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

Jonathan Cameron
2018-04-28T15:08:15Z

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) {