Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752167Ab1CKRXp (ORCPT ); Fri, 11 Mar 2011 12:23:45 -0500 Received: from mail-vx0-f174.google.com ([209.85.220.174]:54486 "EHLO mail-vx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750819Ab1CKRXo (ORCPT ); Fri, 11 Mar 2011 12:23:44 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=subject:from:to:content-type:date:message-id:mime-version:x-mailer :content-transfer-encoding; b=WA/eo6WjrkgCNRn3TcbpFMU0Vd4LBmABzdLCB46Liscm/Q1Ax0T5sett7/Ekr8N8mc ZG6bsMlt8jl6L7MUuNoocg45vl4kArYMacbfamhI7Eu2LfTMngx3EOPs0r9bqb8axFUn yUlt9anuxBLyaXQAxHHyxxzWZqwXAYFzL/RWQ= Subject: [PATCH] Add 1-wire (w1) reset and resume command API support From: Jean-Francois Dagenais To: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Date: Fri, 11 Mar 2011 12:23:41 -0500 Message-ID: <1299864221.8754.11.camel@jfddesk> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3011 Lines: 89 This is needed for my next patch about DS2408 >From aba11ba9d50c0fa7a29c81ecb81c13afb986b042 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Jean-Fran=C3=A7ois=20Dagenais?= Date: Thu, 10 Mar 2011 11:04:16 -0500 Subject: [PATCH] Add 1-wire (w1) reset and resume command API support MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit To: johnpol@2ka.mipt.ru Cc: linux-kernel@vger.kernel.org Signed-off-by: Jean-François Dagenais --- drivers/w1/w1.h | 2 ++ drivers/w1/w1_io.c | 26 ++++++++++++++++++++++++++ 2 files changed, 28 insertions(+), 0 deletions(-) diff --git a/drivers/w1/w1.h b/drivers/w1/w1.h index d8a9709..f804eba 100644 --- a/drivers/w1/w1.h +++ b/drivers/w1/w1.h @@ -55,6 +55,7 @@ struct w1_reg_num #define W1_READ_ROM 0x33 #define W1_READ_PSUPPLY 0xB4 #define W1_MATCH_ROM 0x55 +#define W1_RESUME_CMD 0xA5 #define W1_SLAVE_ACTIVE 0 @@ -213,6 +214,7 @@ void w1_write_block(struct w1_master *, const u8 *, int); void w1_touch_block(struct w1_master *, u8 *, int); u8 w1_read_block(struct w1_master *, u8 *, int); int w1_reset_select_slave(struct w1_slave *sl); +int w1_reset_resume_command(struct w1_master *); void w1_next_pullup(struct w1_master *, int); static inline struct w1_slave* dev_to_w1_slave(struct device *dev) diff --git a/drivers/w1/w1_io.c b/drivers/w1/w1_io.c index 3ebe972..8e8b64c 100644 --- a/drivers/w1/w1_io.c +++ b/drivers/w1/w1_io.c @@ -390,6 +390,32 @@ int w1_reset_select_slave(struct w1_slave *sl) EXPORT_SYMBOL_GPL(w1_reset_select_slave); /** + * When the workflow with a slave amongst many requires several + * successive commands a reset between each, this function is similar + * to doing a reset then a match ROM for the last matched ROM. The + * advantage being that the matched ROM step is skipped in favor of the + * resume command. The slave must support the command of course. + * + * If the bus has only one slave, traditionnaly the match ROM is skipped + * and a "SKIP ROM" is done for efficiency. On multi-slave busses, this + * doesn't work of course, but the resume command is the next best thing. + * + * The w1 master lock must be held. + * + * @param dev the master device + */ +int w1_reset_resume_command(struct w1_master *dev) +{ + if (w1_reset_bus(dev)) + return -1; + + /* This will make only the last matched slave perform a skip ROM. */ + w1_write_8(dev, W1_RESUME_CMD); + return 0; +} +EXPORT_SYMBOL_GPL(w1_reset_resume_command); + +/** * Put out a strong pull-up of the specified duration after the next write * operation. Not all hardware supports strong pullups. Hardware that * doesn't support strong pullups will sleep for the given time after the -- 1.7.4.1 -- 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/