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 7F532C433F5 for ; Tue, 30 Nov 2021 21:01:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343935AbhK3VEc (ORCPT ); Tue, 30 Nov 2021 16:04:32 -0500 Received: from mga01.intel.com ([192.55.52.88]:3406 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343957AbhK3VDs (ORCPT ); Tue, 30 Nov 2021 16:03:48 -0500 X-IronPort-AV: E=McAfee;i="6200,9189,10184"; a="260283481" X-IronPort-AV: E=Sophos;i="5.87,277,1631602800"; d="scan'208";a="260283481" Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2021 13:00:25 -0800 X-IronPort-AV: E=Sophos;i="5.87,277,1631602800"; d="scan'208";a="559738624" Received: from smile.fi.intel.com ([10.237.72.184]) by fmsmga008-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Nov 2021 13:00:23 -0800 Received: from andy by smile.fi.intel.com with local (Exim 4.95) (envelope-from ) id 1msADf-000iYw-RX; Tue, 30 Nov 2021 22:59:19 +0200 Date: Tue, 30 Nov 2021 22:59:19 +0200 From: Andy Shevchenko To: Bartosz Golaszewski Cc: Kent Gibson , Linus Walleij , Shuah Khan , Geert Uytterhoeven , "open list:GPIO SUBSYSTEM" , Linux Kernel Mailing List , linux-kselftest@vger.kernel.org Subject: Re: [PATCH v11 2/6] gpiolib: allow to specify the firmware node in struct gpio_chip Message-ID: References: <20211130154127.12272-1-brgl@bgdev.pl> <20211130154127.12272-3-brgl@bgdev.pl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org 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; > Also it's not just about the gpio_chip of_node assignment - > drivers also use a bunch of OF APIs all around the place. I would > prefer that it be done one by one and every modified driver be tested. That's why we want to eliminate dev->fwnode explicit dereference as a first step (see dev_fwnode() / device_set_node() APIs). -- With Best Regards, Andy Shevchenko