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 DE087C433EF for ; Wed, 1 Dec 2021 13:12:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349533AbhLANPe (ORCPT ); Wed, 1 Dec 2021 08:15:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55656 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1349511AbhLANPC (ORCPT ); Wed, 1 Dec 2021 08:15:02 -0500 Received: from mail-ed1-x52b.google.com (mail-ed1-x52b.google.com [IPv6:2a00:1450:4864:20::52b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF651C06174A for ; Wed, 1 Dec 2021 05:11:40 -0800 (PST) Received: by mail-ed1-x52b.google.com with SMTP id z5so36347880edd.3 for ; Wed, 01 Dec 2021 05:11:40 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bgdev-pl.20210112.gappssmtp.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=liC6iBHdVHj8wrS34Mv4qj/s+gn0Mtz6/NZeXb3PmG0=; b=CW883sHA/ZsErtuI3bBKwZH7FrSIo6SF/udDvszUZTIfAWjof6aw/X6qtqF6e/83+e Qz50HsrZj7OUdZoK9oP6fKMs/blgQZ0ffMhE1aJGR1dzTa0lTeMFAhvBjqbeVigBkTaM PWbItNOZEKHzVZ92ZsfTsGwAHNMEfG5wPpYBPd8sCNiVnnRABSTnZCAUrHvEL7nyyJc2 cJzm/1+U9eb+I8rCxW90/bqbNbx95VrX3Iu68TelOmXj4Z6WqnMlAqkV8tjkJbgiiJze 6FM+UqTZzC2OeqKQsofRWnuTdYE2vYadOSzCHKAxD5MRkew2GtOQ3s+M0yX35D98WXLs piyQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=liC6iBHdVHj8wrS34Mv4qj/s+gn0Mtz6/NZeXb3PmG0=; b=vqx32M5pG0/S4cgpBtReAu02PamyAxfZGLIoX1H2HfLJNmZVkFa+1Dg7WXSmT6RVz8 7RNucsun0ywGQppevm34A3b3RkcUM+Aa7n3/SnZJo2NxVTHryUfl9ZNh0EYMVB40b4Yc HtVs2oFPnMqYVvgthzmcMJPkc3QKwrSlu4imXVQUuSA58aw93gymL447dZpuyPsb7EO0 y/+EU6av2kpP1a8QSuNVGpcbCHUL20RPASLU0NQdke3tsQQNpVo/KnJuv5zgraMsxF49 rYk3GToFSlO6rpyqdYhOn97Fmf+51y5hyqB200CEqoYzoC+lmovz06mqp/4aa+N2324s f8Iw== X-Gm-Message-State: AOAM532r1DfFEp27sR9vH4QBoMy3FRHMCyCnW3IgSy779Nu9yP4BMaMD +oT0gBgahajvlY8t1WdyMNn4vSNaYCyb4UjFxVKTs/RzhOwqiw== X-Google-Smtp-Source: ABdhPJzXpOwR/zmaQijtGvVMihRvtGN4y1YzAc1jjrZxJxi1juTyRwOdjlj1BPD38T9PG+TZgGcLPYM5+xi2wbTzz5k= X-Received: by 2002:a17:907:3e9a:: with SMTP id hs26mr7104471ejc.433.1638364299412; Wed, 01 Dec 2021 05:11:39 -0800 (PST) MIME-Version: 1.0 References: <20211130154127.12272-1-brgl@bgdev.pl> <20211130154127.12272-3-brgl@bgdev.pl> In-Reply-To: From: Bartosz Golaszewski Date: Wed, 1 Dec 2021 14:11:28 +0100 Message-ID: Subject: Re: [PATCH v11 2/6] gpiolib: allow to specify the firmware node in struct gpio_chip To: Andy Shevchenko Cc: Kent Gibson , Linus Walleij , Shuah Khan , Geert Uytterhoeven , "open list:GPIO SUBSYSTEM" , Linux Kernel Mailing List , linux-kselftest@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org On Tue, Nov 30, 2021 at 10:04 PM Bartosz Golaszewski wrote: > > On Tue, Nov 30, 2021 at 10:00 PM Andy Shevchenko > wrote: > > > > On Tue, Nov 30, 2021 at 09:25:35PM +0100, Bartosz Golaszewski wrote: > > > On Tue, Nov 30, 2021 at 5:15 PM Andy Shevchenko > > > wrote: > > > > > > > > On Tue, Nov 30, 2021 at 04:41:23PM +0100, Bartosz Golaszewski wrote: > > > > > Software nodes allow us to represent hierarchies for device components > > > > > that don't have their struct device representation yet - for instance: > > > > > banks of GPIOs under a common GPIO expander. The core gpiolib core > > > > > > > > core .. core ?! > > > > > > > > > however doesn't offer any way of passing this information from the > > > > > drivers. > > > > > > > > > > This extends struct gpio_chip with a pointer to fwnode that can be set > > > > > by the driver and used to pass device properties for child nodes. > > > > > > > > > > This is similar to how we handle device-tree sub-nodes with > > > > > CONFIG_OF_GPIO enabled. > > > > > > > > Not sure I understand the proposal. Can you provide couple of (simplest) > > > > examples? > > > > > > > > And also it sounds like reinventing a wheel. What problem do you have that you > > > > need to solve this way? > > > > > > > > ... > > > > > > > > > +#if IS_ENABLED(CONFIG_OF_GPIO) > > > > > + if (gc->of_node && gc->fwnode) { > > > > > + pr_err("%s: tried to set both the of_node and fwnode in gpio_chip\n", > > > > > + __func__); > > > > > + return -EINVAL; > > > > > + } > > > > > +#endif /* CONFIG_OF_GPIO */ > > > > > > > > I don't like this. It seems like a hack right now. > > > > > > > > Is it possible to convert all GPIO controller drivers to provide an fwnode > > > > rather than doing this? (I believe in most of the drivers we can drop > > > > completely the of_node assignment). > > > > > > > > > > Yes, it's definitely a good idea but I would be careful with just > > > dropping the of_node assignments as callbacks may depend on them > > > later. > > > > GPIO library does it for us among these lines: > > > > struct fwnode_handle *fwnode = gc->parent ? dev_fwnode(gc->parent) : NULL; > > > > of_gpio_dev_init(gc, gdev); <<< HERE! > > acpi_gpio_dev_init(gc, gdev); > > > > /* > > * Assign fwnode depending on the result of the previous calls, > > * if none of them succeed, assign it to the parent's one. > > */ > > gdev->dev.fwnode = dev_fwnode(&gdev->dev) ?: fwnode; > > > > Except that it doesn't and I noticed that when working on the > subsequent patch. The child gpiochipX devices all had the parent's > fwnode assigned as their primary fwnode and no secondary fwnode. > > Note that this driver doesn't use neither OF nor ACPI in which case > gdev->dev has no fwnode and the parent's one is used. This patch > addresses it. If you have a better idea, let me know. > > Bart Let me maybe rephrase the problem: currently, for GPIO devices instantiating multiple banks created outside of the OF or ACPI frameworks (e.g. instantiated manually and configured using a hierarchy of software nodes with a single parent swnode and a number of child swnodes representing the children), it is impossible to assign firmware nodes other than the one representing the top GPIO device to the gpiochip child devices. In fact if we want to drop the OF APIs entirely from gpiolib - this would be the right first step as for gpio-sim it actually replaces the gc->of_node = some_of_node; assignment that OF-based drivers do for sub-nodes defining banks and it does work with device-tree (I verified that too) thanks to the fwnode abstraction layer. Linus: Do you have anything against this change? Bart