Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755090AbYJHHa4 (ORCPT ); Wed, 8 Oct 2008 03:30:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753147AbYJHHar (ORCPT ); Wed, 8 Oct 2008 03:30:47 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:45181 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751289AbYJHHaq convert rfc822-to-8bit (ORCPT ); Wed, 8 Oct 2008 03:30:46 -0400 From: "Gadiyar, Anand" To: "johnpol@2ka.mipt.ru" CC: "linux-kernel@vger.kernel.org" , "linux-omap@vger.kernel.org" , "Chikkature Rajashekar, Madhusudhan" Date: Wed, 8 Oct 2008 12:56:33 +0530 Subject: [PATCH 5/5] HDQ: Documentation for OMAP HDQ Thread-Topic: [PATCH 5/5] HDQ: Documentation for OMAP HDQ Thread-Index: AckpFzD8L/bz9btRRCmGA+EZO/Pp+A== Message-ID: <5A47E75E594F054BAF48C5E4FC4B92AB02D6107AF7@dbde02.ent.ti.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2795 Lines: 65 From: Madhusudhan Chikkature This patch adds a brief documentation about omap2430/3430 HDQ/1-wire driver. Signed-off-by: Madhusudhan Chikkature Acked-by: Evgeniy Polyakov --- Documentation/w1/masters/omap-hdq | 46 ++++++++++++++++++++++++++++++++++++++ 1 files changed, 46 insertions(+) Index: linux-omap-2.6/Documentation/w1/masters/omap-hdq =================================================================== --- /dev/null 1970-01-01 00:00:00.000000000 +0000 +++ linux-omap-2.6/Documentation/w1/masters/omap-hdq 2007-12-17 15:43:26.306248879 +0530 @@ -0,0 +1,46 @@ +Kernel driver for omap HDQ/1-wire module. +======================================== + +Supported chips: +================ + HDQ/1-wire controller on the TI OMAP 2430/3430 platforms. + +A useful link about HDQ basics: +=============================== +http://focus.ti.com/lit/an/slua408/slua408.pdf + +Description: +============ +The HDQ/1-Wire module of TI OMAP2430/3430 platforms implement the hardware +protocol of the master functions of the Benchmark HDQ and the Dallas +Semiconductor 1-Wire protocols. These protocols use a single wire for +communication between the master (HDQ/1-Wire controller) and the slave +(HDQ/1-Wire external compliant device). + +A typical application of the HDQ/1-Wire module is the communication with battery +monitor (gas gauge) integrated circuits. + +The controller supports operation in both HDQ and 1-wire mode. The essential +difference between the HDQ and 1-wire mode is how the slave device responds to +initialization pulse.In HDQ mode, the firmware does not require the host to +create an initialization pulse to the slave.However, the slave can be reset by +using an initialization pulse (also referred to as a break pulse).The slave +does not respond with a presence pulse as it does in the 1-Wire protocol. + +Remarks: +======== +The driver (drivers/w1/masters/omap_hdq.c) supports the HDQ mode of the +controller. In this mode, as we can not read the ID which obeys the W1 +spec(family:id:crc), a module parameter can be passed to the driver which will +be used to calculate the CRC and pass back an appropriate slave ID to the W1 +core. + +By default the master driver and the BQ slave i/f +driver(drivers/w1/slaves/w1_bq27000.c) sets the ID to 1. +Please note to load both the modules with a different ID if required, but note +that the ID used should be same for both master and slave driver loading. + +e.g: +insmod omap_hdq.ko W1_ID=2 +inamod w1_bq27000.ko F_ID=2 +-- 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/