From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH v2 0/7] Change snvs rtc and poweroff to use syscon add pwrkey driver Date: Wed, 20 May 2015 17:20:43 -0700 Message-ID: <20150521002043.GI23809@dtor-ws> References: <1432055082-28983-1-git-send-email-Frank.Li@freescale.com> <20150520015851.GB1071@dragon> <20150520182540.GQ2067@n2100.arm.linux.org.uk> <20150520183050.GR2067@n2100.arm.linux.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20150520183050.GR2067@n2100.arm.linux.org.uk> Sender: linux-pm-owner@vger.kernel.org To: Russell King - ARM Linux Cc: Shawn Guo , a.zummo@towertech.it, Frank.Li@freescale.com, rtc-linux@googlegroups.com, linux-pm@vger.kernel.org, devicetree@vger.kernel.org, robh+dt@kernel.org, alexandre.belloni@free-electrons.com, p.zabel@pengutronix.de, linux-input@vger.kernel.org, lznuaa@gmail.com, shawn.guo@linaro.org, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On Wed, May 20, 2015 at 07:30:50PM +0100, Russell King - ARM Linux wrote: > On Wed, May 20, 2015 at 07:25:41PM +0100, Russell King - ARM Linux wrote: > > On Wed, May 20, 2015 at 09:58:51AM +0800, Shawn Guo wrote: > > > On Wed, May 20, 2015 at 01:04:35AM +0800, Frank.Li@freescale.com wrote: > > > > Frank Li (6): > > > > arm: imx: power-off: change to syscon to access register > > > > rtc: arm: imx: snvs: change use syscon to access register > > > > Document: dt: fsl: snvs: change support syscon > > > > arm: dts: imx: update snvs to use syscon access register > > > > document: devicetree: input: imx: i.mx snvs power device tree bindings > > > > arm: dts: imx6sx: enable snvs power key > > > > > > So, the series will break existing DTBs for RTC and poweroff, right? > > > If this is unavoidable, should we at least have some warning messages > > > telling users about his breakage? > > > > What's the justification for breaking existing DTBs? Really, this is > > something we should strive to avoid, _and_ actually avoid by providing > > backwards compatibility. > > Looking at the RTC code, it would be pretty trivial to do. > > Rather than passing around struct regmap, pass around the private data > structure. > > Rename the regmap_* function calls to be private accessors. Implement > a set of new accessors - if the private data has the regmap, use the > regmap API. Otherwise, use the old method, and print a warning that an > old DT is being used. Or maybe have drivers create regmap themselves if they see old DTS and not bother with the 2 sets of accessors? Thanks. -- Dmitry