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 66581C433FE for ; Mon, 18 Apr 2022 12:53:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238355AbiDRMzy (ORCPT ); Mon, 18 Apr 2022 08:55:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51054 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240310AbiDRMzK (ORCPT ); Mon, 18 Apr 2022 08:55:10 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9C8417655; Mon, 18 Apr 2022 05:36:26 -0700 (PDT) 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 5CF69B80EC4; Mon, 18 Apr 2022 12:36:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B2B9FC385A1; Mon, 18 Apr 2022 12:36:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1650285384; bh=X0t+T/PV6H7afRr7VxLAQykE69EkNrL4/q4ZlSkuoE4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Ec5LpsY0Y4eCY89WvJb9JgOIj/XnKZhuxUDmSO3+LSO7UmbWR5ZQx1AnXDCz0djek vHzdLZrbMT+cmRhnWKqn2E1sm+/aE9qkpL91Opj8+tdyj98/Musg7cb3EyJ/R9Ro9u 2meltaV4Q1xoqDUfSIVct7V2m3Xmg7/CLi9d52+k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?UTF-8?q?Martin=20Povi=C5=A1er?= , Sven Peter , Wolfram Sang Subject: [PATCH 5.15 173/189] i2c: pasemi: Wait for write xfers to finish Date: Mon, 18 Apr 2022 14:13:13 +0200 Message-Id: <20220418121207.732245569@linuxfoundation.org> X-Mailer: git-send-email 2.35.3 In-Reply-To: <20220418121200.312988959@linuxfoundation.org> References: <20220418121200.312988959@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: stable@vger.kernel.org From: Martin Povišer commit bd8963e602c77adc76dbbbfc3417c3cf14fed76b upstream. Wait for completion of write transfers before returning from the driver. At first sight it may seem advantageous to leave write transfers queued for the controller to carry out on its own time, but there's a couple of issues with it: * Driver doesn't check for FIFO space. * The queued writes can complete while the driver is in its I2C read transfer path which means it will get confused by the raising of XEN (the 'transaction ended' signal). This can cause a spurious ENODATA error due to premature reading of the MRXFIFO register. Adding the wait fixes some unreliability issues with the driver. There's some efficiency cost to it (especially with pasemi_smb_waitready doing its polling), but that will be alleviated once the driver receives interrupt support. Fixes: beb58aa39e6e ("i2c: PA Semi SMBus driver") Signed-off-by: Martin Povišer Reviewed-by: Sven Peter Signed-off-by: Wolfram Sang Signed-off-by: Greg Kroah-Hartman --- drivers/i2c/busses/i2c-pasemi.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/i2c/busses/i2c-pasemi.c +++ b/drivers/i2c/busses/i2c-pasemi.c @@ -137,6 +137,12 @@ static int pasemi_i2c_xfer_msg(struct i2 TXFIFO_WR(smbus, msg->buf[msg->len-1] | (stop ? MTXFIFO_STOP : 0)); + + if (stop) { + err = pasemi_smb_waitready(smbus); + if (err) + goto reset_out; + } } return 0;