From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751547AbeBWMwG (ORCPT ); Fri, 23 Feb 2018 07:52:06 -0500 Received: from mx08-00178001.pphosted.com ([91.207.212.93]:11127 "EHLO mx07-00178001.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751404AbeBWMwC (ORCPT ); Fri, 23 Feb 2018 07:52:02 -0500 From: Fabrice Gasnier To: CC: , , , , , , , , , , Subject: [PATCH 7/7] iio: adc: stm32-dfsdm: add check on spi-max-frequency Date: Fri, 23 Feb 2018 13:51:01 +0100 Message-ID: <1519390261-25453-8-git-send-email-fabrice.gasnier@st.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1519390261-25453-1-git-send-email-fabrice.gasnier@st.com> References: <1519390261-25453-1-git-send-email-fabrice.gasnier@st.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.75.127.45] X-ClientProxiedBy: SFHDAG3NODE3.st.com (10.75.127.9) To SFHDAG5NODE3.st.com (10.75.127.15) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-23_04:,, signatures=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org spi-max-frequency is requested for SPI master mode (only), to tune output clock. It may happen requested frequency isn't reachable. Add explicit check, so probe fails with error in this case. Otherwise, output clock may simply be silently turned off (conversions fail). Signed-off-by: Fabrice Gasnier --- drivers/iio/adc/stm32-dfsdm-core.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/iio/adc/stm32-dfsdm-core.c b/drivers/iio/adc/stm32-dfsdm-core.c index e50efdc..1d0d823 100644 --- a/drivers/iio/adc/stm32-dfsdm-core.c +++ b/drivers/iio/adc/stm32-dfsdm-core.c @@ -227,6 +227,11 @@ static int stm32_dfsdm_parse_of(struct platform_device *pdev, } priv->spi_clk_out_div = div_u64_rem(clk_freq, spi_freq, &rem) - 1; + if (!priv->spi_clk_out_div) { + /* spi_clk_out_div == 0 means ckout is OFF */ + dev_err(&pdev->dev, "spi-max-frequency not achievable\n"); + return -EINVAL; + } priv->dfsdm.spi_master_freq = spi_freq; if (rem) { -- 1.9.1