From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 733F3C2D0DB for ; Fri, 24 Jan 2020 09:55:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4610020718 for ; Fri, 24 Jan 2020 09:55:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579859750; bh=+cwP9XADjrvZI1b705EfYZDrZt+Y9lRU5CyBykThi80=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=VSirueck/z60ic4xEN4EEcgNpO9A4rmTQyReoAcoPk9ytJ6C1ViSZOMyONl1NKFrI qzF1JtpMNgV6yOBHmT0HFY7SvJ+C4+AUeJBqu4iryJMArhOQaqMvw9cZYI0xePsvCB WPo540DVBqDSE3a6y14hV9lNnfCSP7CRjLotnxZI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388424AbgAXJzt (ORCPT ); Fri, 24 Jan 2020 04:55:49 -0500 Received: from mail.kernel.org ([198.145.29.99]:59336 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731598AbgAXJzr (ORCPT ); Fri, 24 Jan 2020 04:55:47 -0500 Received: from localhost (unknown [145.15.244.15]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 80F2C2087E; Fri, 24 Jan 2020 09:55:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579859747; bh=+cwP9XADjrvZI1b705EfYZDrZt+Y9lRU5CyBykThi80=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=e5GUdBC8OxYM/uoWm6djr2veO2BduiV/i71W+PoSka4FK9aOw/zoZYaXI+ljNC1T4 nOUoI/lqrySXlnf7M4s0dJigruQWcYHtvjDmRKkd7KUDg2mse6wWNXaWhcD1HIOxvh uuRXJf0iTitfXEAZqr27Swr0SfLuS9v8EAJyKUDk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Martin Sperl , Stefan Wahren , Mark Brown , Sasha Levin Subject: [PATCH 4.14 162/343] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios Date: Fri, 24 Jan 2020 10:29:40 +0100 Message-Id: <20200124092941.263416729@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200124092919.490687572@linuxfoundation.org> References: <20200124092919.490687572@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Martin Sperl [ Upstream commit 509c583620e9053e43d611bf1614fc3d3abafa96 ] The original driver by default defines num_chipselects as -1. This actually allicates an array of 65535 entries in of_spi_register_master. There is a side-effect for buggy device trees that (contrary to dt-binding documentation) have no cs-gpio defined. This mode was never supported by the driver due to limitations of native cs and additional code complexity and is explicitly not stated to be implemented. To keep backwards compatibility with such buggy DTs we limit the number of chip_selects to 1, as for all practical purposes it is only ever realistic to use a single chip select in native cs mode without negative side-effects. Fixes: 1ea29b39f4c812ec ("spi: bcm2835aux: add bcm2835 auxiliary spi device...") Signed-off-by: Martin Sperl Acked-by: Stefan Wahren Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-bcm2835aux.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-bcm2835aux.c b/drivers/spi/spi-bcm2835aux.c index 5c89bbb05441b..e075712c501e8 100644 --- a/drivers/spi/spi-bcm2835aux.c +++ b/drivers/spi/spi-bcm2835aux.c @@ -416,7 +416,18 @@ static int bcm2835aux_spi_probe(struct platform_device *pdev) platform_set_drvdata(pdev, master); master->mode_bits = (SPI_CPOL | SPI_CS_HIGH | SPI_NO_CS); master->bits_per_word_mask = SPI_BPW_MASK(8); - master->num_chipselect = -1; + /* even though the driver never officially supported native CS + * allow a single native CS for legacy DT support purposes when + * no cs-gpio is configured. + * Known limitations for native cs are: + * * multiple chip-selects: cs0-cs2 are all simultaniously asserted + * whenever there is a transfer - this even includes SPI_NO_CS + * * SPI_CS_HIGH: is ignores - 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 + * a spi_transfer + */ + master->num_chipselect = 1; master->transfer_one = bcm2835aux_spi_transfer_one; master->handle_err = bcm2835aux_spi_handle_err; master->prepare_message = bcm2835aux_spi_prepare_message; -- 2.20.1