iio: temperature: mlx90635 MLX90635 IR Temperature sensor

MLX90635 is an Infra Red contactless temperature sensor most suitable
for consumer applications where measured object temperature is in range
between -20 to 100 degrees Celsius. It has improved accuracy for
measurements within temperature range of human body and can operate in
ambient temperature range between -20 to 85 degrees Celsius.

Driver provides simple power management possibility as it returns to
lowest possible power mode (Step sleep mode) in which temperature
measurements can still be performed, yet for continuous measuring it
switches to Continuous power mode where measurements constantly change
without triggering.

Signed-off-by: Crt Mori<cmo@melexis.com>
Link: https://lore.kernel.org/r/c6590e4fb8d993a5317b486a3e45e1bb6e9e3318.1701872051.git.cmo@melexis.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

3 files changed, 1110 insertions, 0 deletions

diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
index ea2ce364b2e9..ed0e4963362f 100644
--- a/drivers/iio/temperature/Kconfig
+++ b/drivers/iio/temperature/Kconfig
@@ -76,6 +76,18 @@ config MLX90632
 	  This driver can also be built as a module. If so, the module will
 	  be called mlx90632.
 
+config MLX90635
+	tristate "MLX90635 contact-less infrared sensor with medical accuracy"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for the Melexis
+	  MLX90635 contact-less infrared sensor with medical accuracy
+	  connected with I2C.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called mlx90635.
+
 config TMP006
 	tristate "TMP006 infrared thermopile sensor"
 	depends on I2C
diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
index 9330d4a39598..07d6e65709f7 100644
--- a/drivers/iio/temperature/Makefile
+++ b/drivers/iio/temperature/Makefile
@@ -13,6 +13,7 @@ obj-$(CONFIG_MAX31865) += max31865.o
 obj-$(CONFIG_MCP9600) += mcp9600.o
 obj-$(CONFIG_MLX90614) += mlx90614.o
 obj-$(CONFIG_MLX90632) += mlx90632.o
+obj-$(CONFIG_MLX90632) += mlx90635.o
 obj-$(CONFIG_TMP006) += tmp006.o
 obj-$(CONFIG_TMP007) += tmp007.o
 obj-$(CONFIG_TMP117) += tmp117.o
diff --git a/drivers/iio/temperature/mlx90635.c b/drivers/iio/temperature/mlx90635.c
new file mode 100644
index 000000000000..1f5c962c1818
--- /dev/null
+++ b/drivers/iio/temperature/mlx90635.c
@@ -0,0 +1,1097 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * mlx90635.c - Melexis MLX90635 contactless IR temperature sensor
+ *
+ * Copyright (c) 2023 Melexis <cmo@melexis.com>
+ *
+ * Driver for the Melexis MLX90635 I2C 16-bit IR thermopile sensor
+ */
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/gpio/consumer.h>
+#include <linux/i2c.h>
+#include <linux/iopoll.h>
+#include <linux/jiffies.h>
+#include <linux/kernel.h>
+#include <linux/limits.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/math64.h>
+#include <linux/pm_runtime.h>
+#include <linux/regmap.h>
+#include <linux/regulator/consumer.h>
+
+#include <linux/iio/iio.h>
+
+/* Memory sections addresses */
+#define MLX90635_ADDR_RAM	0x0000 /* Start address of ram */
+#define MLX90635_ADDR_EEPROM	0x0018 /* Start address of user eeprom */
+
+/* EEPROM addresses - used at startup */
+#define MLX90635_EE_I2C_CFG	0x0018 /* I2C address register initial value */
+#define MLX90635_EE_CTRL1	0x001A /* Control register1 initial value */
+#define MLX90635_EE_CTRL2	0x001C /* Control register2 initial value */
+
+#define MLX90635_EE_Ha		0x001E /* Ha customer calib value reg 16bit */
+#define MLX90635_EE_Hb		0x0020 /* Hb customer calib value reg 16bit */
+#define MLX90635_EE_Fa		0x0026 /* Fa calibration register 32bit */
+#define MLX90635_EE_FASCALE	0x002A /* Scaling coefficient for Fa register 16bit */
+#define MLX90635_EE_Ga		0x002C /* Ga calibration register 16bit */
+#define MLX90635_EE_Fb		0x002E /* Fb calibration register 16bit */
+#define MLX90635_EE_Ea		0x0030 /* Ea calibration register 32bit */
+#define MLX90635_EE_Eb		0x0034 /* Eb calibration register 32bit */
+#define MLX90635_EE_P_G		0x0038 /* P_G calibration register 16bit */
+#define MLX90635_EE_P_O		0x003A /* P_O calibration register 16bit */
+#define MLX90635_EE_Aa		0x003C /* Aa calibration register 16bit */
+#define MLX90635_EE_VERSION	0x003E /* Version bits 4:7 and 12:15 */
