[7/7] iio: adc: stm32-dfsdm: add check on spi-max-frequency
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Message ID 1519390261-25453-8-git-send-email-fabrice.gasnier@st.com
State New, archived
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Series
  • iio: adc: stm32-dfsdm: misc fixes and improvements
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Commit Message

Fabrice Gasnier Feb. 23, 2018, 12:51 p.m. UTC
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(+)

Patch
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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) {