From patchwork Thu Jan 18 11:24:12 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 10172915 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 33F6860230 for ; Thu, 18 Jan 2018 11:24:18 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2441D2684F for ; Thu, 18 Jan 2018 11:24:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 19182269A3; Thu, 18 Jan 2018 11:24:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0DC122684F for ; Thu, 18 Jan 2018 11:24:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932340AbeARLYQ (ORCPT ); Thu, 18 Jan 2018 06:24:16 -0500 Received: from heliosphere.sirena.org.uk ([172.104.155.198]:32962 "EHLO heliosphere.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932338AbeARLYP (ORCPT ); Thu, 18 Jan 2018 06:24:15 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sirena.org.uk; s=20170815-heliosphere; h=Date:Message-Id:In-Reply-To: Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:References: List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner: List-Archive; bh=Fdtatu+vof7MNrrUGJ3NHL22sK6rqAiMuj62Mz9hiXU=; b=XfdktzqJABCU tcaXVgaVwob/lRjOoX+4s88oHtBhaiao6mnWzKLzHe1EGuDZC3E32KU6Bmm1vfcp8IXAQyuYi14c2 BULXLXyxv3O4yY0qH5kcfm0+Vd+Rax2vUI8su8rEjSkqaVdik0RVZjCEFNiVEhH+DAkmgkwDFgfJx vP+84=; Received: from debutante.sirena.org.uk ([2001:470:1f1d:6b5::3] helo=debutante) by heliosphere.sirena.org.uk with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1ec8Im-0007Kv-VQ; Thu, 18 Jan 2018 11:24:13 +0000 Received: from broonie by debutante with local (Exim 4.90) (envelope-from ) id 1ec8Im-0003vW-Gx; Thu, 18 Jan 2018 11:24:12 +0000 From: Mark Brown To: Maxime Chevallier Cc: Mark Brown , broonie@kernel.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, gregory.clement@free-electrons.com, linux-spi@vger.kernel.org Subject: Applied "spi: a3700: Clear DATA_OUT when performing a read" to the spi tree In-Reply-To: <1516205728-3256-2-git-send-email-maxime.chevallier@smile.fr> Message-Id: Date: Thu, 18 Jan 2018 11:24:12 +0000 Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The patch spi: a3700: Clear DATA_OUT when performing a read has been applied to the spi tree at https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark From 44a5f423e70374e5b42cecd85e78f2d79334e0f2 Mon Sep 17 00:00:00 2001 From: Maxime Chevallier Date: Wed, 17 Jan 2018 17:15:25 +0100 Subject: [PATCH] spi: a3700: Clear DATA_OUT when performing a read When performing a read using FIFO mode, the spi controller shifts out the last 2 bytes that were written in a previous transfer on MOSI. This undocumented behaviour can cause devices to misinterpret the transfer, so we explicitly clear the WFIFO before each read. This behaviour was noticed on EspressoBin. Signed-off-by: Maxime Chevallier Signed-off-by: Mark Brown --- drivers/spi/spi-armada-3700.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/spi/spi-armada-3700.c b/drivers/spi/spi-armada-3700.c index 77fe55ce790c..4857b0119556 100644 --- a/drivers/spi/spi-armada-3700.c +++ b/drivers/spi/spi-armada-3700.c @@ -607,6 +607,11 @@ static int a3700_spi_transfer_one(struct spi_master *master, a3700_spi_header_set(a3700_spi); if (xfer->rx_buf) { + /* Clear WFIFO, since it's last 2 bytes are shifted out during + * a read operation + */ + spireg_write(a3700_spi, A3700_SPI_DATA_OUT_REG, 0); + /* Set read data length */ spireg_write(a3700_spi, A3700_SPI_IF_DIN_CNT_REG, a3700_spi->buf_len);