On 9/22/21 5:34 PM, Olivier Moysan wrote:
> Add st,min-sample-time-nsecs to channel generic binding.
> Sample time can be defined par channel node. If a channel
> is configured as differential, the same sample time applies
> for both inputs.
> Keep support of legacy st,min-sample-time-nsecs property
> for backward compatibility.
>
> Signed-off-by: Olivier Moysan <olivier.moysan@xxxxxxxxxxx>
> ---
> drivers/iio/adc/stm32-adc.c | 70 +++++++++++++++++++++----------------
> 1 file changed, 39 insertions(+), 31 deletions(-)
>
> diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
> index c427e439bf4a..cfd11ff0cf36 100644
> --- a/drivers/iio/adc/stm32-adc.c
> +++ b/drivers/iio/adc/stm32-adc.c
> @@ -1809,6 +1809,11 @@ static void stm32_adc_smpr_init(struct stm32_adc *adc, int channel, u32 smp_ns)
> u32 period_ns, shift = smpr->shift, mask = smpr->mask;
> unsigned int smp, r = smpr->reg;
>
> + /*
> + * For vrefint channel, ensure that the sampling time cannot
> + * be lower than the one specified in the datasheet
> + */
> +
Hi Olivier,
I had a quick look at this series. It looks like some code is missing
here, e.g. to check "ts_vrefint_ns".
Thanks & BR,
Fabrice
> /* Determine sampling time (ADC clock cycles) */
> period_ns = NSEC_PER_SEC / adc->common->rate;
> for (smp = 0; smp <= STM32_ADC_MAX_SMP; smp++)
> @@ -1885,6 +1890,13 @@ static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm
> num_channels += ret;
> }
>
> + /* Optional sample time is provided either for each, or all channels */
> + ret = of_property_count_u32_elems(node, "st,min-sample-time-nsecs");
> + if (ret > 1 && ret != num_channels) {
> + dev_err(&indio_dev->dev, "Invalid st,min-sample-time-nsecs\n");
> + return -EINVAL;
> + }
> +
> return num_channels;
> }
>
> @@ -1900,6 +1912,7 @@ static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
> int scan_index = 0, val, ret, i;
> struct property *prop;
> const __be32 *cur;
> + u32 smp = 0;
>
> if (num_diff) {
> ret = of_property_read_u32_array(node, "st,adc-diff-channels",
> @@ -1942,6 +1955,19 @@ static int stm32_adc_legacy_chan_init(struct iio_dev *indio_dev,
> scan_index++;
> }
>
> + for (i = 0; i < scan_index; i++) {
> + /*
> + * Using of_property_read_u32_index(), smp value will only be
> + * modified if valid u32 value can be decoded. This allows to
> + * get either no value, 1 shared value for all indexes, or one
> + * value per channel.
> + */
> + of_property_read_u32_index(node, "st,min-sample-time-nsecs", i, &smp);
> +
> + /* Prepare sampling time settings */
> + stm32_adc_smpr_init(adc, channels[i].channel, smp);
> + }
> +
> return scan_index;
> }
>
> @@ -2034,6 +2060,19 @@ static int stm32_adc_generic_chan_init(struct iio_dev *indio_dev,
>
> stm32_adc_chan_init_one(indio_dev, &channels[scan_index], val,
> vin[1], scan_index, differential);
> +
> + ret = of_property_read_u32(child, "st,min-sample-time-nsecs", &val);
> + /* st,min-sample-time-nsecs is optional */
> + if (!ret) {
> + stm32_adc_smpr_init(adc, channels[scan_index].channel, val);
> + if (differential)
> + stm32_adc_smpr_init(adc, vin[1], val);
> + } else if (ret != -EINVAL) {
> + dev_err(&indio_dev->dev, "Invalid st,min-sample-time-nsecs property %d\n",
> + ret);
> + goto err;
> + }
> +
> scan_index++;
> }
>
> @@ -2052,7 +2091,6 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
> const struct stm32_adc_info *adc_info = adc->cfg->adc_info;
> struct iio_chan_spec *channels;
> int scan_index = 0, num_channels = 0, ret, i;
> - u32 smp = 0;
> bool legacy = false;
>
> for (i = 0; i < STM32_ADC_INT_CH_NB; i++)
> @@ -2080,13 +2118,6 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
> return -EINVAL;
> }
>
> - /* Optional sample time is provided either for each, or all channels */
> - ret = of_property_count_u32_elems(node, "st,min-sample-time-nsecs");
> - if (ret > 1 && ret != num_channels) {
> - dev_err(&indio_dev->dev, "Invalid st,min-sample-time-nsecs\n");
> - return -EINVAL;
> - }
> -
> if (timestamping)
> num_channels++;
>
> @@ -2103,29 +2134,6 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping)
> return ret;
> scan_index = ret;
>
> - for (i = 0; i < scan_index; i++) {
> - /*
> - * Using of_property_read_u32_index(), smp value will only be
> - * modified if valid u32 value can be decoded. This allows to
> - * get either no value, 1 shared value for all indexes, or one
> - * value per channel.
> - */
> - of_property_read_u32_index(node, "st,min-sample-time-nsecs",
> - i, &smp);
> -
> - /*
> - * For vrefint channel, ensure that the sampling time cannot
> - * be lower than the one specified in the datasheet
> - */
> - if (channels[i].channel == adc->int_ch[STM32_ADC_INT_CH_VREFINT] &&
> - smp < adc->cfg->ts_vrefint_ns) {
> - smp = adc->cfg->ts_vrefint_ns;
> - }
> -
> - /* Prepare sampling time settings */
> - stm32_adc_smpr_init(adc, channels[i].channel, smp);
> - }
> -
> if (timestamping) {
> struct iio_chan_spec *timestamp = &channels[scan_index];
>
>
