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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 85C54C33CAF for ; Thu, 16 Jan 2020 17:39:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 56990246F7 for ; Thu, 16 Jan 2020 17:39:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579196344; bh=mwhEdmkbM4fEVCkSGlL/oVNz+TJTmE1F+zNFLP58JAo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=opCUGOKxI/OYjo5jpyQqeKqjvzfKr67CBO4zcFAM7IYuKLUPDRGu9SAeL8yuuzDL3 7AZ9DbyJHivvJ6CqsHaGGtdZ8rjiqcFXEyukLca2ct7HAloF6Y4Nm4tXyjqYoOzWaV SLTwOi1kGNqTZzi9eV9qa1fYG89sPtTwKslXNRhM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393416AbgAPRjD (ORCPT ); Thu, 16 Jan 2020 12:39:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:54166 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404926AbgAPRiV (ORCPT ); Thu, 16 Jan 2020 12:38:21 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 3C175246C3; Thu, 16 Jan 2020 17:38:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1579196300; bh=mwhEdmkbM4fEVCkSGlL/oVNz+TJTmE1F+zNFLP58JAo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZPvTlbZZ/syx30DLB0QTbO024K8h+0dPPeTi/TcOryEqfXkSJeX3R5QB/tGqOqu7D wZ6wCXSCoh2T3VD52KPBblfB1756sqyabhdEyeBCfVKtL6L3sd+LeWm8w0YqzhY+fU KiANTn5rviG/xFiHVTj9b5oRjgBWPusLz1tnEkwg= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Martin Sperl , Stefan Wahren , Mark Brown , Sasha Levin , linux-spi@vger.kernel.org, bcm-kernel-feedback-list@broadcom.com, linux-rpi-kernel@lists.infradead.org, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 4.9 111/251] spi: bcm2835aux: fix driver to not allow 65535 (=-1) cs-gpios Date: Thu, 16 Jan 2020 12:34:20 -0500 Message-Id: <20200116173641.22137-71-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200116173641.22137-1-sashal@kernel.org> References: <20200116173641.22137-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore 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 5c89bbb05441..e075712c501e 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