From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 220AB3164A5; Tue, 10 Feb 2026 10:41:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770720104; cv=none; b=AKCyGCzio00LdkUk2TeOBT9HLfLAASbEZuLxLaSrx8P1HMC+DlahJb9J2cWB2onGl+mR1umMaPSOk9fgGJ6/HR5R0e1Df3vs42WTG3G8ZvqUjQE4sIj6NhYb9lbFvT5db60y4Q351sf9WXjv6IR4XvoQBLPp523IAeuD++7czzY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770720104; c=relaxed/simple; bh=b2GOcGwn5DzDpShBURk8TYAQ9YVP1nK5iYwXXc1HUCw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tQbGO4psvNyhrcxHjmZ3t412D110ehuBGckdBBN2g6pldcNwhKnLGRo8x+iqC7j76a1A4K9S2ZkIWgL6wKl7G46/oyg2DMr8IJaqQwAZbI7WKk8cM1gM30q4o81XTc++otkknSApfZirzqUqMnpPJZ05zFQUd3r5aYWx9ik0RSM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=D1XLD7df; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="D1XLD7df" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 82270C116C6; Tue, 10 Feb 2026 10:41:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1770720103; bh=b2GOcGwn5DzDpShBURk8TYAQ9YVP1nK5iYwXXc1HUCw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=D1XLD7df9wGt3WGmpnFj2sTKRNleRcQridocbYNT+S2bnNoZZLvNciE4jmYJS+KCs lvyRdkNDTdLUhZPGvu3l8LiIuR1aZQ5ZsLRaozZ7RTlj9TP7nlmZKEHHE10PsV0wy6 RDuWuG3kx2/vp5nNLwcHzCASpEyPrk1M1hqwrDqFhm0rAvNUCj8YIXBMZ0NRhQBeZ0 2xoQ8zxzZc+hVo0U8ne4SYUB10JxYMPE+ME7PccvWIgqg/S633I+eGDcPvUVoYjj1M GVEIkTQq1f5PRhbah/uIZCkIdEd6lyWtuD5LcWhA0kPSFumf7om5x7H+D6+n2Ub0rt AC4fWjQzIYy6g== Message-ID: <75e26353-2704-4dda-9537-5d22a4887553@kernel.org> Date: Tue, 10 Feb 2026 11:41:39 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] gpio: swnode: restore the swnode-name-against-chip-label matching To: Bartosz Golaszewski , Linus Walleij , Bartosz Golaszewski , Andy Shevchenko , Greg Kroah-Hartman , Dmitry Torokhov , Arnd Bergmann , =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= Cc: linux-gpio@vger.kernel.org, linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org, stable@vger.kernel.org References: <20260210094806.38146-1-bartosz.golaszewski@oss.qualcomm.com> From: Hans de Goede Content-Language: en-US, nl In-Reply-To: <20260210094806.38146-1-bartosz.golaszewski@oss.qualcomm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Hi, On 10-Feb-26 10:48, Bartosz Golaszewski wrote: > Using the remote firmware node for software node lookup is the right > thing to do. The GPIO controller we want to resolve should have the > software node we scooped out of the reference attached to it. However, > there are existing users who abuse the software node API by creating > dummy swnodes whose name is set to the expected label string of the GPIO > controller whose pins they want to control and use them in their local > swnode references as GPIO properties. > > This used to work when we compared the software node's name to the > chip's label. When we switched to using a real fwnode lookup, these > users broke down because the firmware nodes in question were never > attached to the controllers they were looking for. > > Restore the label matching as a fallback to fix the broken users but add > a big FIXME urging for a better solution. > > Link: https://lore.kernel.org/all/aYmV5Axyfo76D19T@smile.fi.intel.com/ > Cc: stable@vger.kernel.org # v6.18, v6.19 > Fixes: 216c12047571 ("gpio: swnode: allow referencing GPIO chips by firmware nodes") > Signed-off-by: Bartosz Golaszewski > --- > drivers/gpio/gpiolib-swnode.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/drivers/gpio/gpiolib-swnode.c b/drivers/gpio/gpiolib-swnode.c > index 21478b45c127d..c88313b0026b9 100644 > --- a/drivers/gpio/gpiolib-swnode.c > +++ b/drivers/gpio/gpiolib-swnode.c > @@ -42,6 +42,25 @@ static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode) > > fwnode_lookup: > gdev = gpio_device_find_by_fwnode(fwnode); > + if (!gdev) This needs to be: if (!gdev && gdev_node->name) gdev_node->name may be NULL and calling gpio_device_find_by_label() with a NULL pointer does not end well. Regards, Hans > + /* > + * FIXME: We shouldn't need to compare the GPIO controller's > + * label against the software node that is supposedly attached > + * to it. However there are currently GPIO users that - knowing > + * the expected label of the GPIO chip whose pins they want to > + * control - set up dummy software nodes named after those GPIO > + * controllers, which aren't actually attached to them. In this > + * case gpio_device_find_by_fwnode() will fail as no device on > + * the GPIO bus is actually associated with the fwnode we're > + * looking for. > + * > + * As a fallback: continue checking the label if we have no > + * match. However, the situation described above is an abuse > + * of the software node API and should be phased out and the > + * following line - eventually removed. > + */ > + gdev = gpio_device_find_by_label(gdev_node->name); > + > return gdev ?: ERR_PTR(-EPROBE_DEFER); > } >