[7/7] iio: adc: stm32-dfsdm: add check on spi-max-frequency
diff mbox

Message ID 1519390261-25453-8-git-send-email-fabrice.gasnier@st.com
State New
Headers show

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(+)

Comments

Jonathan Cameron April 28, 2018, 3:07 p.m. UTC | #1
On Fri, 23 Feb 2018 13:51:01 +0100
Fabrice Gasnier <fabrice.gasnier@st.com> wrote:

> 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>
Applied to the togreg branch of iio.git and pushed out as testing
for the autobuilders to play with.

Thanks,

Jonathan

> ---
>  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) {

--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Patch
diff mbox

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) {