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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0F818C433EF for ; Wed, 10 Nov 2021 12:17:40 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id D36B16124D for ; Wed, 10 Nov 2021 12:17:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D36B16124D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: 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=Pgu8LTcKYYUGpKNRGJ5frP1GEIrugfYtqFY1BiuQ/lQ=; b=zplDmMJRIzERfq 7/L9gaFaS8LGs/wwYHhoEs8ne/n1K65mzsOQjX0HYNkPizVqcxMBtrp93oQLaRRfMQiIm7pj1DPp5 ThxKZXoOaQmvbCvmgtG51DNwzWMC16j8rf/BQLXWxvgyPxE/slJPzX6lOgVIguo30CYMzS0uY7CHJ mT9qVYsiXyEb9e6eOx25mZSVU+f5UPhZk44bC7wsczMGmtkPD4mrrMPGX3z0bojILxCTqhJj2DduS xFYJWcZOwmGquJ5MQ2k9tzhIpKngwj2Hl/l69oxnqsrNe8diWmOdv4HO7N9tytTmKjc6ZQtGXaJCT z9Jfu3jTrsXotlEJ05vg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1mkmWj-005N3w-P8; Wed, 10 Nov 2021 12:16:29 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1mkmWf-005N30-EZ; Wed, 10 Nov 2021 12:16:27 +0000 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0B97761247; Wed, 10 Nov 2021 12:16:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1636546584; bh=ZYFWL/ZZSINDrj9gVT8HDnC1qKVafjx6t2mJPgowNVQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=reIhBKYtcg8k442u+V9YxuQbe8lxhoFCd41JIRHoPfobRr49BEKhEDTBUAwCjT0Vf Rp0CEx223jng3x8zHBLJMnLNfaS0xrx15PkY/xJ/7cFe1uXdqc3JdekDpP+80ysXF5 uUmkOdyU7+Wi/2sF8m32JRo1J72u5NLS28WSnUedYUGEo6g9aIKdkF6VK8DT/14LCF ldkxpAYsUNmVgj31jZvsa4NSzTQ1O+B7RtbRT0Ib8LuZGZcG8gaFJ6KBFy1462TVDu 9u7Yz0LaUUv7rD9tiA3F07iRoRI1/GvF2wO12X+hvrZa8UwsCawwpXMey99vsww45J VbXyxJRP5OlBw== Date: Wed, 10 Nov 2021 14:16:18 +0200 From: Abel Vesa To: Saravana Kannan Cc: Russell King , Neil Armstrong , Geert Uytterhoeven , Magnus Damm , Tony Lindgren , Catalin Marinas , Will Deacon , Damien Le Moal , Greg Kroah-Hartman , Ulf Hansson , Rob Herring , kernel-team@android.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-oxnas@groups.io, linux-renesas-soc@vger.kernel.org, linux-omap@vger.kernel.org, linux-riscv@lists.infradead.org Subject: Re: [PATCH v4 1/2] drivers: bus: simple-pm-bus: Add support for probing simple bus only devices Message-ID: References: <20210929000735.585237-1-saravanak@google.com> <20210929000735.585237-2-saravanak@google.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210929000735.585237-2-saravanak@google.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20211110_041625_569953_1D956DD0 X-CRM114-Status: GOOD ( 36.08 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 21-09-28 17:07:33, Saravana Kannan wrote: > fw_devlink could end up creating device links for bus only devices. > However, bus only devices don't get probed and can block probe() or > sync_state() [1] call backs of other devices. To avoid this, probe these > devices using the simple-pm-bus driver. > > However, there are instances of devices that are not simple buses (they get > probed by their specific drivers) that also list the "simple-bus" (or other > bus only compatible strings) in their compatible property to automatically > populate their child devices. We still want these devices to get probed by > their specific drivers. So, we make sure this driver only probes devices > that are only buses. > > [1] - https://lore.kernel.org/lkml/CAPDyKFo9Bxremkb1dDrr4OcXSpE0keVze94Cm=zrkOVxHHxBmQ@mail.gmail.com/ > Fixes: c442a0d18744 ("driver core: Set fw_devlink to "permissive" behavior by default") > Signed-off-by: Saravana Kannan > Tested-by: Saravana Kannan > Tested-by: Ulf Hansson > --- > drivers/bus/simple-pm-bus.c | 42 ++++++++++++++++++++++++++++++++++--- > 1 file changed, 39 insertions(+), 3 deletions(-) > > diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c > index 01a3d0cd08ed..6b8d6257ed8a 100644 > --- a/drivers/bus/simple-pm-bus.c > +++ b/drivers/bus/simple-pm-bus.c > @@ -13,11 +13,36 @@ > #include > #include > > - > static int simple_pm_bus_probe(struct platform_device *pdev) > { > - const struct of_dev_auxdata *lookup = dev_get_platdata(&pdev->dev); > - struct device_node *np = pdev->dev.of_node; > + const struct device *dev = &pdev->dev; > + const struct of_dev_auxdata *lookup = dev_get_platdata(dev); > + struct device_node *np = dev->of_node; > + const struct of_device_id *match; > + > + /* > + * Allow user to use driver_override to bind this driver to a > + * transparent bus device which has a different compatible string > + * that's not listed in simple_pm_bus_of_match. We don't want to do any > + * of the simple-pm-bus tasks for these devices, so return early. > + */ > + if (pdev->driver_override) > + return 0; > + > + match = of_match_device(dev->driver->of_match_table, dev); > + /* > + * These are transparent bus devices (not simple-pm-bus matches) that > + * have their child nodes populated automatically. So, don't need to > + * do anything more. We only match with the device if this driver is > + * the most specific match because we don't want to incorrectly bind to > + * a device that has a more specific driver. > + */ > + if (match && match->data) { > + if (of_property_match_string(np, "compatible", match->compatible) == 0) > + return 0; > + else > + return -ENODEV; > + } This change is breaking the expected behavior for the already existent simple-bus nodes. All the simple-bus compatibles should be replaced now to simple-pm-bus. In my case, on some i.MX8 platforms, without the devlink, the devices suspend sequence changes (and even breaks). To avoid breaking the already existent simple-bus nodes, maybe the logic should've been reversed: keep the simple-bus as is and add another compatible, IDK, something like simple-trasnparent-bus, or something. > > dev_dbg(&pdev->dev, "%s\n", __func__); > > @@ -31,14 +56,25 @@ static int simple_pm_bus_probe(struct platform_device *pdev) > > static int simple_pm_bus_remove(struct platform_device *pdev) > { > + const void *data = of_device_get_match_data(&pdev->dev); > + > + if (pdev->driver_override || data) > + return 0; > + > dev_dbg(&pdev->dev, "%s\n", __func__); > > pm_runtime_disable(&pdev->dev); > return 0; > } > > +#define ONLY_BUS ((void *) 1) /* Match if the device is only a bus. */ > + > static const struct of_device_id simple_pm_bus_of_match[] = { > { .compatible = "simple-pm-bus", }, > + { .compatible = "simple-bus", .data = ONLY_BUS }, > + { .compatible = "simple-mfd", .data = ONLY_BUS }, > + { .compatible = "isa", .data = ONLY_BUS }, > + { .compatible = "arm,amba-bus", .data = ONLY_BUS }, > { /* sentinel */ } > }; > MODULE_DEVICE_TABLE(of, simple_pm_bus_of_match); > -- > 2.33.0.685.g46640cef36-goog > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel