From patchwork Sun Feb 24 12:54:33 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Martin Sperl X-Patchwork-Id: 10827907 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 3DEBC6C2 for ; Sun, 24 Feb 2019 12:55:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 280E22B589 for ; Sun, 24 Feb 2019 12:55:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1C9962B595; Sun, 24 Feb 2019 12:55:53 +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=-5.2 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED autolearn=unavailable version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id C8FB12B589 for ; Sun, 24 Feb 2019 12:55:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:References: In-Reply-To:Message-Id:Date:Subject:To:From:Reply-To:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Owner; bh=armUVZ5I5h2ba0MrU258VcTeeTMdSiAwZCMBcFuCwuY=; b=fp/6YYTf7WDvPLiQd1YnXpPTDU LJ1TLTbxyHks7B9KwEpNgCT1uHeWWcMdwpIgYktNRzqaJICvRqAy3WxU0OE+ha+iwkuYtM9lljbGz h7s23OdwwXq75J798ZnYYMwpdJG9ZA4S4qsdTz2J4JL9gATSEP4tYlJ2RPOGuj5WZkMWWP7fCsVL1 exc61zWFKbZYc2r1omPfOtBEDCLdDdomN3N5Bin8fyM4IDFLMgwtd8vz8io86q2OVtm25A3U3wbc/ xoJ2BPkbxfmRhZWrWv8oCabF31Gpv8WKbXx2j0L/w6K0S14VSUggnAJDdTrZP9AbxrgbJWEziz64Y pYV9AgTw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gxtJw-00021R-4T; Sun, 24 Feb 2019 12:55:52 +0000 Received: from 212-186-180-163.static.upcbusiness.at ([212.186.180.163] helo=cgate.sperl.org) by bombadil.infradead.org with esmtp (Exim 4.90_1 #2 (Red Hat Linux)) id 1gxtJa-0001f9-MA; Sun, 24 Feb 2019 12:55:32 +0000 Received: from hc1.intern.sperl.org (account martin@sperl.org [10.10.10.59] verified) by sperl.org (CommuniGate Pro SMTP 6.2.1 _community_) with ESMTPSA id 7757560; Sun, 24 Feb 2019 12:55:07 +0000 From: kernel@martin.sperl.org To: Mark Brown , Eric Anholt , Stefan Wahren , Hubert Denkmair , linux-spi@vger.kernel.org, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH 2/9] spi: bcm2835aux: warn in dmesg that native cs is not really supported Date: Sun, 24 Feb 2019 12:54:33 +0000 Message-Id: <20190224125440.16117-3-kernel@martin.sperl.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20190224125440.16117-1-kernel@martin.sperl.org> References: <20190224125440.16117-1-kernel@martin.sperl.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190224_045531_065064_7BD006E6 X-CRM114-Status: GOOD ( 12.32 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Martin Sperl MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP From: Martin Sperl From personal bad experience (even as the author of the original driver) it shows that native-cs is "somewhat" supported by the spi bus driver when using a buggy device tree. So make sure that the driver is warning in dmesg about this fact that we are running in a not supported mode that may have surprizing limitations. Fixes: 1ea29b39f4c812ece2f936065a0a3d6fe44a263e Signed-off-by: Martin Sperl --- drivers/spi/spi-bcm2835aux.c | 33 +++++++++++++++++++++++++++++++++ 1 file changed, 33 insertions(+) -- 2.11.0 diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index 2ece25250d86..4b6fdcb2cf4b 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -420,6 +420,38 @@ static void bcm2835aux_spi_handle_err(struct spi_master *master, bcm2835aux_spi_reset_hw(bs); } +static int bcm2835aux_spi_setup(struct spi_device *spi) +{ + int ret; + + if (spi->mode & SPI_NO_CS) + return 0; + /* sanity check for native cs */ + if (!gpio_is_valid(spi->cs_gpio)) { + /* for dt-backwards compatibility: only support native on CS0 + * known things not supported with broken native CS: + * * multiple chip-selects: cs0-cs2 are all + * simultaniously asserted whenever there is a transfer + * this even includes SPI_NO_CS + * * SPI_CS_HIGH: cs are always asserted low + * * cs_change: cs is deasserted after each spi_transfer + * * cs_delay_usec: cs is always deasserted one SCK cycle + * after the last transfer + * probably more... + */ + if (spi->chip_select == 0) { + dev_err(&spi->dev, + "native CS is not supported but may work for some use-cases for cs = 0 - please define a valid value cs-gpios in DT for complete feature set\n"); + return 0; + } + dev_err(&spi->dev, + "native CS is not supported for cs > 0 - please define a valid value cs-gpios in DT to enable multiple cs\n"); + return -EINVAL; + } + + return 0; +} + static int bcm2835aux_spi_probe(struct platform_device *pdev) { struct spi_master *master; @@ -449,6 +481,7 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) * a spi_transfer */ master->num_chipselect = 1; + master->setup = bcm2835aux_spi_setup; master->transfer_one = bcm2835aux_spi_transfer_one; master->handle_err = bcm2835aux_spi_handle_err; master->prepare_message = bcm2835aux_spi_prepare_message;