From patchwork Tue Nov 15 16:26:53 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Frieder Schrempf X-Patchwork-Id: 625045 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 13D17C43217 for ; Tue, 15 Nov 2022 16:27:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238603AbiKOQ1O (ORCPT ); Tue, 15 Nov 2022 11:27:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238692AbiKOQ1G (ORCPT ); Tue, 15 Nov 2022 11:27:06 -0500 Received: from mail.fris.de (mail.fris.de [116.203.77.234]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 68A292496D; Tue, 15 Nov 2022 08:27:05 -0800 (PST) Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id BF9FBBFB36; Tue, 15 Nov 2022 17:26:59 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fris.de; s=dkim; t=1668529622; h=from:subject:date:message-id:to:cc:mime-version: content-transfer-encoding; bh=5tgKf+p7vookHNtY0coTIkhFiTMT/dbT9kfNLD5BJEk=; b=PuDasNOCxilEj2ZLt3Ng3PC9aw+m7AzQ5cN0UluxpTopBj4tpJTrnYEtTnC18ZtKpG3dpz LCKfShB4UHon957EwvINZUg4loKUD4fakqlFhGLIldq0yqwfkjXIUQqG96H4SQGz9VEbxJ Yi+TObf5Pr937nCfotNQXd3wjiIr1+PZ0f38G/9rDspqwhTbKaCb/5zlnZ/dFA8TPmFilH ZyI/17zlxT2M2xE2ADHgQfYobclQt9qbF0CQDEeyowEo4I8VHp4rSzM3YEHUUyuJCFhAkA Abg649ddL6Y3JRkoGlbYxqRl6tW7cu/QRl6VEWOb6V8Xbzz642tPBpofZqxTwQ== From: Frieder Schrempf To: David Jander , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, Marc Kleine-Budde , Mark Brown , Sascha Hauer , Shawn Guo Cc: Frieder Schrempf , Fabio Estevam , Marek Vasut , stable@vger.kernel.org, Baruch Siach , Minghao Chi , NXP Linux Team , Pengutronix Kernel Team Subject: [PATCH v2] spi: spi-imx: Fix spi_bus_clk if requested clock is higher than input clock Date: Tue, 15 Nov 2022 17:26:53 +0100 Message-Id: <20221115162654.2016820-1-frieder@fris.de> MIME-Version: 1.0 X-Last-TLS-Session-Version: TLSv1.3 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org From: Frieder Schrempf In case the requested bus clock is higher than the input clock, the correct dividers (pre = 0, post = 0) are returned from mx51_ecspi_clkdiv(), but *fres is left uninitialized and therefore contains an arbitrary value. This causes trouble for the recently introduced PIO polling feature as the value in spi_imx->spi_bus_clk is used there to calculate for which transfers to enable PIO polling. Fix this by setting *fres even if no clock dividers are in use. This issue was observed on Kontron BL i.MX8MM with an SPI peripheral clock set to 50 MHz by default and a requested SPI bus clock of 80 MHz for the SPI NOR flash. With the fix applied the debug message from mx51_ecspi_clkdiv() now prints the following: spi_imx 30820000.spi: mx51_ecspi_clkdiv: fin: 50000000, fspi: 50000000, post: 0, pre: 0 Fixes: 07e759387788 ("spi: spi-imx: add PIO polling support") Cc: Marc Kleine-Budde Cc: David Jander Cc: Fabio Estevam Cc: Mark Brown Cc: Marek Vasut Cc: stable@vger.kernel.org Signed-off-by: Frieder Schrempf Tested-by: Fabio Estevam --- Changes for v2: * Remove the reference and the Fixes tag for commit 6fd8b8503a0d as it is incorrect. --- drivers/spi/spi-imx.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/spi/spi-imx.c b/drivers/spi/spi-imx.c index 30d82cc7300b..468ce0a2b282 100644 --- a/drivers/spi/spi-imx.c +++ b/drivers/spi/spi-imx.c @@ -444,8 +444,7 @@ static unsigned int mx51_ecspi_clkdiv(struct spi_imx_data *spi_imx, unsigned int pre, post; unsigned int fin = spi_imx->spi_clk; - if (unlikely(fspi > fin)) - return 0; + fspi = min(fspi, fin); post = fls(fin) - fls(fspi); if (fin > fspi << post)