From patchwork Thu Jul 17 14:48:36 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bastian Hecht X-Patchwork-Id: 4576051 Return-Path: X-Original-To: patchwork-linux-sh@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id DC7E0C0514 for ; Thu, 17 Jul 2014 14:50:46 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id C87E72017D for ; Thu, 17 Jul 2014 14:50:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E1AD92011B for ; Thu, 17 Jul 2014 14:50:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933518AbaGQOtG (ORCPT ); Thu, 17 Jul 2014 10:49:06 -0400 Received: from mail-wi0-f169.google.com ([209.85.212.169]:43578 "EHLO mail-wi0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933342AbaGQOtD (ORCPT ); Thu, 17 Jul 2014 10:49:03 -0400 Received: by mail-wi0-f169.google.com with SMTP id n3so7269141wiv.4 for ; Thu, 17 Jul 2014 07:49:02 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id; bh=LgeH+64h+/29WKGIQKODBrRXz7k2tLwQF70AVzISBf4=; b=oZE3kVrpuohINOb4Ch81buG/FKMN+F0NnSly94r8cF2ujLd/49nTGrNi79bq8GN8cS z1Y9jGibmsrs0N4AgOSEq0+M9MLD5mETy5l/Nrx/eZa5KYsY1AvnBGvJ0NmUWA8qfkGR 8uIHrXLWDyKGH2P74Z6ZiYSwsPOFkJdYrnmj4DwAECmKg8+C+XIMwrId9QQCXBErS5OF HeWC37/3WYiBlHxPjjE/CI7GPIG0gPvWCjx6R6rMuqNRI8AeETY5Fdulg3Oh/Ha1s6MV fC2VkTlKeOqg/Oplhg0KB76zjv2pio1JD/tDlukjw401v4cmWsXrg/gCYHjvPERcJ1X7 7/dA== X-Received: by 10.194.158.164 with SMTP id wv4mr4822258wjb.124.1405608542371; Thu, 17 Jul 2014 07:49:02 -0700 (PDT) Received: from ipanema.Speedport_W723_V_Typ_A_1_01_001 (p5B3C7F4A.dip0.t-ipconnect.de. [91.60.127.74]) by mx.google.com with ESMTPSA id di7sm6646044wjb.34.2014.07.17.07.49.00 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 17 Jul 2014 07:49:01 -0700 (PDT) From: Bastian Hecht To: linux-i2c@vger.kernel.org Cc: Linux-SH , Tomoya MORINAGA , Wolfram Sang , linux-arm-kernel@lists.infradead.org, Bastian Hecht , linux-kernel@vger.kernel.org (open list) Subject: [PATCH v2 1/5] i2c: Don't start transfers when suspended Date: Thu, 17 Jul 2014 16:48:36 +0200 Message-Id: <1405608520-5644-1-git-send-email-hechtb@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED, DKIM_SIGNED, FREEMAIL_FROM, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, T_DKIM_INVALID, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP i2c transfer requests come in very uncontrolled, like from interrupt routines. We might be suspended when this happens. To avoid i2c timeouts caused by powered down busses we check for suspension. Several bus drivers handle this problem on their own. We can clean things up by moving the protection mechanism into the core. Signed-off-by: Bastian Hecht --- changelog v2: - commit message extended. - initialization added for adap->suspended - swapped branch for increased performance drivers/i2c/i2c-core.c | 25 ++++++++++++++++++++++++- include/linux/i2c.h | 1 + 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c index 7c7f4b8..b15dc20 100644 --- a/drivers/i2c/i2c-core.c +++ b/drivers/i2c/i2c-core.c @@ -343,6 +343,13 @@ static int i2c_legacy_resume(struct device *dev) static int i2c_device_pm_suspend(struct device *dev) { const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + struct i2c_adapter *adap = i2c_verify_adapter(dev); + + if (adap) { + i2c_lock_adapter(adap); + adap->suspended = true; + i2c_unlock_adapter(adap); + } if (pm) return pm_generic_suspend(dev); @@ -353,6 +360,13 @@ static int i2c_device_pm_suspend(struct device *dev) static int i2c_device_pm_resume(struct device *dev) { const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL; + struct i2c_adapter *adap = i2c_verify_adapter(dev); + + if (adap) { + i2c_lock_adapter(adap); + adap->suspended = false; + i2c_unlock_adapter(adap); + } if (pm) return pm_generic_resume(dev); @@ -1243,6 +1257,7 @@ static int i2c_register_adapter(struct i2c_adapter *adap) dev_set_name(&adap->dev, "i2c-%d", adap->nr); adap->dev.bus = &i2c_bus_type; adap->dev.type = &i2c_adapter_type; + adap->suspended = false; res = device_register(&adap->dev); if (res) goto out_list; @@ -1819,7 +1834,10 @@ int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) i2c_lock_adapter(adap); } - ret = __i2c_transfer(adap, msgs, num); + if (!adap->suspended) + ret = __i2c_transfer(adap, msgs, num); + else + ret = -EIO; i2c_unlock_adapter(adap); return ret; @@ -2577,6 +2595,10 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, if (adapter->algo->smbus_xfer) { i2c_lock_adapter(adapter); + if (adapter->suspended) { + res = -EIO; + goto unlock; + } /* Retry automatically on arbitration loss */ orig_jiffies = jiffies; @@ -2590,6 +2612,7 @@ s32 i2c_smbus_xfer(struct i2c_adapter *adapter, u16 addr, unsigned short flags, orig_jiffies + adapter->timeout)) break; } +unlock: i2c_unlock_adapter(adapter); if (res != -EOPNOTSUPP || !adapter->algo->master_xfer) diff --git a/include/linux/i2c.h b/include/linux/i2c.h index b556e0a..af08c75 100644 --- a/include/linux/i2c.h +++ b/include/linux/i2c.h @@ -434,6 +434,7 @@ struct i2c_adapter { int timeout; /* in jiffies */ int retries; struct device dev; /* the adapter device */ + unsigned int suspended:1; int nr; char name[48];