From patchwork Mon Jul 19 14:50:13 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 481303 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=-20.2 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, 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 2E7AFC07E95 for ; Mon, 19 Jul 2021 15:12:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A15561249 for ; Mon, 19 Jul 2021 15:12:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243409AbhGSOcB (ORCPT ); Mon, 19 Jul 2021 10:32:01 -0400 Received: from mail.kernel.org ([198.145.29.99]:39348 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243631AbhGSO2u (ORCPT ); Mon, 19 Jul 2021 10:28:50 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id B7D8160551; Mon, 19 Jul 2021 15:08:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1626707299; bh=LWgaDsjxuJiUaMVNUtyez3baQyH7MED6hRzLbuOOj3I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JNXUq3dxmJjBHO13md8DlES2/EYZ3KREnYVETFYJQ1CPUvQWVD2JEIYRWAQBORsKk d432IL4e4RviBHd+daQ4pOrB+26+xIPVhzlnTfTyIPzQmy+adkboguPdXlZgJdHNfo 40p8ugt2W7OLZWXovhpjhmWuYaLFHnXfLwq4Ndtg= 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 4.9 071/245] spi: spi-sun6i: Fix chipselect/clock bug Date: Mon, 19 Jul 2021 16:50:13 +0200 Message-Id: <20210719144942.701040735@linuxfoundation.org> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20210719144940.288257948@linuxfoundation.org> References: <20210719144940.288257948@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 17068e62e792..8c3f5a00fd9e 100644 --- a/drivers/spi/spi-sun6i.c +++ b/drivers/spi/spi-sun6i.c @@ -251,6 +251,10 @@ 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) @@ -334,7 +338,7 @@ 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;