Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 489 insertions, 0 deletions

diff --git a/drivers/iio/temperature/max31856.c b/drivers/iio/temperature/max31856.c
new file mode 100644
index 0000000000..8307aae2cb
--- /dev/null
+++ b/drivers/iio/temperature/max31856.c
@@ -0,0 +1,489 @@
+// SPDX-License-Identifier: GPL-2.0
+/* max31856.c
+ *
+ * Maxim MAX31856 thermocouple sensor driver
+ *
+ * Copyright (C) 2018-2019 Rockwell Collins
+ */
+
+#include <linux/ctype.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/property.h>
+#include <linux/spi/spi.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/util_macros.h>
+#include <asm/unaligned.h>
+#include <dt-bindings/iio/temperature/thermocouple.h>
+/*
+ * The MSB of the register value determines whether the following byte will
+ * be written or read. If it is 0, one or more byte reads will follow.
+ */
+#define MAX31856_RD_WR_BIT         BIT(7)
+
+#define MAX31856_CR0_AUTOCONVERT   BIT(7)
+#define MAX31856_CR0_1SHOT         BIT(6)
+#define MAX31856_CR0_OCFAULT       BIT(4)
+#define MAX31856_CR0_OCFAULT_MASK  GENMASK(5, 4)
+#define MAX31856_CR0_FILTER_50HZ   BIT(0)
+#define MAX31856_AVERAGING_MASK    GENMASK(6, 4)
+#define MAX31856_AVERAGING_SHIFT   4
+#define MAX31856_TC_TYPE_MASK      GENMASK(3, 0)
+#define MAX31856_FAULT_OVUV        BIT(1)
+#define MAX31856_FAULT_OPEN        BIT(0)
+
+/* The MAX31856 registers */
+#define MAX31856_CR0_REG           0x00
+#define MAX31856_CR1_REG           0x01
+#define MAX31856_MASK_REG          0x02
+#define MAX31856_CJHF_REG          0x03
+#define MAX31856_CJLF_REG          0x04
+#define MAX31856_LTHFTH_REG        0x05
+#define MAX31856_LTHFTL_REG        0x06
+#define MAX31856_LTLFTH_REG        0x07
+#define MAX31856_LTLFTL_REG        0x08
+#define MAX31856_CJTO_REG          0x09
+#define MAX31856_CJTH_REG          0x0A
+#define MAX31856_CJTL_REG          0x0B
+#define MAX31856_LTCBH_REG         0x0C
+#define MAX31856_LTCBM_REG         0x0D
+#define MAX31856_LTCBL_REG         0x0E
+#define MAX31856_SR_REG            0x0F
+
+static const struct iio_chan_spec max31856_channels[] = {
+	{	/* Thermocouple Temperature */
+		.type = IIO_TEMP,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE) |
+			BIT(IIO_CHAN_INFO_THERMOCOUPLE_TYPE),
+		.info_mask_shared_by_type =
+			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO)
+	},
+	{	/* Cold Junction Temperature */
+		.type = IIO_TEMP,
+		.channel2 = IIO_MOD_TEMP_AMBIENT,
+		.modified = 1,
+		.info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE),
+		.info_mask_shared_by_type =
+			BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO)
+	},
+};
+
+struct max31856_data {
+	struct spi_device *spi;
+	u32 thermocouple_type;
+	bool filter_50hz;
+	int averaging;
+};
+
+static const char max31856_tc_types[] = {
+	'B', 'E', 'J', 'K', 'N', 'R', 'S', 'T'
+};
+
+static int max31856_read(struct max31856_data *data, u8 reg,
+			 u8 val[], unsigned int read_size)
+{
+	return spi_write_then_read(data->spi, &reg, 1, val, read_size);
+}
+
+static int max31856_write(struct max31856_data *data, u8 reg,
+			  unsigned int val)
+{
+	u8 buf[2];
+
+	buf[0] = reg | (MAX31856_RD_WR_BIT);
+	buf[1] = val;
+
