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 94E7AC43446 for ; Mon, 27 Jul 2020 23:25:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F0DF208E4 for ; Mon, 27 Jul 2020 23:25:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595892325; bh=e45O64EGQzQMOrrWcSMj0I5jzsqG5i/oLqrPSK2fkXQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=z3EADvgh/IfIEG95w7SQFyUOy0O9rAYchenN1yjk1vgbMbenAVB2elYtXaJ0o7Yc8 TtuiD+lifvhdQ/Ed23Cqd46sDs+g/meRzux5sOZAStSpBSDk0JU9wfcRMyhBh5ngz+ mTDVGGD2LE3WHXmmsmnGNy4l4vRyqIRLEfZPHn7I= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728602AbgG0XZY (ORCPT ); Mon, 27 Jul 2020 19:25:24 -0400 Received: from mail.kernel.org ([198.145.29.99]:36694 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726269AbgG0XZY (ORCPT ); Mon, 27 Jul 2020 19:25:24 -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 7F80220A8B; Mon, 27 Jul 2020 23:25:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595892323; bh=e45O64EGQzQMOrrWcSMj0I5jzsqG5i/oLqrPSK2fkXQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IxrandHv3ItSHIrlu3DhNgHOMDNueK4c8HSja/OCVR0F9vS6AI9zE80DnNAdt0fUj 5QMZoO74O73jSONirkYmC5stzdMQJh3JCyw9nobyo2MQqc2y7G/Fs9h3HshkWQCgoG n1a5KGaY9AALL9P189Zop9lPFx7R+UkF8SXJBjW0= 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 4.9 6/7] Revert "i2c: cadence: Fix the hold bit setting" Date: Mon, 27 Jul 2020 19:25:13 -0400 Message-Id: <20200727232514.718265-6-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200727232514.718265-1-sashal@kernel.org> References: <20200727232514.718265-1-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 59c08d5b75d6a..45d6771fac8ce 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 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=-13.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 41A6BC43478 for ; Mon, 27 Jul 2020 23:27:14 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 0CAE820A8B for ; Mon, 27 Jul 2020 23:27:14 +0000 (UTC) Authentication-Results: mail.kernel.org; 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a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1595892323; bh=e45O64EGQzQMOrrWcSMj0I5jzsqG5i/oLqrPSK2fkXQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IxrandHv3ItSHIrlu3DhNgHOMDNueK4c8HSja/OCVR0F9vS6AI9zE80DnNAdt0fUj 5QMZoO74O73jSONirkYmC5stzdMQJh3JCyw9nobyo2MQqc2y7G/Fs9h3HshkWQCgoG n1a5KGaY9AALL9P189Zop9lPFx7R+UkF8SXJBjW0= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH AUTOSEL 4.9 6/7] Revert "i2c: cadence: Fix the hold bit setting" Date: Mon, 27 Jul 2020 19:25:13 -0400 Message-Id: <20200727232514.718265-6-sashal@kernel.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200727232514.718265-1-sashal@kernel.org> References: <20200727232514.718265-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200727_192524_305430_60EC0095 X-CRM114-Status: GOOD ( 18.28 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Raviteja Narayanam , Sasha Levin , Michal Simek , Wolfram Sang , linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 59c08d5b75d6a..45d6771fac8ce 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel