From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.19]) (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 B290A41F341; Mon, 17 Aug 2026 13:01:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.19 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786971700; cv=none; b=GvyHVhBBj+Q0NbEjd2bkj7raJfT9UWYXW7LKuzioUU/RYK9uvgiTCMnzW4OxhkaA6XgzCgRoKZ9rJVydrpafXBX0vLtzifrJwH5kr4MuQhyYoOO7eU3mcN5igpHM7EbkRgWZpV3W4fZgDIDNvNfnIrh+6ai+FFIUBvIjXy4TTQE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786971700; c=relaxed/simple; bh=zoVTlgD3cD2htjt1jPfKTgtfncDVduw8Z413cvKsh88=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=A4eiyaQWc2bbZgQB3Y9RBnCaPVIzoPPm1N7eqNR9TKF0kVlUzTB0iu/H/hiwqe3Shf9qD2y/H1vvn7gGv+GMAhEHKtjIBNVxxtorccJ/UGkFxv7BIPAQQjIy9jEM4VVdPR1zJMNRLd+Z230dD73Tgz9x5nyNmbfhf+kN0JJ/0rU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=miIRVYkp; arc=none smtp.client-ip=198.175.65.19 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="miIRVYkp" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1786971697; x=1818507697; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=zoVTlgD3cD2htjt1jPfKTgtfncDVduw8Z413cvKsh88=; b=miIRVYkpDIf4QrOQRKccQZmoZkosi77RBP5do+QYa2+fe2Bmn87MfBUl U52RQwBrEYnV3iUmffGY11yadH36vHwh0u3+IMztkAAbln+nk5ZJ0dGFH VmF7MuJdoNTkfgy14JoXCPShx/Irf7074sFqRxuUgfa6VTy74zhH3BOor yAc6KUhgdMT0zslJUaqr9UJjQ7NllXVPDTi6w6c6mqualA8bLJZK4wv3w 3MV6UMdGspNUJUuKkfvMwJsD3I7jRaJRgjw8fnpYc97CQoUUTWAs4xlqQ girJhKbUHLM+JyyUCaqBP8g65BrZbpsQOYxFuiZBl2W55bMUap7zBg3AD A==; X-CSE-ConnectionGUID: RzVl9RYdRTGx2d5TjCE3vA== X-CSE-MsgGUID: FetLo2L/TjiFei7aMstdhQ== X-IronPort-AV: E=McAfee;i="6800,10657,11877"; a="87363062" X-IronPort-AV: E=Sophos;i="6.25,228,1779174000"; d="scan'208";a="87363062" Received: from fmviesa009.fm.intel.com ([10.60.135.149]) by orvoesa111.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Aug 2026 06:01:35 -0700 X-CSE-ConnectionGUID: azCg8Rr7T/S8kwEPBqJd8w== X-CSE-MsgGUID: yVvpOZZwRqG5LMVSYbkNLw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.25,228,1779174000"; d="scan'208";a="258705916" Received: from black.igk.intel.com ([10.91.253.5]) by fmviesa009.fm.intel.com with ESMTP; 17 Aug 2026 06:01:27 -0700 Received: by black.igk.intel.com (Postfix, from userid 1003) id 4048899; Mon, 17 Aug 2026 15:01:26 +0200 (CEST) Date: Mon, 17 Aug 2026 15:01:26 +0200 From: Andy Shevchenko To: Manivannan Sadhasivam Cc: Krzysztof Kozlowski , Dmitry Torokhov , manivannan.sadhasivam@oss.qualcomm.com, Rob Herring , Greg Kroah-Hartman , Jiri Slaby , Nathan Chancellor , Nicolas Schier , Hans de Goede , Ilpo =?iso-8859-1?Q?J=E4rvinen?= , Mark Pearson , "Derek J. Clark" , Conor Dooley , Marcel Holtmann , Luiz Augusto von Dentz , Bartosz Golaszewski , Daniel Scally , Heikki Krogerus , Sakari Ailus , "Rafael J. Wysocki" , Danilo Krummrich , Bartosz Golaszewski , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-pci@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-pm@vger.kernel.org, Stephan Gerhold , Dmitry Baryshkov , linux-acpi@vger.kernel.org, Sui Jingfeng Subject: Re: [PATCH v3 03/14] software node: Implement device_get_match_data fwnode callback Message-ID: References: <20260110-pci-m2-e-v3-0-4faee7d0d5ae@oss.qualcomm.com> <20260110-pci-m2-e-v3-3-4faee7d0d5ae@oss.qualcomm.com> <6l3rs5pv6xnrbygpvqrdxqoqtybjyefsltk5bl4336q56rfoza@ejo3sxuufghe> <6peb6afhpm4l7opxbdt3b5sx32longevwds5c3dlqji2hr5dlh@kxuvj55jkqgi> Precedence: bulk X-Mailing-List: linux-kbuild@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: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo On Mon, Aug 17, 2026 at 