From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751701AbcFYPxz (ORCPT ); Sat, 25 Jun 2016 11:53:55 -0400 Received: from mail-pf0-f173.google.com ([209.85.192.173]:36438 "EHLO mail-pf0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751541AbcFYPxx (ORCPT ); Sat, 25 Jun 2016 11:53:53 -0400 Date: Sat, 25 Jun 2016 08:53:49 -0700 From: Dmitry Torokhov To: Neil Armstrong Cc: andy.gross@linaro.org, david.brown@linaro.org, lee.jones@linaro.org, lgirdwood@gmail.com, broonie@kernel.org, a.zummo@towertech.it, alexandre.belloni@free-electrons.com, linux-input@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org, rtc-linux@googlegroups.com, Rob Herring Subject: Re: [PATCH v2 2/5] input: pmic8xxx-pwrkey: Add support for pm8018 pwrkey Message-ID: <20160625155349.GD17812@dtor-ws> References: <1466759887-25394-1-git-send-email-narmstrong@baylibre.com> <1466759887-25394-3-git-send-email-narmstrong@baylibre.com> <20160624220748.GB11719@dtor-ws> <576E41FC.1080102@baylibre.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <576E41FC.1080102@baylibre.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 25, 2016 at 10:34:04AM +0200, Neil Armstrong wrote: > On 06/25/2016 12:07 AM, Dmitry Torokhov wrote: > > On Fri, Jun 24, 2016 at 11:18:04AM +0200, Neil Armstrong wrote: > >> In order to support pwrkey for Qualcomm MDM9615 SoC, add support > >> for the pm8018 pwrkey in pmic8xxx-pwrkey. > >> > >> Reviewed-by: Bjorn Andersson > >> Signed-off-by: Neil Armstrong > > > > NAK. > > Hi Dmitry, > > Actually, the new compatible string make sense, because the driver is compatible with the > "pm8018" pwrkey but from a system point of view, it's not a pm8921 pwrkey, hence the new > compatible string. A lot of systems note this fact in DTS, but not require driver changes, by specifying several compatible strings: compatible = "nvidia,tegra114-sdhci", "nvidia,tegra30-sdhci"; compatible = "fsl,imx6q-i2c", "fsl,imx21-i2c"; compatible = "rockchip,rk3036-timer", "rockchip,rk3288-timer"; > > Rob Herring was very clear with me with this policy, and it will simplify further driver Could I get a pointer to this discussion so I can educate myself better about DT policies? > architecture change since it will not imply devicetree changes anymore. Would we need the driver changes? What are the differences in power key functionality between 8018 and 8921? > > My point of view is that the devicetree describes the hardware and need to have SoC specific > compatible string since it describes the actual silicon, and drivers must make sure to handle > all the SoC or family variants using the compatible string and the match data. No, the compatible string means that the hardware is *compatible* with something. It does not mean that we need to adjust driver every time a company pumps out a new package including said hardware. Thanks. -- Dmitry