From patchwork Fri Aug 5 07:43:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Conor Dooley X-Patchwork-Id: 595668 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 4BFC3C00140 for ; Fri, 5 Aug 2022 07:43:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236888AbiHEHnh (ORCPT ); Fri, 5 Aug 2022 03:43:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45218 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230441AbiHEHng (ORCPT ); Fri, 5 Aug 2022 03:43:36 -0400 Received: from esa.microchip.iphmx.com (esa.microchip.iphmx.com [68.232.154.123]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 06D59FE0; Fri, 5 Aug 2022 00:43:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=microchip.com; i=@microchip.com; q=dns/txt; s=mchp; t=1659685416; x=1691221416; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=zyhxpEY3V0ezRF2TAPWgZETEsQajOrAZag7J08YVniY=; b=L/C9vzWfC2cSMbQeePRdahtpc9FHEWjHv5H9ysCDkoXxxpibrqJ5n56b rK9XJM8d0QKQzKneAzlH20lSprHr8zRRcgyhUI56/NraoYaLG9cj83kNg HQLqg3aJXAUAYsWdXIPMcBsokcSePjKFIIEFqj9eX6jh6Q1BT9TA0YtDY T3vsPXhW1bGsvJT+ZnjEZJzfTIh3fozaH23T/OfbNoxRWBx/WAEWQjDFs 7oHh5AnMsxGSO5O3O+oisa69d9mQwxH4dNiae8miNL5YT56iVoVK/eNM7 NzF8JvqQ3/muW17arHI7Q6Ces3uFJ44fDdcPFoYco6iMLEQjVdyHgcpY2 A==; X-IronPort-AV: E=Sophos;i="5.93,216,1654585200"; d="scan'208";a="107704825" Received: from unknown (HELO email.microchip.com) ([170.129.1.10]) by esa6.microchip.iphmx.com with ESMTP/TLS/AES256-SHA256; 05 Aug 2022 00:43:35 -0700 Received: from chn-vm-ex01.mchp-main.com (10.10.85.143) by chn-vm-ex02.mchp-main.com (10.10.85.144) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.17; Fri, 5 Aug 2022 00:43:31 -0700 Received: from wendy.microchip.com (10.10.115.15) by chn-vm-ex01.mchp-main.com (10.10.85.143) with Microsoft SMTP Server id 15.1.2375.17 via Frontend Transport; Fri, 5 Aug 2022 00:43:29 -0700 From: Conor Dooley To: Wolfram Sang , Daire McNamara CC: Conor Dooley , , , Andreas Buerkler , Lewis Hanly Subject: [PATCH] i2c: microchip-core: fix erroneous late ack send Date: Fri, 5 Aug 2022 08:43:46 +0100 Message-ID: <20220805074346.4123650-1-conor.dooley@microchip.com> X-Mailer: git-send-email 2.36.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org A late ack is currently being sent at the end of a transfer due to incorrect logic in mchp_corei2c_empty_rx(). Currently the Assert Ack bit is being written to the controller's control reg after the last byte has been received, causing it to sent another byte with the ack. Instead, the AA flag should be written to to the contol register when the penultimate byte is read so it is sent out for the last byte. Reported-by: Andreas Buerkler Fixes: 64a6f1c4987e ("i2c: add support for microchip fpga i2c controllers") Tested-by: Lewis Hanly Signed-off-by: Conor Dooley --- FYI Wolfram, I am still sitting on the MAINTAINERS update as the SoC updates have not been pulled yet for 6.0 (AFAICT) drivers/i2c/busses/i2c-microchip-corei2c.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-microchip-corei2c.c b/drivers/i2c/busses/i2c-microchip-corei2c.c index 6df0f1c33278..4d7e9b25f018 100644 --- a/drivers/i2c/busses/i2c-microchip-corei2c.c +++ b/drivers/i2c/busses/i2c-microchip-corei2c.c @@ -206,7 +206,7 @@ static void mchp_corei2c_empty_rx(struct mchp_corei2c_dev *idev) idev->msg_len--; } - if (idev->msg_len == 0) { + if (idev->msg_len <= 1) { ctrl = readb(idev->base + CORE_I2C_CTRL); ctrl &= ~CTRL_AA; writeb(ctrl, idev->base + CORE_I2C_CTRL);