Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751828AbdGYMO2 (ORCPT ); Tue, 25 Jul 2017 08:14:28 -0400 Received: from mail-out.m-online.net ([212.18.0.9]:39082 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750897AbdGYMO0 (ORCPT ); Tue, 25 Jul 2017 08:14:26 -0400 X-Auth-Info: XTQZv38Sdfcm+EhqyNeo8O//UQGoNJsrS89lWcVJ5cI= Date: Tue, 25 Jul 2017 14:14:16 +0200 From: Anatolij Gustschin To: Johan Hovold Cc: Lee Jones , Linus Walleij , Alan Tull , Moritz Fischer , linux-gpio@vger.kernel.org, linux-fpga@vger.kernel.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, David Laight Subject: Re: [PATCH 1/3] mfd: Add support for FTDI FT232H devices Message-ID: <20170725141416.5b7764ed@crub> In-Reply-To: <20170725115235.GO2729@localhost> References: <1499374158-12388-1-git-send-email-agust@denx.de> <1499374158-12388-2-git-send-email-agust@denx.de> <20170710125210.GK29638@localhost> <20170719085934.GU29638@localhost> <20170719145900.42172f44@crub> <20170725115235.GO2729@localhost> X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1822 Lines: 39 On Tue, 25 Jul 2017 13:52:35 +0200 Johan Hovold johan@kernel.org wrote: >On Wed, Jul 19, 2017 at 02:59:00PM +0200, Anatolij Gustschin wrote: >> On Wed, 19 Jul 2017 10:59:34 +0200 >> Johan Hovold johan@kernel.org wrote: > >> >> And as David Laight already pointed out, your ftdi-fifo-fpp-mgr driver >> >> seems too application specific for a generic chip like this. >> > >> >Of which this is one is one of the major. >> >> Thanks all for feedback. I'm still pondering how to interface the >> fpga manager driver to FTDI FIFO driver. >> >> >In short, your driver is much to application specific and is probably >> >something that needs to be implemented in userspace using libftdi. >> >> I have a requirement to use the fpga manager framework, therefore the >> kernel driver is needed. Our usage scenario is a multi stage fpga >> configuration process, the first stage is a pre-configuration via >> FTDI SPI/FIFO, all subsequent stages are also done by other fpga >> manager drivers. libftdi based driver already existed for hardware >> bring-up, now I need similar functionality as kernel fpga manager. > >How are you even accessing these fpga-managers from userspace? I thought >current interface was for in-kernel use only? We have different possibilities to access to these fpga-managers from userspace. On platforms with device-tree support there is a DT-Overlay configfs interface for inserting a blob with configuration data and fpga device description. After inserting the blob the fpga manager is invoked automatically. There are also fpga-mgr debugfs config interface patches in Altera linux-socfpga git tree for accessing from userspace. I used them for initial testing, but now I'm using additional kernel module with a single configuration interface for different managers. Thanks, Anatolij