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 C17BA1CD2B for ; Fri, 18 Oct 2024 14:31:24 +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=1729261884; cv=none; b=DawA9+HDwKsqwdomi+e9iOXaatsTg3SyvaTYq+fFbMd9izAseGQilbRKCFT793NDRbICgg2IVcyVJBJl6rFEzSSVfuzmf7vQ6KsgiujMMp97dQjPx0xi3OWQPWzR0eWhyQvOmnIH2d5DR+RbETFoOKEsS3CYIqHBxV7UJ7hs0Io= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729261884; c=relaxed/simple; bh=JfB9lvxMoWET2hOxXPNBdT2uKL/PscD/8S5+uwWZoes=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sMri+GjN/7psAgRbbWh/mirjoO+ApN45deDnSG1TBca/c0U2FMPWKRFHBsDkkDKpFsZuA43xnbk30VYUBF6arsxYnm/M9Oq1qDu4Km5B4nLEr1yP9qHjVAG40aDCGBfd+U9HNLkgD2lk6ysw41aVp25hnHY8OinDDNcmelA+BTk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=TTrL2xL6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="TTrL2xL6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B0463C4CEC3; Fri, 18 Oct 2024 14:31:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1729261884; bh=JfB9lvxMoWET2hOxXPNBdT2uKL/PscD/8S5+uwWZoes=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TTrL2xL6DSDIbCrJeORRxW4iIZGoSXIE5we4tnNvBvudicT0CH0YiKnQeLb8wU2K0 kuIXEq2odpz3i1ZKHSsHjCaGmmOD+ByVDizU3w+RJCpGV8X6LXUqJkhvDiLpszpLVP EloqGQO8A+Oje0nEp/wEl2VIMVEgzaKTKkKr2k70= Date: Fri, 18 Oct 2024 16:31:21 +0200 From: Greg KH To: Laurent Pinchart Cc: Geert Uytterhoeven , Douglas Anderson , Linus Walleij , Andrzej Hajda , Neil Armstrong , Robert Foss , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , dri-devel@lists.freedesktop.org, linux-renesas-soc@vger.kernel.org Subject: Re: [PATCH] drm/bridge: ti-sn65dsi86: Fix multiple instances Message-ID: <2024101837-crushed-emphasis-b496@gregkh> References: <8c2df6a903f87d4932586b25f1d3bd548fe8e6d1.1729180470.git.geert+renesas@glider.be> <20241018131035.GA20602@pendragon.ideasonboard.com> <2024101855-judo-tattered-bc3c@gregkh> <20241018142522.GA28934@pendragon.ideasonboard.com> Precedence: bulk X-Mailing-List: linux-renesas-soc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20241018142522.GA28934@pendragon.ideasonboard.com> On Fri, Oct 18, 2024 at 05:25:22PM +0300, Laurent Pinchart wrote: > Hi Greg, > > On Fri, Oct 18, 2024 at 04:09:26PM +0200, Greg KH wrote: > > On Fri, Oct 18, 2024 at 03:36:48PM +0200, Geert Uytterhoeven wrote: > > > On Fri, Oct 18, 2024 at 3:10 PM Laurent Pinchart wrote: > > > > On Fri, Oct 18, 2024 at 09:45:52AM +0200, Geert Uytterhoeven wrote: > > > > > Each bridge instance creates up to four auxiliary devices with different > > > > > names. However, their IDs are always zero, causing duplicate filename > > > > > errors when a system has multiple bridges: > > > > > > > > > > sysfs: cannot create duplicate filename '/bus/auxiliary/devices/ti_sn65dsi86.gpio.0' > > > > > > > > > > Fix this by using a unique instance ID per bridge instance. > > > > > > > > Isn't this something that should be handled by the AUX core ? The code > > > > below would otherwise need to be duplicated by all drivers, which seems > > > > a burden we should avoid. > > > > > > According to the documentation, this is the responsibility of the caller > > > https://elixir.bootlin.com/linux/v6.11.4/source/include/linux/auxiliary_bus.h#L81 > > > I believe this is the same for platform devices. > > > See also the example at > > > https://elixir.bootlin.com/linux/v6.11.4/source/include/linux/auxiliary_bus.h#L116 > > > > > > Note: the platform bus supports PLATFORM_DEVID_AUTO, but the auxiliary > > > bus does not. > > > > Yes, it does not as it's up to the caller to create a unique name, like > > your patch here does. I'd argue that platform should also not do > > automatic device ids, but that's a different argument :) > > __auxiliary_device_add() creates the device name with > > dev_set_name(dev, "%s.%s.%d", modname, auxdev->name, auxdev->id); > > I'm not calling for a PLATFORM_DEVID_AUTO-like feature here, but > shouldn't the first component of the device name use the parent's name > instead of the module name ? Why would the parent's name not be the module name? That name is guaranteed unique in the system. If you want "uniqueness" within the driver/module, use the name and id field please. That's worked well so far, but to be fair, aux devices are pretty new. What problem is this naming scheme causing? thanks, greg k-h