From patchwork Thu Aug 17 14:14:44 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 9907375 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 82A16600CC for ; Fri, 18 Aug 2017 00:37:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 754DF28BB1 for ; Fri, 18 Aug 2017 00:37:29 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6A2A128C08; Fri, 18 Aug 2017 00:37:29 +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=-4.2 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_MED autolearn=ham version=3.3.1 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 146C628BB1 for ; Fri, 18 Aug 2017 00:37:29 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id E8E006E68D; Fri, 18 Aug 2017 00:37:07 +0000 (UTC) X-Original-To: dri-devel@lists.freedesktop.org Delivered-To: dri-devel@lists.freedesktop.org Received: from pokefinder.org (sauhun.de [88.99.104.3]) by gabe.freedesktop.org (Postfix) with ESMTP id 1BB2B6E36B for ; Thu, 17 Aug 2017 14:22:42 +0000 (UTC) Received: from localhost (p54B3365B.dip0.t-ipconnect.de [84.179.54.91]) by pokefinder.org (Postfix) with ESMTPSA id 64E1F2C2F8D; Thu, 17 Aug 2017 16:14:52 +0200 (CEST) From: Wolfram Sang To: linux-i2c@vger.kernel.org Subject: [RFC PATCH v4 1/6] i2c: add a message flag for DMA safe buffers Date: Thu, 17 Aug 2017 16:14:44 +0200 Message-Id: <20170817141449.23958-2-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170817141449.23958-1-wsa+renesas@sang-engineering.com> References: <20170817141449.23958-1-wsa+renesas@sang-engineering.com> X-Mailman-Approved-At: Fri, 18 Aug 2017 00:37:02 +0000 Cc: linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-renesas-soc@vger.kernel.org, Wolfram Sang , linux-input@vger.kernel.org, linux-media@vger.kernel.org X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 */