From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757239Ab3HGQiJ (ORCPT ); Wed, 7 Aug 2013 12:38:09 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:43462 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757082Ab3HGQiG (ORCPT ); Wed, 7 Aug 2013 12:38:06 -0400 Date: Wed, 7 Aug 2013 17:38:04 +0100 From: Mark Rutland To: Laxman Dewangan Cc: "akpm@linux-foundation.org" , "grant.likely@linaro.org" , "rob.herring@calxeda.com" , "rob@landley.net" , "devicetree@vger.kernel.org" , "linux-doc@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "rtc-linux@googlegroups.com" , "gg@slimlogic.co.uk" , "kishon@ti.com" , "swarren@nvidia.com" , Pawel Moll , "ian.campbell@citrix.com" , "broonie@kernel.org" Subject: Re: [PATCH V4] drivers/rtc/rtc-palmas.c: support for backup battery charging Message-ID: <20130807163804.GL28558@e106331-lin.cambridge.arm.com> References: <1375871392-871-1-git-send-email-ldewangan@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1375871392-871-1-git-send-email-ldewangan@nvidia.com> User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 07, 2013 at 11:29:52AM +0100, Laxman Dewangan wrote: > Palmas series device like TPS65913, TPS80036 supports the backup battery > for powering the RTC when no other energy source is available. > > The backup battery is optional, connected to the VBACKUP pin, and can be > nonrechargeable or rechargeable. The rechargeable battery can be charged > from the system supply using the backup battery charger. > > Add support for enabling charging of this backup battery. Also add the DT > binding document and the new properties to have this support. > > Signed-off-by: Laxman Dewangan > Reviewed-by: Stephen Warren > Reviewed-by: Felipe Balbi > --- > Changes from V1: > - Converted DT property to boolean. > - cleanups as use "...". > Changes from V2: > - Correct the property name. > Changes from V3: > - Nit cleanups: properly capatilise the palmas to make it Palmas. > - Added reviewed by of Felipe and Stephen. > > .../devicetree/bindings/rtc/rtc-palmas.txt | 29 ++++++++++++++++ > drivers/rtc/rtc-palmas.c | 35 ++++++++++++++++++++ > 2 files changed, 64 insertions(+), 0 deletions(-) > create mode 100644 Documentation/devicetree/bindings/rtc/rtc-palmas.txt > > diff --git a/Documentation/devicetree/bindings/rtc/rtc-palmas.txt b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt > new file mode 100644 > index 0000000..41bb445 > --- /dev/null > +++ b/Documentation/devicetree/bindings/rtc/rtc-palmas.txt > @@ -0,0 +1,29 @@ > +Palmas RTC controller bindings > + > +Required properties: > +- compatible: > + - "ti,palmas-rtc" for Palmas series of the RTC controller > +- interrupt-parent: Parent interrupt device, must be handle of Palmas node. > +- interrupts: Interrupt number of RTC submodule on device. > + > +Optional properties: > +- ti,back-battery-charge-enable: The Palmas series device like TPS65913 or > + TPS80036 supports the battery backup for powering the RTC when main > + battery is removed or in very low power state. This flag will enable > + the backup battery charging. I don't like the wording here as it implies that an OS *must* charge the device, rather than that it *can* charge the device. How about: - ti,backup-battery-chargeable: There is a chargeable backup battery present. > +- ti,back-battery-charge-low-current: Configure lower charging current. Device > + supports the charging current as < 100mA or >100mA. Low current will > + set as <100mA. This is somewhat unclear as it reads as a runtime configuration choice, rather than some instances of the device only support being changed at low currents (as I assume is the case?). How about: - ti,backup-battery-low-current: The backup battery is only chargeable at currents below 100mA. What happens if we charge at the wrong current? Thanks, Mark.