Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761539AbYGOCSb (ORCPT ); Mon, 14 Jul 2008 22:18:31 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761357AbYGOCRj (ORCPT ); Mon, 14 Jul 2008 22:17:39 -0400 Received: from SpacedOut.fries.net ([67.64.210.234]:56249 "EHLO SpacedOut.fries.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761310AbYGOCRi (ORCPT ); Mon, 14 Jul 2008 22:17:38 -0400 Date: Mon, 14 Jul 2008 21:16:56 -0500 From: David Fries To: Randy Dunlap Cc: Evgeniy Polyakov , linux-kernel@vger.kernel.org, Andrew Morton Subject: Re: [PATCH 29/30] W1: Documentation/w1/masters/ds2490 update Message-ID: <20080715021656.GQ5621@spacedout.fries.net> References: <12157843054074-git-send-email-johnpol@2ka.mipt.ru> <12157843071043-git-send-email-johnpol@2ka.mipt.ru> <20080714134002.e5dfaaae.randy.dunlap@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080714134002.e5dfaaae.randy.dunlap@oracle.com> User-Agent: Mutt/1.5.4i X-Greylist: Sender is SPF-compliant, not delayed by milter-greylist-3.0 (SpacedOut.fries.net [127.0.0.1]); Mon, 14 Jul 2008 21:17:03 -0500 (CDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1993 Lines: 40 On Mon, Jul 14, 2008 at 01:40:02PM -0700, Randy Dunlap wrote: > > +- The number of USB bus transactions could be reduced if w1_reset_send > > + was added to the API. The name is just a suggestion. It would take > > + a write buffer and a read buffer (along with sizes) as arguments. > > + It would add match rom and rom to the send buffer, reset the bus, > ~~~~~~~~~~~~~~~~~ > Can you clarify above? I re-wrote the paragraph. In the one wire protocol a bus reset is followed by a one byte command, in this case match rom which tells all the devices on the bus to expect an 8byte rom (slave device id) and only the slave device that matches the rom is to respond to the following message. I was assuming people reading it would be familiar with the one wire bus protocol. Do you have any of the one wire hardware? - The number of USB bus transactions could be reduced if w1_reset_send was added to the API. The name is just a suggestion. It would take a write buffer and a read buffer (along with sizes) as arguments. The ds2490 block I/O command supports reset, write buffer, read buffer, and strong pullup all in one command, instead of the current 1 reset bus, 2 write the match rom command and slave rom id, 3 block write and read data. The write buffer needs to have the match rom command and slave rom id prepended to the front of the requested write buffer, both of which are known to the driver. The next paragraph was removed, I decided that listing the commands giong from three to one was enough, I didn't need to count all the USB bus transactions. I'll send the patch again in the next e-mail. -- David Fries http://fries.net/~david/ (PGP encryption key available) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/