+#define MLX90635_EE_Gb		0x0040 /* Gb calibration register 16bit */
+
+/* Device status register - volatile */
+#define MLX90635_REG_STATUS	0x0000
+#define   MLX90635_STAT_BUSY BIT(6) /* Device busy indicator */
+#define   MLX90635_STAT_BRST BIT(5) /* Brown out reset indicator */
+#define   MLX90635_STAT_CYCLE_POS GENMASK(4, 2) /* Data position */
+#define   MLX90635_STAT_END_CONV BIT(1) /* End of conversion indicator */
+#define   MLX90635_STAT_DATA_RDY BIT(0) /* Data ready indicator */
+
+/* EEPROM control register address - volatile */
+#define MLX90635_REG_EE		0x000C
+#define   MLX90635_EE_ACTIVE BIT(4) /* Power-on EEPROM */
+#define   MLX90635_EE_BUSY_MASK	BIT(15)
+
+#define MLX90635_REG_CMD	0x0010 /* Command register address */
+
+/* Control register1 address - volatile */
+#define MLX90635_REG_CTRL1	0x0014
+#define   MLX90635_CTRL1_REFRESH_RATE_MASK GENMASK(2, 0)
+#define   MLX90635_CTRL1_RES_CTRL_MASK GENMASK(4, 3)
+#define   MLX90635_CTRL1_TABLE_MASK BIT(15) /* Table select */
+
+/* Control register2 address - volatile */
+#define   MLX90635_REG_CTRL2	0x0016
+#define   MLX90635_CTRL2_BURST_CNT_MASK GENMASK(10, 6) /* Burst count */
+#define   MLX90635_CTRL2_MODE_MASK GENMASK(12, 11) /* Power mode */
+#define   MLX90635_CTRL2_SOB_MASK BIT(15)
+
+/* PowerModes statuses */
+#define MLX90635_PWR_STATUS_HALT 0
+#define MLX90635_PWR_STATUS_SLEEP_STEP 1
+#define MLX90635_PWR_STATUS_STEP 2
+#define MLX90635_PWR_STATUS_CONTINUOUS 3
+
+/* Measurement data addresses */
+#define MLX90635_RESULT_1   0x0002
+#define MLX90635_RESULT_2   0x0004
+#define MLX90635_RESULT_3   0x0006
+#define MLX90635_RESULT_4   0x0008
+#define MLX90635_RESULT_5   0x000A
+
+/* Timings (ms) */
+#define MLX90635_TIMING_RST_MIN 200 /* Minimum time after addressed reset command */
+#define MLX90635_TIMING_RST_MAX 250 /* Maximum time after addressed reset command */
+#define MLX90635_TIMING_POLLING 10000 /* Time between bit polling*/
+#define MLX90635_TIMING_EE_ACTIVE_MIN 100 /* Minimum time after activating the EEPROM for read */
+#define MLX90635_TIMING_EE_ACTIVE_MAX 150 /* Maximum time after activating the EEPROM for read */
+
+/* Magic constants */
+#define MLX90635_ID_DSPv1 0x01 /* EEPROM DSP version */
+#define MLX90635_RESET_CMD  0x0006 /* Reset sensor (address or global) */
+#define MLX90635_MAX_MEAS_NUM   31 /* Maximum number of measurements in list */
+#define MLX90635_PTAT_DIV 12   /* Used to divide the PTAT value in pre-processing */
+#define MLX90635_IR_DIV 24   /* Used to divide the IR value in pre-processing */
+#define MLX90635_SLEEP_DELAY_MS 6000 /* Autosleep delay */
+#define MLX90635_MEAS_MAX_TIME 2000 /* Max measurement time in ms for the lowest refresh rate */
+#define MLX90635_READ_RETRIES 100 /* Number of read retries before quitting with timeout error */
+#define MLX90635_VERSION_MASK (GENMASK(15, 12) | GENMASK(7, 4))
+#define MLX90635_DSP_VERSION(reg) (((reg & GENMASK(14, 12)) >> 9) | ((reg & GENMASK(6, 4)) >> 4))
+#define MLX90635_DSP_FIXED BIT(15)
+
+
+/**
+ * struct mlx90635_data - private data for the MLX90635 device
+ * @client: I2C client of the device
+ * @lock: Internal mutex because multiple reads are needed for single triggered
+ *	  measurement to ensure data consistency
+ * @regmap: Regmap of the device registers
+ * @regmap_ee: Regmap of the device EEPROM which can be cached
+ * @emissivity: Object emissivity from 0 to 1000 where 1000 = 1
+ * @regulator: Regulator of the device
+ * @powerstatus: Current POWER status of the device
+ * @interaction_ts: Timestamp of the last temperature read that is used
+ *		    for power management in jiffies
+ */
+struct mlx90635_data {
+	struct i2c_client *client;
+	struct mutex lock;
+	struct regmap *regmap;
+	struct regmap *regmap_ee;
+	u16 emissivity;
+	struct regulator *regulator;
+	int powerstatus;
+	unsigned long interaction_ts;
+};
+
+static const struct regmap_range mlx90635_volatile_reg_range[] = {
+	regmap_reg_range(MLX90635_REG_STATUS, MLX90635_REG_STATUS),
+	regmap_reg_range(MLX90635_RESULT_1, MLX90635_RESULT_5),
+	regmap_reg_range(MLX90635_REG_EE, MLX90635_REG_EE),
+	regmap_reg_range(MLX90635_REG_CMD, MLX90635_REG_CMD),
+	regmap_reg_range(MLX90635_REG_CTRL1, MLX90635_REG_CTRL2),
+};
+
+static const struct regmap_access_table mlx90635_volatile_regs_tbl = {
+	.yes_ranges = mlx90635_volatile_reg_range,
+	.n_yes_ranges = ARRAY_SIZE(mlx90635_volatile_reg_range),
+};
+
+static const struct regmap_range mlx90635_read_reg_range[] = {
+	regmap_reg_range(MLX90635_REG_STATUS, MLX90635_REG_STATUS),
+	regmap_reg_range(MLX90635_RESULT_1, MLX90635_RESULT_5),
+	regmap_reg_range(MLX90635_REG_EE, MLX90635_REG_EE),
+	regmap_reg_range(MLX90635_REG_CMD, MLX90635_REG_CMD),
+	regmap_reg_range(MLX90635_REG_CTRL1, MLX90635_REG_CTRL2),
+};
+
+static const struct regmap_access_table mlx90635_readable_regs_tbl = {
+	.yes_ranges = mlx90635_read_reg_range,
+	.n_yes_ranges = ARRAY_SIZE(mlx90635_read_reg_range),
+};
+
+static const struct regmap_range mlx90635_no_write_reg_range[] = {
+	regmap_reg_range(MLX90635_RESULT_1, MLX90635_RESULT_5),
+};
+
+static const struct regmap_access_table mlx90635_writeable_regs_tbl = {
+	.no_ranges = mlx90635_no_write_reg_range,
+	.n_no_ranges = ARRAY_SIZE(mlx90635_no_write_reg_range),
+};
+
+static const struct regmap_config mlx90635_regmap = {
+	.name = "mlx90635-registers",
+	.reg_stride = 1,
+	.reg_bits = 16,
+	.val_bits = 16,
+
+	.volatile_table = &mlx90635_volatile_regs_tbl,
+	.rd_table = &mlx90635_readable_regs_tbl,
+	.wr_table = &mlx90635_writeable_regs_tbl,
+
+	.use_single_read = true,
+	.use_single_write = true,
+	.can_multi_write = false,
+	.reg_format_endian = REGMAP_ENDIAN_BIG,
+	.val_format_endian = REGMAP_ENDIAN_BIG,
+	.cache_type = REGCACHE_RBTREE,
+};
+
+static const struct regmap_range mlx90635_read_ee_range[] = {
+	regmap_reg_range(MLX90635_EE_I2C_CFG, MLX90635_EE_CTRL2),
+	regmap_reg_range(MLX90635_EE_Ha, MLX90635_EE_Gb),
+};
+
+static const struct regmap_access_table mlx90635_readable_ees_tbl = {
+	.yes_ranges = mlx90635_read_ee_range,
+	.n_yes_ranges = ARRAY_SIZE(mlx90635_read_ee_range),
+};
+
+static const struct regmap_range mlx90635_no_write_ee_range[] = {
+	regmap_reg_range(MLX90635_ADDR_EEPROM, MLX90635_EE_Gb),
+};
+
+static const struct regmap_access_table mlx90635_writeable_ees_tbl = {
+	.no_ranges = mlx90635_no_write_ee_range,
+	.n_no_ranges = ARRAY_SIZE(mlx90635_no_write_ee_range),
+};
+
+static const struct regmap_config mlx90635_regmap_ee = {
+	.name = "mlx90635-eeprom",
+	.reg_stride = 1,
+	.reg_bits = 16,
+	.val_bits = 16,
+
+	.volatile_table = NULL,
+	.rd_table = &mlx90635_readable_ees_tbl,
+	.wr_table = &mlx90635_writeable_ees_tbl,
+
+	.use_single_read = true,
+	.use_single_write = true,
+	.can_multi_write = false,
+	.reg_format_endian = REGMAP_ENDIAN_BIG,
+	.val_format_endian = REGMAP_ENDIAN_BIG,
+	.cache_type = REGCACHE_RBTREE,
+};
+
+/**
+ * mlx90635_reset_delay() - Give the mlx90635 some time to reset properly
+ * If this is not done, the following I2C command(s) will not be accepted.
+ */
+static void mlx90635_reset_delay(void)
+{
+	usleep_range(MLX90635_TIMING_RST_MIN, MLX90635_TIMING_RST_MAX);
+}
+
+static int mlx90635_pwr_sleep_step(struct mlx90635_data *data)
+{
+	int ret;
+
+	if (data->powerstatus == MLX90635_PWR_STATUS_SLEEP_STEP)
+		return 0;
+
+	ret = regmap_write_bits(data->regmap, MLX90635_REG_CTRL2, MLX90635_CTRL2_MODE_MASK,
+				FIELD_PREP(MLX90635_CTRL2_MODE_MASK, MLX90635_PWR_STATUS_SLEEP_STEP));
+	if (ret < 0)
+		return ret;
+
+	data->powerstatus = MLX90635_PWR_STATUS_SLEEP_STEP;
+	return 0;
+}
+
+static int mlx90635_pwr_continuous(struct mlx90635_data *data)
+{
+	int ret;
+
+	if (data->powerstatus == MLX90635_PWR_STATUS_CONTINUOUS)
+		return 0;
+
+	ret = regmap_write_bits(data->regmap, MLX90635_REG_CTRL2, MLX90635_CTRL2_MODE_MASK,
+				FIELD_PREP(MLX90635_CTRL2_MODE_MASK, MLX90635_PWR_STATUS_CONTINUOUS));
+	if (ret < 0)
+		return ret;
+
+	data->powerstatus = MLX90635_PWR_STATUS_CONTINUOUS;
+	return 0;
+}
+
+static int mlx90635_read_ee_register(struct regmap *regmap, u16 reg_lsb,
+				     s32 *reg_value)
+{
+	unsigned int read;
+	u32 value;
+	int ret;
+
+	ret = regmap_read(regmap, reg_lsb + 2, &read);
+	if (ret < 0)
+		return ret;
+
+	value = read;
+
+	ret = regmap_read(regmap, reg_lsb, &read);
+	if (ret < 0)
+		return ret;
+
+	*reg_value = (read << 16) | (value & 0xffff);
+
+	return 0;
+}
+
+static int mlx90635_read_ee_ambient(struct regmap *regmap, s16 *PG, s16 *PO, s16 *Gb)
+{
+	unsigned int read_tmp;
+	int ret;
+
+	ret = regmap_read(regmap, MLX90635_EE_P_O, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*PO = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_EE_P_G, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*PG = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_EE_Gb, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*Gb = (u16)read_tmp;
+
+	return 0;
+}
+
+static int mlx90635_read_ee_object(struct regmap *regmap, u32 *Ea, u32 *Eb, u32 *Fa, s16 *Fb,
+				   s16 *Ga, s16 *Gb, s16 *Ha, s16 *Hb, u16 *Fa_scale)
+{
+	unsigned int read_tmp;
+	int ret;
+
+	ret = mlx90635_read_ee_register(regmap, MLX90635_EE_Ea, Ea);
+	if (ret < 0)
+		return ret;
+
+	ret = mlx90635_read_ee_register(regmap, MLX90635_EE_Eb, Eb);
+	if (ret < 0)
+		return ret;
+
+	ret = mlx90635_read_ee_register(regmap, MLX90635_EE_Fa, Fa);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_read(regmap, MLX90635_EE_Ha, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*Ha = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_EE_Hb, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*Hb = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_EE_Ga, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*Ga = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_EE_Gb, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*Gb = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_EE_Fb, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*Fb = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_EE_FASCALE, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*Fa_scale = (u16)read_tmp;
+
+	return 0;
+}
+
+static int mlx90635_calculate_dataset_ready_time(struct mlx90635_data *data, int *refresh_time)
+{
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(data->regmap, MLX90635_REG_CTRL1, &reg);
+	if (ret < 0)
+		return ret;
+
+	*refresh_time = 2 * (MLX90635_MEAS_MAX_TIME >> FIELD_GET(MLX90635_CTRL1_REFRESH_RATE_MASK, reg)) + 80;
+
+	return 0;
+}
+
+static int mlx90635_perform_measurement_burst(struct mlx90635_data *data)
+{
+	unsigned int reg_status;
+	int refresh_time;
+	int ret;
+
+	ret = regmap_write_bits(data->regmap, MLX90635_REG_STATUS,
+				MLX90635_STAT_END_CONV, MLX90635_STAT_END_CONV);
+	if (ret < 0)
+		return ret;
+
+	ret = mlx90635_calculate_dataset_ready_time(data, &refresh_time);
+	if (ret < 0)
+		return ret;
+
+	ret = regmap_write_bits(data->regmap, MLX90635_REG_CTRL2,
+				FIELD_PREP(MLX90635_CTRL2_SOB_MASK, 1),
+				FIELD_PREP(MLX90635_CTRL2_SOB_MASK, 1));
+	if (ret < 0)
+		return ret;
+
+	msleep(refresh_time); /* Wait minimum time for dataset to be ready */
+
+	ret = regmap_read_poll_timeout(data->regmap, MLX90635_REG_STATUS, reg_status,
+				       (!(reg_status & MLX90635_STAT_END_CONV)) == 0,
+				       MLX90635_TIMING_POLLING, MLX90635_READ_RETRIES * 10000);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "data not ready");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
+
+static int mlx90635_read_ambient_raw(struct regmap *regmap,
+				     s16 *ambient_new_raw, s16 *ambient_old_raw)
+{
+	unsigned int read_tmp;
+	int ret;
+
+	ret = regmap_read(regmap, MLX90635_RESULT_2, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*ambient_new_raw = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_RESULT_3, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*ambient_old_raw = (s16)read_tmp;
+
+	return 0;
+}
+
+static int mlx90635_read_object_raw(struct regmap *regmap, s16 *object_raw)
+{
+	unsigned int read_tmp;
+	s16 read;
+	int ret;
+
+	ret = regmap_read(regmap, MLX90635_RESULT_1, &read_tmp);
+	if (ret < 0)
+		return ret;
+
+	read = (s16)read_tmp;
+
+	ret = regmap_read(regmap, MLX90635_RESULT_4, &read_tmp);
+	if (ret < 0)
+		return ret;
+	*object_raw = (read - (s16)read_tmp) / 2;
+
+	return 0;
+}
+
+static int mlx90635_read_all_channel(struct mlx90635_data *data,
+				     s16 *ambient_new_raw, s16 *ambient_old_raw,
+				     s16 *object_raw)
+{
+	int ret;
+
+	mutex_lock(&data->lock);
+	if (data->powerstatus == MLX90635_PWR_STATUS_SLEEP_STEP) {
+		/* Trigger measurement in Sleep Step mode */
+		ret = mlx90635_perform_measurement_burst(data);
+		if (ret < 0)
+			goto read_unlock;
+	}
+
+	ret = mlx90635_read_ambient_raw(data->regmap, ambient_new_raw,
+					ambient_old_raw);
