From patchwork Mon Jul 12 06:09:17 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 474536 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=-19.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 1E144C07E9C for ; Mon, 12 Jul 2021 06:22:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 08CDA61042 for ; Mon, 12 Jul 2021 06:22:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234691AbhGLGZG (ORCPT ); Mon, 12 Jul 2021 02:25:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:41280 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234995AbhGLGY0 (ORCPT ); Mon, 12 Jul 2021 02:24:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 6633061167; Mon, 12 Jul 2021 06:21:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626070861; bh=LjeavIVDuUT8GZy4PXD7XhVGklbogZs1tTHwV88Muc0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=N6tIhb6MJR+xMt8frSVk9DPe4nYatpgkQdscWNdEu7N7g7qj4f3g910cKbZKJ4Vz0 9ztT2CsO2PpSXd/RLRjdqrYJBoR/OPOCiH0hopugLTiSSpu/pPW5CK38SpzVcXLwRB FyKn1LT4pA6Ro1/Mrb9OQqCkiGov8G5MI70wdDKc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Mirko Vogt , Ralf Schlatterbeck , Mark Brown , Sasha Levin Subject: [PATCH 5.4 173/348] spi: spi-sun6i: Fix chipselect/clock bug Date: Mon, 12 Jul 2021 08:09:17 +0200 Message-Id: <20210712060723.846339293@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210712060659.886176320@linuxfoundation.org> References: <20210712060659.886176320@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Mirko Vogt [ Upstream commit 0d7993b234c9fad8cb6bec6adfaa74694ba85ecb ] The current sun6i SPI implementation initializes the transfer too early, resulting in SCK going high before the transfer. When using an additional (gpio) chipselect with sun6i, the chipselect is asserted at a time when clock is high, making the SPI transfer fail. This is due to SUN6I_GBL_CTL_BUS_ENABLE being written into SUN6I_GBL_CTL_REG at an early stage. Moving that to the transfer function, hence, right before the transfer starts, mitigates that problem. Fixes: 3558fe900e8af (spi: sunxi: Add Allwinner A31 SPI controller driver) Signed-off-by: Mirko Vogt Signed-off-by: Ralf Schlatterbeck Link: https://lore.kernel.org/r/20210614144507.y3udezjfbko7eavv@runtux.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-sun6i.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c index 956df79035d5..3a8acd78308f 100644 --- a/drivers/spi/spi-sun6i.c +++ b/drivers/spi/spi-sun6i.c @@ -297,6 +297,10 @@ static int sun6i_spi_transfer_one(struct spi_master *master, } sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg); + /* Finally enable the bus - doing so before might raise SCK to HIGH */ + reg = sun6i_spi_read(sspi, SUN6I_GBL_CTL_REG); + reg |= SUN6I_GBL_CTL_BUS_ENABLE; + sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG, reg); /* Setup the transfer now... */ if (sspi->tx_buf) @@ -405,7 +409,7 @@ static int sun6i_spi_runtime_resume(struct device *dev) } sun6i_spi_write(sspi, SUN6I_GBL_CTL_REG, - SUN6I_GBL_CTL_BUS_ENABLE | SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP); + SUN6I_GBL_CTL_MASTER | SUN6I_GBL_CTL_TP); return 0;