From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:6f8:1178:4:290:27ff:fe1d:cc33]) by canuck.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1QjmkC-0007DN-DQ for barebox@lists.infradead.org; Thu, 21 Jul 2011 06:28:25 +0000 Date: Thu, 21 Jul 2011 08:28:18 +0200 From: Sascha Hauer Message-ID: <20110721062818.GU20587@pengutronix.de> References: <20110720203156.GT20587@pengutronix.de> <20110721031224.GL15388@game.jcrosoft.org> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110721031224.GL15388@game.jcrosoft.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: barebox-bounces@lists.infradead.org Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: Re: serial_ns16550 driver question To: Jean-Christophe PLAGNIOL-VILLARD Cc: barebox On Thu, Jul 21, 2011 at 05:12:24AM +0200, Jean-Christophe PLAGNIOL-VILLARD wrote: > On 22:31 Wed 20 Jul , Sascha Hauer wrote: > > On Wed, Jul 20, 2011 at 11:51:04PM +0400, Antony Pavlov wrote: > > > Hi! > > > > > > In include/ns16550.h we have: > > > > > > struct NS16550_plat { > > > unsigned int clock; > > > unsigned char f_caps; > > > /** > > > * register read access capability > > > */ > > > unsigned int (*reg_read) (unsigned long base, unsigned char reg_offset); > > > /** > > > * register write access capability > > > */ > > > void (*reg_write) (unsigned int val, unsigned long base, > > > unsigned char reg_offset); > > > }; > > > > > > Why reg_read and reg_write's argument base has type unsigned long? > > > IMHO pointer type (void * or char *) is more natural. > > > > You're right, I also wondered about this recently when looking at a > > patch on the list. I would also rather see void __iomem *. The problem > > is that this driver is also used on X86 which uses inb/outb which take > > an integer argument. > > The Linux driver works around this by having a membase and a iobase > > field along with different register accessors. While being cleaner > > I'm unsure if we want to go this way. > > we can do it via resoure and the flasgs IORESOURCE_MEM_8BIT, > IORESOURCE_MEM_168BITi etc.. Yes, but this does not solve the problem with different accessor functions (and their argument type). Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox