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 8703D35AC25; Thu, 12 Mar 2026 15:25:20 +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=1773329120; cv=none; b=Uz80KAhk4qJCrgKRBaZ61424kE3kq1bInTc2TvBFbhsTvFTCzQ05MS18NxO3RHgL4++d9Fo4UCoA0NSk1qLHQjp27h8tRgZudEKoRHZmy+wScLWJAM4eFaRyUjGqoyfLKTYKziK/JRLTSECi28C+wE+3bffmZg0DoB8I5XVSu7c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773329120; c=relaxed/simple; bh=PRo1H3AkrAn5CN91lSlcAttTHvGYCwJejSgeqavNRoI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=t9F7oqxrKFb4NIh91HjddwLNlYQe/zzgGZu0Sb/gwiYcX6nqPdijMu2x1hvq5eh0SDQ7JfJF6vDAxkaGtdG69clMv3NAlleHRUlIep8TPUAJqrKTTt+SzoxzTj4mm6c76UzWkJTmPAhUGro1BTT5R5Vo2gAePv2b5if2ylNWYNU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=lql86yy2; 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="lql86yy2" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7FDDBC19424; Thu, 12 Mar 2026 15:25:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773329120; bh=PRo1H3AkrAn5CN91lSlcAttTHvGYCwJejSgeqavNRoI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lql86yy2FN8tLqLicquRdgpjggL2vrKdD60VbViutWeYzWjb3pVajNhWIpEalgkZa SfTBrlGWdJRdzpBoRbIIWAUMAE9nFttpvTYi1cmhoJ6oqku+dxeFZGeSFewu+KfU9E RcqAoTiwPARxL4OF64EzwIvZnVpcGX4XJfxD6tQE= Date: Thu, 12 Mar 2026 16:25:14 +0100 From: Greg Kroah-Hartman To: Bartosz Golaszewski Cc: Shivendra Pratap , Bartosz Golaszewski , "Rafael J. Wysocki" , Danilo Krummrich , linux-arm-msm@vger.kernel.org, driver-core@lists.linux.dev, linux-kernel@vger.kernel.org Subject: Re: [PATCH RFT] driver core: faux: allow to set the firmware node for a faux device Message-ID: <2026031209-detoxify-rubbing-1e6b@gregkh> References: <20260306-faux-dev-with-fwnode-v1-1-792a86a62530@oss.qualcomm.com> <2026030649-evacuate-emotion-422c@gregkh> <2026030612-collapse-empower-285f@gregkh> <5488a169-777b-4bb3-9566-78083613d40a@oss.qualcomm.com> <2026030921-dwindling-tarnish-6141@gregkh> <2026031034-blazer-equal-871e@gregkh> Precedence: bulk X-Mailing-List: driver-core@lists.linux.dev 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: On Tue, Mar 10, 2026 at 02:18:36PM +0100, Bartosz Golaszewski wrote: > On Tue, Mar 10, 2026 at 1:43 PM Greg Kroah-Hartman > wrote: > > > > On Tue, Mar 10, 2026 at 01:29:53PM +0100, Bartosz Golaszewski wrote: > > > On a completely unrelated note though - Greg: I think this patch could > > > still be considered because we now have quite a lot of functionality > > > put into software nodes and already have some auxiliary devices that > > > use software nodes as a source of device properties/config using the > > > same API as platform devices (fwnode). I think faux devices could also > > > profit from it and not necessairly use custom struct. If that sounds > > > good to you, I may convert one or two faux devices and send a series > > > with actual users of this. > > > > I don't understand why a device that has a fwnode would ever be a "faux" > > device? Why wouldn't that just be a normal platform device? > > > > faux devices were created to be not platform devices, to take away the > > abuse where platform devices were being used because the api was simple > > and people wanted a device in the tree somewhere, but there was not > > actually any backing platform device present. > > > > So the use of a fwnode here feels very odd to me, what am I missing? > > > > A firmware node can be a dynamic software node created just for that > faux device to pass to it its configuration instead of using a custom > platform data structure. Ah, ok, that makes a bit more sense, but faux devices should not need any "configuration" passed to it that I can see, as that would imply some sort of "resource" that it needs, which implies it has some backing hardware (i.e. a platform device) :) Maybe I'm just missing something here, have a real example (other than this one, which everyone seems confused about) that would need this? thanks, greg k-h