Commit 796e5d0b authored by Olivier Moysan's avatar Olivier Moysan Committed by Jonathan Cameron
Browse files

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: default avatarOlivier Moysan <olivier.moysan@foss.st.com>
Reviewed-by: default avatarFabrice Gasnier <fabrice.gasnier@foss.st.com>
Link: https://lore.kernel.org/r/20211014131228.4692-8-olivier.moysan@foss.st.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent 0e346b2c

drivers/iio/adc/stm32-adc.c

+41 −29
Original line number Diff line number Diff line
@@ -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];