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=-11.2 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_SANE_1 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 4D153C433DF for ; Fri, 9 Oct 2020 08:14:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00D792222C for ; Fri, 9 Oct 2020 08:14:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732536AbgJIIOs (ORCPT ); Fri, 9 Oct 2020 04:14:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732337AbgJIIOo (ORCPT ); Fri, 9 Oct 2020 04:14:44 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0DDCAC0613D2 for ; Fri, 9 Oct 2020 01:14:44 -0700 (PDT) Received: from dude.hi.pengutronix.de ([2001:67c:670:100:1d::7]) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kQnXn-0006kZ-A8; Fri, 09 Oct 2020 10:14:27 +0200 Received: from ore by dude.hi.pengutronix.de with local (Exim 4.92) (envelope-from ) id 1kQnXl-00053q-Gt; Fri, 09 Oct 2020 10:14:25 +0200 Date: Fri, 9 Oct 2020 10:14:25 +0200 From: Oleksij Rempel To: Christian Eggers Cc: Oleksij Rempel , Shawn Guo , Sascha Hauer , Fabio Estevam , Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , David Laight , linux-kernel@vger.kernel.org, Krzysztof Kozlowski , NXP Linux Team , Pengutronix Kernel Team , stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-i2c@vger.kernel.org Subject: Re: [PATCH v5 3/3] i2c: imx: Don't generate STOP condition if arbitration has been lost Message-ID: <20201009081425.GD817@pengutronix.de> References: <20201007084524.10835-1-ceggers@arri.de> <20201007084524.10835-4-ceggers@arri.de> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201007084524.10835-4-ceggers@arri.de> X-Sent-From: Pengutronix Hildesheim X-URL: http://www.pengutronix.de/ X-IRC: #ptxdist @freenode X-Accept-Language: de,en X-Accept-Content-Type: text/plain X-Uptime: 10:13:39 up 35 days, 22:21, 227 users, load average: 10.92, 14.39, 9.84 User-Agent: Mutt/1.10.1 (2018-07-13) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::7 X-SA-Exim-Mail-From: ore@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-i2c@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org On Wed, Oct 07, 2020 at 10:45:24AM +0200, Christian Eggers wrote: > 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 > Cc: stable@vger.kernel.org # Requires trivial backporting, simple remove > # the 3rd argument from the calls to > # i2c_imx_bus_busy(). Acked-by: Oleksij Rempel Thank you! > --- > 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 63575af41c09..5d8a79319b2b 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: > -- > Christian Eggers > Embedded software developer > > Arnold & Richter Cine Technik GmbH & Co. Betriebs KG > Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRA 57918 > Persoenlich haftender Gesellschafter: Arnold & Richter Cine Technik GmbH > Sitz: Muenchen - Registergericht: Amtsgericht Muenchen - Handelsregisternummer: HRB 54477 > Geschaeftsfuehrer: Dr. Michael Neuhaeuser; Stephan Schenk; Walter Trauninger; Markus Zeiler > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel > -- Pengutronix e.K. | | Steuerwalder Str. 21 | http://www.pengutronix.de/ | 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 |