From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753274AbdF0Ri4 (ORCPT ); Tue, 27 Jun 2017 13:38:56 -0400 Received: from mga07.intel.com ([134.134.136.100]:39486 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752487AbdF0Ris (ORCPT ); Tue, 27 Jun 2017 13:38:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,271,1496127600"; d="scan'208";a="119433631" Date: Tue, 27 Jun 2017 10:38:44 -0700 (PDT) From: matthew.gerlach@linux.intel.com X-X-Sender: mgerlach@mgerlach-VirtualBox To: Marek Vasut cc: vndao@altera.com, dwmw2@infradead.org, computersforpeace@gmail.com, boris.brezillon@free-electrons.com, richard@nod.at, cyrille.pitchen@wedev4u.fr, robh+dt@kernel.org, mark.rutland@arm.com, linux-mtd@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org, davem@davemloft.net, mchehab@kernel.org Subject: Re: [PATCH 3/3] mtd: spi-nor: Altera Quadspi Flash Controller v2 Platform driver In-Reply-To: <5f0e2ddd-d329-cb3d-01bc-c101247281a7@gmail.com> Message-ID: References: <1498493619-4633-1-git-send-email-matthew.gerlach@linux.intel.com> <1498493619-4633-4-git-send-email-matthew.gerlach@linux.intel.com> <2ac33989-5665-33e0-c6f0-6791c8e46b0d@gmail.com> <5f0e2ddd-d329-cb3d-01bc-c101247281a7@gmail.com> User-Agent: Alpine 2.20 (DEB 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 27 Jun 2017, Marek Vasut wrote: > On 06/27/2017 05:15 PM, matthew.gerlach@linux.intel.com wrote: >> >> >> On Tue, 27 Jun 2017, Marek Vasut wrote: >> >>> On 06/26/2017 06:13 PM, matthew.gerlach@linux.intel.com wrote: >>>> From: Matthew Gerlach >>> >>> Just wrap it into the Altera QSPI driver , no need for separate platform >>> driver IMO. >> >> Hi Marek, >> >> I answered this question when you asked why the header file was >> necessary, but I think further discussion could be helpful, since this >> problem is becoming more prevelent. The Altera Quadspi component is a >> soft IP in a >> FPGA, and the processor using the component may or may not have device >> tree support compiled into the Linux kernel. Since device tree support >> may or may not be available, the device tree specific code must be >> separated >> from the core driver code. > > I see, that's fine, although there is no PCIe or other support in this > submission. Is that planned ? You probably would not see a PCIe driver for a card with a FPGA that would only have the Altera Quadspi component on it. Usually a FPGA has several components, each requiring their own driver which are considered sub-drivers of the PCIe driver. I will be adding Altera Quadspi support to the Intel-FPGA PCIe driver that is currently under review. We have also seen people use the Altera Quadspi with a NIOS-II soft processor, and I expect someone would want to use the component with ARM SOCFPGAs. Matthew Gerlach > >> One can certainly make the case, that device tree support could/should >> be available everywhere, but the current reality is most x86 Linux >> kernel configurations do not include device tree support. >> >> For the record, I believe device trees, and more specifically device >> tree overlays, are the best way for Linux to use FPGAs, but I have to >> deal with the current realities. >> >> Thanks again for all the great feedback. >> >> Matthew Gerlach > > [...] > > -- > Best regards, > Marek Vasut >