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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id ED160C43217 for ; Sat, 19 Nov 2022 02:24:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235946AbiKSCYY (ORCPT ); Fri, 18 Nov 2022 21:24:24 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59532 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236142AbiKSCWu (ORCPT ); Fri, 18 Nov 2022 21:22:50 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6F5FAC7229; Fri, 18 Nov 2022 18:15:17 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 128FDB8267B; Sat, 19 Nov 2022 02:15:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C168EC433C1; Sat, 19 Nov 2022 02:15:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668824115; bh=3QZrYsemDCeiXBZP6oM5UaMWSwjYjDGUHFDPrQMen+c=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=scYAqAvRWQAKjKa/Vws1CAwrXhHaFvu1zigZw7Hs228g0RSM9Vs8xNY1sgp28F0B+ dd1yvQuZY1zBn21buctRvIRvdWmdye0txhpk4qBdzJ96KGUjmE23QnxNyWGgM+h5tu JQwp5w1m8PZuKi8StS1Iqn8IdpvlxTKrFIM9WSL6NqkkSZTEDchIixmra1aErudC/a fvUOR6wO4s7EDXs647VH47sVr1DYsRSKqkiekomhToJ4fH4gUqgfGPuA4tDhmi6fjM Th7WaoyUqog717K3mUlI8OpuJvLPvXpgEeZAxjxihGFqcncUr9wW08E39aaJ3UWnqd q2IdmaVSJTwxw== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Sean Nyekjaer , Mark Brown , Sasha Levin , alain.volmat@foss.st.com, mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, linux-spi@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org Subject: [PATCH AUTOSEL 5.10 07/18] spi: stm32: fix stm32_spi_prepare_mbr() that halves spi clk for every run Date: Fri, 18 Nov 2022 21:14:48 -0500 Message-Id: <20221119021459.1775052-7-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221119021459.1775052-1-sashal@kernel.org> References: <20221119021459.1775052-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org From: Sean Nyekjaer [ Upstream commit 62aa1a344b0904549f6de7af958e8a1136fd5228 ] When this driver is used with a driver that uses preallocated spi_transfer structs. The speed_hz is halved by every run. This results in: spi_stm32 44004000.spi: SPI transfer setup failed ads7846 spi0.0: SPI transfer failed: -22 Example when running with DIV_ROUND_UP(): - First run; speed_hz = 1000000, spi->clk_rate 125000000 div 125 -> mbrdiv = 7, cur_speed = 976562 - Second run; speed_hz = 976562 div 128,00007 (roundup to 129) -> mbrdiv = 8, cur_speed = 488281 - Third run; speed_hz = 488281 div 256,000131072067109 (roundup to 257) and then -EINVAL is returned. Use DIV_ROUND_CLOSEST to allow to round down and allow us to keep the set speed. Signed-off-by: Sean Nyekjaer Link: https://lore.kernel.org/r/20221103080043.3033414-1-sean@geanix.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-stm32.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index a6dfc8fef20c..e2d796e0eda6 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -443,7 +443,7 @@ static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz, u32 div, mbrdiv; /* Ensure spi->clk_rate is even */ - div = DIV_ROUND_UP(spi->clk_rate & ~0x1, speed_hz); + div = DIV_ROUND_CLOSEST(spi->clk_rate & ~0x1, speed_hz); /* * SPI framework set xfer->speed_hz to master->max_speed_hz if -- 2.35.1