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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 81C6BC433EF for ; Wed, 15 Dec 2021 17:28:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234826AbhLOR2B (ORCPT ); Wed, 15 Dec 2021 12:28:01 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:43388 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245681AbhLOR0j (ORCPT ); Wed, 15 Dec 2021 12:26:39 -0500 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 ams.source.kernel.org (Postfix) with ESMTPS id 51876B82029; Wed, 15 Dec 2021 17:26:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97595C36AE3; Wed, 15 Dec 2021 17:26:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1639589197; bh=ieMRINSLQZOaXtUuMPBG7qs30pirXAP4drjmkWcEZrE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=H/Edioqusbjk1kWegEPM8v0Y57UwSWFCuJGHwTWYnDAmZQv6vuqmvF0V1oG1xnLbG NgDIBl/eF2YVjtZNZ3NnlCopY/9GJnnvSQKRqCA2BQulnpVWDcBqoR3zFHudsohk8g DG4ucUfrRqtOWAE2PyTCbZOB3rvfAEue/wQhMDI0= 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 5.4 05/18] i2c: rk3x: Handle a spurious start completion interrupt flag Date: Wed, 15 Dec 2021 18:21:26 +0100 Message-Id: <20211215172022.997127046@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211215172022.795825673@linuxfoundation.org> References: <20211215172022.795825673@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 1a33007b03e9e..1107a5e7229e4 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -422,8 +422,8 @@ 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) -- 2.33.0