+	if (ret < 0)
+		goto read_unlock;
+
+	ret = mlx90635_read_object_raw(data->regmap, object_raw);
+read_unlock:
+	mutex_unlock(&data->lock);
+	return ret;
+}
+
+static s64 mlx90635_preprocess_temp_amb(s16 ambient_new_raw,
+					s16 ambient_old_raw, s16 Gb)
+{
+	s64 VR_Ta, kGb, tmp;
+
+	kGb = ((s64)Gb * 1000LL) >> 10ULL;
+	VR_Ta = (s64)ambient_old_raw * 1000000LL +
+		kGb * div64_s64(((s64)ambient_new_raw * 1000LL),
+			(MLX90635_PTAT_DIV));
+	tmp = div64_s64(
+			 div64_s64(((s64)ambient_new_raw * 1000000000000LL),
+				   (MLX90635_PTAT_DIV)), VR_Ta);
+	return div64_s64(tmp << 19ULL, 1000LL);
+}
+
+static s64 mlx90635_preprocess_temp_obj(s16 object_raw,
+					s16 ambient_new_raw,
+					s16 ambient_old_raw, s16 Gb)
+{
+	s64 VR_IR, kGb, tmp;
+
+	kGb = ((s64)Gb * 1000LL) >> 10ULL;
+	VR_IR = (s64)ambient_old_raw * 1000000LL +
+		kGb * (div64_s64((s64)ambient_new_raw * 1000LL,
+			MLX90635_PTAT_DIV));
+	tmp = div64_s64(
+			div64_s64((s64)(object_raw * 1000000LL),
+				   MLX90635_IR_DIV) * 1000000LL,
+			VR_IR);
+	return div64_s64((tmp << 19ULL), 1000LL);
+}
+
+static s32 mlx90635_calc_temp_ambient(s16 ambient_new_raw, s16 ambient_old_raw,
+				      u16 P_G, u16 P_O, s16 Gb)
+{
+	s64 kPG, kPO, AMB;
+
+	AMB = mlx90635_preprocess_temp_amb(ambient_new_raw, ambient_old_raw,
+					   Gb);
+	kPG = ((s64)P_G * 1000000LL) >> 9ULL;
+	kPO = AMB - (((s64)P_O * 1000LL) >> 1ULL);
+
+	return 30 * 1000LL + div64_s64(kPO * 1000000LL, kPG);
+}
+
+static s32 mlx90635_calc_temp_object_iteration(s32 prev_object_temp, s64 object,
+					       s64 TAdut, s64 TAdut4, s16 Ga,
+					       u32 Fa, u16 Fa_scale, s16 Fb,
+					       s16 Ha, s16 Hb, u16 emissivity)
+{
+	s64 calcedGa, calcedGb, calcedFa, Alpha_corr;
+	s64 Ha_customer, Hb_customer;
+
+	Ha_customer = ((s64)Ha * 1000000LL) >> 14ULL;
+	Hb_customer = ((s64)Hb * 100) >> 10ULL;
+
+	calcedGa = ((s64)((s64)Ga * (prev_object_temp - 35 * 1000LL)
+			     * 1000LL)) >> 24LL;
+	calcedGb = ((s64)(Fb * (TAdut - 30 * 1000000LL))) >> 24LL;
+
+	Alpha_corr = ((s64)((s64)Fa * Ha_customer * 10000LL) >> Fa_scale);
+	Alpha_corr *= ((s64)(1 * 1000000LL + calcedGa + calcedGb));
+
+	Alpha_corr = div64_s64(Alpha_corr, 1000LL);
+	Alpha_corr *= emissivity;
+	Alpha_corr = div64_s64(Alpha_corr, 100LL);
+	calcedFa = div64_s64((s64)object * 100000000000LL, Alpha_corr);
+
+	return (int_sqrt64(int_sqrt64(calcedFa * 100000000LL + TAdut4))
+		- 27315 - Hb_customer) * 10;
+}
+
+static s64 mlx90635_calc_ta4(s64 TAdut, s64 scale)
+{
+	return (div64_s64(TAdut, scale) + 27315) *
+		(div64_s64(TAdut, scale) + 27315) *
+		(div64_s64(TAdut, scale) + 27315) *
+		(div64_s64(TAdut, scale) + 27315);
+}
+
+static s32 mlx90635_calc_temp_object(s64 object, s64 ambient, u32 Ea, u32 Eb,
+				     s16 Ga, u32 Fa, u16 Fa_scale, s16 Fb, s16 Ha, s16 Hb,
+				     u16 tmp_emi)
+{
+	s64 kTA, kTA0, TAdut, TAdut4;
+	s64 temp = 35000;
+	s8 i;
+
+	kTA = (Ea * 1000LL) >> 16LL;
+	kTA0 = (Eb * 1000LL) >> 8LL;
+	TAdut = div64_s64(((ambient - kTA0) * 1000000LL), kTA) + 30 * 1000000LL;
+	TAdut4 = mlx90635_calc_ta4(TAdut, 10000LL);
+
+	/* Iterations of calculation as described in datasheet */
+	for (i = 0; i < 5; ++i) {
+		temp = mlx90635_calc_temp_object_iteration(temp, object, TAdut, TAdut4,
+							   Ga, Fa, Fa_scale, Fb, Ha, Hb,
+							   tmp_emi);
+	}
+	return temp;
+}
+
+static int mlx90635_calc_object(struct mlx90635_data *data, int *val)
+{
+	s16 ambient_new_raw, ambient_old_raw, object_raw;
+	s16 Fb, Ga, Gb, Ha, Hb;
+	s64 object, ambient;
+	u32 Ea, Eb, Fa;
+	u16 Fa_scale;
+	int ret;
+
+	ret = mlx90635_read_ee_object(data->regmap_ee, &Ea, &Eb, &Fa, &Fb, &Ga, &Gb, &Ha, &Hb, &Fa_scale);
+	if (ret < 0)
+		return ret;
+
+	ret = mlx90635_read_all_channel(data,
+					&ambient_new_raw, &ambient_old_raw,
+					&object_raw);
+	if (ret < 0)
+		return ret;
+
+	ambient = mlx90635_preprocess_temp_amb(ambient_new_raw,
+					       ambient_old_raw, Gb);
+	object = mlx90635_preprocess_temp_obj(object_raw,
+					      ambient_new_raw,
+					      ambient_old_raw, Gb);
+
+	*val = mlx90635_calc_temp_object(object, ambient, Ea, Eb, Ga, Fa, Fa_scale, Fb,
+					 Ha, Hb, data->emissivity);
+	return 0;
+}
+
+static int mlx90635_calc_ambient(struct mlx90635_data *data, int *val)
+{
+	s16 ambient_new_raw, ambient_old_raw;
+	s16 PG, PO, Gb;
+	int ret;
+
+	ret = mlx90635_read_ee_ambient(data->regmap_ee, &PG, &PO, &Gb);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&data->lock);
+	if (data->powerstatus == MLX90635_PWR_STATUS_SLEEP_STEP) {
+		ret = mlx90635_perform_measurement_burst(data);
+		if (ret < 0)
+			goto read_ambient_unlock;
+	}
+
+	ret = mlx90635_read_ambient_raw(data->regmap, &ambient_new_raw,
+					&ambient_old_raw);
+read_ambient_unlock:
+	mutex_unlock(&data->lock);
+	if (ret < 0)
+		return ret;
+
+	*val = mlx90635_calc_temp_ambient(ambient_new_raw, ambient_old_raw,
+					  PG, PO, Gb);
+	return ret;
+}
+
+static int mlx90635_get_refresh_rate(struct mlx90635_data *data,
+				     unsigned int *refresh_rate)
+{
+	unsigned int reg;
+	int ret;
+
+	ret = regmap_read(data->regmap, MLX90635_REG_CTRL1, &reg);
+	if (ret < 0)
+		return ret;
+
+	*refresh_rate = FIELD_GET(MLX90635_CTRL1_REFRESH_RATE_MASK, reg);
+
+	return 0;
+}
+
+static const struct {
+	int val;
+	int val2;
+} mlx90635_freqs[] = {
+	{ 0, 200000 },
+	{ 0, 500000 },
+	{ 0, 900000 },
+	{ 1, 700000 },
+	{ 3, 0 },
+	{ 4, 800000 },
+	{ 6, 900000 },
+	{ 8, 900000 }
+};
+
+/**
+ * mlx90635_pm_interaction_wakeup() - Measure time between user interactions to change powermode
+ * @data: pointer to mlx90635_data object containing interaction_ts information
+ *
+ * Switch to continuous mode when interaction is faster than MLX90635_MEAS_MAX_TIME. Update the
+ * interaction_ts for each function call with the jiffies to enable measurement between function
+ * calls. Initial value of the interaction_ts needs to be set before this function call.
+ */
+static int mlx90635_pm_interaction_wakeup(struct mlx90635_data *data)
+{
+	unsigned long now;
+	int ret;
+
+	now = jiffies;
+	if (time_in_range(now, data->interaction_ts,
+			  data->interaction_ts +
+			  msecs_to_jiffies(MLX90635_MEAS_MAX_TIME + 100))) {
+		ret = mlx90635_pwr_continuous(data);
+		if (ret < 0)
+			return ret;
+	}
+
+	data->interaction_ts = now;
+
+	return 0;
+}
+
+static int mlx90635_read_raw(struct iio_dev *indio_dev,
+			     struct iio_chan_spec const *channel, int *val,
+			     int *val2, long mask)
+{
+	struct mlx90635_data *data = iio_priv(indio_dev);
+	int ret;
+	int cr;
+
+	pm_runtime_get_sync(&data->client->dev);
+	ret = mlx90635_pm_interaction_wakeup(data);
+	if (ret < 0)
+		goto mlx90635_read_raw_pm;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_PROCESSED:
+		switch (channel->channel2) {
+		case IIO_MOD_TEMP_AMBIENT:
+			ret = mlx90635_calc_ambient(data, val);
+			if (ret < 0)
+				goto mlx90635_read_raw_pm;
+
+			ret = IIO_VAL_INT;
+			break;
+		case IIO_MOD_TEMP_OBJECT:
+			ret = mlx90635_calc_object(data, val);
+			if (ret < 0)
+				goto mlx90635_read_raw_pm;
+
+			ret = IIO_VAL_INT;
+			break;
+		default:
+			ret = -EINVAL;
+			break;
+		}
+		break;
+	case IIO_CHAN_INFO_CALIBEMISSIVITY:
+		if (data->emissivity == 1000) {
+			*val = 1;
+			*val2 = 0;
+		} else {
+			*val = 0;
+			*val2 = data->emissivity * 1000;
+		}
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = mlx90635_get_refresh_rate(data, &cr);
+		if (ret < 0)
+			goto mlx90635_read_raw_pm;
+
+		*val = mlx90635_freqs[cr].val;
+		*val2 = mlx90635_freqs[cr].val2;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+mlx90635_read_raw_pm:
+	pm_runtime_mark_last_busy(&data->client->dev);
+	pm_runtime_put_autosuspend(&data->client->dev);
+	return ret;
+}
+
+static int mlx90635_write_raw(struct iio_dev *indio_dev,
+			      struct iio_chan_spec const *channel, int val,
+			      int val2, long mask)
+{
+	struct mlx90635_data *data = iio_priv(indio_dev);
+	int ret;
+	int i;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_CALIBEMISSIVITY:
+		/* Confirm we are within 0 and 1.0 */
+		if (val < 0 || val2 < 0 || val > 1 ||
+		    (val == 1 && val2 != 0))
+			return -EINVAL;
+		data->emissivity = val * 1000 + val2 / 1000;
+		return 0;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		for (i = 0; i < ARRAY_SIZE(mlx90635_freqs); i++) {
+			if (val == mlx90635_freqs[i].val &&
+			    val2 == mlx90635_freqs[i].val2)
+				break;
+		}
+		if (i == ARRAY_SIZE(mlx90635_freqs))
+			return -EINVAL;
+
+		ret = regmap_write_bits(data->regmap, MLX90635_REG_CTRL1,
+					MLX90635_CTRL1_REFRESH_RATE_MASK, i);
+
+		return ret;
+	default:
+		return -EINVAL;
+	}
+}
+
+static int mlx90635_read_avail(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       const int **vals, int *type, int *length,
+			       long mask)
+{
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		*vals = (int *)mlx90635_freqs;
+		*type = IIO_VAL_INT_PLUS_MICRO;
+		*length = 2 * ARRAY_SIZE(mlx90635_freqs);
+		return IIO_AVAIL_LIST;
+	default:
+		return -EINVAL;
+	}
+}
+
+static const struct iio_chan_spec mlx90635_channels[] = {
+	{
+		.type = IIO_TEMP,
+		.modified = 1,
+		.channel2 = IIO_MOD_TEMP_AMBIENT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	},
+	{
+		.type = IIO_TEMP,
+		.modified = 1,
+		.channel2 = IIO_MOD_TEMP_OBJECT,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
+			BIT(IIO_CHAN_INFO_CALIBEMISSIVITY),
+		.info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+		.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),
+	},
+};
+
+static const struct iio_info mlx90635_info = {
+	.read_raw = mlx90635_read_raw,
+	.write_raw = mlx90635_write_raw,
+	.read_avail = mlx90635_read_avail,
+};
+
+static void mlx90635_sleep(void *_data)
+{
+	struct mlx90635_data *data = _data;
+
+	mlx90635_pwr_sleep_step(data);
+}
+
+static int mlx90635_suspend(struct mlx90635_data *data)
+{
+	return mlx90635_pwr_sleep_step(data);
+}
+
+static int mlx90635_wakeup(struct mlx90635_data *data)
+{
+	s16 Fb, Ga, Gb, Ha, Hb, PG, PO;
+	unsigned int dsp_version;
+	u32 Ea, Eb, Fa;
+	u16 Fa_scale;
+	int ret;
+
+	regcache_cache_bypass(data->regmap_ee, false);
+	regcache_cache_only(data->regmap_ee, false);
+	regcache_cache_only(data->regmap, false);
+
+	ret = mlx90635_pwr_continuous(data);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Switch to continuous mode failed\n");
+		return ret;
+	}
+	ret = regmap_write_bits(data->regmap, MLX90635_REG_EE,
+				MLX90635_EE_ACTIVE, MLX90635_EE_ACTIVE);
+	if (ret < 0) {
+		dev_err(&data->client->dev, "Powering EEPROM failed\n");
+		return ret;
+	}
+	usleep_range(MLX90635_TIMING_EE_ACTIVE_MIN, MLX90635_TIMING_EE_ACTIVE_MAX);
+
+	regcache_mark_dirty(data->regmap_ee);
+
+	ret = regcache_sync(data->regmap_ee);
+	if (ret < 0) {
+		dev_err(&data->client->dev,
+			"Failed to sync cache: %d\n", ret);
+		return ret;
+	}
+
+	ret = mlx90635_read_ee_ambient(data->regmap_ee, &PG, &PO, &Gb);
+	if (ret < 0) {
+		dev_err(&data->client->dev,
+			"Failed to read to cache Ambient coefficients EEPROM region: %d\n", ret);
+		return ret;
+	}
+
+	ret = mlx90635_read_ee_object(data->regmap_ee, &Ea, &Eb, &Fa, &Fb, &Ga, &Gb, &Ha, &Hb, &Fa_scale);
+	if (ret < 0) {
+		dev_err(&data->client->dev,
+			"Failed to read to cache Object coefficients EEPROM region: %d\n", ret);
+		return ret;
+	}
+
+	ret = regmap_read(data->regmap_ee, MLX90635_EE_VERSION, &dsp_version);
+	if (ret < 0) {
+		dev_err(&data->client->dev,
+			"Failed to read to cache of EEPROM version: %d\n", ret);
+		return ret;
+	}
+
+	regcache_cache_only(data->regmap_ee, true);
+
+	return ret;
+}
+
+static void mlx90635_disable_regulator(void *_data)
+{
+	struct mlx90635_data *data = _data;
+	int ret;
+
+	ret = regulator_disable(data->regulator);
+	if (ret < 0)
+		dev_err(regmap_get_device(data->regmap),
+			"Failed to disable power regulator: %d\n", ret);
+}
+
+static int mlx90635_enable_regulator(struct mlx90635_data *data)
+{
+	int ret;
+
+	ret = regulator_enable(data->regulator);
+	if (ret < 0) {
+		dev_err(regmap_get_device(data->regmap), "Failed to enable power regulator!\n");
+		return ret;
+	}
+
+	mlx90635_reset_delay();
+
+	return ret;
+}
+
+static int mlx90635_probe(struct i2c_client *client)
+{
+	struct mlx90635_data *mlx90635;
+	struct iio_dev *indio_dev;
+	unsigned int dsp_version;
+	struct regmap *regmap;
+	struct regmap *regmap_ee;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*mlx90635));
+	if (!indio_dev)
+		return dev_err_probe(&client->dev, -ENOMEM, "failed to allocate device\n");
+
+	regmap = devm_regmap_init_i2c(client, &mlx90635_regmap);
+	if (IS_ERR(regmap))
+		return dev_err_probe(&client->dev, PTR_ERR(regmap),
+				     "failed to allocate regmap\n");
+
+	regmap_ee = devm_regmap_init_i2c(client, &mlx90635_regmap_ee);
+	if (IS_ERR(regmap))
+		return dev_err_probe(&client->dev, PTR_ERR(regmap),
