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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 7905DC43603 for ; Fri, 20 Dec 2019 15:49:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 58E7A21D7D for ; Fri, 20 Dec 2019 15:49:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727362AbfLTPtt (ORCPT ); Fri, 20 Dec 2019 10:49:49 -0500 Received: from mga11.intel.com ([192.55.52.93]:27460 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727270AbfLTPtt (ORCPT ); Fri, 20 Dec 2019 10:49:49 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Dec 2019 07:49:36 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,336,1571727600"; d="scan'208";a="267551905" Received: from pkriegsm-mobl.amr.corp.intel.com (HELO [10.252.132.172]) ([10.252.132.172]) by FMSMGA003.fm.intel.com with ESMTP; 20 Dec 2019 07:49:34 -0800 Subject: Re: [alsa-devel] [PATCH v6 02/11] mfd: wcd934x: add support to wcd9340/wcd9341 codec To: Srinivas Kandagatla , broonie@kernel.org, lee.jones@linaro.org, linus.walleij@linaro.org Cc: robh@kernel.org, alsa-devel@alsa-project.org, bgoswami@codeaurora.org, vinod.koul@linaro.org, devicetree@vger.kernel.org, spapothi@codeaurora.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org References: <20191219103153.14875-1-srinivas.kandagatla@linaro.org> <20191219103153.14875-3-srinivas.kandagatla@linaro.org> <4492b71e-9923-365c-f22c-3766e2d5bae2@linux.intel.com> <3fa4997f-4409-97f6-ba10-a87013383eb7@linaro.org> From: Pierre-Louis Bossart Message-ID: Date: Fri, 20 Dec 2019 09:22:48 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.2.2 MIME-Version: 1.0 In-Reply-To: <3fa4997f-4409-97f6-ba10-a87013383eb7@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org >>> Note these are the child devices of the MFD SLIMBus device. >> >> Ah ok. I guess the creation of those child devices when the parent >> SLIMbus device reports PRESENT initially if fine, it's the part where >> you remove them if the device loses sync or gets powered off which is >> odd. And I guess technically you could still have race conditions >> where a child device starts a transaction just as the parent is no >> longer attached to the bus. > > Losing power to SLIMBus device is very odd usecase and if it happens > suggests that threre are bigger issues on the board design itself. This > case should never happen. Even if it happens we would get timeout errors > on every SLIMbus transactions. > >> >>>> I would however not remove the devices when the status is down but >>>> only on an explicit .remove. >>> >>> Am open for suggestions but I would not like the child devices to >>> talk on the bus once the SLIMbus device is down! Only way to ensure >>> or make it silent is to remove. >> >> it's as if you are missing a mechanism to forward the parent status to >> the children so use remove() for lack of a better solution? > That is true. This gives bit more control on the slave device lifecycle. > Current solution works fine for now with less complexities across > multiple drivers. I also agree that there is scope of improvement in > future for this. ok, makes sense, thanks for the answers. No further questions, so Reviewed-by: Pierre-Louis Bossart