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 03438C433F5 for ; Mon, 6 Dec 2021 21:16:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350998AbhLFVUV (ORCPT ); Mon, 6 Dec 2021 16:20:21 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:55352 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350481AbhLFVUS (ORCPT ); Mon, 6 Dec 2021 16:20:18 -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 6AE3BB8159E; Mon, 6 Dec 2021 21:16:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8B5CCC341C1; Mon, 6 Dec 2021 21:16:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638825407; bh=hPhWCMSayHBcfhH1bYNvUK2TzdlMPbkcPiari3gUW8c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=M3bIzpYW1yDZdj4V2LyXUQkNO8vIqztXNeyZta/yg7D4XHMnTty2zbXE+hlLo1ugG ws6IauHc4W5RO7UjYaDGh61a/h+6/XtxN/drRa5hz7i3Bsd46bxoMN71tz6RJjBJTa dEyUOU0kKaBKKo6KxLQZE9USLzp9okYUXGJdf+bFSyZOW99w05e4HtrXUasNd+IgUh 7Op3XZG7ZXsIK5OYLtAn9X7g0sXYXhS6UyHq7eTLEtFTr92cjgV/RIvuvywZnLnUOR JoyhrQkRLRkXbP3H42gpvJiWC+f1Ghco42zjtUQqGJbpMZc8jt9sdQRUFGfX2JqKEH RNQ66e1lqxj6Q== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ondrej Jirman , John Keeping , Wolfram Sang , Sasha Levin , heiko@sntech.de, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-i2c@vger.kernel.org Subject: [PATCH AUTOSEL 5.10 11/15] i2c: rk3x: Handle a spurious start completion interrupt flag Date: Mon, 6 Dec 2021 16:15:11 -0500 Message-Id: <20211206211520.1660478-11-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211206211520.1660478-1-sashal@kernel.org> References: <20211206211520.1660478-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 819ab4ee517e1..02ddb237f69af 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -423,8 +423,8 @@ 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