From patchwork Wed Nov 30 16:29:27 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Sverdlin, Alexander" X-Patchwork-Id: 629832 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E23AEC4321E for ; Wed, 30 Nov 2022 16:30:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230258AbiK3Qay (ORCPT ); Wed, 30 Nov 2022 11:30:54 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50908 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230238AbiK3Qap (ORCPT ); Wed, 30 Nov 2022 11:30:45 -0500 X-Greylist: delayed 63 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 30 Nov 2022 08:30:41 PST Received: from mta-65-227.siemens.flowmailer.net (mta-65-227.siemens.flowmailer.net [185.136.65.227]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 892FB2B26B for ; Wed, 30 Nov 2022 08:30:41 -0800 (PST) Received: by mta-65-227.siemens.flowmailer.net with ESMTPSA id 20221130162934d7f231af14d2de9982 for ; Wed, 30 Nov 2022 17:29:34 +0100 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=fm1; d=siemens.com; i=alexander.sverdlin@siemens.com; h=Date:From:Subject:To:Message-ID:MIME-Version:Content-Type:Content-Transfer-Encoding:Cc; bh=MtB5tz/j9s9gUxGsjyyYNfEHmDjtAZKu38geeW3NeWE=; b=L4mHrUdkPh9EdH2JANf41RhZvr5a5KYhGv69An6b07S6JQ9hgoL+WU7mqnGWbC/zV2/GTG 7hXrmKMqosRqxwfsRn7FIUAr0TGuUtyrOzJRmsxHsg0H2Y257vVIT/q67SCCH8zIoXIUN7Qf 4sfduKJJ8trdI/MQZKylt9nS7EuoY=; From: "A. Sverdlin" To: linux-spi@vger.kernel.org Cc: Alexander Sverdlin , Mark Brown , linux-kernel@vger.kernel.org, Linus Walleij , Lukas Wunner Subject: [PATCH v2] spi: spidev: mask SPI_CS_HIGH in SPI_IOC_RD_MODE Date: Wed, 30 Nov 2022 17:29:27 +0100 Message-Id: <20221130162927.539512-1-alexander.sverdlin@siemens.com> MIME-Version: 1.0 X-Flowmailer-Platform: Siemens Feedback-ID: 519:519-456497:519-21489:flowmailer Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org From: Alexander Sverdlin Commit f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs") has changed the user-space interface so that bogus SPI_CS_HIGH started to appear in the mask returned by SPI_IOC_RD_MODE even for active-low CS pins. Commit 138c9c32f090 ("spi: spidev: Fix CS polarity if GPIO descriptors are used") fixed only SPI_IOC_WR_MODE part of the problem. Let's fix SPI_IOC_RD_MODE symmetrically. Test case: #include #include #include int main(int argc, char **argv) { char modew = SPI_CPHA; char moder; int f = open("/dev/spidev0.0", O_RDWR); if (f < 0) return 1; ioctl(f, SPI_IOC_WR_MODE, &modew); ioctl(f, SPI_IOC_RD_MODE, &moder); return moder == modew ? 0 : 2; } Fixes: f3186dd87669 ("spi: Optionally use GPIO descriptors for CS GPIOs") Signed-off-by: Alexander Sverdlin --- Changelog: v2: - fix SPI_IOC_RD_MODE32 as well drivers/spi/spidev.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index b2775d82d2d7b..6313e7d0cdf87 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -377,12 +377,23 @@ spidev_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) switch (cmd) { /* read requests */ case SPI_IOC_RD_MODE: - retval = put_user(spi->mode & SPI_MODE_MASK, - (__u8 __user *)arg); - break; case SPI_IOC_RD_MODE32: - retval = put_user(spi->mode & SPI_MODE_MASK, - (__u32 __user *)arg); + tmp = spi->mode; + + { + struct spi_controller *ctlr = spi->controller; + + if (ctlr->use_gpio_descriptors && ctlr->cs_gpiods && + ctlr->cs_gpiods[spi->chip_select]) + tmp &= ~SPI_CS_HIGH; + } + + if (cmd == SPI_IOC_RD_MODE) + retval = put_user(tmp & SPI_MODE_MASK, + (__u8 __user *)arg); + else + retval = put_user(tmp & SPI_MODE_MASK, + (__u32 __user *)arg); break; case SPI_IOC_RD_LSB_FIRST: retval = put_user((spi->mode & SPI_LSB_FIRST) ? 1 : 0,