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 59FF8C433FE for ; Sat, 19 Nov 2022 02:27:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234476AbiKSC1c (ORCPT ); Fri, 18 Nov 2022 21:27:32 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39452 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229935AbiKSC0n (ORCPT ); Fri, 18 Nov 2022 21:26:43 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 247516DFF1; Fri, 18 Nov 2022 18:16:18 -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 dfw.source.kernel.org (Postfix) with ESMTPS id B5577624B7; Sat, 19 Nov 2022 02:16:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D82CC433B5; Sat, 19 Nov 2022 02:16:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1668824177; bh=w9KGRntzBkhBwrHXOH/VZK9iq0Ck1XmrFUPD30d801w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=UlDbsQgoPjxDtGH7IEM89y6b3eFg7jGGg9/bwajLww3CtgT/6zfKSt/WlqXAWhOCZ dH7/JBWjS5sZCuxzML9ZWbnHUPEc5r6I0pyixJu45uUdJcw1huyVnFxjo8W4v1E85L 11+UUdfh/qiwLbQRHGy97tbfo0ebjU4qxtDfVADyeKIO2D/8wPC9oZTV8uP5vjMfYr 1GAmAqKHpJBskWa9URejgX5kJ/oYPaD4OIj/5XdiUmJE1BHL2+QtPDRyzlNNoB/fOT xymIHvSIsz+p9DQrE5tPdkezUDjIKkfGt2kdbdWKffUZ8WxIMPkAnCJurVw5yWO6jF zRsKL4c461UfA== 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 4.19 4/8] spi: stm32: fix stm32_spi_prepare_mbr() that halves spi clk for every run Date: Fri, 18 Nov 2022 21:16:05 -0500 Message-Id: <20221119021610.1775469-4-sashal@kernel.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20221119021610.1775469-1-sashal@kernel.org> References: <20221119021610.1775469-1-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 8d692f16d90a..b8565da54a72 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -255,7 +255,7 @@ 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