From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07443C433E7 for ; Fri, 9 Oct 2020 07:53:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A9A2B22267 for ; Fri, 9 Oct 2020 07:53:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729278AbgJIHxq (ORCPT ); Fri, 9 Oct 2020 03:53:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48476 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725908AbgJIHxq (ORCPT ); Fri, 9 Oct 2020 03:53:46 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BA3AC0613D2 for ; Fri, 9 Oct 2020 00:53:46 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kQnDc-0002nC-33; Fri, 09 Oct 2020 09:53:36 +0200 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1kQnDb-0000D2-KW; Fri, 09 Oct 2020 09:53:35 +0200 Date: Fri, 9 Oct 2020 09:53:35 +0200 From: Oleksij Rempel To: Christian Eggers Cc: Oleksij Rempel , Shawn Guo , Sascha Hauer , Fabio Estevam , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , David Laight , linux-kernel@vger.kernel.org, Krzysztof Kozlowski , NXP Linux Team , Pengutronix Kernel Team , stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org Subject: Re: [PATCH v5 2/3] i2c: imx: Check for I2SR_IAL after every byte Message-ID: <20201009075335.GC817@pengutronix.de> References: <20201007084524.10835-1-ceggers@arri.de> <20201007084524.10835-3-ceggers@arri.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201007084524.10835-3-ceggers@arri.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 09:53:03 up 35 days, 22:00, 231 users, load average: 0.34, 1.03, 4.32 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 07, 2020 at 10:45:23AM +0200, Christian Eggers wrote: > Arbitration Lost (IAL) can happen after every single byte transfer. If > arbitration is lost, the I2C hardware will autonomously switch from > master mode to slave. If a transfer is not aborted in this state, > consecutive transfers will not be executed by the hardware and will > timeout. > > Signed-off-by: Christian Eggers > Tested (not extensively) on Vybrid VF500 (Toradex VF50): > Tested-by: Krzysztof Kozlowski > Cc: stable@vger.kernel.org Acked-by: Oleksij Rempel Thank you! > --- > drivers/i2c/busses/i2c-imx.c | 10 ++++++++++ > 1 file changed, 10 insertions(+) > > diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c > index cbdcab73a055..63575af41c09 100644 > --- a/drivers/i2c/busses/i2c-imx.c > +++ b/drivers/i2c/busses/i2c-imx.c > @@ -490,6 +490,16 @@ static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx, bool atomic) > dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__); > return -ETIMEDOUT; > } > + > + /* check for arbitration lost */ > + if (i2c_imx->i2csr & I2SR_IAL) { > + dev_dbg(&i2c_imx->adapter.dev, "<%s> Arbitration lost\n", __func__); > + i2c_imx_clear_irq(i2c_imx, I2SR_IAL); > + > + i2c_imx->i2csr = 0; > + return -EAGAIN; > + } > + > dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__); > i2c_imx->i2csr = 0; > return 0; > -- > Christian Eggers > Embedded software developer > > Arnold & Richter Cine Technik GmbH & Co. Betriebs KG > Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918 > Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH > Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477 > Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler > > > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |