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iio: adc: stm32-adc: use generic binding for sample-time 

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>
Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20211014131228.4692-8-olivier.moysan@foss.st.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Olivier Moysan 2021-10-14 15:12:28 +02:00 committed by Jonathan Cameron
parent 0e346b2cfa
commit 796e5d0b1e
1 changed files with 41 additions and 29 deletions
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70
drivers/iio/adc/stm32-adc.c
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@ -1805,6 +1805,13 @@ 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 = max(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++)
@ -1881,6 +1888,13 @@ 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;
}
@ -1896,6 +1910,7 @@ 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",
@ -1938,6 +1953,19 @@ 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;
}
@ -2030,6 +2058,19 @@ 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-ns", &val);
/* st,min-sample-time-ns 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-ns property %d\n",
ret);
goto err;
}
scan_index++;
}
@ -2048,7 +2089,6 @@ 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++)
@ -2076,13 +2116,6 @@ 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++;
@ -2099,27 +2132,6 @@ 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 = max(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];