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 4071BC433F5 for ; Mon, 6 Dec 2021 21:21:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351793AbhLFVYo (ORCPT ); Mon, 6 Dec 2021 16:24:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1351472AbhLFVYB (ORCPT ); Mon, 6 Dec 2021 16:24:01 -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 4779CC0613FE; Mon, 6 Dec 2021 13:20:32 -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 92ED0CE1582; Mon, 6 Dec 2021 21:20:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 71740C341C6; Mon, 6 Dec 2021 21:20:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1638825628; bh=UqIoGty3x6i+tPouRMfzEwDwRqaI2XcL1JbTVVMihyY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iii0E+JYjiH2xJJ246ZhfAFEjDSb9Htp0PTHZKyRC4fuMoMYgJWBMkEWysEoyeOW4 LhSH5qGEGXE9SqttEZ8k44uplhH8V0VdklVeCx3Krr0PxHg+QlwjjkqGA0iFRsVp4t JnjGxaqFClF+haRQtiQlWo43eSiwVlflzX5bjNv4Rc4G9lUnmEq8jDbgUlrfAYaQQW xhyKcbTVTRBfTICBSM3U3QyOM5Gpijhh5JIYFPY7jBRoD4jTEfzeMI+6xWVUyOtB// EleAYX2xGImRzPCB1mwixqOOOCIwpIOzC2QASOMoTgCTw+c/2JJItM4tcnE8ak+uWX LWAqKfryQgM8Q== 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 4.9 3/5] i2c: rk3x: Handle a spurious start completion interrupt flag Date: Mon, 6 Dec 2021 16:20:19 -0500 Message-Id: <20211206212021.1661517-3-sashal@kernel.org> X-Mailer: git-send-email 2.33.0 In-Reply-To: <20211206212021.1661517-1-sashal@kernel.org> References: <20211206212021.1661517-1-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 df220666d6274..b4f8cd7dc8b74 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -424,8 +424,8 @@ 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