From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752623AbeDMRoT (ORCPT ); Fri, 13 Apr 2018 13:44:19 -0400 Received: from mail-ot0-f201.google.com ([74.125.82.201]:40324 "EHLO mail-ot0-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751771AbeDMRnM (ORCPT ); Fri, 13 Apr 2018 13:43:12 -0400 X-Google-Smtp-Source: AIpwx48txAh4PDZtm9qwqIDsxAUPXWGBPTqZy5bvbyr51YV+ZWxkouD9EdCgw/342lDF+o99ZzEsaMlAeu3v MIME-Version: 1.0 Date: Fri, 13 Apr 2018 10:42:56 -0700 In-Reply-To: <20180413174257.139182-1-hansens@google.com> Message-Id: <20180413174257.139182-2-hansens@google.com> References: <20180413174257.139182-1-hansens@google.com> X-Mailer: git-send-email 2.17.0.484.g0c8726318c-goog Subject: [PATCH v3 2/3] Documentation/i2c: sync docs with current state of i2c-tools From: Sam Hansen To: linux-i2c@vger.kernel.org, hansens@google.com, wsa@the-dreams.de, corbet@lwn.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Sam Hansen , wsa@the-dreams.de, corbet@lwn.net, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently, Documentation/i2c/dev-interface describes the use of i2c_smbus_* helper routines as static inlined functions provided by linux/i2c-dev.h. Work has been done to refactor the linux/i2c-dev.h file in the i2c-tools project out into its own library. As a result, these docs have become stale. This patch corrects the discrepancy and directs the reader to the i2c-tools project for more information. Signed-off-by: Sam Hansen --- No changes from v2. Documentation/i2c/dev-interface | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) diff --git a/Documentation/i2c/dev-interface b/Documentation/i2c/dev-interface index c8737d502791..f92ee1f59914 100644 --- a/Documentation/i2c/dev-interface +++ b/Documentation/i2c/dev-interface @@ -23,11 +23,6 @@ First, you need to include these two headers: #include #include -(Please note that there are two files named "i2c-dev.h" out there. One is -distributed with the Linux kernel and the other one is included in the -source tree of i2c-tools. They used to be different in content but since 2012 -they're identical. You should use "linux/i2c-dev.h"). - Now, you have to decide which adapter you want to access. You should inspect /sys/class/i2c-dev/ or run "i2cdetect -l" to decide this. Adapter numbers are assigned somewhat dynamically, so you can not @@ -140,8 +135,8 @@ ioctl(file, I2C_RDWR, struct i2c_rdwr_ioctl_data *msgset) set in each message, overriding the values set with the above ioctl's. ioctl(file, I2C_SMBUS, struct i2c_smbus_ioctl_data *args) - Not meant to be called directly; instead, use the access functions - below. + If possible, use the provided i2c_smbus_* methods described below instead + of issuing direct ioctls. You can do plain i2c transactions by using read(2) and write(2) calls. You do not need to pass the address byte; instead, set it through @@ -166,10 +161,9 @@ what happened. The 'write' transactions return 0 on success; the returns the number of values read. The block buffers need not be longer than 32 bytes. -The above functions are all inline functions, that resolve to calls to -the i2c_smbus_access function, that on its turn calls a specific ioctl -with the data in a specific format. Read the source code if you -want to know what happens behind the screens. +The above functions are made available by linking against the libi2c library, +which is provided by the i2c-tools project. See: +https://git.kernel.org/pub/scm/utils/i2c-tools/i2c-tools.git/. Implementation details -- 2.17.0.484.g0c8726318c-goog