From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752420AbbJNI16 (ORCPT ); Wed, 14 Oct 2015 04:27:58 -0400 Received: from lists.s-osg.org ([54.187.51.154]:52599 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751533AbbJNI1z (ORCPT ); Wed, 14 Oct 2015 04:27:55 -0400 Subject: Re: [PATCH 3/4] ARM: multi_v7_defconfig: Enable Maxim 8997 family drivers To: Krzysztof Kozlowski , Javier Martinez Canillas References: <1444699628-3774-1-git-send-email-k.kozlowski@samsung.com> <1444699628-3774-3-git-send-email-k.kozlowski@samsung.com> <561D04BB.1080406@samsung.com> Cc: k.kozlowski.k@gmail.com, Kukjin Kim , "linux-arm-kernel@lists.infradead.org" , "linux-samsung-soc@vger.kernel.org" , Linux Kernel , Arnd Bergmann , Olof Johansson , Kevin Hilman From: Javier Martinez Canillas X-Enigmail-Draft-Status: N1110 Message-ID: <561E1205.1040203@osg.samsung.com> Date: Wed, 14 Oct 2015 10:27:49 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <561D04BB.1080406@samsung.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Krzysztof, On 10/13/2015 03:18 PM, Krzysztof Kozlowski wrote: > W dniu 13.10.2015 o 17:36, Javier Martinez Canillas pisze: >> Hello Krzysztof, >> >> On Tue, Oct 13, 2015 at 3:27 AM, Krzysztof Kozlowski >> wrote: >>> Enable support for Maxim 8997 Multi Function Device present on Trats and >>> Origen boards by toggling on drivers: main MFD, charger, haptic motor, >>> regulator, LED and RTC. >>> >>> This allows to test and usage of these boards with multi_v7 config. >>> >>> Signed-off-by: Krzysztof Kozlowski >>> --- >> >> [snip] >> >>> CONFIG_MFD_MAX77686=y >>> CONFIG_MFD_MAX77693=y >>> CONFIG_MFD_MAX8907=y >>> +CONFIG_MFD_MAX8997=y >> >> Only slightly related with your patch but some of the MFD driver for >> PMICs used in Exynos boards (like MAX77686) have a tristate Kconfig >> symbol while others like this one have a boolean. Do you know if there >> are any restrictions w.r.t build this as module or is just an >> arbitrary decision? I'm asking since probably we should either allow >> this to build as a module or convert the others to boolean. > > First, thanks for reviewing the patches. > You are welcome. > As for the question, I wasn't involved in development of these older > drivers for older boards. I don't know their internals. AFAIK there were > no specific restrictions, except the usual: > > 1. Not all other drivers using resources provided by these, took the > reference to given resource (e.g. get regulator). > > 2. Not all consumer drivers supported deferred probe for given resource > (e.g. regulator, clock), see: "regulators: max77693: register driver > earlier to avoid deferred probe". In general USB gadget subsystem has > this issue. Actually the mentioned max77693 regulator driver should be > changed from tristate to built-in because of this. > > I don't remember any other important issues so if you fix 1 and 2 then > this can be probably safely switched to modules. Of course after testing. > Thanks for the explanation. I neither plan to fix these issues nor changing these symbols to tristate since I don't have access to the hardware to test. I asked mostly because I was curious and to know if I should change the MFD drivers to boolean for the PMIC present in boards I have access, to make it consistent. But as you said is the other way around, that it would be good to allow these drivers to be built as a module. > Best regards, > Krzysztof > > -- Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America