From patchwork Mon Sep 17 21:22:27 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 10603427 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8664317D5 for ; Mon, 17 Sep 2018 21:22:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 79DC92A821 for ; Mon, 17 Sep 2018 21:22:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6D3552A82A; Mon, 17 Sep 2018 21:22:57 +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=-7.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable 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 3A02F2A821 for ; Mon, 17 Sep 2018 21:22:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728517AbeIRCwB (ORCPT ); Mon, 17 Sep 2018 22:52:01 -0400 Received: from heliosphere.sirena.org.uk ([172.104.155.198]:42328 "EHLO heliosphere.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726844AbeIRCwB (ORCPT ); Mon, 17 Sep 2018 22:52:01 -0400 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=lpxRl4lfcEj3mFGEkyL8txqqlmOEI4IENjKywm+todE=; b=NHaLbDvjSjLU pfc2O1+OnmAPQM+E5s/2SqTZTSE+PoqgIBBRP6gk94sQqbmSApXNoYv/kUXrKff7sxAyNkFKivD8j ZlwbCsKYzY2lswgvB7azaO7olaufbC/kDTtAE8lK9E5RaApw4R+PKrM9Svn8TN6uCR0lIIsME6Iab LHJwI=; Received: from [209.121.128.187] (helo=finisterre.ee.mobilebroadband) by heliosphere.sirena.org.uk with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1g20yT-0000l2-Fy; Mon, 17 Sep 2018 21:22:29 +0000 Received: by finisterre.ee.mobilebroadband (Postfix, from userid 1000) id 9D661440079; Mon, 17 Sep 2018 22:22:27 +0100 (BST) From: Mark Brown To: David Lechner Cc: Jonathan Cameron , Mark Brown , linux-spi@vger.kernel.org, linux-iio@vger.kernel.org, Jonathan Cameron , Hartmut Knaack , Lars-Peter Clausen , Peter Meerwald-Stadler , Mark Brown , linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org Subject: Applied "spi: add software implementation for SPI_CS_WORD" to the spi tree In-Reply-To: <20180913003920.30600-3-david@lechnology.com> Message-Id: <20180917212227.9D661440079@finisterre.ee.mobilebroadband> Date: Mon, 17 Sep 2018 22:22:27 +0100 (BST) 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: add software implementation for SPI_CS_WORD 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 cbaa62e0094a840fecc853910e0c0454529cec03 Mon Sep 17 00:00:00 2001 From: David Lechner Date: Wed, 12 Sep 2018 19:39:18 -0500 Subject: [PATCH] spi: add software implementation for SPI_CS_WORD This adds a default software implementation for the SPI_CS_WORD flag for controllers that don't have such a feature. The SPI_CS_WORD flag indicates that the CS line should be toggled between each word sent, not just between each transfer. The implementation works by using existing functions to split transfers into one-word-sized transfers and sets the cs_change bit for each of the new transfers. Signed-off-by: David Lechner Acked-by: Jonathan Cameron Signed-off-by: Mark Brown --- drivers/spi/spi.c | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c index ec395a6baf9c..be73d236919f 100644 --- a/drivers/spi/spi.c +++ b/drivers/spi/spi.c @@ -2774,8 +2774,10 @@ int spi_setup(struct spi_device *spi) return -EINVAL; /* help drivers fail *cleanly* when they need options * that aren't supported with their current controller + * SPI_CS_WORD has a fallback software implementation, + * so it is ignored here. */ - bad_bits = spi->mode & ~spi->controller->mode_bits; + bad_bits = spi->mode & ~(spi->controller->mode_bits | SPI_CS_WORD); ugly_bits = bad_bits & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_RX_DUAL | SPI_RX_QUAD); if (ugly_bits) { @@ -2829,6 +2831,33 @@ static int __spi_validate(struct spi_device *spi, struct spi_message *message) if (list_empty(&message->transfers)) return -EINVAL; + /* If an SPI controller does not support toggling the CS line on each + * transfer (indicated by the SPI_CS_WORD flag), we can emulate it by + * splitting transfers into one-word transfers and ensuring that + * cs_change is set for each transfer. + */ + if ((spi->mode & SPI_CS_WORD) && !(ctlr->mode_bits & SPI_CS_WORD)) { + size_t maxsize; + int ret; + + maxsize = (spi->bits_per_word + 7) / 8; + + /* spi_split_transfers_maxsize() requires message->spi */ + message->spi = spi; + + ret = spi_split_transfers_maxsize(ctlr, message, maxsize, + GFP_KERNEL); + if (ret) + return ret; + + list_for_each_entry(xfer, &message->transfers, transfer_list) { + /* don't change cs_change on the last entry in the list */ + if (list_is_last(&xfer->transfer_list, &message->transfers)) + break; + xfer->cs_change = 1; + } + } + /* Half-duplex links include original MicroWire, and ones with * only one data pin like SPI_3WIRE (switches direction) or where * either MOSI or MISO is missing. They can also be caused by