From patchwork Wed Nov 30 14:39:48 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "A. Sverdlin" X-Patchwork-Id: 13059996 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 DFD26C433FE for ; Wed, 30 Nov 2022 14:41:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229761AbiK3OlG (ORCPT ); Wed, 30 Nov 2022 09:41:06 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40484 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229760AbiK3OlF (ORCPT ); Wed, 30 Nov 2022 09:41:05 -0500 X-Greylist: delayed 62 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Wed, 30 Nov 2022 06:41:01 PST Received: from mta-64-226.siemens.flowmailer.net (mta-64-226.siemens.flowmailer.net [185.136.64.226]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF0BA2FFEE for ; Wed, 30 Nov 2022 06:41:00 -0800 (PST) Received: by mta-64-226.siemens.flowmailer.net with ESMTPSA id 20221130143956988dbcb4638a47785a for ; Wed, 30 Nov 2022 15:39:56 +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=dpt5mrvPw7RM7k6Ey4ll2TJ6SXaTSEx8JWL9PuzsCpk=; b=DRLweHjIruPYZjaXyBdguWxe1SX2EiS6ywDH+hMPwfiN520wk1EfkE4Ofov8tv1Fd3S5GR yTA1gcDL+3KkeFQoqEGxcilvhre+wva8mp+DMiqONebpm+daMZ80GQHD7qDpI66Bn+Rf9D27 Dh8eJdwhEXwI8NsVpCw7p97BRRjLs=; 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] spi: spidev: mask SPI_CS_HIGH in SPI_IOC_RD_MODE Date: Wed, 30 Nov 2022 15:39:48 +0100 Message-Id: <20221130143948.426640-1-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 --- drivers/spi/spidev.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c index b2775d82d2d7b..23177a7c916c3 100644 --- a/drivers/spi/spidev.c +++ b/drivers/spi/spidev.c @@ -377,8 +377,17 @@ 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); + 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; + } + + retval = put_user(tmp & SPI_MODE_MASK, (__u8 __user *)arg); break; case SPI_IOC_RD_MODE32: retval = put_user(spi->mode & SPI_MODE_MASK,