+	return spi_write(data->spi, buf, 2);
+}
+
+static int max31856_init(struct max31856_data *data)
+{
+	int ret;
+	u8 reg_cr0_val, reg_cr1_val;
+
+	/* Start by changing to Off mode before making changes as
+	 * some settings are recommended to be set only when the device
+	 * is off
+	 */
+	ret = max31856_read(data, MAX31856_CR0_REG, &reg_cr0_val, 1);
+	if (ret)
+		return ret;
+
+	reg_cr0_val &= ~MAX31856_CR0_AUTOCONVERT;
+	ret = max31856_write(data, MAX31856_CR0_REG, reg_cr0_val);
+	if (ret)
+		return ret;
+
+	/* Set thermocouple type based on dts property */
+	ret = max31856_read(data, MAX31856_CR1_REG, &reg_cr1_val, 1);
+	if (ret)
+		return ret;
+
+	reg_cr1_val &= ~MAX31856_TC_TYPE_MASK;
+	reg_cr1_val |= data->thermocouple_type;
+
+	reg_cr1_val &= ~MAX31856_AVERAGING_MASK;
+	reg_cr1_val |= data->averaging << MAX31856_AVERAGING_SHIFT;
+
+	ret = max31856_write(data, MAX31856_CR1_REG, reg_cr1_val);
+	if (ret)
+		return ret;
+
+	/*
+	 * Enable Open circuit fault detection
+	 * Read datasheet for more information: Table 4.
+	 * Value 01 means : Enabled (Once every 16 conversions)
+	 */
+	reg_cr0_val &= ~MAX31856_CR0_OCFAULT_MASK;
+	reg_cr0_val |= MAX31856_CR0_OCFAULT;
+
+	/* Set Auto Conversion Mode */
+	reg_cr0_val &= ~MAX31856_CR0_1SHOT;
+	reg_cr0_val |= MAX31856_CR0_AUTOCONVERT;
+
+	if (data->filter_50hz)
+		reg_cr0_val |= MAX31856_CR0_FILTER_50HZ;
+	else
+		reg_cr0_val &= ~MAX31856_CR0_FILTER_50HZ;
+
+	return max31856_write(data, MAX31856_CR0_REG, reg_cr0_val);
+}
+
+static int max31856_thermocouple_read(struct max31856_data *data,
+				      struct iio_chan_spec const *chan,
+				      int *val)
+{
+	int ret, offset_cjto;
+	u8 reg_val[3];
+
+	switch (chan->channel2) {
+	case IIO_NO_MOD:
+		/*
+		 * Multibyte Read
+		 * MAX31856_LTCBH_REG, MAX31856_LTCBM_REG, MAX31856_LTCBL_REG
+		 */
+		ret = max31856_read(data, MAX31856_LTCBH_REG, reg_val, 3);
+		if (ret)
+			return ret;
+		/* Skip last 5 dead bits of LTCBL */
+		*val = get_unaligned_be24(&reg_val[0]) >> 5;
+		/* Check 7th bit of LTCBH reg. value for sign*/
+		if (reg_val[0] & 0x80)
+			*val -= 0x80000;
+		break;
+
+	case IIO_MOD_TEMP_AMBIENT:
+		/*
+		 * Multibyte Read
+		 * MAX31856_CJTO_REG, MAX31856_CJTH_REG, MAX31856_CJTL_REG
+		 */
+		ret = max31856_read(data, MAX31856_CJTO_REG, reg_val, 3);
+		if (ret)
+			return ret;
+		/* Get Cold Junction Temp. offset register value */
+		offset_cjto = reg_val[0];
+		/* Get CJTH and CJTL value and skip last 2 dead bits of CJTL */
+		*val = get_unaligned_be16(&reg_val[1]) >> 2;
+		/* As per datasheet add offset into CJTH and CJTL */
+		*val += offset_cjto;
+		/* Check 7th bit of CJTH reg. value for sign */
+		if (reg_val[1] & 0x80)
+			*val -= 0x4000;
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	ret = max31856_read(data, MAX31856_SR_REG, reg_val, 1);
+	if (ret)
+		return ret;
+	/* Check for over/under voltage or open circuit fault */
+	if (reg_val[0] & (MAX31856_FAULT_OVUV | MAX31856_FAULT_OPEN))
+		return -EIO;
+
+	return ret;
+}
+
+static int max31856_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *chan,
+			     int *val, int *val2, long mask)
+{
+	struct max31856_data *data = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		ret = max31856_thermocouple_read(data, chan, val);
+		if (ret)
+			return ret;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->channel2) {
+		case IIO_MOD_TEMP_AMBIENT:
+			/* Cold junction Temp. Data resolution is 0.015625 */
+			*val = 15;
+			*val2 = 625000; /* 1000 * 0.015625 */
+			ret = IIO_VAL_INT_PLUS_MICRO;
+			break;
+		default:
+			/* Thermocouple Temp. Data resolution is 0.0078125 */
+			*val = 7;
+			*val2 = 812500; /* 1000 * 0.0078125) */
+			return IIO_VAL_INT_PLUS_MICRO;
+		}
+		break;
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		*val = 1 << data->averaging;
+		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
+		*val = max31856_tc_types[data->thermocouple_type];
+		return IIO_VAL_CHAR;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+	return ret;
+}
+
+static int max31856_write_raw_get_fmt(struct iio_dev *indio_dev,
+				      struct iio_chan_spec const *chan,
+				      long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
+		return IIO_VAL_CHAR;
+	default:
+		return IIO_VAL_INT;
+	}
+}
+
+static int max31856_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *chan,
+			      int val, int val2, long mask)
+{
+	struct max31856_data *data = iio_priv(indio_dev);
+	int msb;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
+		if (val > 16 || val < 1)
+			return -EINVAL;
+		msb = fls(val) - 1;
+		/* Round up to next 2pow if needed */
+		if (BIT(msb) < val)
+			msb++;
+
+		data->averaging = msb;
+		max31856_init(data);
+		break;
+	case IIO_CHAN_INFO_THERMOCOUPLE_TYPE:
+	{
+		int tc_type = -1;
+		int i;
+
+		for (i = 0; i < ARRAY_SIZE(max31856_tc_types); i++) {
+			if (max31856_tc_types[i] == toupper(val)) {
+				tc_type = i;
+				break;
+			}
+		}
+		if (tc_type < 0)
+			return -EINVAL;
+
+		data->thermocouple_type = tc_type;
+		max31856_init(data);
+		break;
+	}
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static ssize_t show_fault(struct device *dev, u8 faultbit, char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct max31856_data *data = iio_priv(indio_dev);
+	u8 reg_val;
+	int ret;
+	bool fault;
+
+	ret = max31856_read(data, MAX31856_SR_REG, &reg_val, 1);
+	if (ret)
+		return ret;
+
+	fault = reg_val & faultbit;
+
+	return sysfs_emit(buf, "%d\n", fault);
+}
+
+static ssize_t show_fault_ovuv(struct device *dev,
+			       struct device_attribute *attr,
+			       char *buf)
+{
+	return show_fault(dev, MAX31856_FAULT_OVUV, buf);
+}
+
+static ssize_t show_fault_oc(struct device *dev,
+			     struct device_attribute *attr,
+			     char *buf)
+{
+	return show_fault(dev, MAX31856_FAULT_OPEN, buf);
+}
+
+static ssize_t show_filter(struct device *dev,
+			   struct device_attribute *attr,
+			   char *buf)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct max31856_data *data = iio_priv(indio_dev);
+
+	return sysfs_emit(buf, "%d\n", data->filter_50hz ? 50 : 60);
+}
+
+static ssize_t set_filter(struct device *dev,
+			  struct device_attribute *attr,
+			  const char *buf,
+			  size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct max31856_data *data = iio_priv(indio_dev);
+	unsigned int freq;
+	int ret;
+
+	ret = kstrtouint(buf, 10, &freq);
+	if (ret)
+		return ret;
+
+	switch (freq) {
+	case 50:
+		data->filter_50hz = true;
+		break;
+	case 60:
+		data->filter_50hz = false;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	max31856_init(data);
+	return len;
+}
+
+static IIO_DEVICE_ATTR(fault_ovuv, 0444, show_fault_ovuv, NULL, 0);
+static IIO_DEVICE_ATTR(fault_oc, 0444, show_fault_oc, NULL, 0);
+static IIO_DEVICE_ATTR(in_temp_filter_notch_center_frequency, 0644,
+		       show_filter, set_filter, 0);
+
+static struct attribute *max31856_attributes[] = {
+	&iio_dev_attr_fault_ovuv.dev_attr.attr,
+	&iio_dev_attr_fault_oc.dev_attr.attr,
+	&iio_dev_attr_in_temp_filter_notch_center_frequency.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group max31856_group = {
+	.attrs = max31856_attributes,
+};
+
+static const struct iio_info max31856_info = {
+	.read_raw = max31856_read_raw,
+	.write_raw = max31856_write_raw,
+	.write_raw_get_fmt = max31856_write_raw_get_fmt,
+	.attrs = &max31856_group,
+};
+
+static int max31856_probe(struct spi_device *spi)
+{
+	const struct spi_device_id *id = spi_get_device_id(spi);
+	struct iio_dev *indio_dev;
+	struct max31856_data *data;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	data = iio_priv(indio_dev);
+	data->spi = spi;
+	data->filter_50hz = false;
+
+	spi_set_drvdata(spi, indio_dev);
+
+	indio_dev->info = &max31856_info;
+	indio_dev->name = id->name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->channels = max31856_channels;
+	indio_dev->num_channels = ARRAY_SIZE(max31856_channels);
+
+	ret = device_property_read_u32(&spi->dev, "thermocouple-type", &data->thermocouple_type);
+	if (ret) {
+		dev_info(&spi->dev,
+			 "Could not read thermocouple type DT property, configuring as a K-Type\n");
+		data->thermocouple_type = THERMOCOUPLE_TYPE_K;
+	}
+
+	/*
+	 * no need to translate values as the supported types
+	 * have the same value as the #defines
+	 */
+	switch (data->thermocouple_type) {
+	case THERMOCOUPLE_TYPE_B:
+	case THERMOCOUPLE_TYPE_E:
+	case THERMOCOUPLE_TYPE_J:
+	case THERMOCOUPLE_TYPE_K:
+	case THERMOCOUPLE_TYPE_N:
+	case THERMOCOUPLE_TYPE_R:
+	case THERMOCOUPLE_TYPE_S:
+	case THERMOCOUPLE_TYPE_T:
+		break;
+	default:
+		dev_err(&spi->dev,
+			"error: thermocouple-type %u not supported by max31856\n"
+			, data->thermocouple_type);
+		return -EINVAL;
+	}
+
+	ret = max31856_init(data);
+	if (ret) {
+		dev_err(&spi->dev, "error: Failed to configure max31856\n");
+		return ret;
+	}
+
+	return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static const struct spi_device_id max31856_id[] = {
+	{ "max31856", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, max31856_id);
+
+static const struct of_device_id max31856_of_match[] = {
+	{ .compatible = "maxim,max31856" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, max31856_of_match);
+
+static struct spi_driver max31856_driver = {
+	.driver = {
+		.name = "max31856",
+		.of_match_table = max31856_of_match,
+	},
+	.probe = max31856_probe,
+	.id_table = max31856_id,
+};
+module_spi_driver(max31856_driver);
+
+MODULE_AUTHOR("Paresh Chaudhary <paresh.chaudhary@rockwellcollins.com>");
+MODULE_AUTHOR("Patrick Havelange <patrick.havelange@essensium.com>");
+MODULE_DESCRIPTION("Maxim MAX31856 thermocouple sensor driver");
+MODULE_LICENSE("GPL");