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 462B91E1C02; Mon, 9 Mar 2026 05:56:53 +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=1773035813; cv=none; b=dBzW0Tfku8nUouX80IVseO0T6bms7sVK5HsUHG4h97L7WoKYf5vpl1zGOdUi2ZTf9wwBkcdOl7BYj1X9bT8ggCzgzRBPucypY1pMoS6S4e2799d+DWVrBzUNp0Udn4W2qFlpth9U16P09921hhaVGnz6pOB6EbZdCieFSwat9gA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773035813; c=relaxed/simple; bh=TZ5CCcxnOFFTvnCRUXhipYRB5dJ/QFkxu7cQ6UQGKo8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=JMyZo+cruPLsD++1sryggiVP7z0cs+h93wz1ZlBPICoWq1XwpnwbpmXapw4BngUsQjJS2HphvESFu8tGuCwiL3t/XvO4CgI3z7DSwFlANFTIxX+qx8fLhUTl9vNSw5cYbMfYteGmguBTiSXoyqn5kjslWzh2Edh7bx9xvcEprBA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=prPH29vv; 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="prPH29vv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 72CFAC4CEF7; Mon, 9 Mar 2026 05:56:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773035813; bh=TZ5CCcxnOFFTvnCRUXhipYRB5dJ/QFkxu7cQ6UQGKo8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=prPH29vvtfGq/6h9NnTitlT+jij/7Z/hm+zdLULPtaz6MBWZq6vk8xNoquW9G2tV8 KVkXVstNE/hkdqPYQ5uRabV26bs+eD6Ruxjk6w3DeA4gFCFDXfv6D54Fsko0Kurfws JZtCtfyBw5UPrmLB5vDJq8WgEZ43y7NY7qQl1F40= Date: Mon, 9 Mar 2026 06:56:38 +0100 From: Greg Kroah-Hartman To: Markus Probst Cc: Lee Jones , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Miguel Ojeda , Boqun Feng , Gary Guo , =?iso-8859-1?Q?Bj=F6rn?= Roy Baron , Benno Lossin , Andreas Hindborg , Alice Ryhl , Trevor Gross , Danilo Krummrich , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, rust-for-linux@vger.kernel.org Subject: Re: [PATCH v2 2/2] mfd: Add initial synology microp driver Message-ID: <2026030913-agonizing-shoptalk-ed98@gregkh> References: <20260308-synology_microp_initial-v2-0-9389963f31c5@posteo.de> <20260308-synology_microp_initial-v2-2-9389963f31c5@posteo.de> <2026030827-nautical-overplant-399c@gregkh> <8efdf3e1bbf24504d560c12131cade543bec82f5.camel@posteo.de> Precedence: bulk X-Mailing-List: rust-for-linux@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8efdf3e1bbf24504d560c12131cade543bec82f5.camel@posteo.de> On Sun, Mar 08, 2026 at 07:15:16PM +0000, Markus Probst wrote: > On Sun, 2026-03-08 at 19:55 +0100, Greg Kroah-Hartman wrote: > > On Sun, Mar 08, 2026 at 06:41:20PM +0000, Markus Probst wrote: > > > Add a initial synology microp driver, written in Rust. > > > The driver targets a microcontroller found in Synology NAS devices. It > > > currently only supports controlling of the power led, status led, alert > > > led and usb led. Other components such as fan control or handling > > > on-device buttons will be added once the required rust abstractions are > > > there. > > > > Why is this a mfd device? Shouldn't it be an aux device? > > > > But this is just a serial port connection, so why is a kernel driver > > needed at all? > I am not sure what you mean. Can't this just be controlled from userspace over the tty device to the uart this device uses? Why is a kernel driver needed at all? > It has multiple functions (leds, hwmon, power/reset, input etc.) and > does is a multifunction device (mfd). > > It does not however use mfd-core or anything from the auxiliary device > and instead implements its functionality directly in this driver. If it does not use mfd-core, then it should not be in drivers/mfd/ right? Instead, use the aux bus code to split this up into different devices and attach them that way, as that's what the aux bus code was created for. thanks, greg k-h