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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CFE81CDB474 for ; Fri, 20 Oct 2023 13:45:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377459AbjJTNpk (ORCPT ); Fri, 20 Oct 2023 09:45:40 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47524 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377222AbjJTNpi (ORCPT ); Fri, 20 Oct 2023 09:45:38 -0400 Received: from relay2-d.mail.gandi.net (relay2-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::222]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DAEF0A3 for ; Fri, 20 Oct 2023 06:45:33 -0700 (PDT) Received: by mail.gandi.net (Postfix) with ESMTPSA id C67564000F; Fri, 20 Oct 2023 13:45:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1697809531; 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=lr/z7uihQprUld3MCX8m2TxbGzxLF1jBcFQtsJ1q8Lc=; b=biU7ESoHpgUw+DDQz7V86GfiGC9KtHEliOGtPOBH2lqU8v9/dKa7TpQRy/qtWhw8nFH2iv SPRudRRN8PXjnJSt1sep9Vyoc2uvua23p4NRnADvgbOFKXF9mYrqgSa2XYkuvqGRMkXqih 2Djs7z08wehMsdbDIskMWYzd2tv3SX+rYNAMX16zDcP03I1XMldDNv98b8aUIcFRx3QMyx L58Kusya/Twsickg6kRU0wnTpc5bksBZaWwlRxkmITvRWxHFGXzc/hIhcgXO5l8bd5FHp4 9vTzCJC9Nr0T8VqOiewC15HTEuoOlfOBaNkbhdeIfHIBRzw7WnBR4SGJnvgOnQ== Date: Fri, 20 Oct 2023 15:45:28 +0200 From: Miquel Raynal To: "Zbigniew, Lukwinski" Cc: Frank Li , alexandre.belloni@bootlin.com, conor.culhane@silvaco.com, imx@lists.linux.dev, joe@perches.com, linux-i3c@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/6] i3c: master: add enable(disable) hot join in sys entry Message-ID: <20231020154528.2f5f68f5@xps-13> In-Reply-To: <57efe6de-cf65-32ed-fd1e-a388e1676c70@linux.intel.com> References: <20231018205929.3435110-1-Frank.Li@nxp.com> <20231018205929.3435110-2-Frank.Li@nxp.com> <57efe6de-cf65-32ed-fd1e-a388e1676c70@linux.intel.com> Organization: Bootlin X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-GND-Sasl: miquel.raynal@bootlin.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Lukwinski, zbigniew.lukwinski@linux.intel.com wrote on Fri, 20 Oct 2023 10:55:27 +0200: > On 10/18/2023 10:59 PM, Frank Li wrote: > > Add hotjoin entry in sys file system allow user enable/disable hotjoin > > feature. > > > > Add (*enable(disable)_hotjoin)() to i3c_master_controller_ops. > > Add api i3c_master_enable(disable)_hotjoin(); =20 >=20 > What is the use case for having HJ enable knob in sysfs available for use= r space other than for debug stuff? In other words, does user space really = need to enable/disable HJ in runtime for other reason but debug? If it is o= nly for debug maybe it=C2=A0 could be move to debugFS? I don't think hotjoin should be considered as a debug feature. The problem here is the power consumption which is higher if you enable this feature (you need to keep everything clocked and ready to handle an IBI) whereas if your design is "fixed" (more like an I2C bus) you may save power by disabling this feature. A module parameter does not fit here because it's a per-bus configuration. Thanks, Miqu=C3=A8l