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From: Fabrice Gasnier <fabrice.gasnier@st.com>
To: <jic23@kernel.org>
Cc: <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <mcoquelin.stm32@gmail.com>,
	<alexandre.torgue@st.com>, <fabrice.gasnier@st.com>,
	<linux-iio@vger.kernel.org>, <lars@metafoo.de>, <knaack.h@gmx.de>,
	<pmeerw@pmeerw.net>, <benjamin.gaignard@linaro.org>,
	<arnaud.pouliquen@st.com>
Subject: [PATCH 7/7] iio: adc: stm32-dfsdm: add check on spi-max-frequency
Date: Fri, 23 Feb 2018 13:51:01 +0100	[thread overview]
Message-ID: <1519390261-25453-8-git-send-email-fabrice.gasnier@st.com> (raw)
In-Reply-To: <1519390261-25453-1-git-send-email-fabrice.gasnier@st.com>

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 <fabrice.gasnier@st.com>
---
 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

  parent reply	other threads:[~2018-02-23 12:52 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-23 12:50 [PATCH 0/7] iio: adc: stm32-dfsdm: misc fixes and improvements Fabrice Gasnier
2018-02-23 12:50 ` [PATCH 1/7] iio: adc: stm32-dfsdm: fix compatible data use Fabrice Gasnier
2018-02-24 12:56   ` Jonathan Cameron
2018-02-23 12:50 ` [PATCH 2/7] iio: adc: stm32-dfsdm: fix call to stop channel Fabrice Gasnier
2018-02-24 12:57   ` Jonathan Cameron
2018-02-23 12:50 ` [PATCH 3/7] iio: adc: stm32-dfsdm: fix clock source selection Fabrice Gasnier
2018-02-24 12:59   ` Jonathan Cameron
2018-02-23 12:50 ` [PATCH 4/7] iio: adc: stm32-dfsdm: fix multiple channel initialization Fabrice Gasnier
2018-02-24 13:01   ` Jonathan Cameron
2018-02-23 12:50 ` [PATCH 5/7] iio: adc: stm32-dfsdm: misc style improvements and fixes Fabrice Gasnier
2018-02-24 13:03   ` Jonathan Cameron
2018-02-27  8:21     ` Fabrice Gasnier
2018-03-03 15:09       ` Jonathan Cameron
2018-04-23  7:48     ` Fabrice Gasnier
2018-04-28 14:52       ` Jonathan Cameron
2018-02-23 12:51 ` [PATCH 6/7] iio: adc: stm32-dfsdm: add check on max filter id Fabrice Gasnier
2018-04-28 15:07   ` Jonathan Cameron
2018-02-23 12:51 ` Fabrice Gasnier [this message]
2018-04-28 15:07   ` [PATCH 7/7] iio: adc: stm32-dfsdm: add check on spi-max-frequency Jonathan Cameron
2018-02-23 13:49 ` [PATCH 0/7] iio: adc: stm32-dfsdm: misc fixes and improvements Arnaud Pouliquen

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