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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 93C39CD37A9 for ; Tue, 3 Sep 2024 16:21:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=TOEHRL0jTkqVJGqC1aF4rVCGmks2TS1OH/JK8xFsn/A=; b=ZuwgmFDEkTEXZ+udIOeJ1S8b5X nEMte5kzKUNnfr2CAZAnSFUkgWrVmvrL50Jcfw1voumGtZx6kBwq9qyxFiKcY1hU8o0tmth1dZrst ILo6RRO5n8ZCNBHIMX5brOJHAguufuu//19thFwsAyRNTpIoOx2EarkfDSCEi5O2KMrKDUTka5XXl 588BMg8xFZSmIyGuP31CEWYBnGh8afvoL0NoLlLx7RwhJfve1mDkGcTuGEPOLgJ8RZgX9vr1GLbcV lbFt/fMmG6EHgH7jXvwISlMO3c9A8Tn2vnRujq9pVA5smMFSnvvdyWBk7qeq75KV3DMj4MRHbNplf U+dyh1bg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1slWHg-000000014dB-396i; Tue, 03 Sep 2024 16:21:36 +0000 Received: from relay3-d.mail.gandi.net ([2001:4b98:dc4:8::223]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1slVy7-00000000zte-3PQM for linux-arm-kernel@lists.infradead.org; Tue, 03 Sep 2024 16:01:26 +0000 Received: by mail.gandi.net (Postfix) with ESMTPSA id 1695160003; Tue, 3 Sep 2024 16:01:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1725379280; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=TOEHRL0jTkqVJGqC1aF4rVCGmks2TS1OH/JK8xFsn/A=; b=c+Fmen+107aZTxRPesX1RF0jOVv9G1jUVeZALqhujtGQggZXA7w9Up9m2Q8ybdjodWqpK/ WM+uKhy6OpKV6HrweUA8FA5wjh1QA4ljeH5VoAYJufX0f/z2nnBTXwYrToXqs1C6F+bImD 5sTuQ+ub2E9GLdELHmZb3HsAWADILFlGNR7iAqLPdUT8Op+8sURREaOQMQUB+pVoRnomcC 9AFaVAkqVi6FG/bVN/dETRKnJQslq7jw3IMydXJa50GsULYLzKRSh2TZ+KTyDH+JPYbZ+X O8MRC1YafAcQsnU92sLa/Cw2YKVTqNXq6U/J/ePSLIaPIRFXW8NdkjdTCbAoFg== Date: Tue, 3 Sep 2024 18:01:16 +0200 From: Herve Codina To: Lee Jones Cc: Geert Uytterhoeven , Andy Shevchenko , Simon Horman , Arnd Bergmann , Derek Kiernan , Dragan Cvetic , Greg Kroah-Hartman , Bjorn Helgaas , Philipp Zabel , Lars Povlsen , Steen Hegelund , Daniel Machon , UNGLinuxDriver@microchip.com, Rob Herring , Saravana Kannan , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Horatiu Vultur , Andrew Lunn , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, Allan Nielsen , Luca Ceresoli , Thomas Petazzoni , =?UTF-8?B?Q2zDqW1lbnQgTMOpZ2Vy?= Subject: Re: [PATCH v5 3/8] mfd: syscon: Add reference counting and device managed support Message-ID: <20240903180116.717a499b@bootlin.com> In-Reply-To: <20240903153839.GB6858@google.com> References: <20240808154658.247873-1-herve.codina@bootlin.com> <20240808154658.247873-4-herve.codina@bootlin.com> <20240903153839.GB6858@google.com> Organization: Bootlin X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-GND-Sasl: herve.codina@bootlin.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240903_090124_510541_4BF08DC2 X-CRM114-Status: GOOD ( 22.63 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi Lee, On Tue, 3 Sep 2024 16:38:39 +0100 Lee Jones wrote: > On Thu, 08 Aug 2024, Herve Codina wrote: > > > From: Clément Léger > > > > Syscon releasing is not supported. > > Without release function, unbinding a driver that uses syscon whether > > explicitly or due to a module removal left the used syscon in a in-use > > state. > > > > For instance a syscon_node_to_regmap() call from a consumer retrieves a > > syscon regmap instance. Internally, syscon_node_to_regmap() can create > > syscon instance and add it to the existing syscon list. No API is > > available to release this syscon instance, remove it from the list and > > free it when it is not used anymore. > > > > Introduce reference counting in syscon in order to keep track of syscon > > usage using syscon_{get,put}() and add a device managed version of > > syscon_regmap_lookup_by_phandle(), to automatically release the syscon > > instance on the consumer removal. > > > > Signed-off-by: Clément Léger > > Signed-off-by: Herve Codina > > --- > > drivers/mfd/syscon.c | 138 ++++++++++++++++++++++++++++++++++--- > > include/linux/mfd/syscon.h | 16 +++++ > > 2 files changed, 144 insertions(+), 10 deletions(-) > > This doesn't look very popular. > > What are the potential ramifications for existing users? > Existing user don't use devm_syscon_regmap_lookup_by_phandle() nor syscon_put_regmap(). So refcount is incremented but never decremented. syscon is never released. Exactly the same as current implementation. Nothing change for existing users. Best regards, Hervé