18b1 nNAZPtkIJCLCKJlS4dR5rCoAuiHTbwZB5Z2azfdLRZebMVYTfFPkP0F46qGPc7G4Ugn8nUMP3Ftrx Trxb46LgvkYjjBF9KyiQMb6I9FleJ/KqHVB8tZ5aR/cnF8bNAUDP1Ak2DsFnGdveBhrIZIzumCb9C ehG6V1cCQ==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:44750) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jzzhj-0002fr-Sw; Mon, 27 Jul 2020 10:45:55 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1jzzhh-0003Yi-Sb; Mon, 27 Jul 2020 10:45:53 +0100 Date: Mon, 27 Jul 2020 10:45:53 +0100 From: Russell King - ARM Linux admin To: Alexandre Belloni Cc: Rob Herring , miguelborgesdefreitas@gmail.com, a.zummo@towertech.it, baruch@tkos.co.il, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/3] dt-bindings: rtc: pcf8523: add DSM pm option for battery switch-over Message-ID: <20200727094553.GH1551@shell.armlinux.org.uk> References: <20200719145028.3370-3-miguelborgesdefreitas@gmail.com> <20200720112401.4620-1-miguelborgesdefreitas@gmail.com> <20200720112401.4620-2-miguelborgesdefreitas@gmail.com> <20200723174905.GA596242@bogus> <20200723195755.GV3428@piout.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200723195755.GV3428@piout.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: devicetree-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: devicetree@vger.kernel.org On Thu, Jul 23, 2020 at 09:57:55PM +0200, Alexandre Belloni wrote: > On 23/07/2020 11:49:05-0600, Rob Herring wrote: > > On Mon, Jul 20, 2020 at 12:23:59PM +0100, miguelborgesdefreitas@gmail.com wrote: > > > From: Miguel Borges de Freitas > > > > > > This adds direct-switching mode as a configurable DT flag for > > > RTC modules supporting it (e.g. nxp pcf8523). > > > DSM switches the power source to the battery supply whenever the > > > VDD drops below VBAT. The option is recommended for hw designs > > > where VDD is always expected to be higher than VBAT. > > > > > > Signed-off-by: Miguel Borges de Freitas > > > --- > > > Changes in v2: > > > - Added extended commit message for git history > > > - Separate dt bindings documentation into a single patch > > > > > > Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt | 7 ++++++- > > > Documentation/devicetree/bindings/rtc/rtc.yaml | 7 +++++++ > > > 2 files changed, 13 insertions(+), 1 deletion(-) > > > > > > diff --git a/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt b/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt > > > index 0b1080c..f715a8f 100644 > > > --- a/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt > > > +++ b/Documentation/devicetree/bindings/rtc/nxp,pcf8523.txt > > > @@ -4,10 +4,14 @@ Required properties: > > > - compatible: Should contain "nxp,pcf8523". > > > - reg: I2C address for chip. > > > > > > -Optional property: > > > +Optional properties: > > > - quartz-load-femtofarads: The capacitive load of the quartz(x-tal), > > > expressed in femto Farad (fF). Valid values are 7000 and 12500. > > > Default value (if no value is specified) is 12500fF. > > > +- pm-enable-dsm: battery switch-over function is enabled in direct > > > + switching mode. The power failure condition happens when VDD < VBAT, > > > + without requiring VDD to drop below Vth(sw)bat. > > > + Default value (if not provided) is the standard mode. > > > > > > Example: > > > > > > @@ -15,4 +19,5 @@ pcf8523: rtc@68 { > > > compatible = "nxp,pcf8523"; > > > reg = <0x68>; > > > quartz-load-femtofarads = <7000>; > > > + pm-enable-dsm; > > > }; > > > diff --git a/Documentation/devicetree/bindings/rtc/rtc.yaml b/Documentation/devicetree/bindings/rtc/rtc.yaml > > > index ee237b2..a0048f4 100644 > > > --- a/Documentation/devicetree/bindings/rtc/rtc.yaml > > > +++ b/Documentation/devicetree/bindings/rtc/rtc.yaml > > > @@ -47,4 +47,11 @@ properties: > > > description: > > > Enables wake up of host system on alarm. > > > > > > + pm-enable-dsm: > > > + $ref: /schemas/types.yaml#/definitions/flag > > > + description: > > > + Enables the battery switch-over function in direct switching > > > + mode. Should be set in systems where VDD is higher than VBAT > > > + at all times. > > > > I'm all for common properties, but is this common across vendors? > > > > This is but this shouldn't be a DT property as it has to be changed > dynamically. I'm working on an ioctl interface to change this > configuration. Why does it need to be changed dynamically? If the hardware components are not fitted to allow the RTC to be safely used without DSM, then why should userspace be able to disable DSM? -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!