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=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 A9936C32771 for ; Fri, 24 Jan 2020 11:15:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8142020708 for ; Fri, 24 Jan 2020 11:15:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579864528; bh=Z2e3TdZKupN01dUrMHq1I9q68NvHCMqnkZ6AhniEOHs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=OInLpMz2GHZYkuP4f9HAGG2Sj57g3tWdhC264Fq3ES491j9RBfvZ1cswaUnB12Evm v+rFZgzRvqFwFQI5ZepQ+RjsaUeiQd4qC68DyRTmmzG7okZVuFACupfdj7894A7H1f 09JUMw9QQyKL73pdGOIht9uJ91UsOgk6BaN35vzw= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2390273AbgAXLP1 (ORCPT ); Fri, 24 Jan 2020 06:15:27 -0500 Received: from mail.kernel.org ([198.145.29.99]:51924 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390259AbgAXLPX (ORCPT ); Fri, 24 Jan 2020 06:15:23 -0500 Received: from localhost (ip-213-127-102-57.ip.prioritytelecom.net [213.127.102.57]) (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 7C3542077C; Fri, 24 Jan 2020 11:15:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579864522; bh=Z2e3TdZKupN01dUrMHq1I9q68NvHCMqnkZ6AhniEOHs=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ii2Ucn6iPKlR1En59G3vdntmT2Zri65RJVC9lrdrINa8txEaug94GGVZz7GlZtiAv 1H+3rPqUyguHZ1oSXQUW+YlSc9eUOQMZ7spkTctk2Fz1wsNKaB2BaQkqXE33fsGHcM tMtxSoiDcGhnnoJkYXRYplFvfz8fjXUMzoQM7iNk= 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 4.19 289/639] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios Date: Fri, 24 Jan 2020 10:27:39 +0100 Message-Id: <20200124093123.082918885@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200124093047.008739095@linuxfoundation.org> References: <20200124093047.008739095@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 12c1fa5b06c5b..c63ed402cf860 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