+				     "failed to allocate regmap\n");
+
+	mlx90635 = iio_priv(indio_dev);
+	i2c_set_clientdata(client, indio_dev);
+	mlx90635->client = client;
+	mlx90635->regmap = regmap;
+	mlx90635->regmap_ee = regmap_ee;
+	mlx90635->powerstatus = MLX90635_PWR_STATUS_SLEEP_STEP;
+
+	mutex_init(&mlx90635->lock);
+	indio_dev->name = "mlx90635";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &mlx90635_info;
+	indio_dev->channels = mlx90635_channels;
+	indio_dev->num_channels = ARRAY_SIZE(mlx90635_channels);
+
+	mlx90635->regulator = devm_regulator_get(&client->dev, "vdd");
+	if (IS_ERR(mlx90635->regulator))
+		return dev_err_probe(&client->dev, PTR_ERR(mlx90635->regulator),
+				     "failed to get vdd regulator");
+
+	ret = mlx90635_enable_regulator(mlx90635);
+	if (ret < 0)
+		return ret;
+
+	ret = devm_add_action_or_reset(&client->dev, mlx90635_disable_regulator,
+				       mlx90635);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to setup regulator cleanup action\n");
+
+	ret = mlx90635_wakeup(mlx90635);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret, "wakeup failed\n");
+
+	ret = devm_add_action_or_reset(&client->dev, mlx90635_sleep, mlx90635);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to setup low power cleanup\n");
+
+	ret = regmap_read(mlx90635->regmap_ee, MLX90635_EE_VERSION, &dsp_version);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret, "read of version failed\n");
+
+	dsp_version = dsp_version & MLX90635_VERSION_MASK;
+
+	if (FIELD_GET(MLX90635_DSP_FIXED, dsp_version)) {
+		if (MLX90635_DSP_VERSION(dsp_version) == MLX90635_ID_DSPv1) {
+			dev_dbg(&client->dev,
+				"Detected DSP v1 calibration %x\n", dsp_version);
+		} else {
+			dev_dbg(&client->dev,
+				"Detected Unknown EEPROM calibration %lx\n",
+				MLX90635_DSP_VERSION(dsp_version));
+		}
+	} else {
+		return dev_err_probe(&client->dev, -EPROTONOSUPPORT,
+			"Wrong fixed top bit %x (expected 0x8X0X)\n",
+			dsp_version);
+	}
+
+	mlx90635->emissivity = 1000;
+	mlx90635->interaction_ts = jiffies; /* Set initial value */
+
+	pm_runtime_get_noresume(&client->dev);
+	pm_runtime_set_active(&client->dev);
+
+	ret = devm_pm_runtime_enable(&client->dev);
+	if (ret)
+		return dev_err_probe(&client->dev, ret,
+				     "failed to enable powermanagement\n");
+
+	pm_runtime_set_autosuspend_delay(&client->dev, MLX90635_SLEEP_DELAY_MS);
+	pm_runtime_use_autosuspend(&client->dev);
+	pm_runtime_put_autosuspend(&client->dev);
+
+	return devm_iio_device_register(&client->dev, indio_dev);
+}
+
+static const struct i2c_device_id mlx90635_id[] = {
+	{ "mlx90635" },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, mlx90635_id);
+
+static const struct of_device_id mlx90635_of_match[] = {
+	{ .compatible = "melexis,mlx90635" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, mlx90635_of_match);
+
+static int mlx90635_pm_suspend(struct device *dev)
+{
+	struct mlx90635_data *data = iio_priv(dev_get_drvdata(dev));
+	int ret;
+
+	ret = mlx90635_suspend(data);
+	if (ret < 0)
+		return ret;
+
+	ret = regulator_disable(data->regulator);
+	if (ret < 0)
+		dev_err(regmap_get_device(data->regmap),
+			"Failed to disable power regulator: %d\n", ret);
+
+	return ret;
+}
+
+static int mlx90635_pm_resume(struct device *dev)
+{
+	struct mlx90635_data *data = iio_priv(dev_get_drvdata(dev));
+	int ret;
+
+	ret = mlx90635_enable_regulator(data);
+	if (ret < 0)
+		return ret;
+
+	return mlx90635_wakeup(data);
+}
+
+static int mlx90635_pm_runtime_suspend(struct device *dev)
+{
+	struct mlx90635_data *data = iio_priv(dev_get_drvdata(dev));
+
+	return mlx90635_pwr_sleep_step(data);
+}
+
+static const struct dev_pm_ops mlx90635_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(mlx90635_pm_suspend, mlx90635_pm_resume)
+	RUNTIME_PM_OPS(mlx90635_pm_runtime_suspend, NULL, NULL)
+};
+
+static struct i2c_driver mlx90635_driver = {
+	.driver = {
+		.name	= "mlx90635",
+		.of_match_table = mlx90635_of_match,
+		.pm	= pm_ptr(&mlx90635_pm_ops),
+	},
+	.probe = mlx90635_probe,
+	.id_table = mlx90635_id,
+};
+module_i2c_driver(mlx90635_driver);
+
+MODULE_AUTHOR("Crt Mori <cmo@melexis.com>");
+MODULE_DESCRIPTION("Melexis MLX90635 contactless Infra Red temperature sensor driver");
+MODULE_LICENSE("GPL");