From patchwork Fri Nov 12 13:39:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Corey Minyard X-Patchwork-Id: 1554406 X-Patchwork-Delegate: wolfram@the-dreams.de Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: bilbo.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20210112 header.b=WgIBgVJI; dkim-atps=neutral Authentication-Results: ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=23.128.96.18; helo=vger.kernel.org; envelope-from=linux-i2c-owner@vger.kernel.org; receiver=) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by bilbo.ozlabs.org (Postfix) with ESMTP id 4HrKTM63gxz9sRN for ; Sat, 13 Nov 2021 00:40:07 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235003AbhKLNm4 (ORCPT ); Fri, 12 Nov 2021 08:42:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57814 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231436AbhKLNm4 (ORCPT ); Fri, 12 Nov 2021 08:42:56 -0500 Received: from mail-qk1-x734.google.com (mail-qk1-x734.google.com [IPv6:2607:f8b0:4864:20::734]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 730C8C0613F5; Fri, 12 Nov 2021 05:40:05 -0800 (PST) Received: by mail-qk1-x734.google.com with SMTP id g28so4608899qkk.9; Fri, 12 Nov 2021 05:40:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=uzZyUma5p9ds/38tNYS+sIv6Uq4e934H7mXIASfQ7lA=; b=WgIBgVJICAzaJUo6f+8dcZwd8fb24GbfgdeQT0nlTgDl6AWlCpnNv5U0O/sWzvNs0P AoaCgPjIVXnnal7UMzWMvbLjvmdeOteDzW1nxN+9aHxS5fi5E21wgI4HD8dgVjDvaO/c LCQL8H92/YwbqmAINdEak4A/WtgtEXFYRGFiWxZ4M83Ydp+1BNxcd2P94+NaHalJtkKD iQ5p+FKIZfwQp12eXj8J7lsPjsHOeAmcbv2CTiwmMmdRHZxA8rr0P0gJKyUUetx90IIU owLEy8XhmMR+5fra1Q+gee7OFJj9iagxjht5lOkrhNmoc1Micl9zMTPyaUIdACcIz5Y4 0RVA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :in-reply-to:references:mime-version:content-transfer-encoding; bh=uzZyUma5p9ds/38tNYS+sIv6Uq4e934H7mXIASfQ7lA=; b=7vZWsM+UR69LfLC7RJVqyaXjO+8zu8pcsuHom23WnkBMZQcFXu9xR7o1aiA1yAm+GM S3/k3exUWbMemhJkB5uGlDJI/ieomo/kVwXY0VUDV7mKtiRnxQ5iCIgBV+2ERcu9YmVY BNHCEa4RbZEeaKu0DomWrN10lHet7CLV/vIrjdGYhQhF8eFdQ00eAWRWpIosOFZbPICx m0Bga30dLC+fYbdWtjmNB15RYenp6YYCujeqgv9ONNhweizMlhkB8uRLoKpgUUh6VqtJ BF/bDByAO+i18BMiYcWoMVgaKraMnA7KdC/ih19DE0zNsGh36ItV+B7B3ELJpIGFHdem kQfA== X-Gm-Message-State: AOAM532JirddfivywmTB36FeusZaXOztc8QEzF1GiWBUWbKrydWsD2W9 2YzgAOskkVrUSPGKofXGQQ== X-Google-Smtp-Source: ABdhPJzLPoxprwTwj30iu1WaOXTQLHMFS1pcAV/DPSsctPV1lRdXDUDLpfCLDU1oWb9VeQCR2G8Sow== X-Received: by 2002:a05:620a:1585:: with SMTP id d5mr12078013qkk.96.1636724404584; Fri, 12 Nov 2021 05:40:04 -0800 (PST) Received: from serve.minyard.net (serve.minyard.net. [2001:470:b8f6:1b::1]) by smtp.gmail.com with ESMTPSA id m4sm3019642qtu.87.2021.11.12.05.40.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 12 Nov 2021 05:40:04 -0800 (PST) Sender: Corey Minyard Received: from t560.minyard.net (unknown [IPv6:2001:470:b8f6:1b:3da4:ae9:63f5:5ac8]) by serve.minyard.net (Postfix) with ESMTPA id D432A1800BC; Fri, 12 Nov 2021 13:40:02 +0000 (UTC) From: minyard@acm.org To: Oleksij Rempel Cc: Pengutronix Kernel Team , linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, Corey Minyard , Andrew Manley Subject: [PATCH v2 2/2] i2c:imx: Add an extra read at the end of an I2C slave read Date: Fri, 12 Nov 2021 07:39:56 -0600 Message-Id: <20211112133956.655179-3-minyard@acm.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211112133956.655179-1-minyard@acm.org> References: <20211112133956.655179-1-minyard@acm.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org From: Corey Minyard The I2C slave interface expects that the driver will read ahead one byte. The IMX driver/device doesn't do this, but simulate it so that read operations get their index set correctly. Signed-off-by: Corey Minyard Tested-by: Andrew Manley Reviewed-by: Andrew Manley Reviewed-by: Oleksij Rempel --- drivers/i2c/busses/i2c-imx.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index 27f969b3dc07..41355fc8bff4 100644 --- a/drivers/i2c/busses/i2c-imx.c +++ b/drivers/i2c/busses/i2c-imx.c @@ -771,6 +771,15 @@ static irqreturn_t i2c_imx_slave_handle(struct imx_i2c_struct *i2c_imx, ctl &= ~I2CR_MTX; imx_i2c_write_reg(ctl, i2c_imx, IMX_I2C_I2CR); imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); + + /* + * The i2c slave interface requires one extra dummy + * read at the end to keep things in line. See the + * I2C slave docs for details. + */ + i2c_imx_slave_event(i2c_imx, + I2C_SLAVE_READ_PROCESSED, &value); + i2c_imx_slave_finish_op(i2c_imx); return IRQ_HANDLED; }