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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 D96D8C433E2 for ; Thu, 17 Sep 2020 14:57:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9DD8C206DC for ; Thu, 17 Sep 2020 14:57:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727534AbgIQO5e convert rfc822-to-8bit (ORCPT ); Thu, 17 Sep 2020 10:57:34 -0400 Received: from mailout09.rmx.de ([94.199.88.74]:42461 "EHLO mailout09.rmx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727387AbgIQOv2 (ORCPT ); Thu, 17 Sep 2020 10:51:28 -0400 Received: from kdin01.retarus.com (kdin01.dmz1.retloc [172.19.17.48]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mailout09.rmx.de (Postfix) with ESMTPS id 4Bsf9R3fS6zbhsy; Thu, 17 Sep 2020 16:14:35 +0200 (CEST) Received: from mta.arri.de (unknown [217.111.95.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by kdin01.retarus.com (Postfix) with ESMTPS id 4Bsf925k8gz2xcC; Thu, 17 Sep 2020 16:14:14 +0200 (CEST) Received: from n95hx1g2.localnet (192.168.54.36) by mta.arri.de (192.168.100.104) with Microsoft SMTP Server (TLS) id 14.3.408.0; Thu, 17 Sep 2020 16:13:51 +0200 From: Christian Eggers To: Uwe =?ISO-8859-1?Q?Kleine=2DK=F6nig?= CC: Oleksij Rempel , Shawn Guo , Sascha Hauer , Fabio Estevam , , , NXP Linux Team , Pengutronix Kernel Team , , Subject: Re: [PATCH 1/3] i2c: imx: Fix reset of I2SR_IAL flag Date: Thu, 17 Sep 2020 16:13:50 +0200 Message-ID: <16013235.tl8pWZfNaG@n95hx1g2> Organization: Arnold & Richter Cine Technik GmbH & Co. Betriebs KG In-Reply-To: <20200917140235.igfq2hq63f4qqhrr@pengutronix.de> References: <20200917122029.11121-1-ceggers@arri.de> <20200917122029.11121-2-ceggers@arri.de> <20200917140235.igfq2hq63f4qqhrr@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="iso-8859-1" X-Originating-IP: [192.168.54.36] X-RMX-ID: 20200917-161416-4Bsf925k8gz2xcC-0@kdin01 X-RMX-SOURCE: 217.111.95.66 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Uwe, On Thursday, 17 September 2020, 16:02:35 CEST, Uwe Kleine-König wrote: > Hello, > > On Thu, Sep 17, 2020 at 02:20:27PM +0200, Christian Eggers wrote: > ... > > /* check for arbitration lost */ > > if (temp & I2SR_IAL) { > > temp &= ~I2SR_IAL; > > + temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IAL); > > imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR); > > return -EAGAIN; > ... > This looks strange. First the flag is cleared and then it is (in some > cases) set again. i.MX controllers require writing a 0 to clear these bits. Vybrid controllers need writing a 1 for the same. > If I2SR_IIF is set in temp you ack this irq without handling it. (Which > might happen if atomic is set and irqs are off?!) This patch is only about using the correct processor specific value for acknowledging an IRQ... But I think that returning EAGAIN (which aborts the transfer) should be handling enough. At the next transfer, the controller will be set back to master mode. > I see this idiom is used in a few more places in the driver already, I > didn't check but these might have the same problem maybe? Best regards Christian