From patchwork Wed Sep 20 18:59:51 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 9962073 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8F0EB6056D for ; Wed, 20 Sep 2017 19:01:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 81D1B2904D for ; Wed, 20 Sep 2017 19:01:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 76A5029214; Wed, 20 Sep 2017 19:01:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 33BD2291E6 for ; Wed, 20 Sep 2017 19:01:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751556AbdITTAF (ORCPT ); Wed, 20 Sep 2017 15:00:05 -0400 Received: from sauhun.de ([88.99.104.3]:38834 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751396AbdITTAD (ORCPT ); Wed, 20 Sep 2017 15:00:03 -0400 Received: from localhost (p54B332E6.dip0.t-ipconnect.de [84.179.50.230]) by pokefinder.org (Postfix) with ESMTPSA id DD2652C4397; Wed, 20 Sep 2017 21:00:01 +0200 (CEST) From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-iio@vger.kernel.org, linux-input@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, Wolfram Sang Subject: [RFC PATCH v5 1/6] i2c: add a message flag for DMA safe buffers Date: Wed, 20 Sep 2017 20:59:51 +0200 Message-Id: <20170920185956.13874-2-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170920185956.13874-1-wsa+renesas@sang-engineering.com> References: <20170920185956.13874-1-wsa+renesas@sang-engineering.com> Sender: linux-iio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP I2C has no requirement that the buffer of a message needs to be DMA safe. In case it is, it can now be flagged, so drivers wishing to do DMA can use the buffer directly. Signed-off-by: Wolfram Sang --- include/uapi/linux/i2c.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/uapi/linux/i2c.h b/include/uapi/linux/i2c.h index 009e27bb9abe19..1c683cb319e4b7 100644 --- a/include/uapi/linux/i2c.h +++ b/include/uapi/linux/i2c.h @@ -71,6 +71,9 @@ struct i2c_msg { #define I2C_M_RD 0x0001 /* read data, from slave to master */ /* I2C_M_RD is guaranteed to be 0x0001! */ #define I2C_M_TEN 0x0010 /* this is a ten bit chip address */ +#define I2C_M_DMA_SAFE 0x0200 /* the buffer of this message is DMA safe */ + /* makes only sense in kernelspace */ + /* userspace buffers are copied anyway */ #define I2C_M_RECV_LEN 0x0400 /* length will be first received byte */ #define I2C_M_NO_RD_ACK 0x0800 /* if I2C_FUNC_PROTOCOL_MANGLING */ #define I2C_M_IGNORE_NAK 0x1000 /* if I2C_FUNC_PROTOCOL_MANGLING */