From patchwork Mon Dec 20 14:34:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 526568 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6D1F0C433EF for ; Mon, 20 Dec 2021 14:36:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233912AbhLTOgz (ORCPT ); Mon, 20 Dec 2021 09:36:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59206 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233866AbhLTOgq (ORCPT ); Mon, 20 Dec 2021 09:36:46 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87EEBC06175E; Mon, 20 Dec 2021 06:36:45 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id D8B89CE0F9E; Mon, 20 Dec 2021 14:36:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A2A98C36AEA; Mon, 20 Dec 2021 14:36:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640011002; bh=5WHsyBQsEtEnZ86t/8WCO8RRM2Kyqh/DD9/FU0LArNM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fU4r3TcoYOjic4T6BR8ElT7bRSLZOrRFf56nTP6egJwQprwxeanZhI0I6fbJd4+u/ 5SvQMrWhpDaD5S/AG6MBTNeMe0c7dU/cRhH4aALZMVF1jN1bSJ4tTwsX5gfKJbAMAH jLKPVDYKDwAOLsoFTHBUDb3b2n9eOqqGS/PBmr4c= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ondrej Jirman , John Keeping , Wolfram Sang , Sasha Levin Subject: [PATCH 4.4 03/23] i2c: rk3x: Handle a spurious start completion interrupt flag Date: Mon, 20 Dec 2021 15:34:04 +0100 Message-Id: <20211220143017.950463261@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211220143017.842390782@linuxfoundation.org> References: <20211220143017.842390782@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Ondrej Jirman [ Upstream commit 02fe0fbd8a21e183687925c3a266ae27dda9840f ] In a typical read transfer, start completion flag is being set after read finishes (notice ipd bit 4 being set): trasnfer poll=0 i2c start rk3x-i2c fdd40000.i2c: IRQ: state 1, ipd: 10 i2c read rk3x-i2c fdd40000.i2c: IRQ: state 2, ipd: 1b i2c stop rk3x-i2c fdd40000.i2c: IRQ: state 4, ipd: 33 This causes I2C transfer being aborted in polled mode from a stop completion handler: trasnfer poll=1 i2c start rk3x-i2c fdd40000.i2c: IRQ: state 1, ipd: 10 i2c read rk3x-i2c fdd40000.i2c: IRQ: state 2, ipd: 0 rk3x-i2c fdd40000.i2c: IRQ: state 2, ipd: 1b i2c stop rk3x-i2c fdd40000.i2c: IRQ: state 4, ipd: 13 i2c stop rk3x-i2c fdd40000.i2c: unexpected irq in STOP: 0x10 Clearing the START flag after read fixes the issue without any obvious side effects. This issue was dicovered on RK3566 when adding support for powering off the RK817 PMIC. Signed-off-by: Ondrej Jirman Reviewed-by: John Keeping Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-rk3x.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c index 9096d17beb5bb..587f1a5a10243 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -325,8 +325,8 @@ static void rk3x_i2c_handle_read(struct rk3x_i2c *i2c, unsigned int ipd) if (!(ipd & REG_INT_MBRF)) return; - /* ack interrupt */ - i2c_writel(i2c, REG_INT_MBRF, REG_IPD); + /* ack interrupt (read also produces a spurious START flag, clear it too) */ + i2c_writel(i2c, REG_INT_MBRF | REG_INT_START, REG_IPD); /* Can only handle a maximum of 32 bytes at a time */ if (len > 32)