From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8348 invoked by alias); 19 May 2009 12:00:27 -0000 Received: (qmail 8332 invoked by uid 22791); 19 May 2009 12:00:24 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from londo.lunn.ch (HELO londo.lunn.ch) (80.238.139.98) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 19 May 2009 12:00:17 +0000 Received: from lunn by londo.lunn.ch with local (Exim 3.36 #1 (Debian)) id 1M6NzI-00016A-00; Tue, 19 May 2009 14:00:04 +0200 Date: Tue, 19 May 2009 12:00:00 -0000 From: Andrew Lunn To: Chris Holgate Cc: Simon Kallweit , ecos-devel@sourceware.org Subject: Re: STM32 USB support Message-ID: <20090519120004.GI20046@lunn.ch> References: <4A11CAAA.8040900@intefo.ch> <4A11D861.8090206@zynaptic.com> <4A11E5DF.2000403@intefo.ch> <4A129C34.9090606@zynaptic.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A129C34.9090606@zynaptic.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-IsSubscribed: yes Mailing-List: contact ecos-devel-help@ecos.sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: ecos-devel-owner@ecos.sourceware.org X-SW-Source: 2009-05/txt/msg00026.txt.bz2 > >> There is a significant difference from the other USB drivers which I > >> should probably flag up (and document). The endpoint configuration is > >> generated dynamically from the USB descriptors. This gives a lot of > >> flexibility and potentially allows support for multiple configurations > >> (untested!). However, the downside is that I had to leave out devtab > >> support since the devtab entries need to be set statically. > >> > > Don't you think it's possible to have both options? I haven't looked at > > the USB subsystem or any drivers, but I think a public driver should > > behave as the subsystem intends. Maybe the subsystem could be extended > > for more dynamic usage though. > > The official docs say "To support this the device driver can provide a > devtab entry for each endpoint". I took that to mean that devtab > support was optional - and the dynamic endpoint configuration is a much > more useful feature IMHO. > > Previously supported hardware has had fixed endpoint configurations > which makes the static devtab entries easy to implement. However, with > dynamic endpoint configuration, the low-level driver doesn't know > a-priori what endpoints to generate devtab entries for - and nor should it! The AT91 USB driver has something similar to this. It can configure the endpoints by looking at the USB descriptors. I don't remember how it works with respect to devtab entries. Andrew