09:35:05AM +0300, Andy Shevchenko wrote: > On Fri, Aug 14, 2026 at 02:49:31PM +0200, Manivannan Sadhasivam wrote: > > On Mon, Jan 12, 2026 at 10:01:23PM +0530, Manivannan Sadhasivam wrote: > > > On Mon, Jan 12, 2026 at 02:32:21PM +0530, Manivannan Sadhasivam wrote: > > > > On Mon, Jan 12, 2026 at 10:27:45AM +0200, Andy Shevchenko wrote: > > > > > On Mon, Jan 12, 2026 at 01:49:54PM +0530, Manivannan Sadhasivam wrote: > > > > > > + Dmitry Torokhov (who was against this patch previously) > > > > > > > > > > > > On Mon, Jan 12, 2026 at 09:56:06AM +0200, Andy Shevchenko wrote: > > > > > > > On Sat, Jan 10, 2026 at 12:26:21PM +0530, Manivannan Sadhasivam via B4 Relay wrote: > > > > > > > > > > > > > > > Because the software node backend of the fwnode API framework lacks an > > > > > > > > implementation for the .device_get_match_data function callback. > > > > > > > > > > > > > > Maybe this is done on purpose. Have you thought about this aspect? > > > > > > > > > > > > IMO, software nodes were introduced to add sub-properties to the existing > > > > > > firmware nodes, but it has usecase/potential to go beyond that. More below. > > > > > > > > > > Potential doesn't mean the necessity. > > > > > > > > > > > > > This makes it difficult to use(and/or test) a few drivers that originates > > > > > > > > from DT world on the non-DT platform. > > > > > > > > > > > > > > How difficult? DSA implementation went to the way of taking DT overlay > > > > > > > approach. Why that one can't be applied here? > > > > > > > > > > > > Sometimes you do not have any DT node at all. > > > > > > > > > > Yes, that is exactly the case I have referred to. The PCI core (in Linux) > > > > > is able to create DT subtree on non-OF based platforms. > > > > > > > > Maybe I should look into creating dynamic DT node for the device and insert it > > > > to the uart node. Theoretically it should work. > > > > > > It worked flawlessly. So I sent v4 incorporating this design: > > > https://lore.kernel.org/linux-pci/20260112-pci-m2-e-v4-0-eff84d2c6d26@oss.qualcomm.com/ > > > > Andy, I had to revive this old thread of a merged series as Krzk is not in > > favour of adding DT overlay or dynamic OF nodes for these BT devices [1]. His > > objections are due to the fact that we are just adding BT nodes of a > > discoverable device (M.2 PCIe device) without any resources. So the node just > > contains the compatible to match with the serdev driver and nothing else. > > > > And he suggested to use swnodes or other similar mechanisms to plug with the > > serdev driver as that's the only thing we want here, not a true hardware > > description. > > SW nodes are not for describing HW from scratch. They are for fixing missing > pieces. If you can justify your case as a missing piece for the *existing* > device (which is enumerated using standard mechanisms), you can add a property > that fills the gap. > > Unfortunately I see that there are `PROPERTY_ENTRY_STRING("compatible", ...)` > cases in the kernel (only 9 drivers so far), and I can't say if they describing > missing pieces or a SW-made descriptions of the hardware. For the latter the > DT/ACPI/other means but swnodes should be used. I have read all replies by @krzk and the question here, why don't you use auxiliary bus? It seems the best suit for the case. > > Since you strongly objected the swnode approach in this series, I wanted to hear > > your opinion before I rework the code. > > > [1] https://lore.kernel.org/linux-pci/768142f0-2638-41f3-a34f-dc80bb99eb7f@kernel.org -- With Best Regards, Andy Shevchenko