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 X-Spam-Level: X-Spam-Status: No, score=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 223D2C4363F for ; Mon, 27 Jul 2020 23:27:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00A4E20A8B for ; Mon, 27 Jul 2020 23:27:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595892444; bh=jgApG1A37oBtiR5CjwiKak+vQK6WNvNl+JWHPVFcpb4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=jl5CkcnwNBr35a9DkaDg1U/bS3Myw4afvc93soFeKonbNY2Wj1yUy6xursE0jFo7a KHxiEqP4Cg5TxHkx9xLBRPbF6R36BlEkBNqG6uRL/+pFa9u4WSxb1P+xD1+ouvatqW QuM5lYwaSsNB9Tv0eraLZqJX2fYZAtIWrjLocrhM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728117AbgG0X1X (ORCPT ); Mon, 27 Jul 2020 19:27:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:36112 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728420AbgG0XYy (ORCPT ); Mon, 27 Jul 2020 19:24:54 -0400 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id EEAD920A8B; Mon, 27 Jul 2020 23:24:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595892293; bh=jgApG1A37oBtiR5CjwiKak+vQK6WNvNl+JWHPVFcpb4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0ntuRDQRtEPMZfCveMRaVZ/gR2fRwX2qm6PFLq1NjsMK2MGu6VpX3/MtYDeCZK2XQ CNfjfVG60l3RKUEeYFN4hq16ZEoVEjWt2P1tGi2Fypd8wmDrw1/CP0grVka8WpcPYf 0KUEa4nWjPgNqGSOUnSigh8amZouA4JKpuRTy8Ew= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Raviteja Narayanam , Michal Simek , Wolfram Sang , Sasha Levin , linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 07/10] Revert "i2c: cadence: Fix the hold bit setting" Date: Mon, 27 Jul 2020 19:24:40 -0400 Message-Id: <20200727232443.718000-7-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200727232443.718000-1-sashal@kernel.org> References: <20200727232443.718000-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Raviteja Narayanam [ Upstream commit 0db9254d6b896b587759e2c844c277fb1a6da5b9 ] This reverts commit d358def706880defa4c9e87381c5bf086a97d5f9. There are two issues with "i2c: cadence: Fix the hold bit setting" commit. 1. In case of combined message request from user space, when the HOLD bit is cleared in cdns_i2c_mrecv function, a STOP condition is sent on the bus even before the last message is started. This is because when the HOLD bit is cleared, the FIFOS are empty and there is no pending transfer. The STOP condition should occur only after the last message is completed. 2. The code added by the commit is redundant. Driver is handling the setting/clearing of HOLD bit in right way before the commit. The setting of HOLD bit based on 'bus_hold_flag' is taken care in cdns_i2c_master_xfer function even before cdns_i2c_msend/cdns_i2c_recv functions. The clearing of HOLD bit is taken care at the end of cdns_i2c_msend and cdns_i2c_recv functions based on bus_hold_flag and byte count. Since clearing of HOLD bit is done after the slave address is written to the register (writing to address register triggers the message transfer), it is ensured that STOP condition occurs at the right time after completion of the pending transfer (last message). Signed-off-by: Raviteja Narayanam Acked-by: Michal Simek Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-cadence.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-) diff --git a/drivers/i2c/busses/i2c-cadence.c b/drivers/i2c/busses/i2c-cadence.c index d917cefc5a19c..b136057182916 100644 --- a/drivers/i2c/busses/i2c-cadence.c +++ b/drivers/i2c/busses/i2c-cadence.c @@ -382,10 +382,8 @@ static void cdns_i2c_mrecv(struct cdns_i2c *id) * Check for the message size against FIFO depth and set the * 'hold bus' bit if it is greater than FIFO depth. */ - if ((id->recv_count > CDNS_I2C_FIFO_DEPTH) || id->bus_hold_flag) + if (id->recv_count > CDNS_I2C_FIFO_DEPTH) ctrl_reg |= CDNS_I2C_CR_HOLD; - else - ctrl_reg = ctrl_reg & ~CDNS_I2C_CR_HOLD; cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); @@ -442,11 +440,8 @@ static void cdns_i2c_msend(struct cdns_i2c *id) * Check for the message size against FIFO depth and set the * 'hold bus' bit if it is greater than FIFO depth. */ - if ((id->send_count > CDNS_I2C_FIFO_DEPTH) || id->bus_hold_flag) + if (id->send_count > CDNS_I2C_FIFO_DEPTH) ctrl_reg |= CDNS_I2C_CR_HOLD; - else - ctrl_reg = ctrl_reg & ~CDNS_I2C_CR_HOLD; - cdns_i2c_writereg(ctrl_reg, CDNS_I2C_CR_OFFSET); /* Clear the interrupts in interrupt status register. */ -- 2.25.1