From patchwork Fri Nov 16 19:56:55 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Steven Weaver X-Patchwork-Id: 999119 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=quarantine dis=none) header.from=weaverpad.net Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=weaverpad.net header.i=@weaverpad.net header.b="K21ECNWN"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 42xTXC3YTTz9s3x for ; Sat, 17 Nov 2018 06:56:59 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725763AbeKQGKn (ORCPT ); Sat, 17 Nov 2018 01:10:43 -0500 Received: from weaverpad.net ([107.170.225.214]:49484 "EHLO mail.weaverpad.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725753AbeKQGKn (ORCPT ); Sat, 17 Nov 2018 01:10:43 -0500 Received: from server.chicago.weaver.network (unknown [24.15.188.62]) by mail.weaverpad.net (Postfix) with ESMTPSA id 1F0D541E3A for ; Fri, 16 Nov 2018 19:56:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=weaverpad.net; s=mail; t=1542398217; bh=EnQ8P2kDEajBqd31Ozw7prkmuZgXJhVW/r4KzOhqdtQ=; h=Date:From:To:Subject:From; b=K21ECNWNjE+dpJoo9pdRYusy7cKLcFoWQS/WW1wrRBzcwUN1qqzk4/AE1VpyDlzlJ 9r/PCLOXxBUJY6ttUsHhHpYWqEphlgFuOmg+bn1FVgLr0L41AIINtsbl/Pbyq/DYOj KK7V0RYOG+CEkspET7pxCNb58yeXvxJ+yqfkmV8c8bJ/bglS9f5UrDBVLosCxrVMsE hODZ6dB0Rc0Sjv/Cmur7HqFVGaDsKT1Z6X5beCXyscGZfGCCIRdBHlggQf6tw2pDye 8IFXjqS3YUm1uk9Rh+9pKxqYoJVrp21DTiFe0CQdrCQ3Y5+oXvJLB2XHygtPevMqKD qPfgzhV96CT0g== Date: Fri, 16 Nov 2018 13:56:55 -0600 From: Steven Weaver To: linux-i2c@vger.kernel.org Subject: [PATCH v2] i2c: imx: check bus for busy before signaling start condition. Message-ID: <20181116195651.GA25822@server.chicago.weaver.network> MIME-Version: 1.0 Content-Disposition: inline User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Setting MSTA in I2CR signals a start condition on the bus. In a multi-master scenario, this could clobber a transaction already in progress. Signed-off-by: Steven Weaver --- drivers/i2c/busses/i2c-imx.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index c406700789e1..4720db608489 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -536,6 +536,9 @@ static int i2c_imx_start(struct imx_i2c_struct *i2c_imx) usleep_range(50, 150); /* Start I2C transaction */ + result = i2c_imx_bus_busy(i2c_imx, 1); + if (result) + return result; temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); temp |= I2CR_MSTA; imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);