From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtpout-03.galae.net (smtpout-03.galae.net [185.246.85.4]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C4DCB34B698; Fri, 31 Oct 2025 14:29:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.246.85.4 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761920995; cv=none; b=KBqgEEayQyUxQ6nZOoRnWZkCwz4Zl82LXi5xoWwb8tLr+pKawqij2Rs2lx9aWE35ffUP8FEz3KZ76lFRn0j2dD2iEE+9Wlf2A9AmmMYn6j0lyK3RkNtlWVpDWdoQ45soAjnXhG1P9yY4tNoSO42ZkqNMRucXyqdsQo7jLnLDIDM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761920995; c=relaxed/simple; bh=DpRmmnQNFBCQ/QafgwFnqLT9Yw/H1JWWO9tLoLVtAy4=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=VnCbutT55tMdvFBxqs0VB1p4JZNXfqLhaBOHPdTYYr5YIGi2mpcAGj7J1SlpAIPmkh5oEPaLR/YT0nhK4OsaYf6eLkRjKRkB/o4Q0FIUvI4lc8svUn912wzHYg7/NxtMjVEIgpTe4KYMRoRWjMhRtU2E/dhKO/2I4vF3w8kmNhc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=m/llmHWP; arc=none smtp.client-ip=185.246.85.4 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="m/llmHWP" Received: from smtpout-01.galae.net (smtpout-01.galae.net [212.83.139.233]) by smtpout-03.galae.net (Postfix) with ESMTPS id D63C34E4143C; Fri, 31 Oct 2025 14:29:51 +0000 (UTC) Received: from mail.galae.net (mail.galae.net [212.83.136.155]) by smtpout-01.galae.net (Postfix) with ESMTPS id 9DC5860704; Fri, 31 Oct 2025 14:29:51 +0000 (UTC) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id C4B4A11818003; Fri, 31 Oct 2025 15:29:31 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=dkim; t=1761920989; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=H1xEmCgdr5BM399Kc4ZsWwaTbhEQ52MJYYiQpqbSK6Q=; b=m/llmHWPK2GTOxgP86qebD1Z2Edet7KZozbxg7xHP71zP8WGHqlNCsjTjzbgRJW6AoYEg9 PGGuEBK7TNuc+3zADlLbC1jrjiYc/TXhPfAwEtjv3025kcM3TvB0cUwMNtHDn+fuYXbapk 18lKsj6lpv1/ObuOPQiBVRZx/Tm+zaLVFOXH7eT76X6+OiJSchpc3v+iGXicmC9AbAQ7Fi n3R42rQTkma0JCEYRFgzMb9znRzRns4yCbMUv4DSU7pRjgiVIxLEd6NnupsCZT4TGW2iAp n6HmKRiLt0yJEP375+9QgT+CNjKgF6b7Kiq48SW1im8mtyVm7PYpr3cu982RMw== Date: Fri, 31 Oct 2025 15:29:30 +0100 From: Herve Codina To: Geert Uytterhoeven Cc: Andrew Lunn , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Greg Kroah-Hartman , "Rafael J. Wysocki" , Danilo Krummrich , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , Michael Turquette , Stephen Boyd , Andi Shyti , Wolfram Sang , Peter Rosin , Arnd Bergmann , Saravana Kannan , Bjorn Helgaas , Charles Keepax , Richard Fitzgerald , David Rhodes , Linus Walleij , Ulf Hansson , Mark Brown , Andy Shevchenko , Daniel Scally , Heikki Krogerus , Sakari Ailus , Len Brown , Davidlohr Bueso , Jonathan Cameron , Dave Jiang , Alison Schofield , Vishal Verma , Ira Weiny , Dan Williams , Geert Uytterhoeven , Wolfram Sang , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org, linux-clk@vger.kernel.org, linux-i2c@vger.kernel.org, linux-pci@vger.kernel.org, linux-sound@vger.kernel.org, patches@opensource.cirrus.com, linux-gpio@vger.kernel.org, linux-pm@vger.kernel.org, linux-spi@vger.kernel.org, linux-acpi@vger.kernel.org, linux-cxl@vger.kernel.org, Allan Nielsen , Horatiu Vultur , Steen Hegelund , Luca Ceresoli , Thomas Petazzoni Subject: Re: [PATCH v4 05/29] dt-bindings: bus: Add simple-platform-bus Message-ID: <20251031152930.3c51a313@bootlin.com> In-Reply-To: References: <20251015071420.1173068-1-herve.codina@bootlin.com> <20251015071420.1173068-6-herve.codina@bootlin.com> Organization: Bootlin X-Mailer: Claws Mail 4.3.1 (GTK 3.24.43; x86_64-redhat-linux-gnu) Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Last-TLS-Session-Version: TLSv1.3 On Fri, 31 Oct 2025 09:52:16 +0100 Geert Uytterhoeven wrote: > Hi Hervé, > > On Wed, 15 Oct 2025 at 09:17, Herve Codina wrote: > > A Simple Platform Bus is a transparent bus that doesn't need a specific > > driver to perform operations at bus level. > > > > Similar to simple-bus, a Simple Platform Bus allows to automatically > > instantiate devices connected to this bus. > > > > Those devices are instantiated only by the Simple Platform Bus probe > > function itself. > > > > Signed-off-by: Herve Codina > > Thanks for your patch! > > > --- /dev/null > > +++ b/Documentation/devicetree/bindings/bus/simple-platform-bus.yaml > > @@ -0,0 +1,50 @@ > > +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) > > +%YAML 1.2 > > +--- > > +$id: http://devicetree.org/schemas/bus/simple-platform-bus.yaml# > > +$schema: http://devicetree.org/meta-schemas/core.yaml# > > + > > +title: Simple Platform Bus > > + > > +maintainers: > > + - Herve Codina > > + > > +description: | > > + A Simple Platform Bus is a transparent bus that doesn't need a specific > > + driver to perform operations at bus level. > > + > > + Similar to simple-bus, a Simple Platform Bus allows to automatically > > + instantiate devices connected to this bus. Those devices are instantiated > > + only by the Simple Platform Bus probe function itself. > > So what are the differences with simple-bus? That its children are > instantiated "only by the Simple Platform Bus probe function itself"? > If that is the case, in which other places are simple-bus children > instantiated? In of_platform_populate(). It call of_platform_bus_create() which is recursive: https://elixir.bootlin.com/linux/v6.14/source/drivers/of/platform.c#L374 So children are instantiated out of the bus probe(). > > Do we need properties related to power-management (clocks, power-domains), > or will we need a "simple-pm-platform-bus" later? ;-) > > FTR, I still think we wouldn't have needed the distinction between > "simple-bus" and "simple-pm-bus"... I would like that. Using simple-pm-bus solves my issue but I don't have any clocks or power-domains to set. The simple-pm-bus bus requires at least one of them. Even if the driver itself solved my issue, I cannot be compliant with its binding. Best regards, Hervé