From patchwork Mon Dec 20 14:33:59 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: 527063 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 C9926C433EF for ; Mon, 20 Dec 2021 14:43:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235906AbhLTOnY (ORCPT ); Mon, 20 Dec 2021 09:43:24 -0500 Received: from ams.source.kernel.org ([145.40.68.75]:49458 "EHLO ams.source.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233146AbhLTOmB (ORCPT ); Mon, 20 Dec 2021 09:42:01 -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 1519BB80EE4; Mon, 20 Dec 2021 14:42:00 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5EB32C36AE8; Mon, 20 Dec 2021 14:41:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1640011318; bh=3dMq2PJ2XAZkl3Gogfslwj469eWupVU1ITCKufkSN8w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0mhdGlhsdCT6t8w6a4cid1Jsq4xYiezWcK4EgM0S7HaDH95E1v4I9AlWBaKD4KB27 VyA0b0+CPsQjgo03qbjJP/tv3UIqD6q9atuYHdDIaGkyeucVamwf7iR7K/ehbbZICD jB9m6D/t/dWiCzAuKdC/K1xL8LaJkqNtyvXqafAA= 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 4.19 06/56] i2c: rk3x: Handle a spurious start completion interrupt flag Date: Mon, 20 Dec 2021 15:33:59 +0100 Message-Id: <20211220143023.653113012@linuxfoundation.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20211220143023.451982183@linuxfoundation.org> References: <20211220143023.451982183@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 b8a2728dd4b69..e76ad020a5420 100644 --- a/drivers/i2c/busses/i2c-rk3x.c +++ b/drivers/i2c/busses/i2c-rk3x.c @@ -425,8 +425,8 @@ 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)