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

[Jonathan Cameron]

On Fri, 23 Feb 2018 13:51:01 +0100
Fabrice Gasnier  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 
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, ) - 1;
> + if (!priv->spi_clk_out_div) {
> + /* spi_clk_out_div == 0 means ckout is OFF */
> + dev_err(>dev, "spi-max-frequency not achievable\n");
> + return -EINVAL;
> + }
>   priv->dfsdm.spi_master_freq = spi_freq;
>  
>   if (rem) {

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

[Jonathan Cameron]

On Fri, 23 Feb 2018 13:51:01 +0100
Fabrice Gasnier  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 
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, ) - 1;
> + if (!priv->spi_clk_out_div) {
> + /* spi_clk_out_div == 0 means ckout is OFF */
> + dev_err(>dev, "spi-max-frequency not achievable\n");
> + return -EINVAL;
> + }
>   priv->dfsdm.spi_master_freq = spi_freq;
>  
>   if (rem) {

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

[Fabrice Gasnier]

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, ) - 1;
+   if (!priv->spi_clk_out_div) {
+   /* spi_clk_out_div == 0 means ckout is OFF */
+   dev_err(>dev, "spi-max-frequency not achievable\n");
+   return -EINVAL;
+   }
priv->dfsdm.spi_master_freq = spi_freq;
 
if (rem) {
-- 
1.9.1

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

[Fabrice Gasnier]

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, ) - 1;
+   if (!priv->spi_clk_out_div) {
+   /* spi_clk_out_div == 0 means ckout is OFF */
+   dev_err(>dev, "spi-max-frequency not achievable\n");
+   return -EINVAL;
+   }
priv->dfsdm.spi_master_freq = spi_freq;
 
if (rem) {
-- 
1.9.1