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 BBAF1C33CB2 for ; Tue, 28 Jan 2020 14:37:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 92B3020702 for ; Tue, 28 Jan 2020 14:37:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580222224; bh=+cwP9XADjrvZI1b705EfYZDrZt+Y9lRU5CyBykThi80=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=pijfhbtdCcLK1AdaPjgwTxaOIFmfmetF3zZ/LBqkuFwE+CezTvHUgj6e9OYwoSGBs pp1mFLehP6k39fCfzDER0VBVUyrE7LdoXakwqCh+xe4L+wKlhlAOrhSSLIH4sVQalH X0gdO2EhkiPyLoC3zyw+nyCjhVbV+GTugwhmCB7c= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730222AbgA1OUv (ORCPT ); Tue, 28 Jan 2020 09:20:51 -0500 Received: from mail.kernel.org ([198.145.29.99]:45872 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731144AbgA1OUt (ORCPT ); Tue, 28 Jan 2020 09:20:49 -0500 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (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 503B92071E; Tue, 28 Jan 2020 14:20:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1580221248; bh=+cwP9XADjrvZI1b705EfYZDrZt+Y9lRU5CyBykThi80=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wsIeirpNQRI2M3bEwMAfYx1+SJ/59sv0qkmZ/ItizwCy9pWmsTty1KAYUOLup+D2k x4MQU4jkaGTld6SLoXSG6T47Kxw6SKwh7PbwPLd0+EwAXM/2rpFZG+Ligq+ygRnZjq zrmr5bL6KH17ZWd72BEBPl2zoSJfhkm+q9185of0= 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 4.9 112/271] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios Date: Tue, 28 Jan 2020 15:04:21 +0100 Message-Id: <20200128135900.913030359@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200128135852.449088278@linuxfoundation.org> References: <20200128135852.449088278@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@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