1 // SPDX-License-Identifier: GPL-2.0
6  * Copyright (C) 2018-2019 Rockwell Collins
20 #include <dt-bindings/iio/temperature/thermocouple.h>
65 	{	/* Cold Junction Temperature */
90 	return spi_write_then_read(data->spi, &reg, 1, val, read_size);  in max31856_read()
101 	return spi_write(data->spi, buf, 2);  in max31856_write()
128 	reg_cr1_val |= data->thermocouple_type;  in max31856_init()
131 	reg_cr1_val |= data->averaging << MAX31856_AVERAGING_SHIFT;  in max31856_init()
149 	if (data->filter_50hz)  in max31856_init()
164 	switch (chan->channel2) {  in max31856_thermocouple_read()
177 			*val -= 0x80000;  in max31856_thermocouple_read()
188 		/* Get Cold Junction Temp. offset register value */  in max31856_thermocouple_read()
196 			*val -= 0x4000;  in max31856_thermocouple_read()
200 		return -EINVAL;  in max31856_thermocouple_read()
208 		return -EIO;  in max31856_thermocouple_read()
227 		switch (chan->channel2) {  in max31856_read_raw()
229 			/* Cold junction Temp. Data resolution is 0.015625 */  in max31856_read_raw()
235 			/* Thermocouple Temp. Data resolution is 0.0078125 */  in max31856_read_raw()
242 		*val = 1 << data->averaging;  in max31856_read_raw()
245 		*val = max31856_tc_types[data->thermocouple_type];  in max31856_read_raw()
248 		ret = -EINVAL;  in max31856_read_raw()
277 			return -EINVAL;  in max31856_write_raw()
278 		msb = fls(val) - 1;  in max31856_write_raw()
283 		data->averaging = msb;  in max31856_write_raw()
288 		int tc_type = -1;  in max31856_write_raw()
298 			return -EINVAL;  in max31856_write_raw()
300 		data->thermocouple_type = tc_type;  in max31856_write_raw()
305 		return -EINVAL;  in max31856_write_raw()
349 	return sysfs_emit(buf, "%d\n", data->filter_50hz ? 50 : 60);  in show_filter()
368 		data->filter_50hz = true;  in set_filter()
371 		data->filter_50hz = false;  in set_filter()
374 		return -EINVAL;  in set_filter()
411 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));  in max31856_probe()
413 		return -ENOMEM;  in max31856_probe()
416 	data->spi = spi;  in max31856_probe()
417 	data->filter_50hz = false;  in max31856_probe()
421 	indio_dev->info = &max31856_info;  in max31856_probe()
422 	indio_dev->name = id->name;  in max31856_probe()
423 	indio_dev->modes = INDIO_DIRECT_MODE;  in max31856_probe()
424 	indio_dev->channels = max31856_channels;  in max31856_probe()
425 	indio_dev->num_channels = ARRAY_SIZE(max31856_channels);  in max31856_probe()
427 	ret = device_property_read_u32(&spi->dev, "thermocouple-type", &data->thermocouple_type);  in max31856_probe()
429 		dev_info(&spi->dev,  in max31856_probe()
430 			 "Could not read thermocouple type DT property, configuring as a K-Type\n");  in max31856_probe()
431 		data->thermocouple_type = THERMOCOUPLE_TYPE_K;  in max31856_probe()
438 	switch (data->thermocouple_type) {  in max31856_probe()
449 		dev_err(&spi->dev,  in max31856_probe()
450 			"error: thermocouple-type %u not supported by max31856\n"  in max31856_probe()
451 			, data->thermocouple_type);  in max31856_probe()
452 		return -EINVAL;  in max31856_probe()
457 		dev_err(&spi->dev, "error: Failed to configure max31856\n");  in max31856_probe()
461 	return devm_iio_device_register(&spi->dev, indio_dev);  in max31856_probe()