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@foss.st.com --- drivers/iio/adc/stm32-adc.c | 75 +++++++++++++++++++++---------------- 1 file changed, 43 insertions(+), 32 deletions(-)
diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index 9e52a7de9b16..2d52415770b3 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -1806,6 +1806,14 @@ 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 + */ + if (channel == adc->int_ch[STM32_ADC_INT_CH_VREFINT] && + smp_ns < adc->cfg->ts_vrefint_ns) + smp_ns = adc->cfg->ts_vrefint_ns; + /* Determine sampling time (ADC clock cycles) */ period_ns = NSEC_PER_SEC / adc->common->rate; for (smp = 0; smp <= STM32_ADC_MAX_SMP; smp++) @@ -1884,6 +1892,13 @@ static int stm32_adc_get_legacy_chan_count(struct iio_dev *indio_dev, struct stm return -ENODATA; }
+ /* 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; }
@@ -1899,6 +1914,7 @@ 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", @@ -1941,6 +1957,19 @@ 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; }
@@ -2035,6 +2064,19 @@ 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 (vin[1]) + 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++; }
@@ -2052,8 +2094,7 @@ static int stm32_adc_chan_of_init(struct iio_dev *indio_dev, bool timestamping) struct stm32_adc *adc = iio_priv(indio_dev); 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; + int scan_index = 0, num_channels = 0, ret; bool legacy = false;
num_channels = of_get_available_child_count(node); @@ -2077,13 +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++;
@@ -2100,29 +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];