From patchwork Fri Oct 9 11:03:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christian Eggers X-Patchwork-Id: 268648 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=-12.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 B1669C433DF for ; Fri, 9 Oct 2020 11:07:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 64B0E2225D for ; Fri, 9 Oct 2020 11:07:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387969AbgJILHc (ORCPT ); Fri, 9 Oct 2020 07:07:32 -0400 Received: from mailout05.rmx.de ([94.199.90.90]:54346 "EHLO mailout05.rmx.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732362AbgJILHb (ORCPT ); Fri, 9 Oct 2020 07:07:31 -0400 Received: from kdin02.retarus.com (kdin02.dmz1.retloc [172.19.17.49]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mailout05.rmx.de (Postfix) with ESMTPS id 4C74zL0hc2z9yDC; Fri, 9 Oct 2020 13:07:26 +0200 (CEST) Received: from mta.arri.de (unknown [217.111.95.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by kdin02.retarus.com (Postfix) with ESMTPS id 4C74y91xJRz2TTLj; Fri, 9 Oct 2020 13:06:25 +0200 (CEST) Received: from N95HX1G2.wgnetz.xx (192.168.54.145) by mta.arri.de (192.168.100.104) with Microsoft SMTP Server (TLS) id 14.3.408.0; Fri, 9 Oct 2020 13:05:05 +0200 From: Christian Eggers To: Oleksij Rempel , Oleksij Rempel , Shawn Guo , Sascha Hauer , Fabio Estevam , =?utf-8?q?Uwe_Kleine-K?= =?utf-8?b?w7ZuaWc=?= , "David Laight" CC: Pengutronix Kernel Team , NXP Linux Team , , , , Christian Eggers , Krzysztof Kozlowski , Subject: [PATCH v6 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Date: Fri, 9 Oct 2020 13:03:20 +0200 Message-ID: <20201009110320.20832-4-ceggers@arri.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20201009110320.20832-1-ceggers@arri.de> References: <20201009110320.20832-1-ceggers@arri.de> MIME-Version: 1.0 X-Originating-IP: [192.168.54.145] X-RMX-ID: 20201009-130633-4C74y91xJRz2TTLj-0@kdin02 X-RMX-SOURCE: 217.111.95.66 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org If arbitration is lost, the master automatically changes to slave mode. I2SR_IBB may or may not be reset by hardware. Raising a STOP condition by resetting I2CR_MSTA has no effect and will not clear I2SR_IBB. So calling i2c_imx_bus_busy() is not required and would busy-wait until timeout. Signed-off-by: Christian Eggers Tested (not extensively) on Vybrid VF500 (Toradex VF50): Tested-by: Krzysztof Kozlowski Acked-by: Oleksij Rempel Cc: stable@vger.kernel.org # Requires trivial backporting, simple remove # the 3rd argument from the calls to # i2c_imx_bus_busy(). --- drivers/i2c/busses/i2c-imx.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 69ce5eea9b5a..e98356f3db84 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -615,6 +615,8 @@ static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx, bool atomic) /* Stop I2C transaction */ dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__); temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + if (!(temp & I2CR_MSTA)) + i2c_imx->stopped = 1; temp &= ~(I2CR_MSTA | I2CR_MTX); if (i2c_imx->dma) temp &= ~I2CR_DMAEN; @@ -778,9 +780,12 @@ static int i2c_imx_dma_read(struct imx_i2c_struct *i2c_imx, */ dev_dbg(dev, "<%s> clear MSTA\n", __func__); temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + if (!(temp & I2CR_MSTA)) + i2c_imx->stopped = 1; temp &= ~(I2CR_MSTA | I2CR_MTX); imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); - i2c_imx_bus_busy(i2c_imx, 0, false); + if (!i2c_imx->stopped) + i2c_imx_bus_busy(i2c_imx, 0, false); } else { /* * For i2c master receiver repeat restart operation like: @@ -905,9 +910,12 @@ static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, dev_dbg(&i2c_imx->adapter.dev, "<%s> clear MSTA\n", __func__); temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR); + if (!(temp & I2CR_MSTA)) + i2c_imx->stopped = 1; temp &= ~(I2CR_MSTA | I2CR_MTX); imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR); - i2c_imx_bus_busy(i2c_imx, 0, atomic); + if (!i2c_imx->stopped) + i2c_imx_bus_busy(i2c_imx, 0, atomic); } else { /* * For i2c master receiver repeat restart operation like: