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* [PATCH 1/2] iio: temperature: Add support for LTC2983
@ 2019-09-09 14:45 Nuno Sá
  2019-09-09 14:45 ` [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation Nuno Sá
  2019-09-15 11:27 ` [PATCH 1/2] iio: temperature: Add support for LTC2983 Jonathan Cameron
  0 siblings, 2 replies; 11+ messages in thread
From: Nuno Sá @ 2019-09-09 14:45 UTC (permalink / raw)
  To: linux-iio, devicetree
  Cc: jic23, knaack.h, lars, pmeerw, robh+dt, mark.rutland

The LTC2983 is a Multi-Sensor High Accuracy Digital Temperature
Measurement System. It measures a wide variety of temperature sensors and
digitally outputs the result, in °C or °F, with 0.1°C accuracy and
0.001°C resolution. It can measure the temperature of all standard
thermocouples (type B,E,J,K,N,S,R,T), standard 2-,3-,4-wire RTDs,
thermistors and diodes.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 .../testing/sysfs-bus-iio-temperature-ltc2983 |   43 +
 MAINTAINERS                                   |    7 +
 drivers/iio/temperature/Kconfig               |   10 +
 drivers/iio/temperature/Makefile              |    1 +
 drivers/iio/temperature/ltc2983.c             | 1327 +++++++++++++++++
 5 files changed, 1388 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983
 create mode 100644 drivers/iio/temperature/ltc2983.c

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983 b/Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983
new file mode 100644
index 000000000000..3ad3440c0986
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983
@@ -0,0 +1,43 @@
+What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_thermistor_raw
+KernelVersion:
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reads the raw (unscaled no bias removal etc) temperature from
+		channel Y. The value is returned by a Thermistor sensor measurement.
+		Units after application of scale are degrees Celsius or Fahrenheit
+		depending on the device configuration.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_thermocouple_raw
+KernelVersion:
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reads the raw (unscaled no bias removal etc) temperature from
+		channel Y. The value is returned by a Thermocouple sensor measurement.
+		Units after application of scale are degrees Celsius or Fahrenheit
+		depending on the device configuration.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_rtd_raw
+KernelVersion:
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reads the raw (unscaled no bias removal etc) temperature from
+		channel Y. The value is returned by a RTD sensor measurement.
+		Units after application of scale are degrees Celsius or Fahrenheit
+		depending on the device configuration.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_diode_raw
+KernelVersion:
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reads the raw (unscaled no bias removal etc) temperature from
+		channel Y. The value is returned by a Diode sensor measurement.
+		Units after application of scale are degrees Celsius or Fahrenheit
+		depending on the device configuration.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_direct_adc_raw
+KernelVersion:
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Reads the raw (unscaled no bias removal etc) voltage from
+		channel Y. The value is returned by a direct ADC measurement.
+		Units after application of scale are Volts.
diff --git a/MAINTAINERS b/MAINTAINERS
index f0c03740b9fb..14a256e785ca 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9491,6 +9491,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/iio/dac/ltc1660.txt
 F:	drivers/iio/dac/ltc1660.c
 
+LTC2983 IIO TEMPERATURE DRIVER
+M:	Nuno Sá <nuno.sa@analog.com>
+W:	http://ez.analog.com/community/linux-device-drivers
+L:	linux-iio@vger.kernel.org
+S:	Supported
+F:	drivers/iio/temperature/ltc2983.c
+
 LTC4261 HARDWARE MONITOR DRIVER
 M:	Guenter Roeck <linux@roeck-us.net>
 L:	linux-hwmon@vger.kernel.org
diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
index 737faa0901fe..04b5a67b593c 100644
--- a/drivers/iio/temperature/Kconfig
+++ b/drivers/iio/temperature/Kconfig
@@ -4,6 +4,16 @@
 #
 menu "Temperature sensors"
 
+config LTC2983
+	tristate "Analog Devices Multi-Sensor Digital Temperature Measurement System"
+	depends on SPI
+	help
+	  Say yes here to build support for the LTC2983 Multi-Sensor
+	  high accuracy digital temperature measurement system.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called ltc2983.
+
 config MAXIM_THERMOCOUPLE
 	tristate "Maxim thermocouple sensors"
 	depends on SPI
diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
index baca4776ca0d..d6b850b0cf63 100644
--- a/drivers/iio/temperature/Makefile
+++ b/drivers/iio/temperature/Makefile
@@ -3,6 +3,7 @@
 # Makefile for industrial I/O temperature drivers
 #
 
+obj-$(CONFIG_LTC2983) += ltc2983.o
 obj-$(CONFIG_HID_SENSOR_TEMP) += hid-sensor-temperature.o
 obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o
 obj-$(CONFIG_MAX31856) += max31856.o
diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
new file mode 100644
index 000000000000..2d97b5019e3b
--- /dev/null
+++ b/drivers/iio/temperature/ltc2983.c
@@ -0,0 +1,1327 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
+ * driver
+ *
+ * Copyright 2019 Analog Devices Inc.
+ */
+#include <linux/bitfield.h>
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/iio/iio.h>
+#include <linux/interrupt.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of_gpio.h>
+#include <linux/regmap.h>
+#include <linux/spi/spi.h>
+
+/* register map */
+#define LTC2983_STATUS_REG			0x0000
+#define LTC2983_TEMP_RES_START_REG		0x0010
+#define LTC2983_TEMP_RES_END_REG		0x005F
+#define LTC2983_GLOBAL_CONFIG_REG		0x00F0
+#define LTC2983_MULT_CHANNEL_START_REG		0x00F4
+#define LTC2983_MULT_CHANNEL_END_REG		0x00F7
+#define LTC2983_MUX_CONFIG_REG			0x00FF
+#define LTC2983_CHAN_ASSIGN_START_REG		0x0200
+#define LTC2983_CHAN_ASSIGN_END_REG		0x024F
+#define LTC2983_CUST_SENS_TBL_START_REG		0x0250
+#define LTC2983_CUST_SENS_TBL_END_REG		0x03CF
+
+#define LTC2983_DIFFERENTIAL_CHAN_MIN		2
+#define LTC2983_MAX_CHANNELS_NR			20
+#define LTC2983_MIN_CHANNELS_NR			1
+#define LTC2983_SLEEP				0x97
+#define LTC2983_CUSTOM_STEINHART_SIZE		24
+#define LTC2983_CUSTOM_SENSOR_ENTRY_SZ		6
+#define LTC2983_CUSTOM_STEINHART_ENTRY_SZ	4
+
+#define LTC2983_CHAN_START_ADDR(chan) \
+			(((chan - 1) * 4) + LTC2983_CHAN_ASSIGN_START_REG)
+#define LTC2983_CHAN_RES_ADDR(chan) \
+			(((chan - 1) * 4) + LTC2983_TEMP_RES_START_REG)
+#define LTC2983_THERMOCOUPLE_DIFF_MASK		BIT(3)
+#define LTC2983_THERMISTOR_DIFF_MASK		BIT(2)
+#define LTC2983_DIODE_DIFF_MASK			BIT(2)
+#define LTC2983_RTD_4_WIRE_MASK			BIT(3)
+#define LTC2983_RTD_ROTATION_MASK		BIT(1)
+#define LTC2983_RTD_KELVIN_R_SENSE_MASK		GENMASK(3, 2)
+
+#define LTC2983_COMMON_HARD_FAULT_MASK	GENMASK(31, 30)
+#define LTC2983_COMMON_SOFT_FAULT_MASK	GENMASK(27, 25)
+
+#define	LTC2983_STATUS_START_MASK	BIT(7)
+#define	LTC2983_STATUS_START(x)		FIELD_PREP(LTC2983_STATUS_START_MASK, x)
+
+#define	LTC2983_STATUS_CHAN_SEL_MASK	GENMASK(4, 0)
+#define	LTC2983_STATUS_CHAN_SEL(x) \
+				FIELD_PREP(LTC2983_STATUS_CHAN_SEL_MASK, x)
+
+#define LTC2983_TEMP_UNITS_MASK		BIT(2)
+#define LTC2983_TEMP_UNITS(x)		FIELD_PREP(LTC2983_TEMP_UNITS_MASK, x)
+
+#define LTC2983_NOTCH_FREQ_MASK		GENMASK(1, 0)
+#define LTC2983_NOTCH_FREQ(x)		FIELD_PREP(LTC2983_NOTCH_FREQ_MASK, x)
+
+#define LTC2983_RES_VALID_MASK		BIT(24)
+#define LTC2983_DATA_MASK		GENMASK(23, 0)
+#define LTC2983_DATA_SIGN_BIT		23
+
+#define LTC2983_CHAN_TYPE_MASK		GENMASK(31, 27)
+#define LTC2983_CHAN_TYPE(x)		FIELD_PREP(LTC2983_CHAN_TYPE_MASK, x)
+
+/* cold junction for thermocouples and rsense for rtd's and thermistor's */
+#define LTC2983_CHAN_ASSIGN_MASK	GENMASK(26, 22)
+#define LTC2983_CHAN_ASSIGN(x)		FIELD_PREP(LTC2983_CHAN_ASSIGN_MASK, x)
+
+#define LTC2983_CUSTOM_LEN_MASK		GENMASK(5, 0)
+#define LTC2983_CUSTOM_LEN(x)		FIELD_PREP(LTC2983_CUSTOM_LEN_MASK, x)
+
+#define LTC2983_CUSTOM_ADDR_MASK	GENMASK(11, 6)
+#define LTC2983_CUSTOM_ADDR(x)		FIELD_PREP(LTC2983_CUSTOM_ADDR_MASK, x)
+
+#define LTC2983_THERMOCOUPLE_CFG_MASK	GENMASK(21, 18)
+#define LTC2983_THERMOCOUPLE_CFG(x) \
+				FIELD_PREP(LTC2983_THERMOCOUPLE_CFG_MASK, x)
+#define LTC2983_THERMOCOUPLE_HARD_FAULT_MASK	GENMASK(31, 29)
+#define LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK	GENMASK(28, 25)
+
+#define LTC2983_RTD_CFG_MASK		GENMASK(21, 18)
+#define LTC2983_RTD_CFG(x)		FIELD_PREP(LTC2983_RTD_CFG_MASK, x)
+#define LTC2983_RTD_EXC_CURRENT_MASK	GENMASK(17, 14)
+#define LTC2983_RTD_EXC_CURRENT(x) \
+				FIELD_PREP(LTC2983_RTD_EXC_CURRENT_MASK, x)
+#define LTC2983_RTD_CURVE_MASK		GENMASK(13, 12)
+#define LTC2983_RTD_CURVE(x)		FIELD_PREP(LTC2983_RTD_CURVE_MASK, x)
+
+#define LTC2983_THERMISTOR_CFG_MASK	GENMASK(21, 19)
+#define LTC2983_THERMISTOR_CFG(x) \
+				FIELD_PREP(LTC2983_THERMISTOR_CFG_MASK, x)
+#define LTC2983_THERMISTOR_EXC_CURRENT_MASK	GENMASK(18, 15)
+#define LTC2983_THERMISTOR_EXC_CURRENT(x) \
+			FIELD_PREP(LTC2983_THERMISTOR_EXC_CURRENT_MASK, x)
+
+#define LTC2983_DIODE_CFG_MASK		GENMASK(26, 24)
+#define LTC2983_DIODE_CFG(x)		FIELD_PREP(LTC2983_DIODE_CFG_MASK, x)
+#define LTC2983_DIODE_EXC_CURRENT_MASK	GENMASK(23, 22)
+#define LTC2983_DIODE_EXC_CURRENT(x) \
+				FIELD_PREP(LTC2983_DIODE_EXC_CURRENT_MASK, x)
+#define LTC2983_DIODE_IDEAL_FACTOR_MASK	GENMASK(21, 0)
+#define LTC2983_DIODE_IDEAL_FACTOR(x) \
+				FIELD_PREP(LTC2983_DIODE_IDEAL_FACTOR_MASK, x)
+
+#define LTC2983_R_SENSE_VAL_MASK	GENMASK(26, 0)
+#define LTC2983_R_SENSE_VAL(x)		FIELD_PREP(LTC2983_R_SENSE_VAL_MASK, x)
+
+#define LTC2983_ADC_SINGLE_ENDED_MASK	BIT(26)
+#define LTC2983_ADC_SINGLE_ENDED(x) \
+				FIELD_PREP(LTC2983_ADC_SINGLE_ENDED_MASK, x)
+
+enum {
+	LTC2983_SENSOR_THERMOCOUPLE = 1,
+	LTC2983_SENSOR_THERMOCOUPLE_CUSTOM = 9,
+	LTC2983_SENSOR_RTD = 10,
+	LTC2983_SENSOR_RTD_CUSTOM = 18,
+	LTC2983_SENSOR_THERMISTOR = 19,
+	LTC2983_SENSOR_THERMISTOR_STEINHART = 26,
+	LTC2983_SENSOR_THERMISTOR_CUSTOM = 27,
+	LTC2983_SENSOR_DIODE = 28,
+	LTC2983_SENSOR_SENSE_RESISTOR = 29,
+	LTC2983_SENSOR_DIRECT_ADC = 30,
+};
+
+#define to_thermocouple(_sensor) \
+		container_of(_sensor, struct ltc2983_thermocouple, sensor)
+
+#define to_rtd(_sensor) \
+		container_of(_sensor, struct ltc2983_rtd, sensor)
+
+#define to_thermistor(_sensor) \
+		container_of(_sensor, struct ltc2983_thermistor, sensor)
+
+#define to_diode(_sensor) \
+		container_of(_sensor, struct ltc2983_diode, sensor)
+
+#define to_rsense(_sensor) \
+		container_of(_sensor, struct ltc2983_rsense, sensor)
+
+#define to_adc(_sensor) \
+		container_of(_sensor, struct ltc2983_adc, sensor)
+
+struct ltc2983_data {
+	struct regmap *regmap;
+	struct spi_device *spi;
+	struct mutex lock;
+	struct completion completion;
+	struct iio_chan_spec *iio_chan;
+	struct ltc2983_sensor **sensors;
+	u32 mux_delay_config;
+	u32 filter_notch_freq;
+	u16 custom_table_size;
+	u8 num_channels;
+	u8 iio_channels;
+	bool temp_farenheit;
+	bool reset;
+};
+
+struct ltc2983_sensor {
+	int (*fault_handler)(const struct ltc2983_data *st, const u32 result);
+	int (*assign_chan)(struct ltc2983_data *st,
+			   const struct ltc2983_sensor *sensor);
+	const char *name;
+	/* specifies the sensor channel */
+	u32 chan;
+	/* sensor type */
+	u32 type;
+};
+
+struct ltc2983_custom_sensor {
+	/* raw table sensor data */
+	u8 *table;
+	size_t size;
+	/* address offset */
+	s8 offset;
+	bool is_steinhart;
+};
+
+struct ltc2983_thermocouple {
+	struct ltc2983_sensor sensor;
+	struct ltc2983_custom_sensor *custom;
+	u32 sensor_config;
+	u32 cold_junction_chan;
+};
+
+struct ltc2983_rtd {
+	struct ltc2983_sensor sensor;
+	struct ltc2983_custom_sensor *custom;
+	u32 sensor_config;
+	u32 r_sense_chan;
+	u32 excitation_current;
+	u32 rtd_curve;
+};
+
+struct ltc2983_thermistor {
+	struct ltc2983_sensor sensor;
+	struct ltc2983_custom_sensor *custom;
+	u32 sensor_config;
+	u32 r_sense_chan;
+	u32 excitation_current;
+};
+
+struct ltc2983_diode {
+	struct ltc2983_sensor sensor;
+	u32 sensor_config;
+	u32 excitation_current;
+	u32 ideal_factor_value;
+};
+
+struct ltc2983_rsense {
+	struct ltc2983_sensor sensor;
+	u32 r_sense_val;
+};
+
+struct ltc2983_adc {
+	struct ltc2983_sensor sensor;
+	bool single_ended;
+};
+
+/*
+ * Convert to Q format numbers. These number's are integers where
+ * the number of integer and fractional bits are specified. The resolution
+ * is given by 1/@resolution and tell us the number of fractional bits. For
+ * instance a resolution of 2^-10 means we have 10 fractional bits.
+ */
+static u32 __convert_to_raw(const u64 val, const u32 resolution)
+{
+	u64 __res = val * resolution;
+
+	/* all values are multiplied by 1000000 to remove the fraction */
+	do_div(__res, 1000000);
+
+	return __res;
+}
+
+static u32 __convert_to_raw_sign(const u64 val, const u32 resolution)
+{
+	s64 __res = -(s32)val;
+
+	__res = __convert_to_raw(__res, resolution);
+
+	return (u32)-__res;
+}
+
+static int __ltc2983_fault_handler(const struct ltc2983_data *st,
+				   const u32 result, const u32 hard_mask,
+				   const u32 soft_mask)
+{
+	const struct device *dev = &st->spi->dev;
+
+	if (result & hard_mask) {
+		dev_err(dev, "Invalid conversion: Sensor HARD fault\n");
+		return -EIO;
+	} else if (result & soft_mask) {
+		/* just print a warning */
+		dev_warn(dev, "Suspicious conversion: Sensor SOFT fault\n");
+	}
+
+	return 0;
+}
+
+static int __ltc2983_chan_assign_common(const struct ltc2983_data *st,
+					const struct ltc2983_sensor *sensor,
+					u32 chan_val)
+{
+	u32 reg = LTC2983_CHAN_START_ADDR(sensor->chan);
+	__be32 __chan_val;
+
+	chan_val |= LTC2983_CHAN_TYPE(sensor->type);
+	dev_dbg(&st->spi->dev, "Assign %s, reg:0x%04X, val:0x%08X\n",
+							sensor->name,
+							reg, chan_val);
+	__chan_val = cpu_to_be32(chan_val);
+	return regmap_bulk_write(st->regmap, reg, &__chan_val,
+				 sizeof(__chan_val));
+}
+
+static int __ltc2983_chan_custom_sensor_assign(struct ltc2983_data *st,
+					  struct ltc2983_custom_sensor *custom,
+					  u32 *chan_val)
+{
+	u32 reg;
+	u8 mult = custom->is_steinhart ? LTC2983_CUSTOM_STEINHART_ENTRY_SZ :
+		LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
+	const struct device *dev = &st->spi->dev;
+	/*
+	 * custom->size holds the raw size of the table. However, when
+	 * configuring the sensor channel, we must write the number of
+	 * entries of the table minus 1. For steinhart sensors 0 is written
+	 * since the size is constant!
+	 */
+	const u8 len = custom->is_steinhart ? 0 :
+		(custom->size / LTC2983_CUSTOM_SENSOR_ENTRY_SZ) - 1;
+	/*
+	 * Check if the offset was assigned already. It should be for steinhart
+	 * sensors. When coming from sleep, it should be assigned for all.
+	 */
+	if (custom->offset < 0) {
+		/*
+		 * This needs to be done again here because, from the moment
+		 * when this test was done (successfully) for this custom
+		 * sensor, a steinhart sensor might have been added changing
+		 * custom_table_size...
+		 */
+		if (st->custom_table_size + custom->size >
+		    (LTC2983_CUST_SENS_TBL_END_REG -
+		     LTC2983_CUST_SENS_TBL_START_REG) + 1) {
+			dev_err(dev,
+				"Not space left(%d) for new custom sensor(%zu)",
+							st->custom_table_size,
+							custom->size);
+			return -EINVAL;
+		}
+
+		custom->offset = st->custom_table_size /
+					LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
+		st->custom_table_size += custom->size;
+	}
+
+	reg = (custom->offset * mult) + LTC2983_CUST_SENS_TBL_START_REG;
+
+	*chan_val |= LTC2983_CUSTOM_LEN(len);
+	*chan_val |= LTC2983_CUSTOM_ADDR(custom->offset);
+	dev_dbg(dev, "Assign custom sensor, reg:0x%04X, off:%d, sz:%zu",
+							reg, custom->offset,
+							custom->size);
+	/* write custom sensor table */
+	return regmap_bulk_write(st->regmap, reg, custom->table, custom->size);
+}
+
+static struct ltc2983_custom_sensor *__ltc2983_custom_sensor_new(
+						struct ltc2983_data *st,
+						const struct device_node *np,
+						const bool is_steinhart,
+						const u32 resolution,
+						const bool has_signed)
+{
+	struct ltc2983_custom_sensor *new_custom;
+	u8 index, n_entries, tbl = 0;
+	struct device *dev = &st->spi->dev;
+	/*
+	 * For custom steinhart, the full u32 is taken. For all the others
+	 * the MSB is discarded.
+	 */
+	const u8 n_size = (is_steinhart == true) ? 4 : 3;
+
+	n_entries = of_property_count_elems_of_size(np, "adi,custom-sensor",
+						sizeof(u64));
+	/* n_entries must be an even number */
+	if (!n_entries || (n_entries % 2) != 0) {
+		dev_err(dev, "Number of entries either 0 or not even\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	new_custom = devm_kzalloc(dev, sizeof(*new_custom), GFP_KERNEL);
+	if (!new_custom)
+		return ERR_PTR(-ENOMEM);
+
+	new_custom->size = n_entries * n_size;
+	/* check Steinhart size */
+	if (is_steinhart && new_custom->size != LTC2983_CUSTOM_STEINHART_SIZE) {
+		dev_err(dev, "Steinhart sensors size(%zu) must be 24",
+							new_custom->size);
+		return ERR_PTR(-EINVAL);
+	}
+	/* Check space on the table. */
+	if (st->custom_table_size + new_custom->size >
+	    (LTC2983_CUST_SENS_TBL_END_REG -
+	     LTC2983_CUST_SENS_TBL_START_REG) + 1) {
+		dev_err(dev, "No space left(%d) for new custom sensor(%zu)",
+				st->custom_table_size, new_custom->size);
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* allocate the table */
+	new_custom->table = devm_kzalloc(dev, new_custom->size, GFP_KERNEL);
+	if (!new_custom->table)
+		return ERR_PTR(-ENOMEM);
+
+	for (index = 0; index < n_entries; index++) {
+		u64 temp = 0, j;
+
+		of_property_read_u64_index(np, "adi,custom-sensor", index,
+					   &temp);
+		/*
+		 * Steinhart sensors are configured with raw values in the
+		 * devicetree. For the other sensors we must convert the
+		 * value to raw. The odd index's correspond to temperarures
+		 * and always have 1/1024 of resolution. Temperatures also
+		 * come in kelvin, so signed values is not possible
+		 */
+		if (!is_steinhart) {
+			if ((index % 2) != 0)
+				temp = __convert_to_raw(temp, 1024);
+			else if (has_signed && (s64)temp < 0)
+				temp = __convert_to_raw_sign(temp, resolution);
+			else
+				temp = __convert_to_raw(temp, resolution);
+		}
+
+		for (j = 0; j < n_size; j++)
+			new_custom->table[tbl++] =
+				temp >> (8 * (n_size - j - 1));
+	}
+
+	new_custom->is_steinhart = is_steinhart;
+	/*
+	 * This is done to first add all the steinhart sensors to the table,
+	 * in order to maximize the table usage. If we mix adding steinhart
+	 * with the other sensors, we might have to do some roundup to make
+	 * sure that sensor_addr - 0x250(start address) is a multiple of 4
+	 * (for steinhart), and a multiple of 6 for all the other sensors.
+	 * Since we have const 24 bytes for steinhart sensors and 24 is
+	 * also a multiple of 6, we guarantee that the first non-steinhart
+	 * sensor will sit in a correct address without the need of filling
+	 * addresses.
+	 */
+	if (is_steinhart) {
+		new_custom->offset = st->custom_table_size /
+					LTC2983_CUSTOM_STEINHART_ENTRY_SZ;
+		st->custom_table_size += new_custom->size;
+	} else {
+		/* mark as unset. This is checked later on the assign phase */
+		new_custom->offset = -1;
+	}
+
+	return new_custom;
+}
+
+static int ltc2983_thermocouple_fault_handler(const struct ltc2983_data *st,
+					      const u32 result)
+{
+	return __ltc2983_fault_handler(st, result,
+				       LTC2983_THERMOCOUPLE_HARD_FAULT_MASK,
+				       LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK);
+}
+
+static int ltc2983_common_fault_handler(const struct ltc2983_data *st,
+					const u32 result)
+{
+	return __ltc2983_fault_handler(st, result,
+				       LTC2983_COMMON_HARD_FAULT_MASK,
+				       LTC2983_COMMON_SOFT_FAULT_MASK);
+}
+
+static int ltc2983_thermocouple_assign_chan(struct ltc2983_data *st,
+				const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_thermocouple *thermo = to_thermocouple(sensor);
+	u32 chan_val;
+
+	chan_val = LTC2983_CHAN_ASSIGN(thermo->cold_junction_chan);
+	chan_val |= LTC2983_THERMOCOUPLE_CFG(thermo->sensor_config);
+
+	if (thermo->custom) {
+		int ret;
+
+		ret = __ltc2983_chan_custom_sensor_assign(st, thermo->custom,
+							  &chan_val);
+		if (ret)
+			return ret;
+	}
+	return __ltc2983_chan_assign_common(st, sensor, chan_val);
+}
+
+static int ltc2983_rtd_assign_chan(struct ltc2983_data *st,
+				   const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_rtd *rtd = to_rtd(sensor);
+	u32 chan_val;
+
+	chan_val = LTC2983_CHAN_ASSIGN(rtd->r_sense_chan);
+	chan_val |= LTC2983_RTD_CFG(rtd->sensor_config);
+	chan_val |= LTC2983_RTD_EXC_CURRENT(rtd->excitation_current);
+	chan_val |= LTC2983_RTD_CURVE(rtd->rtd_curve);
+
+	if (rtd->custom) {
+		int ret;
+
+		ret = __ltc2983_chan_custom_sensor_assign(st, rtd->custom,
+							  &chan_val);
+		if (ret)
+			return ret;
+	}
+	return __ltc2983_chan_assign_common(st, sensor, chan_val);
+}
+
+static int ltc2983_thermistor_assign_chan(struct ltc2983_data *st,
+					  const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_thermistor *thermistor = to_thermistor(sensor);
+	u32 chan_val;
+
+	chan_val = LTC2983_CHAN_ASSIGN(thermistor->r_sense_chan);
+	chan_val |= LTC2983_THERMISTOR_CFG(thermistor->sensor_config);
+	chan_val |=
+		LTC2983_THERMISTOR_EXC_CURRENT(thermistor->excitation_current);
+
+	if (thermistor->custom) {
+		int ret;
+
+		ret = __ltc2983_chan_custom_sensor_assign(st,
+							  thermistor->custom,
+							  &chan_val);
+		if (ret)
+			return ret;
+	}
+	return __ltc2983_chan_assign_common(st, sensor, chan_val);
+}
+
+static int ltc2983_diode_assign_chan(struct ltc2983_data *st,
+				     const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_diode *diode = to_diode(sensor);
+	u32 chan_val;
+
+	chan_val = LTC2983_DIODE_CFG(diode->sensor_config);
+	chan_val |= LTC2983_DIODE_EXC_CURRENT(diode->excitation_current);
+	chan_val |= LTC2983_DIODE_IDEAL_FACTOR(diode->ideal_factor_value);
+
+	return __ltc2983_chan_assign_common(st, sensor, chan_val);
+}
+
+static int ltc2983_r_sense_assign_chan(struct ltc2983_data *st,
+				       const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_rsense *rsense = to_rsense(sensor);
+	u32 chan_val;
+
+	chan_val = LTC2983_R_SENSE_VAL(rsense->r_sense_val);
+
+	return __ltc2983_chan_assign_common(st, sensor, chan_val);
+}
+
+static int ltc2983_adc_assign_chan(struct ltc2983_data *st,
+				   const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_adc *adc = to_adc(sensor);
+	u32 chan_val;
+
+	chan_val = LTC2983_ADC_SINGLE_ENDED(adc->single_ended);
+
+	return __ltc2983_chan_assign_common(st, sensor, chan_val);
+}
+
+static struct ltc2983_sensor *ltc2983_thermocouple_new(
+					const struct device_node *child,
+					struct ltc2983_data *st,
+					const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_thermocouple *thermo;
+	struct device_node *phandle;
+
+	thermo = devm_kzalloc(&st->spi->dev, sizeof(*thermo), GFP_KERNEL);
+	if (!thermo)
+		return ERR_PTR(-ENOMEM);
+
+	of_property_read_u32(child, "adi,sensor-config",
+				 &thermo->sensor_config);
+	/* validate channel index */
+	if (!(thermo->sensor_config & LTC2983_THERMOCOUPLE_DIFF_MASK) &&
+	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
+		dev_err(&st->spi->dev,
+			"Invalid chann:%d for differential thermocouple",
+								sensor->chan);
+		return ERR_PTR(-EINVAL);
+	}
+
+	phandle = of_parse_phandle(child, "adi,cold-junction-handle", 0);
+	if (phandle) {
+		int ret;
+
+		ret = of_property_read_u32(phandle, "reg",
+					   &thermo->cold_junction_chan);
+		if (ret) {
+			/*
+			 * This would be catched later but we can just return
+			 * the error right away.
+			 */
+			dev_err(&st->spi->dev, "Property reg must be given\n");
+			of_node_put(phandle);
+			return ERR_PTR(-EINVAL);
+		}
+	}
+
+	/* check custom sensor */
+	if (sensor->type == LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
+		thermo->custom = __ltc2983_custom_sensor_new(st, child, false,
+							     16384, true);
+		if (IS_ERR(thermo->custom)) {
+			of_node_put(phandle);
+			return ERR_CAST(thermo->custom);
+		}
+	}
+
+	/* set common parameters */
+	thermo->sensor.name = "thermocouple";
+	thermo->sensor.fault_handler = ltc2983_thermocouple_fault_handler;
+	thermo->sensor.assign_chan = ltc2983_thermocouple_assign_chan;
+
+	of_node_put(phandle);
+	return &thermo->sensor;
+}
+
+static struct ltc2983_sensor *ltc2983_rtd_new(const struct device_node *child,
+					  struct ltc2983_data *st,
+					  const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_rtd *rtd;
+	int ret = 0;
+	struct device *dev = &st->spi->dev;
+	struct device_node *phandle;
+
+	rtd = devm_kzalloc(dev, sizeof(*rtd), GFP_KERNEL);
+	if (!rtd)
+		return ERR_PTR(-ENOMEM);
+
+	phandle = of_parse_phandle(child, "adi,rsense-handle", 0);
+	if (!phandle) {
+		dev_err(dev, "Property adi,rsense-handle missing or invalid");
+		return ERR_PTR(-EINVAL);
+	}
+
+	ret = of_property_read_u32(phandle, "reg",
+				&rtd->r_sense_chan);
+	if (ret) {
+		dev_err(dev, "Property reg must be given\n");
+		goto fail;
+	}
+
+	of_property_read_u32(child, "adi,sensor-config", &rtd->sensor_config);
+	/*
+	 * rtd channel indexes are a bit more complicated to validate.
+	 * For 4wire RTD with rotation, the channel selection cannot be
+	 * >=19 since the chann + 1 is used in this configuration.
+	 * For 4wire RTDs with kelvin rsense, the rsense channel cannot be
+	 * <=1 since chanel - 1 and channel - 2 are used.
+	 */
+	if (rtd->sensor_config & LTC2983_RTD_4_WIRE_MASK) {
+		/* 4-wire */
+		u8 min = LTC2983_DIFFERENTIAL_CHAN_MIN,
+			max = LTC2983_MAX_CHANNELS_NR;
+
+		if (rtd->sensor_config & LTC2983_RTD_ROTATION_MASK)
+			max = LTC2983_MAX_CHANNELS_NR - 1;
+
+		if (((rtd->sensor_config & LTC2983_RTD_KELVIN_R_SENSE_MASK)
+		     == LTC2983_RTD_KELVIN_R_SENSE_MASK) &&
+		    (rtd->r_sense_chan <=  min)) {
+			/* kelvin rsense*/
+			dev_err(dev,
+				"Invalid rsense chann:%d to use in kelvin rsense",
+							rtd->r_sense_chan);
+
+			ret = -EINVAL;
+			goto fail;
+		}
+
+		if (sensor->chan < min || sensor->chan > max) {
+			dev_err(dev, "Invalid chann:%d for the rtd config",
+								sensor->chan);
+
+			ret = -EINVAL;
+			goto fail;
+		}
+	} else {
+		/* same as differential case */
+		if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
+			dev_err(&st->spi->dev,
+				"Invalid chann:%d for RTD", sensor->chan);
+
+			ret = -EINVAL;
+			goto fail;
+		}
+	}
+
+	/* check custom sensor */
+	if (sensor->type == LTC2983_SENSOR_RTD_CUSTOM) {
+		rtd->custom = __ltc2983_custom_sensor_new(st, child, false,
+							  2048, false);
+		if (IS_ERR(rtd->custom)) {
+			of_node_put(phandle);
+			return ERR_CAST(rtd->custom);
+		}
+	}
+
+	/* set common parameters */
+	rtd->sensor.name = "rtd";
+	rtd->sensor.fault_handler = ltc2983_common_fault_handler;
+	rtd->sensor.assign_chan = ltc2983_rtd_assign_chan;
+
+	ret = of_property_read_u32(child, "adi,excitation-current",
+				   &rtd->excitation_current);
+	if (ret)
+		/* default to 1uA */
+		rtd->excitation_current = 1;
+
+	of_property_read_u32(child, "adi,rtd-curve", &rtd->rtd_curve);
+
+	of_node_put(phandle);
+	return &rtd->sensor;
+fail:
+	of_node_put(phandle);
+	return ERR_PTR(ret);
+}
+
+static struct ltc2983_sensor *ltc2983_thermistor_new(
+					const struct device_node *child,
+					struct ltc2983_data *st,
+					const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_thermistor *thermistor;
+	struct device *dev = &st->spi->dev;
+	struct device_node *phandle;
+	int ret = 0;
+
+	thermistor = devm_kzalloc(dev, sizeof(*thermistor), GFP_KERNEL);
+	if (!thermistor)
+		return ERR_PTR(-ENOMEM);
+
+	phandle = of_parse_phandle(child, "adi,rsense-handle", 0);
+	if (!phandle) {
+		dev_err(dev, "Property adi,rsense-handle missing or invalid");
+		return ERR_PTR(-EINVAL);
+	}
+
+	ret = of_property_read_u32(phandle, "reg",
+				   &thermistor->r_sense_chan);
+	if (ret) {
+		dev_err(dev, "rsense channel must be configured...\n");
+		goto fail;
+	}
+
+	of_property_read_u32(child, "adi,sensor-config",
+			     &thermistor->sensor_config);
+	/* validate channel index */
+	if (!(thermistor->sensor_config & LTC2983_THERMISTOR_DIFF_MASK) &&
+	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
+		dev_err(&st->spi->dev,
+			"Invalid chann:%d for differential thermistor",
+								sensor->chan);
+		ret = -EINVAL;
+		goto fail;
+	}
+
+	/* check custom sensor */
+	if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART) {
+		thermistor->custom = __ltc2983_custom_sensor_new(st, child,
+			sensor->type == LTC2983_SENSOR_THERMISTOR_STEINHART ?
+							  true : false, 64,
+							  false);
+		if (IS_ERR(thermistor->custom)) {
+			of_node_put(phandle);
+			return ERR_CAST(thermistor->custom);
+		}
+	}
+	/* set common parameters */
+	thermistor->sensor.name = "thermistor";
+	thermistor->sensor.fault_handler = ltc2983_common_fault_handler;
+	thermistor->sensor.assign_chan = ltc2983_thermistor_assign_chan;
+
+	ret = of_property_read_u32(child, "adi,excitation-current",
+				   &thermistor->excitation_current);
+	if (ret)
+		/* default to auto-range */
+		thermistor->excitation_current = 0x0c;
+
+	of_node_put(phandle);
+	return &thermistor->sensor;
+fail:
+	of_node_put(phandle);
+	return ERR_PTR(ret);
+}
+
+static struct ltc2983_sensor *ltc2983_diode_new(
+					const struct device_node *child,
+					const struct ltc2983_data *st,
+					const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_diode *diode;
+	u32 temp = 0;
+
+	diode = devm_kzalloc(&st->spi->dev, sizeof(*diode), GFP_KERNEL);
+	if (!diode)
+		return ERR_PTR(-ENOMEM);
+
+	of_property_read_u32(child, "adi,sensor-config", &diode->sensor_config);
+	/* validate channel index */
+	if (!(diode->sensor_config & LTC2983_DIODE_DIFF_MASK) &&
+	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
+		dev_err(&st->spi->dev,
+			"Invalid chann:%d for differential thermistor",
+								sensor->chan);
+		return ERR_PTR(-EINVAL);
+	}
+	/* set common parameters */
+	diode->sensor.name = "diode";
+	diode->sensor.fault_handler = ltc2983_common_fault_handler;
+	diode->sensor.assign_chan = ltc2983_diode_assign_chan;
+
+	of_property_read_u32(child, "adi,excitation-current",
+			     &diode->excitation_current);
+
+	of_property_read_u32(child, "adi,ideal-factor-value", &temp);
+
+	/* 2^20 resolution */
+	diode->ideal_factor_value = __convert_to_raw(temp, 1048576);
+
+	return &diode->sensor;
+}
+
+static struct ltc2983_sensor *ltc2983_r_sense_new(struct device_node *child,
+					struct ltc2983_data *st,
+					const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_rsense *rsense;
+	int ret;
+	u64 temp;
+
+	rsense = devm_kzalloc(&st->spi->dev, sizeof(*rsense), GFP_KERNEL);
+	if (!rsense)
+		return ERR_PTR(-ENOMEM);
+
+	/* validate channel index */
+	if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
+		dev_err(&st->spi->dev, "Invalid chann:%d for r_sense",
+							sensor->chan);
+		return ERR_PTR(-EINVAL);
+	}
+	/* get raw value */
+	ret = of_property_read_u64(child, "adi,rsense-val-micro-ohms", &temp);
+	if (ret) {
+		dev_err(&st->spi->dev, "Property adi,rsense-val-micro-ohms missing\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	/* 2^10 resolution */
+	rsense->r_sense_val = __convert_to_raw(temp, 1024);
+
+	/* set common parameters */
+	rsense->sensor.name = "r_sense";
+	rsense->sensor.assign_chan = ltc2983_r_sense_assign_chan;
+
+	return &rsense->sensor;
+}
+
+static struct ltc2983_sensor *ltc2983_adc_new(struct device_node *child,
+					 struct ltc2983_data *st,
+					 const struct ltc2983_sensor *sensor)
+{
+	struct ltc2983_adc *adc;
+
+	adc = devm_kzalloc(&st->spi->dev, sizeof(*adc), GFP_KERNEL);
+	if (!adc)
+		return ERR_PTR(-ENOMEM);
+
+	if (of_property_read_bool(child, "adi,single-ended"))
+		adc->single_ended = true;
+
+	if (!adc->single_ended &&
+	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
+		dev_err(&st->spi->dev, "Invalid chan:%d for differential adc\n",
+								sensor->chan);
+		return ERR_PTR(-EINVAL);
+	}
+	/* set common parameters */
+	adc->sensor.name = "direct_adc";
+	adc->sensor.assign_chan = ltc2983_adc_assign_chan;
+	adc->sensor.fault_handler = ltc2983_common_fault_handler;
+
+	return &adc->sensor;
+}
+
+static int ltc2983_chan_read(struct ltc2983_data *st,
+			const struct ltc2983_sensor *sensor, int *val)
+{
+	u32 start_conversion = 0;
+	int ret;
+	unsigned long time;
+	__be32 temp;
+
+	/*
+	 * Do not allow channel readings if device is in sleep state.
+	 * A read/write on the spi bus would bring the device prematurely
+	 * out of sleep.
+	 */
+	if (st->reset)
+		return -EPERM;
+
+	start_conversion = LTC2983_STATUS_START(true);
+	start_conversion |= LTC2983_STATUS_CHAN_SEL(sensor->chan);
+	dev_dbg(&st->spi->dev, "Start conversion on chan:%d, status:%02X\n",
+		sensor->chan, start_conversion);
+	/* start conversion */
+	ret = regmap_write(st->regmap, LTC2983_STATUS_REG, start_conversion);
+	if (ret)
+		return ret;
+
+	reinit_completion(&st->completion);
+	/*
+	 * wait for conversion to complete.
+	 * 300 ms should be more than enough to complete the conversion.
+	 * Depending on the sensor configuration, there are 2/3 conversions
+	 * cycles of 82ms.
+	 */
+	time = wait_for_completion_timeout(&st->completion,
+					   msecs_to_jiffies(300));
+	if (!time) {
+		dev_warn(&st->spi->dev, "Conversion timed out\n");
+		return -ETIMEDOUT;
+	}
+
+	/* read the converted data */
+	ret = regmap_bulk_read(st->regmap, LTC2983_CHAN_RES_ADDR(sensor->chan),
+			       &temp, sizeof(temp));
+	if (ret)
+		return ret;
+
+	*val = __be32_to_cpu(temp);
+	dev_dbg(&st->spi->dev, "Converted data: 0x%08X (addr:0x%04X)\n", *val,
+					LTC2983_CHAN_RES_ADDR(sensor->chan));
+
+	if (!(LTC2983_RES_VALID_MASK & *val)) {
+		dev_err(&st->spi->dev, "Invalid conversion detected\n");
+		return -EIO;
+	}
+
+	ret = sensor->fault_handler(st, *val);
+	if (ret)
+		return ret;
+
+	*val = sign_extend32((*val) & LTC2983_DATA_MASK, LTC2983_DATA_SIGN_BIT);
+	return 0;
+}
+
+static int ltc2983_read_raw(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int *val, int *val2, long mask)
+{
+	struct ltc2983_data *st = iio_priv(indio_dev);
+	int ret;
+
+	/* sanity check */
+	if (chan->address >= st->num_channels) {
+		dev_err(&st->spi->dev, "Invalid chan address:%ld",
+							chan->address);
+		return -EINVAL;
+	}
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		mutex_lock(&st->lock);
+		ret = ltc2983_chan_read(st, st->sensors[chan->address], val);
+		mutex_unlock(&st->lock);
+		return ret ?: IIO_VAL_INT;
+	case IIO_CHAN_INFO_SCALE:
+		switch (chan->type) {
+		case IIO_TEMP:
+			*val = 1;
+			/* 2^10 */
+			*val2 = 1024;
+			return IIO_VAL_FRACTIONAL;
+		case IIO_VOLTAGE:
+			*val = 1;
+			/* 2^21 */
+			*val2 = 2097152;
+			return IIO_VAL_FRACTIONAL;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static int ltc2983_reg_access(struct iio_dev *indio_dev,
+			      unsigned int reg,
+			      unsigned int writeval,
+			      unsigned int *readval)
+{
+	struct ltc2983_data *st = iio_priv(indio_dev);
+
+	/* check comment in ltc2983_chan_read() */
+	if (st->reset)
+		return -EPERM;
+
+	if (readval)
+		return regmap_read(st->regmap, reg, readval);
+	else
+		return regmap_write(st->regmap, reg, writeval);
+}
+
+static irqreturn_t ltc2983_irq_handler(int irq, void *data)
+{
+	struct ltc2983_data *st = data;
+
+	complete(&st->completion);
+	return IRQ_HANDLED;
+}
+
+#define LTC2983_CHAN(__type, index, __address, ext_name) ({ \
+	struct iio_chan_spec __chan = { \
+		.type = __type, \
+		.indexed = 1, \
+		.channel = index, \
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+		.address = __address, \
+		.extend_name = ext_name, \
+	}; \
+	__chan; \
+})
+
+static int ltc2983_parse_dt(struct ltc2983_data *st)
+{
+	struct device_node *child;
+	struct device *dev = &st->spi->dev;
+	int ret = 0, chan = 0, channel_avail_mask = 0;
+
+	if (!of_property_read_bool(dev->of_node, "adi,temperature-celcius"))
+		st->temp_farenheit = true;
+
+	of_property_read_u32(dev->of_node, "adi,mux-delay-config",
+			     &st->mux_delay_config);
+
+	of_property_read_u32(dev->of_node, "adi,filter-notch-freq",
+			     &st->filter_notch_freq);
+
+	st->num_channels = of_get_available_child_count(dev->of_node);
+	st->sensors = devm_kcalloc(dev, st->num_channels, sizeof(*st->sensors),
+				   GFP_KERNEL);
+	if (!st->sensors)
+		return -ENOMEM;
+
+	st->iio_channels = st->num_channels;
+	for_each_available_child_of_node(dev->of_node, child) {
+		struct ltc2983_sensor sensor;
+
+		ret = of_property_read_u32(child, "reg", &sensor.chan);
+		if (ret) {
+			dev_err(dev, "reg property must given for child nodes\n");
+			return ret;
+		}
+
+		/* check if we have a valid channel */
+		if (sensor.chan < LTC2983_MIN_CHANNELS_NR ||
+		    sensor.chan > LTC2983_MAX_CHANNELS_NR) {
+			dev_err(dev,
+				"chan:%d must be from 1 to 20\n", sensor.chan);
+			return -EINVAL;
+		} else if (channel_avail_mask & BIT(sensor.chan)) {
+			dev_err(dev, "chan:%d already in use\n", sensor.chan);
+			return -EINVAL;
+		}
+
+		ret = of_property_read_u32(child, "adi,sensor-type",
+					       &sensor.type);
+		if (ret) {
+			dev_err(dev,
+				"adi,sensor-type property must given for child nodes\n");
+			return ret;
+		}
+
+		dev_dbg(dev, "Create new sensor, type %u, chann %u",
+								sensor.type,
+								sensor.chan);
+
+		if (sensor.type >= LTC2983_SENSOR_THERMOCOUPLE &&
+		    sensor.type <= LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
+			st->sensors[chan] = ltc2983_thermocouple_new(child, st,
+								     &sensor);
+		} else if (sensor.type >= LTC2983_SENSOR_RTD &&
+			   sensor.type <= LTC2983_SENSOR_RTD_CUSTOM) {
+			st->sensors[chan] = ltc2983_rtd_new(child, st, &sensor);
+		} else if (sensor.type >= LTC2983_SENSOR_THERMISTOR &&
+			   sensor.type <= LTC2983_SENSOR_THERMISTOR_CUSTOM) {
+			st->sensors[chan] = ltc2983_thermistor_new(child, st,
+								   &sensor);
+		} else if (sensor.type == LTC2983_SENSOR_DIODE) {
+			st->sensors[chan] = ltc2983_diode_new(child, st,
+							      &sensor);
+		} else if (sensor.type == LTC2983_SENSOR_SENSE_RESISTOR) {
+			st->sensors[chan] = ltc2983_r_sense_new(child, st,
+								&sensor);
+			/* don't add rsense to iio */
+			st->iio_channels--;
+		} else if (sensor.type == LTC2983_SENSOR_DIRECT_ADC) {
+			st->sensors[chan] = ltc2983_adc_new(child, st, &sensor);
+		} else {
+			dev_err(dev, "Unknown sensor type %d\n", sensor.type);
+			return -EINVAL;
+		}
+
+		if (IS_ERR(st->sensors[chan])) {
+			dev_err(dev, "Failed to create sensor %ld",
+						PTR_ERR(st->sensors[chan]));
+			return PTR_ERR(st->sensors[chan]);
+		}
+		/* set generic sensor parameters */
+		st->sensors[chan]->chan = sensor.chan;
+		st->sensors[chan]->type = sensor.type;
+
+		channel_avail_mask |= BIT(sensor.chan);
+		chan++;
+	}
+	/* allocate iio_chan array */
+	st->iio_chan = devm_kzalloc(dev,
+				    st->iio_channels * sizeof(*st->iio_chan),
+				    GFP_KERNEL);
+	if (!st->iio_chan)
+		return -ENOMEM;
+
+	return 0;
+}
+
+static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
+{
+	u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0;
+	u32 global_cfg = 0;
+	int ret;
+	unsigned long time;
+
+	/* make sure the device is up */
+	time = wait_for_completion_timeout(&st->completion,
+					    msecs_to_jiffies(250));
+	if (!time) {
+		dev_err(&st->spi->dev, "Device startup timed out\n");
+		return -ETIMEDOUT;
+	}
+	/* set generic global cfg and mux delay */
+	global_cfg = LTC2983_NOTCH_FREQ(st->filter_notch_freq);
+	global_cfg |= LTC2983_TEMP_UNITS(st->temp_farenheit);
+	regmap_write(st->regmap, LTC2983_GLOBAL_CONFIG_REG, global_cfg);
+	regmap_write(st->regmap, LTC2983_MUX_CONFIG_REG, st->mux_delay_config);
+	/* setup channels */
+	for (chan = 0; chan < st->num_channels; chan++) {
+		u32 chan_type = 0, *iio_chan;
+
+		ret = st->sensors[chan]->assign_chan(st, st->sensors[chan]);
+		if (ret)
+			return ret;
+		/*
+		 * The assign_iio flag is necessary for when the device is
+		 * coming out of sleep. In that case, we just need to
+		 * re-configure the device channels.
+		 * We also don't assign iio channels for rsense.
+		 */
+		if (st->sensors[chan]->type == LTC2983_SENSOR_SENSE_RESISTOR ||
+		    !assign_iio)
+			continue;
+
+		/* assign iio channel */
+		if (st->sensors[chan]->type != LTC2983_SENSOR_DIRECT_ADC) {
+			chan_type = IIO_TEMP;
+			iio_chan = &iio_chan_t;
+		} else {
+			chan_type = IIO_VOLTAGE;
+			iio_chan = &iio_chan_v;
+		}
+
+		/*
+		 * add chan as the iio .address so that, we can directly
+		 * reference the sensor given the iio_chan_spec
+		 */
+		st->iio_chan[iio_idx++] = LTC2983_CHAN(chan_type, (*iio_chan)++,
+						       chan,
+						       st->sensors[chan]->name);
+	}
+
+	return 0;
+}
+
+static const struct regmap_range ltc2983_reg_ranges[] = {
+	regmap_reg_range(LTC2983_STATUS_REG, LTC2983_STATUS_REG),
+	regmap_reg_range(LTC2983_TEMP_RES_START_REG, LTC2983_TEMP_RES_END_REG),
+	regmap_reg_range(LTC2983_GLOBAL_CONFIG_REG, LTC2983_GLOBAL_CONFIG_REG),
+	regmap_reg_range(LTC2983_MULT_CHANNEL_START_REG,
+			 LTC2983_MULT_CHANNEL_END_REG),
+	regmap_reg_range(LTC2983_MUX_CONFIG_REG, LTC2983_MUX_CONFIG_REG),
+	regmap_reg_range(LTC2983_CHAN_ASSIGN_START_REG,
+			 LTC2983_CHAN_ASSIGN_END_REG),
+	regmap_reg_range(LTC2983_CUST_SENS_TBL_START_REG,
+			 LTC2983_CUST_SENS_TBL_END_REG),
+};
+
+static const struct regmap_access_table ltc2983_reg_table = {
+	.yes_ranges = ltc2983_reg_ranges,
+	.n_yes_ranges = ARRAY_SIZE(ltc2983_reg_ranges),
+};
+/*
+ *  The reg_bits are actually 12 but the device needs the first *complete*
+ *  byte for the command (R/W).
+ */
+static const struct regmap_config ltc2983_regmap_config = {
+	.reg_bits = 24,
+	.val_bits = 8,
+	.wr_table = &ltc2983_reg_table,
+	.rd_table = &ltc2983_reg_table,
+	.read_flag_mask = GENMASK(1, 0),
+	.write_flag_mask = BIT(1),
+};
+
+static const struct  iio_info ltc2983_iio_info = {
+	.read_raw = ltc2983_read_raw,
+	.debugfs_reg_access = ltc2983_reg_access,
+};
+
+static int ltc2983_probe(struct spi_device *spi)
+{
+	struct ltc2983_data *st;
+	struct iio_dev *indio_dev;
+	const char *name = spi_get_device_id(spi)->name;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+	if (!indio_dev)
+		return -ENOMEM;
+
+	st = iio_priv(indio_dev);
+
+	st->regmap = devm_regmap_init_spi(spi, &ltc2983_regmap_config);
+	if (IS_ERR(st->regmap)) {
+		dev_err(&spi->dev, "Failed to initialize regmap\n");
+		return PTR_ERR(st->regmap);
+	}
+
+	mutex_init(&st->lock);
+	init_completion(&st->completion);
+	st->spi = spi;
+	spi_set_drvdata(spi, st);
+
+	ret = ltc2983_parse_dt(st);
+	if (ret)
+		return ret;
+	/*
+	 * let's request the irq now so it is used to sync the device
+	 * startup in ltc2983_setup()
+	 */
+	ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
+					ltc2983_irq_handler, IRQF_ONESHOT |
+					IRQF_TRIGGER_RISING, name, st);
+	if (ret) {
+		dev_err(&spi->dev, "failed to request an irq, %d", ret);
+		return ret;
+	}
+
+	ret = ltc2983_setup(st, true);
+	if (ret)
+		return ret;
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = name;
+	indio_dev->num_channels = st->iio_channels;
+	indio_dev->channels = st->iio_chan;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->info = &ltc2983_iio_info;
+
+	return devm_iio_device_register(&spi->dev, indio_dev);
+}
+
+static int __maybe_unused ltc2983_resume(struct device *dev)
+{
+	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
+	int ret;
+
+	mutex_lock(&st->lock);
+	/* dummy read to bring the device out of sleep */
+	regmap_read(st->regmap, LTC2983_STATUS_REG, &ret);
+	/* we need to re-assign the channels */
+	ret = ltc2983_setup(st, false);
+	st->reset = false;
+	mutex_unlock(&st->lock);
+
+	return ret;
+}
+
+static int __maybe_unused ltc2983_suspend(struct device *dev)
+{
+	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
+	int ret;
+
+	mutex_lock(&st->lock);
+	ret = regmap_write(st->regmap, LTC2983_STATUS_REG, LTC2983_SLEEP);
+	st->reset = true;
+	mutex_unlock(&st->lock);
+
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(ltc2983_pm_ops, ltc2983_suspend, ltc2983_resume);
+
+static const struct spi_device_id ltc2983_id_table[] = {
+	{ "ltc2983" },
+	{},
+};
+MODULE_DEVICE_TABLE(spi, ltc2983_id_table);
+
+static const struct of_device_id ltc2983_of_match[] = {
+	{ .compatible = "adi,ltc2983" },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ltc2983_id_table);
+
+static struct spi_driver ltc2983_driver = {
+	.driver = {
+		.name = "ltc2983",
+		.of_match_table = ltc2983_of_match,
+		.pm = &ltc2983_pm_ops,
+	},
+	.probe = ltc2983_probe,
+	.id_table = ltc2983_id_table,
+};
+
+module_spi_driver(ltc2983_driver);
+
+MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
+MODULE_DESCRIPTION("Analog Devices LTC2983 SPI Temperature sensors");
+MODULE_LICENSE("GPL");
-- 
2.23.0


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation
  2019-09-09 14:45 [PATCH 1/2] iio: temperature: Add support for LTC2983 Nuno Sá
@ 2019-09-09 14:45 ` Nuno Sá
  2019-09-13 14:36   ` Rob Herring
  2019-09-15 11:27 ` [PATCH 1/2] iio: temperature: Add support for LTC2983 Jonathan Cameron
  1 sibling, 1 reply; 11+ messages in thread
From: Nuno Sá @ 2019-09-09 14:45 UTC (permalink / raw)
  To: linux-iio, devicetree
  Cc: jic23, knaack.h, lars, pmeerw, robh+dt, mark.rutland

Document the LTC2983 temperature sensor devicetree bindings.

Signed-off-by: Nuno Sá <nuno.sa@analog.com>
---
 .../bindings/iio/temperature/adi,ltc2983.yaml | 442 ++++++++++++++++++
 MAINTAINERS                                   |   1 +
 2 files changed, 443 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml

diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
new file mode 100644
index 000000000000..2b468b3ed177
--- /dev/null
+++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
@@ -0,0 +1,442 @@
+# SPDX-License-Identifier: GPL-2.0
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Analog Devices LTC2983 Multi-sensor Temperature system
+
+maintainers:
+  - Nuno Sá <nuno.sa@analog.com>
+
+description: |
+  Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
+  https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
+
+properties:
+  compatible:
+    enum:
+      - adi,ltc2983
+
+  reg:
+    maxItems: 1
+
+  interrupts:
+    maxItems: 1
+
+  adi,temperature-celcius:
+    description:
+      If this property is present, the temperature is reported in Celsius.
+    type: boolean
+    maxItems: 1
+
+  adi,mux-delay-config:
+    description:
+      The LTC2983 performs 2 or 3 internal conversion cycles per temperature result.
+      Each conversion cycle is performed with different excitation and input multiplexer
+      configurations. Prior to each conversion, these excitation circuits and input
+      switch configurations are changed and an internal 1ms delay ensures settling prior
+      to the conversion cycle in most cases. An extra delay can be configured using this
+      property. The value written here is multiplied by 100us.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - maximum: 255
+        maxItems: 1
+
+  adi,filter-notch-freq:
+    description:
+      Set's the default setting of the digital filter. The default is simultaneous
+      50/60Hz rejection.
+    allOf:
+      - $ref: /schemas/types.yaml#/definitions/uint32
+      - enum: [0, 1, 2]
+    maxItems: 1
+
+  '#address-cells':
+    const: 1
+
+  '#size-cells':
+    const: 0
+
+patternProperties:
+  "^thermocouple@([1-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a thermocouple sensor which is connected to one of the device channels.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+          Note that, for differential thermocouples, the minimum is 2.
+        minimum: 1
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+           Identifies the type of thermocouple connected to the device.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [1 2 3 4 5 6 7 8]
+        maxItems: 1
+
+      adi,sensor-config:
+        description: |
+          Raw value which set's the sensor configuration. Look at table 14 of the
+          datasheet for how to set this value for thermocouples.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - minimum: 1
+          - maximun: 15
+        maxItems: 1
+
+      adi,cold-junction-handle:
+        description: |
+          Phandle which points to a sensor object responsible for measuring the
+          thermocouple cold junction temperature.
+        $ref: "/schemas/types.yaml#/definitions/phandle"
+        maxItems: 1
+
+      adi,custom-sensor:
+        description: |
+          This is a table, where each entry should be a pair of voltage(mv)-temperature(K).
+          The entries must be given in nv and uK so that, the original values must be
+          multiplied by 1000000. For more details look at table 69 and 70.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/int64-array
+        minItems: 6
+        maxItems: 128
+    required:
+      - reg
+      - adi,sensor-type
+
+patternProperties:
+  "^diode@([1-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a diode sensor which is connected to one of the device channels.
+
+    properties:
+      reg:
+        description:
+          The channel number. It can be connected to one of the 20 channels of the device.
+          Note that, for differential diodes, the minimum is 2.
+        minimum: 1
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the sensor as a diode.
+        const: 28
+        maxItems: 1
+
+      adi,sensor-config:
+        description: |
+          Raw value which set's the sensor configuration. Look at table 17 of the
+          datasheet for how to set this value for diodes.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 2 3 4 5 6 7]
+        maxItems: 1
+
+      adi,excitation-current:
+        description: |
+          This property controls the magnitude of the excitation current applied
+          to the diode. Look at table 19 of the datasheet for more info.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 2 3]
+        maxItems: 1
+
+      adi,ideal-factor-value:
+        description: |
+          This property sets the diode ideality factor. The real value must be
+          multiplied by 1000000 to remove the fractional part. For more information
+          look at table 20 of the datasheet.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+        maxItems: 1
+
+    required:
+      - reg
+      - adi,sensor-type
+
+patternProperties:
+  "^rtd@([2-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a rtd sensor which is connected to one of the device channels.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+        minimum: 2
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the type of RTD connected to the device.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [10 11 12 13 14 15 16 17]
+        maxItems: 1
+
+      adi,rsense-handle:
+        description: |
+          Phandle pointing to a rsense object associated with this RTD.
+        $ref: "/schemas/types.yaml#/definitions/phandle"
+        maxItems: 1
+
+      adi,sensor-config:
+        description: |
+          Raw value which set's the sensor configuration. Look at table 28 of the
+          datasheet for how to set this value for RTD's.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 4 5 8 9 10 12 13 14]
+        maxItems: 1
+
+      adi,excitation-current:
+        description: |
+          This property controls the magnitude of the excitation current applied
+          to the RTD. Look at table 29 of the datasheet for more info.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [1 2 3 4 5 6 7 8]
+        maxItems: 1
+
+      adi,rtd-curve:
+        description: |
+          This property set the RTD curve used and the corresponding Callendar-Van
+          Dusen constants. Look at table 30 of the datasheet.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 2 3]
+        maxItems: 1
+
+      adi,custom-sensor:
+        description: |
+          This is a table, where each entry should be a pair of resistance(ohm)-temperature(K).
+          The entries added here are in uohm and uK. For more details values look at table 74 and 75.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint64-array
+        minItems: 6
+        maxItems: 128
+    required:
+      - reg
+      - adi,sensor-type
+      - adi,rsense-handle
+
+patternProperties:
+  "^thermistor@([1-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a thermistor sensor which is connected to one of the device channels.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+          Note that, for differential thermistors, the minimum is 2.
+        minimum: 1
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the type of thermistor connected to the device.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [19 20 21 22 23 24 25]
+        maxItems: 1
+
+      adi,rsense-handle:
+        description: |
+          Phandle pointing to a rsense object associated with this thermistor.
+        $ref: "/schemas/types.yaml#/definitions/phandle"
+        maxItems: 1
+
+      adi,sensor-config:
+        description: |
+          Raw value which set's the sensor configuration. Look at table 52 of the
+          datasheet for how to set this value for thermistors.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32
+          - enum: [0 1 2 4]
+        maxItems: 1
+
+      adi,excitation-current:
+        description: |
+          This property controls the magnitude of the excitation current applied
+          to the thermistor. Look at table 53 of the datasheet for more info.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint32-array
+          - enum: [1 2 3 4 5 6 7 8 9 10 11 12]
+        maxItems: 1
+
+      adi,custom-sensor:
+        description: |
+          This is a table, where each entry should be a pair of resistance(ohm)-temperature(K).
+          The entries added here are in uohm and uK only for custom thermistors.
+          For more details look at table 78 and 79.
+          Steinhart-Hart coefficients are also supported and can be programmed into the
+          device memory using this property. For Steinhart sensors, this table has a constant
+          size of 6 entries (defining the coefficients) and the values are given in the raw format.
+          Look at table 82 for more information.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint64-array
+        minItems: 6
+        maxItems: 128
+    required:
+      - reg
+      - adi,sensor-type
+      - adi,rsense-handle
+
+patternProperties:
+  "^adc@([1-9]|1[0-9]|20)$":
+    type: object
+    description: Represents a channel which is being used as a direct adc.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+          Note that, for differential adc's, the minimum is 2.
+        minimum: 1
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the sensor as a direct adc.
+        const: 30
+        maxItems: 1
+
+      adi,single-ended:
+        description: |
+          Boolean property which set's the adc as single-ended.
+        type: boolean
+
+    required:
+      - reg
+      - adi,sensor-type
+
+patternProperties:
+  "^rsense@([2-9]|1[0-9]|20)$":
+    type: object
+    description: |
+      Represents a rsense which is connected to one of the device channels.
+      Rsense are used by thermistors and RTD's.
+
+    properties:
+      reg:
+        description: |
+          The channel number. It can be connected to one of the 20 channels of the device.
+        minimum: 2
+        maximum: 20
+        maxItems: 1
+
+      adi,sensor-type:
+        description: |
+          Identifies the sensor as a rsense.
+        const: 29
+        maxItems: 1
+
+      adi,rsense-val-micro-ohms:
+        description: |
+          Sets the value of the sense resistor. Look at table 20 of the datasheet
+          for information.
+        allOf:
+          - $ref: /schemas/types.yaml#/definitions/uint64
+        maxItems: 1
+
+    required:
+      - reg
+      - adi,sensor-type
+      - adi, rsense-val
+
+required:
+  - compatible
+  - reg
+  - interrupts
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    spi0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        sensor_ltc2983: ltc2983@0 {
+                compatible = "adi,ltc2983";
+                reg = <0>;
+
+                #address-cells = <1>;
+                #size-cells = <0>;
+
+                adi,temperature-celcius;
+                interrupts = <20 IRQ_TYPE_EDGE_RISING>;
+                interrupt-parent = <&gpio>;
+
+                thermocouple@18 {
+                        reg = <18>;
+                        adi,sensor-type = <8>; //Type B
+                        adi,sensor-config = <1>; //Differential, open-circuit current
+                        adi,cold-junction-handle = <&diode5>;
+                };
+
+                diode5: diode@5 {
+                        reg = <5>;
+                        adi,sensor-type = <28>;
+                };
+
+                rsense2: rsense@2 {
+                        reg = <2>;
+                        adi,sensor-type = <29>;
+                        adi,rsense-val-micro-ohms = /bits/ 64 <1200000000>; //1.2Kohms
+                };
+
+                rtd@14 {
+                        reg = <14>;
+                        adi,sensor-type = <15>; //PT1000
+                        /*2-wire, internal gnd, no current rotation*/
+                        adi,sensor-config = <1>;
+                        adi,excitation-current = <7>; //500uA
+                        adi,rsense-handle = <&rsense2>;
+                };
+
+                adc@10 {
+                        reg = <10>;
+                        adi,sensor-type = <30>;
+                        adi,single-ended;
+                };
+
+                thermistor@12 {
+                        reg = <12>;
+                        adi,sensor-type = <26>; //Steinhart
+                        adi,rsense-handle = <&rsense2>;
+                        adi,custom-sensor = /bits/ 64 <0x00F371EC 0x12345678
+                                        0x2C0F8733 0x10018C66 0xA0FEACCD
+                                        0x90021D99>; //6 entries
+                };
+
+                thermocouple@20 {
+                        reg = <20>;
+                        adi,sensor-type = <9>; //custom thermocouple
+                        adi,sensor-config = <8>; //single-ended
+                        adi,custom-sensor = /bits/ 64
+                                 <(-50220000) 0
+                                  (-30200000) 99100000
+                                  (-5300000) 135400000
+                                  0 273150000
+                                  40200000 361200000
+                                  55300000 522100000
+                                  88300000 720300000
+                                  132200000 811200000
+                                  188700000 922500000
+                                  460400000 1000000000>; //10 pairs
+               };
+
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index 14a256e785ca..f747a9dc27f5 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -9497,6 +9497,7 @@ W:	http://ez.analog.com/community/linux-device-drivers
 L:	linux-iio@vger.kernel.org
 S:	Supported
 F:	drivers/iio/temperature/ltc2983.c
+F:	Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
 
 LTC4261 HARDWARE MONITOR DRIVER
 M:	Guenter Roeck <linux@roeck-us.net>
-- 
2.23.0


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation
  2019-09-09 14:45 ` [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation Nuno Sá
@ 2019-09-13 14:36   ` Rob Herring
  2019-09-15 11:07     ` Jonathan Cameron
  0 siblings, 1 reply; 11+ messages in thread
From: Rob Herring @ 2019-09-13 14:36 UTC (permalink / raw)
  To: Nuno Sá
  Cc: linux-iio, devicetree, jic23, knaack.h, lars, pmeerw, mark.rutland

On Mon, Sep 09, 2019 at 04:45:50PM +0200, Nuno Sá wrote:
> Document the LTC2983 temperature sensor devicetree bindings.
> 
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> ---
>  .../bindings/iio/temperature/adi,ltc2983.yaml | 442 ++++++++++++++++++
>  MAINTAINERS                                   |   1 +
>  2 files changed, 443 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> 
> diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> new file mode 100644
> index 000000000000..2b468b3ed177
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> @@ -0,0 +1,442 @@
> +# SPDX-License-Identifier: GPL-2.0
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Analog Devices LTC2983 Multi-sensor Temperature system
> +
> +maintainers:
> +  - Nuno Sá <nuno.sa@analog.com>
> +
> +description: |
> +  Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
> +  https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,ltc2983
> +
> +  reg:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  adi,temperature-celcius:
> +    description:
> +      If this property is present, the temperature is reported in Celsius.
> +    type: boolean
> +    maxItems: 1

It's a boolean, not an array so 'maxItems' doesn't make sense.

Running 'make dt_binding_check' should tell you this. You may need to 
update dt-schema install though.

> +
> +  adi,mux-delay-config:
> +    description:
> +      The LTC2983 performs 2 or 3 internal conversion cycles per temperature result.
> +      Each conversion cycle is performed with different excitation and input multiplexer
> +      configurations. Prior to each conversion, these excitation circuits and input
> +      switch configurations are changed and an internal 1ms delay ensures settling prior
> +      to the conversion cycle in most cases. An extra delay can be configured using this
> +      property. The value written here is multiplied by 100us.
> +    allOf:
> +      - $ref: /schemas/types.yaml#/definitions/uint32
> +      - maximum: 255
> +        maxItems: 1

Drop this.

> +
> +  adi,filter-notch-freq:
> +    description:
> +      Set's the default setting of the digital filter. The default is simultaneous
> +      50/60Hz rejection.
> +    allOf:
> +      - $ref: /schemas/types.yaml#/definitions/uint32
> +      - enum: [0, 1, 2]
> +    maxItems: 1

Drop this.

> +
> +  '#address-cells':
> +    const: 1
> +
> +  '#size-cells':
> +    const: 0
> +
> +patternProperties:
> +  "^thermocouple@([1-9]|1[0-9]|20)$":
> +    type: object
> +    description: Represents a thermocouple sensor which is connected to one of the device channels.

Wrap lines at 80 char.

> +
> +    properties:
> +      reg:
> +        description: |
> +          The channel number. It can be connected to one of the 20 channels of the device.
> +          Note that, for differential thermocouples, the minimum is 2.
> +        minimum: 1
> +        maximum: 20
> +        maxItems: 1

Drop this and pretty much everywhere else that is never an array.

> +
> +      adi,sensor-type:
> +        description: |
> +           Identifies the type of thermocouple connected to the device.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [1 2 3 4 5 6 7 8]

Missing commas which may not even parse. Maybe be consistent with 
elsewhere and use minimum and maximum.

> +        maxItems: 1
> +
> +      adi,sensor-config:
> +        description: |
> +          Raw value which set's the sensor configuration. Look at table 14 of the
> +          datasheet for how to set this value for thermocouples.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - minimum: 1
> +          - maximun: 15
> +        maxItems: 1
> +
> +      adi,cold-junction-handle:
> +        description: |
> +          Phandle which points to a sensor object responsible for measuring the
> +          thermocouple cold junction temperature.
> +        $ref: "/schemas/types.yaml#/definitions/phandle"
> +        maxItems: 1
> +
> +      adi,custom-sensor:
> +        description: |
> +          This is a table, where each entry should be a pair of voltage(mv)-temperature(K).
> +          The entries must be given in nv and uK so that, the original values must be
> +          multiplied by 1000000. For more details look at table 69 and 70.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/int64-array
> +        minItems: 6
> +        maxItems: 128
> +    required:
> +      - reg
> +      - adi,sensor-type
> +
> +patternProperties:
> +  "^diode@([1-9]|1[0-9]|20)$":
> +    type: object
> +    description: Represents a diode sensor which is connected to one of the device channels.
> +
> +    properties:
> +      reg:
> +        description:
> +          The channel number. It can be connected to one of the 20 channels of the device.
> +          Note that, for differential diodes, the minimum is 2.
> +        minimum: 1
> +        maximum: 20
> +        maxItems: 1
> +
> +      adi,sensor-type:
> +        description: |
> +          Identifies the sensor as a diode.
> +        const: 28
> +        maxItems: 1
> +
> +      adi,sensor-config:
> +        description: |
> +          Raw value which set's the sensor configuration. Look at table 17 of the
> +          datasheet for how to set this value for diodes.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [0 1 2 3 4 5 6 7]
> +        maxItems: 1
> +
> +      adi,excitation-current:
> +        description: |
> +          This property controls the magnitude of the excitation current applied
> +          to the diode. Look at table 19 of the datasheet for more info.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [0 1 2 3]
> +        maxItems: 1
> +
> +      adi,ideal-factor-value:
> +        description: |
> +          This property sets the diode ideality factor. The real value must be
> +          multiplied by 1000000 to remove the fractional part. For more information
> +          look at table 20 of the datasheet.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +        maxItems: 1
> +
> +    required:
> +      - reg
> +      - adi,sensor-type
> +
> +patternProperties:
> +  "^rtd@([2-9]|1[0-9]|20)$":
> +    type: object
> +    description: Represents a rtd sensor which is connected to one of the device channels.
> +
> +    properties:
> +      reg:
> +        description: |
> +          The channel number. It can be connected to one of the 20 channels of the device.
> +        minimum: 2
> +        maximum: 20
> +        maxItems: 1

As this is pretty much the same for all child nodes, make a pattern that 
matches all child nodes and put this there rather than duplicating it. 
Then you only need 'minimum: 2' in the cases needing that.

> +
> +      adi,sensor-type:
> +        description: |
> +          Identifies the type of RTD connected to the device.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [10 11 12 13 14 15 16 17]
> +        maxItems: 1
> +
> +      adi,rsense-handle:
> +        description: |
> +          Phandle pointing to a rsense object associated with this RTD.
> +        $ref: "/schemas/types.yaml#/definitions/phandle"
> +        maxItems: 1
> +
> +      adi,sensor-config:
> +        description: |
> +          Raw value which set's the sensor configuration. Look at table 28 of the
> +          datasheet for how to set this value for RTD's.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [0 1 4 5 8 9 10 12 13 14]
> +        maxItems: 1
> +
> +      adi,excitation-current:
> +        description: |
> +          This property controls the magnitude of the excitation current applied
> +          to the RTD. Look at table 29 of the datasheet for more info.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [1 2 3 4 5 6 7 8]
> +        maxItems: 1
> +
> +      adi,rtd-curve:
> +        description: |
> +          This property set the RTD curve used and the corresponding Callendar-Van
> +          Dusen constants. Look at table 30 of the datasheet.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [0 1 2 3]
> +        maxItems: 1
> +
> +      adi,custom-sensor:
> +        description: |
> +          This is a table, where each entry should be a pair of resistance(ohm)-temperature(K).
> +          The entries added here are in uohm and uK. For more details values look at table 74 and 75.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint64-array
> +        minItems: 6
> +        maxItems: 128
> +    required:
> +      - reg
> +      - adi,sensor-type
> +      - adi,rsense-handle
> +
> +patternProperties:
> +  "^thermistor@([1-9]|1[0-9]|20)$":
> +    type: object
> +    description: Represents a thermistor sensor which is connected to one of the device channels.
> +
> +    properties:
> +      reg:
> +        description: |
> +          The channel number. It can be connected to one of the 20 channels of the device.
> +          Note that, for differential thermistors, the minimum is 2.
> +        minimum: 1
> +        maximum: 20
> +        maxItems: 1
> +
> +      adi,sensor-type:
> +        description: |
> +          Identifies the type of thermistor connected to the device.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [19 20 21 22 23 24 25]
> +        maxItems: 1
> +
> +      adi,rsense-handle:
> +        description: |
> +          Phandle pointing to a rsense object associated with this thermistor.
> +        $ref: "/schemas/types.yaml#/definitions/phandle"
> +        maxItems: 1
> +
> +      adi,sensor-config:
> +        description: |
> +          Raw value which set's the sensor configuration. Look at table 52 of the
> +          datasheet for how to set this value for thermistors.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32
> +          - enum: [0 1 2 4]
> +        maxItems: 1
> +
> +      adi,excitation-current:
> +        description: |
> +          This property controls the magnitude of the excitation current applied
> +          to the thermistor. Look at table 53 of the datasheet for more info.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint32-array
> +          - enum: [1 2 3 4 5 6 7 8 9 10 11 12]
> +        maxItems: 1
> +
> +      adi,custom-sensor:
> +        description: |
> +          This is a table, where each entry should be a pair of resistance(ohm)-temperature(K).
> +          The entries added here are in uohm and uK only for custom thermistors.
> +          For more details look at table 78 and 79.
> +          Steinhart-Hart coefficients are also supported and can be programmed into the
> +          device memory using this property. For Steinhart sensors, this table has a constant
> +          size of 6 entries (defining the coefficients) and the values are given in the raw format.
> +          Look at table 82 for more information.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint64-array
> +        minItems: 6
> +        maxItems: 128
> +    required:
> +      - reg
> +      - adi,sensor-type
> +      - adi,rsense-handle
> +
> +patternProperties:
> +  "^adc@([1-9]|1[0-9]|20)$":
> +    type: object
> +    description: Represents a channel which is being used as a direct adc.
> +
> +    properties:
> +      reg:
> +        description: |
> +          The channel number. It can be connected to one of the 20 channels of the device.
> +          Note that, for differential adc's, the minimum is 2.
> +        minimum: 1
> +        maximum: 20
> +        maxItems: 1
> +
> +      adi,sensor-type:
> +        description: |
> +          Identifies the sensor as a direct adc.
> +        const: 30
> +        maxItems: 1
> +
> +      adi,single-ended:
> +        description: |
> +          Boolean property which set's the adc as single-ended.
> +        type: boolean
> +
> +    required:
> +      - reg
> +      - adi,sensor-type
> +
> +patternProperties:
> +  "^rsense@([2-9]|1[0-9]|20)$":
> +    type: object
> +    description: |
> +      Represents a rsense which is connected to one of the device channels.
> +      Rsense are used by thermistors and RTD's.
> +
> +    properties:
> +      reg:
> +        description: |
> +          The channel number. It can be connected to one of the 20 channels of the device.
> +        minimum: 2
> +        maximum: 20
> +        maxItems: 1
> +
> +      adi,sensor-type:
> +        description: |
> +          Identifies the sensor as a rsense.
> +        const: 29
> +        maxItems: 1
> +
> +      adi,rsense-val-micro-ohms:
> +        description: |
> +          Sets the value of the sense resistor. Look at table 20 of the datasheet
> +          for information.
> +        allOf:
> +          - $ref: /schemas/types.yaml#/definitions/uint64
> +        maxItems: 1
> +
> +    required:
> +      - reg
> +      - adi,sensor-type
> +      - adi, rsense-val
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +    spi0 {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        sensor_ltc2983: ltc2983@0 {
> +                compatible = "adi,ltc2983";
> +                reg = <0>;
> +
> +                #address-cells = <1>;
> +                #size-cells = <0>;
> +
> +                adi,temperature-celcius;
> +                interrupts = <20 IRQ_TYPE_EDGE_RISING>;
> +                interrupt-parent = <&gpio>;
> +
> +                thermocouple@18 {
> +                        reg = <18>;
> +                        adi,sensor-type = <8>; //Type B
> +                        adi,sensor-config = <1>; //Differential, open-circuit current
> +                        adi,cold-junction-handle = <&diode5>;
> +                };
> +
> +                diode5: diode@5 {
> +                        reg = <5>;
> +                        adi,sensor-type = <28>;
> +                };
> +
> +                rsense2: rsense@2 {
> +                        reg = <2>;
> +                        adi,sensor-type = <29>;
> +                        adi,rsense-val-micro-ohms = /bits/ 64 <1200000000>; //1.2Kohms
> +                };
> +
> +                rtd@14 {
> +                        reg = <14>;
> +                        adi,sensor-type = <15>; //PT1000
> +                        /*2-wire, internal gnd, no current rotation*/
> +                        adi,sensor-config = <1>;
> +                        adi,excitation-current = <7>; //500uA
> +                        adi,rsense-handle = <&rsense2>;
> +                };
> +
> +                adc@10 {
> +                        reg = <10>;
> +                        adi,sensor-type = <30>;
> +                        adi,single-ended;
> +                };
> +
> +                thermistor@12 {
> +                        reg = <12>;
> +                        adi,sensor-type = <26>; //Steinhart
> +                        adi,rsense-handle = <&rsense2>;
> +                        adi,custom-sensor = /bits/ 64 <0x00F371EC 0x12345678
> +                                        0x2C0F8733 0x10018C66 0xA0FEACCD
> +                                        0x90021D99>; //6 entries
> +                };
> +
> +                thermocouple@20 {
> +                        reg = <20>;
> +                        adi,sensor-type = <9>; //custom thermocouple
> +                        adi,sensor-config = <8>; //single-ended
> +                        adi,custom-sensor = /bits/ 64
> +                                 <(-50220000) 0
> +                                  (-30200000) 99100000
> +                                  (-5300000) 135400000
> +                                  0 273150000
> +                                  40200000 361200000
> +                                  55300000 522100000
> +                                  88300000 720300000
> +                                  132200000 811200000
> +                                  188700000 922500000
> +                                  460400000 1000000000>; //10 pairs
> +               };
> +
> +        };
> +    };
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 14a256e785ca..f747a9dc27f5 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9497,6 +9497,7 @@ W:	http://ez.analog.com/community/linux-device-drivers
>  L:	linux-iio@vger.kernel.org
>  S:	Supported
>  F:	drivers/iio/temperature/ltc2983.c
> +F:	Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
>  
>  LTC4261 HARDWARE MONITOR DRIVER
>  M:	Guenter Roeck <linux@roeck-us.net>
> -- 
> 2.23.0
> 


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation
  2019-09-13 14:36   ` Rob Herring
@ 2019-09-15 11:07     ` Jonathan Cameron
  2019-09-16 15:20       ` Sa, Nuno
  0 siblings, 1 reply; 11+ messages in thread
From: Jonathan Cameron @ 2019-09-15 11:07 UTC (permalink / raw)
  To: Rob Herring
  Cc: Nuno Sá,
	linux-iio, devicetree, knaack.h, lars, pmeerw, mark.rutland

On Fri, 13 Sep 2019 15:36:21 +0100
Rob Herring <robh@kernel.org> wrote:

> On Mon, Sep 09, 2019 at 04:45:50PM +0200, Nuno Sá wrote:
> > Document the LTC2983 temperature sensor devicetree bindings.
> > 
> > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > ---
> >  .../bindings/iio/temperature/adi,ltc2983.yaml | 442 ++++++++++++++++++
> >  MAINTAINERS                                   |   1 +
> >  2 files changed, 443 insertions(+)
> >  create mode 100644 Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > 
> > diff --git a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > new file mode 100644
> > index 000000000000..2b468b3ed177
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> > @@ -0,0 +1,442 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +%YAML 1.2
> > +---
> > +$id: http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
> > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > +
> > +title: Analog Devices LTC2983 Multi-sensor Temperature system
> > +
> > +maintainers:
> > +  - Nuno Sá <nuno.sa@analog.com>
> > +
> > +description: |
> > +  Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
> > +  https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
> > +
> > +properties:
> > +  compatible:
> > +    enum:
> > +      - adi,ltc2983
> > +
> > +  reg:
> > +    maxItems: 1
> > +
> > +  interrupts:
> > +    maxItems: 1
> > +
> > +  adi,temperature-celcius:
> > +    description:
> > +      If this property is present, the temperature is reported in Celsius.
> > +    type: boolean
> > +    maxItems: 1  
> 
> It's a boolean, not an array so 'maxItems' doesn't make sense.
> 
> Running 'make dt_binding_check' should tell you this. You may need to 
> update dt-schema install though.
> 
> > +
> > +  adi,mux-delay-config:
> > +    description:
> > +      The LTC2983 performs 2 or 3 internal conversion cycles per temperature result.
> > +      Each conversion cycle is performed with different excitation and input multiplexer
> > +      configurations. Prior to each conversion, these excitation circuits and input
> > +      switch configurations are changed and an internal 1ms delay ensures settling prior
> > +      to the conversion cycle in most cases. An extra delay can be configured using this
> > +      property. The value written here is multiplied by 100us.

Make this adi,mux-delay-config-us and state it is rounded to nearest 100us.

> > +    allOf:
> > +      - $ref: /schemas/types.yaml#/definitions/uint32
> > +      - maximum: 255
> > +        maxItems: 1  
> 
> Drop this.
> 
> > +
> > +  adi,filter-notch-freq:
> > +    description:
> > +      Set's the default setting of the digital filter. The default is simultaneous
> > +      50/60Hz rejection.
> > +    allOf:
> > +      - $ref: /schemas/types.yaml#/definitions/uint32
> > +      - enum: [0, 1, 2]
> > +    maxItems: 1  
> 
> Drop this.
> 
> > +
> > +  '#address-cells':
> > +    const: 1
> > +
> > +  '#size-cells':
> > +    const: 0
> > +
> > +patternProperties:
> > +  "^thermocouple@([1-9]|1[0-9]|20)$":
> > +    type: object
> > +    description: Represents a thermocouple sensor which is connected to one of the device channels.  
> 
> Wrap lines at 80 char.
> 
> > +
> > +    properties:
> > +      reg:
> > +        description: |
> > +          The channel number. It can be connected to one of the 20 channels of the device.
> > +          Note that, for differential thermocouples, the minimum is 2.
> > +        minimum: 1
> > +        maximum: 20
> > +        maxItems: 1  
> 
> Drop this and pretty much everywhere else that is never an array.
> 
> > +
> > +      adi,sensor-type:
> > +        description: |
> > +           Identifies the type of thermocouple connected to the device.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [1 2 3 4 5 6 7 8]  
> 
> Missing commas which may not even parse. Maybe be consistent with 
> elsewhere and use minimum and maximum.
> 
> > +        maxItems: 1
> > +
> > +      adi,sensor-config:
> > +        description: |
> > +          Raw value which set's the sensor configuration. Look at table 14 of the
> > +          datasheet for how to set this value for thermocouples.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - minimum: 1
> > +          - maximun: 15
> > +        maxItems: 1
> > +
> > +      adi,cold-junction-handle:
> > +        description: |
> > +          Phandle which points to a sensor object responsible for measuring the
> > +          thermocouple cold junction temperature.
> > +        $ref: "/schemas/types.yaml#/definitions/phandle"
> > +        maxItems: 1
> > +
> > +      adi,custom-sensor:
> > +        description: |
> > +          This is a table, where each entry should be a pair of voltage(mv)-temperature(K).
> > +          The entries must be given in nv and uK so that, the original values must be
> > +          multiplied by 1000000. For more details look at table 69 and 70.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/int64-array
> > +        minItems: 6
> > +        maxItems: 128
> > +    required:
> > +      - reg
> > +      - adi,sensor-type
> > +
> > +patternProperties:
> > +  "^diode@([1-9]|1[0-9]|20)$":
> > +    type: object
> > +    description: Represents a diode sensor which is connected to one of the device channels.
> > +
> > +    properties:
> > +      reg:
> > +        description:
> > +          The channel number. It can be connected to one of the 20 channels of the device.
> > +          Note that, for differential diodes, the minimum is 2.
> > +        minimum: 1
> > +        maximum: 20
> > +        maxItems: 1
> > +
> > +      adi,sensor-type:
> > +        description: |
> > +          Identifies the sensor as a diode.
> > +        const: 28
> > +        maxItems: 1
> > +
> > +      adi,sensor-config:
> > +        description: |
> > +          Raw value which set's the sensor configuration. Look at table 17 of the
> > +          datasheet for how to set this value for diodes.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [0 1 2 3 4 5 6 7]
> > +        maxItems: 1
> > +
> > +      adi,excitation-current:
> > +        description: |
> > +          This property controls the magnitude of the excitation current applied
> > +          to the diode. Look at table 19 of the datasheet for more info.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [0 1 2 3]
> > +        maxItems: 1
> > +
> > +      adi,ideal-factor-value:
> > +        description: |
> > +          This property sets the diode ideality factor. The real value must be
> > +          multiplied by 1000000 to remove the fractional part. For more information
> > +          look at table 20 of the datasheet.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +        maxItems: 1
> > +
> > +    required:
> > +      - reg
> > +      - adi,sensor-type
> > +
> > +patternProperties:
> > +  "^rtd@([2-9]|1[0-9]|20)$":
> > +    type: object
> > +    description: Represents a rtd sensor which is connected to one of the device channels.
> > +
> > +    properties:
> > +      reg:
> > +        description: |
> > +          The channel number. It can be connected to one of the 20 channels of the device.
> > +        minimum: 2
> > +        maximum: 20
> > +        maxItems: 1  
> 
> As this is pretty much the same for all child nodes, make a pattern that 
> matches all child nodes and put this there rather than duplicating it. 
> Then you only need 'minimum: 2' in the cases needing that.
> 
> > +
> > +      adi,sensor-type:
> > +        description: |
> > +          Identifies the type of RTD connected to the device.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [10 11 12 13 14 15 16 17]
> > +        maxItems: 1
> > +
> > +      adi,rsense-handle:
> > +        description: |
> > +          Phandle pointing to a rsense object associated with this RTD.
> > +        $ref: "/schemas/types.yaml#/definitions/phandle"
> > +        maxItems: 1
> > +
> > +      adi,sensor-config:
> > +        description: |
> > +          Raw value which set's the sensor configuration. Look at table 28 of the
> > +          datasheet for how to set this value for RTD's.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [0 1 4 5 8 9 10 12 13 14]
> > +        maxItems: 1
> > +
> > +      adi,excitation-current:
> > +        description: |
> > +          This property controls the magnitude of the excitation current applied
> > +          to the RTD. Look at table 29 of the datasheet for more info.

Any way we can make this real units?  Can list valid value here.

> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [1 2 3 4 5 6 7 8]
> > +        maxItems: 1
> > +
> > +      adi,rtd-curve:
> > +        description: |
> > +          This property set the RTD curve used and the corresponding Callendar-Van
> > +          Dusen constants. Look at table 30 of the datasheet.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [0 1 2 3]
> > +        maxItems: 1
> > +
> > +      adi,custom-sensor:
> > +        description: |
> > +          This is a table, where each entry should be a pair of resistance(ohm)-temperature(K).
> > +          The entries added here are in uohm and uK. For more details values look at table 74 and 75.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint64-array
> > +        minItems: 6
> > +        maxItems: 128
> > +    required:
> > +      - reg
> > +      - adi,sensor-type
> > +      - adi,rsense-handle
> > +
> > +patternProperties:
> > +  "^thermistor@([1-9]|1[0-9]|20)$":
> > +    type: object
> > +    description: Represents a thermistor sensor which is connected to one of the device channels.
> > +
> > +    properties:
> > +      reg:
> > +        description: |
> > +          The channel number. It can be connected to one of the 20 channels of the device.
> > +          Note that, for differential thermistors, the minimum is 2.
> > +        minimum: 1
> > +        maximum: 20
> > +        maxItems: 1
> > +
> > +      adi,sensor-type:
> > +        description: |
> > +          Identifies the type of thermistor connected to the device.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [19 20 21 22 23 24 25]
> > +        maxItems: 1
> > +
> > +      adi,rsense-handle:
> > +        description: |
> > +          Phandle pointing to a rsense object associated with this thermistor.
> > +        $ref: "/schemas/types.yaml#/definitions/phandle"
> > +        maxItems: 1
> > +
> > +      adi,sensor-config:
> > +        description: |
> > +          Raw value which set's the sensor configuration. Look at table 52 of the
> > +          datasheet for how to set this value for thermistors.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > +          - enum: [0 1 2 4]
> > +        maxItems: 1
> > +
> > +      adi,excitation-current:
> > +        description: |
> > +          This property controls the magnitude of the excitation current applied
> > +          to the thermistor. Look at table 53 of the datasheet for more info.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint32-array
> > +          - enum: [1 2 3 4 5 6 7 8 9 10 11 12]
> > +        maxItems: 1
> > +
> > +      adi,custom-sensor:
> > +        description: |
> > +          This is a table, where each entry should be a pair of resistance(ohm)-temperature(K).
> > +          The entries added here are in uohm and uK only for custom thermistors.
> > +          For more details look at table 78 and 79.
> > +          Steinhart-Hart coefficients are also supported and can be programmed into the
> > +          device memory using this property. For Steinhart sensors, this table has a constant
> > +          size of 6 entries (defining the coefficients) and the values are given in the raw format.
> > +          Look at table 82 for more information.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint64-array
> > +        minItems: 6
> > +        maxItems: 128
> > +    required:
> > +      - reg
> > +      - adi,sensor-type
> > +      - adi,rsense-handle
> > +
> > +patternProperties:
> > +  "^adc@([1-9]|1[0-9]|20)$":
> > +    type: object
> > +    description: Represents a channel which is being used as a direct adc.
> > +
> > +    properties:
> > +      reg:
> > +        description: |
> > +          The channel number. It can be connected to one of the 20 channels of the device.
> > +          Note that, for differential adc's, the minimum is 2.
> > +        minimum: 1
> > +        maximum: 20
> > +        maxItems: 1
> > +
> > +      adi,sensor-type:
> > +        description: |
> > +          Identifies the sensor as a direct adc.
> > +        const: 30
> > +        maxItems: 1
> > +
> > +      adi,single-ended:
> > +        description: |
> > +          Boolean property which set's the adc as single-ended.
> > +        type: boolean
> > +
> > +    required:
> > +      - reg
> > +      - adi,sensor-type
> > +
> > +patternProperties:
> > +  "^rsense@([2-9]|1[0-9]|20)$":
> > +    type: object
> > +    description: |
> > +      Represents a rsense which is connected to one of the device channels.
> > +      Rsense are used by thermistors and RTD's.
> > +
> > +    properties:
> > +      reg:
> > +        description: |
> > +          The channel number. It can be connected to one of the 20 channels of the device.
> > +        minimum: 2
> > +        maximum: 20
> > +        maxItems: 1
> > +
> > +      adi,sensor-type:
> > +        description: |
> > +          Identifies the sensor as a rsense.
> > +        const: 29
> > +        maxItems: 1
> > +
> > +      adi,rsense-val-micro-ohms:
> > +        description: |
> > +          Sets the value of the sense resistor. Look at table 20 of the datasheet
> > +          for information.
> > +        allOf:
> > +          - $ref: /schemas/types.yaml#/definitions/uint64
> > +        maxItems: 1
> > +
> > +    required:
> > +      - reg
> > +      - adi,sensor-type
> > +      - adi, rsense-val
> > +
> > +required:
> > +  - compatible
> > +  - reg
> > +  - interrupts
> > +
> > +examples:
> > +  - |
> > +    #include <dt-bindings/interrupt-controller/irq.h>
> > +    spi0 {
> > +        #address-cells = <1>;
> > +        #size-cells = <0>;
> > +
> > +        sensor_ltc2983: ltc2983@0 {
> > +                compatible = "adi,ltc2983";
> > +                reg = <0>;
> > +
> > +                #address-cells = <1>;
> > +                #size-cells = <0>;
> > +
> > +                adi,temperature-celcius;
> > +                interrupts = <20 IRQ_TYPE_EDGE_RISING>;
> > +                interrupt-parent = <&gpio>;
> > +
> > +                thermocouple@18 {
> > +                        reg = <18>;
> > +                        adi,sensor-type = <8>; //Type B
> > +                        adi,sensor-config = <1>; //Differential, open-circuit current
> > +                        adi,cold-junction-handle = <&diode5>;
> > +                };
> > +
> > +                diode5: diode@5 {
> > +                        reg = <5>;
> > +                        adi,sensor-type = <28>;
> > +                };
> > +
> > +                rsense2: rsense@2 {
> > +                        reg = <2>;
> > +                        adi,sensor-type = <29>;
> > +                        adi,rsense-val-micro-ohms = /bits/ 64 <1200000000>; //1.2Kohms
> > +                };
> > +
> > +                rtd@14 {
> > +                        reg = <14>;
> > +                        adi,sensor-type = <15>; //PT1000
> > +                        /*2-wire, internal gnd, no current rotation*/
> > +                        adi,sensor-config = <1>;
> > +                        adi,excitation-current = <7>; //500uA
> > +                        adi,rsense-handle = <&rsense2>;
> > +                };
> > +
> > +                adc@10 {
> > +                        reg = <10>;
> > +                        adi,sensor-type = <30>;
> > +                        adi,single-ended;
> > +                };
> > +
> > +                thermistor@12 {
> > +                        reg = <12>;
> > +                        adi,sensor-type = <26>; //Steinhart
> > +                        adi,rsense-handle = <&rsense2>;
> > +                        adi,custom-sensor = /bits/ 64 <0x00F371EC 0x12345678
> > +                                        0x2C0F8733 0x10018C66 0xA0FEACCD
> > +                                        0x90021D99>; //6 entries
> > +                };
> > +
> > +                thermocouple@20 {
> > +                        reg = <20>;
> > +                        adi,sensor-type = <9>; //custom thermocouple
> > +                        adi,sensor-config = <8>; //single-ended
> > +                        adi,custom-sensor = /bits/ 64
> > +                                 <(-50220000) 0
> > +                                  (-30200000) 99100000
> > +                                  (-5300000) 135400000
> > +                                  0 273150000
> > +                                  40200000 361200000
> > +                                  55300000 522100000
> > +                                  88300000 720300000
> > +                                  132200000 811200000
> > +                                  188700000 922500000
> > +                                  460400000 1000000000>; //10 pairs
> > +               };
> > +
> > +        };
> > +    };
> > +...
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 14a256e785ca..f747a9dc27f5 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -9497,6 +9497,7 @@ W:	http://ez.analog.com/community/linux-device-drivers
> >  L:	linux-iio@vger.kernel.org
> >  S:	Supported
> >  F:	drivers/iio/temperature/ltc2983.c
> > +F:	Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml
> >  
> >  LTC4261 HARDWARE MONITOR DRIVER
> >  M:	Guenter Roeck <linux@roeck-us.net>
> > -- 
> > 2.23.0
> >   
> 


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 1/2] iio: temperature: Add support for LTC2983
  2019-09-09 14:45 [PATCH 1/2] iio: temperature: Add support for LTC2983 Nuno Sá
  2019-09-09 14:45 ` [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation Nuno Sá
@ 2019-09-15 11:27 ` Jonathan Cameron
  2019-09-16  9:37   ` Sa, Nuno
  1 sibling, 1 reply; 11+ messages in thread
From: Jonathan Cameron @ 2019-09-15 11:27 UTC (permalink / raw)
  To: Nuno Sá
  Cc: linux-iio, devicetree, knaack.h, lars, pmeerw, robh+dt, mark.rutland

On Mon, 9 Sep 2019 16:45:49 +0200
Nuno Sá <nuno.sa@analog.com> wrote:

> The LTC2983 is a Multi-Sensor High Accuracy Digital Temperature
> Measurement System. It measures a wide variety of temperature sensors and
> digitally outputs the result, in °C or °F, with 0.1°C accuracy and
> 0.001°C resolution. It can measure the temperature of all standard
> thermocouples (type B,E,J,K,N,S,R,T), standard 2-,3-,4-wire RTDs,
> thermistors and diodes.
> 
> Signed-off-by: Nuno Sá <nuno.sa@analog.com>
Some comments inline.  Main concern is around the interface, rest is minor
stuff.

Jonathan

> ---
>  .../testing/sysfs-bus-iio-temperature-ltc2983 |   43 +
>  MAINTAINERS                                   |    7 +
>  drivers/iio/temperature/Kconfig               |   10 +
>  drivers/iio/temperature/Makefile              |    1 +
>  drivers/iio/temperature/ltc2983.c             | 1327 +++++++++++++++++
>  5 files changed, 1388 insertions(+)
>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983
>  create mode 100644 drivers/iio/temperature/ltc2983.c
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983 b/Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983
> new file mode 100644
> index 000000000000..3ad3440c0986
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983
> @@ -0,0 +1,43 @@
> +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_thermistor_raw
For each of these, I presume we know which type of device is attached at any time?
Using the channel naming to convey this (and I assume the fact that different
conversions need to be done in userspace?) is a bit messy.  If we need
to convey the channel type, then a separate in_tempY_mode attribute may make more
sense.  That would keep this ABI 'closer' to standard. Software that just logs
an unprocessed value could just work for example.

I'm not sure I've totally understood what is going on here though.

> +KernelVersion:
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reads the raw (unscaled no bias removal etc) temperature from
> +		channel Y. The value is returned by a Thermistor sensor measurement.
> +		Units after application of scale are degrees Celsius or Fahrenheit
> +		depending on the device configuration.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_thermocouple_raw
> +KernelVersion:
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reads the raw (unscaled no bias removal etc) temperature from
> +		channel Y. The value is returned by a Thermocouple sensor measurement.
> +		Units after application of scale are degrees Celsius or Fahrenheit
> +		depending on the device configuration.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_rtd_raw
> +KernelVersion:
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reads the raw (unscaled no bias removal etc) temperature from
> +		channel Y. The value is returned by a RTD sensor measurement.
> +		Units after application of scale are degrees Celsius or Fahrenheit
> +		depending on the device configuration.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_diode_raw
> +KernelVersion:
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reads the raw (unscaled no bias removal etc) temperature from
> +		channel Y. The value is returned by a Diode sensor measurement.
> +		Units after application of scale are degrees Celsius or Fahrenheit
> +		depending on the device configuration.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_direct_adc_raw
> +KernelVersion:
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Reads the raw (unscaled no bias removal etc) voltage from
> +		channel Y. The value is returned by a direct ADC measurement.
> +		Units after application of scale are Volts.

What is the extended name adding?

in_voltageY_raw already tells you it's the raw voltage from channel y.

> diff --git a/MAINTAINERS b/MAINTAINERS
> index f0c03740b9fb..14a256e785ca 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -9491,6 +9491,13 @@ S:	Maintained
>  F:	Documentation/devicetree/bindings/iio/dac/ltc1660.txt
>  F:	drivers/iio/dac/ltc1660.c
>  
> +LTC2983 IIO TEMPERATURE DRIVER
> +M:	Nuno Sá <nuno.sa@analog.com>
> +W:	http://ez.analog.com/community/linux-device-drivers
> +L:	linux-iio@vger.kernel.org
> +S:	Supported
> +F:	drivers/iio/temperature/ltc2983.c
> +
>  LTC4261 HARDWARE MONITOR DRIVER
>  M:	Guenter Roeck <linux@roeck-us.net>
>  L:	linux-hwmon@vger.kernel.org
> diff --git a/drivers/iio/temperature/Kconfig b/drivers/iio/temperature/Kconfig
> index 737faa0901fe..04b5a67b593c 100644
> --- a/drivers/iio/temperature/Kconfig
> +++ b/drivers/iio/temperature/Kconfig
> @@ -4,6 +4,16 @@
>  #
>  menu "Temperature sensors"
>  
> +config LTC2983
> +	tristate "Analog Devices Multi-Sensor Digital Temperature Measurement System"
> +	depends on SPI
> +	help
> +	  Say yes here to build support for the LTC2983 Multi-Sensor
> +	  high accuracy digital temperature measurement system.
> +
> +	  To compile this driver as a module, choose M here: the module
> +	  will be called ltc2983.
> +
>  config MAXIM_THERMOCOUPLE
>  	tristate "Maxim thermocouple sensors"
>  	depends on SPI
> diff --git a/drivers/iio/temperature/Makefile b/drivers/iio/temperature/Makefile
> index baca4776ca0d..d6b850b0cf63 100644
> --- a/drivers/iio/temperature/Makefile
> +++ b/drivers/iio/temperature/Makefile
> @@ -3,6 +3,7 @@
>  # Makefile for industrial I/O temperature drivers
>  #
>  
> +obj-$(CONFIG_LTC2983) += ltc2983.o
>  obj-$(CONFIG_HID_SENSOR_TEMP) += hid-sensor-temperature.o
>  obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o
>  obj-$(CONFIG_MAX31856) += max31856.o
> diff --git a/drivers/iio/temperature/ltc2983.c b/drivers/iio/temperature/ltc2983.c
> new file mode 100644
> index 000000000000..2d97b5019e3b
> --- /dev/null
> +++ b/drivers/iio/temperature/ltc2983.c
> @@ -0,0 +1,1327 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Analog Devices LTC2983 Multi-Sensor Digital Temperature Measurement System
> + * driver
> + *
> + * Copyright 2019 Analog Devices Inc.
> + */
> +#include <linux/bitfield.h>
> +#include <linux/completion.h>
> +#include <linux/device.h>
> +#include <linux/kernel.h>
> +#include <linux/iio/iio.h>
> +#include <linux/interrupt.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/of_gpio.h>
> +#include <linux/regmap.h>
> +#include <linux/spi/spi.h>
> +
> +/* register map */
> +#define LTC2983_STATUS_REG			0x0000
> +#define LTC2983_TEMP_RES_START_REG		0x0010
> +#define LTC2983_TEMP_RES_END_REG		0x005F
> +#define LTC2983_GLOBAL_CONFIG_REG		0x00F0
> +#define LTC2983_MULT_CHANNEL_START_REG		0x00F4
> +#define LTC2983_MULT_CHANNEL_END_REG		0x00F7
> +#define LTC2983_MUX_CONFIG_REG			0x00FF
> +#define LTC2983_CHAN_ASSIGN_START_REG		0x0200
> +#define LTC2983_CHAN_ASSIGN_END_REG		0x024F
> +#define LTC2983_CUST_SENS_TBL_START_REG		0x0250
> +#define LTC2983_CUST_SENS_TBL_END_REG		0x03CF
> +
> +#define LTC2983_DIFFERENTIAL_CHAN_MIN		2
> +#define LTC2983_MAX_CHANNELS_NR			20
> +#define LTC2983_MIN_CHANNELS_NR			1
> +#define LTC2983_SLEEP				0x97
> +#define LTC2983_CUSTOM_STEINHART_SIZE		24
> +#define LTC2983_CUSTOM_SENSOR_ENTRY_SZ		6
> +#define LTC2983_CUSTOM_STEINHART_ENTRY_SZ	4
> +
> +#define LTC2983_CHAN_START_ADDR(chan) \
> +			(((chan - 1) * 4) + LTC2983_CHAN_ASSIGN_START_REG)
> +#define LTC2983_CHAN_RES_ADDR(chan) \
> +			(((chan - 1) * 4) + LTC2983_TEMP_RES_START_REG)
> +#define LTC2983_THERMOCOUPLE_DIFF_MASK		BIT(3)
> +#define LTC2983_THERMISTOR_DIFF_MASK		BIT(2)
> +#define LTC2983_DIODE_DIFF_MASK			BIT(2)
> +#define LTC2983_RTD_4_WIRE_MASK			BIT(3)
> +#define LTC2983_RTD_ROTATION_MASK		BIT(1)
> +#define LTC2983_RTD_KELVIN_R_SENSE_MASK		GENMASK(3, 2)
> +
> +#define LTC2983_COMMON_HARD_FAULT_MASK	GENMASK(31, 30)
> +#define LTC2983_COMMON_SOFT_FAULT_MASK	GENMASK(27, 25)
> +
> +#define	LTC2983_STATUS_START_MASK	BIT(7)
> +#define	LTC2983_STATUS_START(x)		FIELD_PREP(LTC2983_STATUS_START_MASK, x)
> +
> +#define	LTC2983_STATUS_CHAN_SEL_MASK	GENMASK(4, 0)
> +#define	LTC2983_STATUS_CHAN_SEL(x) \
> +				FIELD_PREP(LTC2983_STATUS_CHAN_SEL_MASK, x)
> +
> +#define LTC2983_TEMP_UNITS_MASK		BIT(2)
> +#define LTC2983_TEMP_UNITS(x)		FIELD_PREP(LTC2983_TEMP_UNITS_MASK, x)
> +
> +#define LTC2983_NOTCH_FREQ_MASK		GENMASK(1, 0)
> +#define LTC2983_NOTCH_FREQ(x)		FIELD_PREP(LTC2983_NOTCH_FREQ_MASK, x)
> +
> +#define LTC2983_RES_VALID_MASK		BIT(24)
> +#define LTC2983_DATA_MASK		GENMASK(23, 0)
> +#define LTC2983_DATA_SIGN_BIT		23
> +
> +#define LTC2983_CHAN_TYPE_MASK		GENMASK(31, 27)
> +#define LTC2983_CHAN_TYPE(x)		FIELD_PREP(LTC2983_CHAN_TYPE_MASK, x)
> +
> +/* cold junction for thermocouples and rsense for rtd's and thermistor's */
> +#define LTC2983_CHAN_ASSIGN_MASK	GENMASK(26, 22)
> +#define LTC2983_CHAN_ASSIGN(x)		FIELD_PREP(LTC2983_CHAN_ASSIGN_MASK, x)
> +
> +#define LTC2983_CUSTOM_LEN_MASK		GENMASK(5, 0)
> +#define LTC2983_CUSTOM_LEN(x)		FIELD_PREP(LTC2983_CUSTOM_LEN_MASK, x)
> +
> +#define LTC2983_CUSTOM_ADDR_MASK	GENMASK(11, 6)
> +#define LTC2983_CUSTOM_ADDR(x)		FIELD_PREP(LTC2983_CUSTOM_ADDR_MASK, x)
> +
> +#define LTC2983_THERMOCOUPLE_CFG_MASK	GENMASK(21, 18)
> +#define LTC2983_THERMOCOUPLE_CFG(x) \
> +				FIELD_PREP(LTC2983_THERMOCOUPLE_CFG_MASK, x)
> +#define LTC2983_THERMOCOUPLE_HARD_FAULT_MASK	GENMASK(31, 29)
> +#define LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK	GENMASK(28, 25)
> +
> +#define LTC2983_RTD_CFG_MASK		GENMASK(21, 18)
> +#define LTC2983_RTD_CFG(x)		FIELD_PREP(LTC2983_RTD_CFG_MASK, x)
> +#define LTC2983_RTD_EXC_CURRENT_MASK	GENMASK(17, 14)
> +#define LTC2983_RTD_EXC_CURRENT(x) \
> +				FIELD_PREP(LTC2983_RTD_EXC_CURRENT_MASK, x)
> +#define LTC2983_RTD_CURVE_MASK		GENMASK(13, 12)
> +#define LTC2983_RTD_CURVE(x)		FIELD_PREP(LTC2983_RTD_CURVE_MASK, x)
> +
> +#define LTC2983_THERMISTOR_CFG_MASK	GENMASK(21, 19)
> +#define LTC2983_THERMISTOR_CFG(x) \
> +				FIELD_PREP(LTC2983_THERMISTOR_CFG_MASK, x)
> +#define LTC2983_THERMISTOR_EXC_CURRENT_MASK	GENMASK(18, 15)
> +#define LTC2983_THERMISTOR_EXC_CURRENT(x) \
> +			FIELD_PREP(LTC2983_THERMISTOR_EXC_CURRENT_MASK, x)
> +
> +#define LTC2983_DIODE_CFG_MASK		GENMASK(26, 24)
> +#define LTC2983_DIODE_CFG(x)		FIELD_PREP(LTC2983_DIODE_CFG_MASK, x)
> +#define LTC2983_DIODE_EXC_CURRENT_MASK	GENMASK(23, 22)
> +#define LTC2983_DIODE_EXC_CURRENT(x) \
> +				FIELD_PREP(LTC2983_DIODE_EXC_CURRENT_MASK, x)
> +#define LTC2983_DIODE_IDEAL_FACTOR_MASK	GENMASK(21, 0)
> +#define LTC2983_DIODE_IDEAL_FACTOR(x) \
> +				FIELD_PREP(LTC2983_DIODE_IDEAL_FACTOR_MASK, x)
> +
> +#define LTC2983_R_SENSE_VAL_MASK	GENMASK(26, 0)
> +#define LTC2983_R_SENSE_VAL(x)		FIELD_PREP(LTC2983_R_SENSE_VAL_MASK, x)
> +
> +#define LTC2983_ADC_SINGLE_ENDED_MASK	BIT(26)
> +#define LTC2983_ADC_SINGLE_ENDED(x) \
> +				FIELD_PREP(LTC2983_ADC_SINGLE_ENDED_MASK, x)
> +
> +enum {
> +	LTC2983_SENSOR_THERMOCOUPLE = 1,
> +	LTC2983_SENSOR_THERMOCOUPLE_CUSTOM = 9,
> +	LTC2983_SENSOR_RTD = 10,
> +	LTC2983_SENSOR_RTD_CUSTOM = 18,
> +	LTC2983_SENSOR_THERMISTOR = 19,
> +	LTC2983_SENSOR_THERMISTOR_STEINHART = 26,
> +	LTC2983_SENSOR_THERMISTOR_CUSTOM = 27,
> +	LTC2983_SENSOR_DIODE = 28,
> +	LTC2983_SENSOR_SENSE_RESISTOR = 29,
> +	LTC2983_SENSOR_DIRECT_ADC = 30,
> +};
> +
> +#define to_thermocouple(_sensor) \
> +		container_of(_sensor, struct ltc2983_thermocouple, sensor)
> +
> +#define to_rtd(_sensor) \
> +		container_of(_sensor, struct ltc2983_rtd, sensor)
> +
> +#define to_thermistor(_sensor) \
> +		container_of(_sensor, struct ltc2983_thermistor, sensor)
> +
> +#define to_diode(_sensor) \
> +		container_of(_sensor, struct ltc2983_diode, sensor)
> +
> +#define to_rsense(_sensor) \
> +		container_of(_sensor, struct ltc2983_rsense, sensor)
> +
> +#define to_adc(_sensor) \
> +		container_of(_sensor, struct ltc2983_adc, sensor)
> +
> +struct ltc2983_data {
> +	struct regmap *regmap;
> +	struct spi_device *spi;
> +	struct mutex lock;
> +	struct completion completion;
> +	struct iio_chan_spec *iio_chan;
> +	struct ltc2983_sensor **sensors;
> +	u32 mux_delay_config;
> +	u32 filter_notch_freq;
> +	u16 custom_table_size;
> +	u8 num_channels;
> +	u8 iio_channels;
> +	bool temp_farenheit;
> +	bool reset;
> +};
> +
> +struct ltc2983_sensor {
> +	int (*fault_handler)(const struct ltc2983_data *st, const u32 result);
> +	int (*assign_chan)(struct ltc2983_data *st,
> +			   const struct ltc2983_sensor *sensor);
> +	const char *name;
> +	/* specifies the sensor channel */
> +	u32 chan;
> +	/* sensor type */
> +	u32 type;
> +};
> +
> +struct ltc2983_custom_sensor {
> +	/* raw table sensor data */
> +	u8 *table;
> +	size_t size;
> +	/* address offset */
> +	s8 offset;
> +	bool is_steinhart;
> +};
> +
> +struct ltc2983_thermocouple {
> +	struct ltc2983_sensor sensor;
> +	struct ltc2983_custom_sensor *custom;
> +	u32 sensor_config;
> +	u32 cold_junction_chan;
> +};
> +
> +struct ltc2983_rtd {
> +	struct ltc2983_sensor sensor;
> +	struct ltc2983_custom_sensor *custom;
> +	u32 sensor_config;
> +	u32 r_sense_chan;
> +	u32 excitation_current;
> +	u32 rtd_curve;
> +};
> +
> +struct ltc2983_thermistor {
> +	struct ltc2983_sensor sensor;
> +	struct ltc2983_custom_sensor *custom;
> +	u32 sensor_config;
> +	u32 r_sense_chan;
> +	u32 excitation_current;
> +};
> +
> +struct ltc2983_diode {
> +	struct ltc2983_sensor sensor;
> +	u32 sensor_config;
> +	u32 excitation_current;
> +	u32 ideal_factor_value;
> +};
> +
> +struct ltc2983_rsense {
> +	struct ltc2983_sensor sensor;
> +	u32 r_sense_val;
> +};
> +
> +struct ltc2983_adc {
> +	struct ltc2983_sensor sensor;
> +	bool single_ended;
> +};
> +
> +/*
> + * Convert to Q format numbers. These number's are integers where
> + * the number of integer and fractional bits are specified. The resolution
> + * is given by 1/@resolution and tell us the number of fractional bits. For
> + * instance a resolution of 2^-10 means we have 10 fractional bits.
> + */
> +static u32 __convert_to_raw(const u64 val, const u32 resolution)
> +{
> +	u64 __res = val * resolution;
> +
> +	/* all values are multiplied by 1000000 to remove the fraction */
> +	do_div(__res, 1000000);
> +
> +	return __res;
> +}
> +
> +static u32 __convert_to_raw_sign(const u64 val, const u32 resolution)
> +{
> +	s64 __res = -(s32)val;
> +
> +	__res = __convert_to_raw(__res, resolution);
> +
> +	return (u32)-__res;
> +}
> +
> +static int __ltc2983_fault_handler(const struct ltc2983_data *st,
> +				   const u32 result, const u32 hard_mask,
> +				   const u32 soft_mask)
> +{
> +	const struct device *dev = &st->spi->dev;
> +
> +	if (result & hard_mask) {
> +		dev_err(dev, "Invalid conversion: Sensor HARD fault\n");
> +		return -EIO;
> +	} else if (result & soft_mask) {
> +		/* just print a warning */
> +		dev_warn(dev, "Suspicious conversion: Sensor SOFT fault\n");
> +	}
> +
> +	return 0;
> +}
> +
> +static int __ltc2983_chan_assign_common(const struct ltc2983_data *st,
> +					const struct ltc2983_sensor *sensor,
> +					u32 chan_val)
> +{
> +	u32 reg = LTC2983_CHAN_START_ADDR(sensor->chan);
> +	__be32 __chan_val;
> +
> +	chan_val |= LTC2983_CHAN_TYPE(sensor->type);
> +	dev_dbg(&st->spi->dev, "Assign %s, reg:0x%04X, val:0x%08X\n",
> +							sensor->name,
> +							reg, chan_val);
> +	__chan_val = cpu_to_be32(chan_val);
> +	return regmap_bulk_write(st->regmap, reg, &__chan_val,
> +				 sizeof(__chan_val));
> +}
> +
> +static int __ltc2983_chan_custom_sensor_assign(struct ltc2983_data *st,
> +					  struct ltc2983_custom_sensor *custom,
> +					  u32 *chan_val)
> +{
> +	u32 reg;
> +	u8 mult = custom->is_steinhart ? LTC2983_CUSTOM_STEINHART_ENTRY_SZ :
> +		LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
> +	const struct device *dev = &st->spi->dev;
> +	/*
> +	 * custom->size holds the raw size of the table. However, when
> +	 * configuring the sensor channel, we must write the number of
> +	 * entries of the table minus 1. For steinhart sensors 0 is written
> +	 * since the size is constant!
> +	 */
> +	const u8 len = custom->is_steinhart ? 0 :
> +		(custom->size / LTC2983_CUSTOM_SENSOR_ENTRY_SZ) - 1;
> +	/*
> +	 * Check if the offset was assigned already. It should be for steinhart
> +	 * sensors. When coming from sleep, it should be assigned for all.
> +	 */
> +	if (custom->offset < 0) {
> +		/*
> +		 * This needs to be done again here because, from the moment
> +		 * when this test was done (successfully) for this custom
> +		 * sensor, a steinhart sensor might have been added changing
> +		 * custom_table_size...
> +		 */
> +		if (st->custom_table_size + custom->size >
> +		    (LTC2983_CUST_SENS_TBL_END_REG -
> +		     LTC2983_CUST_SENS_TBL_START_REG) + 1) {
> +			dev_err(dev,
> +				"Not space left(%d) for new custom sensor(%zu)",
> +							st->custom_table_size,
> +							custom->size);
> +			return -EINVAL;
> +		}
> +
> +		custom->offset = st->custom_table_size /
> +					LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
> +		st->custom_table_size += custom->size;
> +	}
> +
> +	reg = (custom->offset * mult) + LTC2983_CUST_SENS_TBL_START_REG;
> +
> +	*chan_val |= LTC2983_CUSTOM_LEN(len);
> +	*chan_val |= LTC2983_CUSTOM_ADDR(custom->offset);
> +	dev_dbg(dev, "Assign custom sensor, reg:0x%04X, off:%d, sz:%zu",
> +							reg, custom->offset,
> +							custom->size);
> +	/* write custom sensor table */
> +	return regmap_bulk_write(st->regmap, reg, custom->table, custom->size);
> +}
> +
> +static struct ltc2983_custom_sensor *__ltc2983_custom_sensor_new(
> +						struct ltc2983_data *st,
> +						const struct device_node *np,
> +						const bool is_steinhart,
> +						const u32 resolution,
> +						const bool has_signed)
> +{
> +	struct ltc2983_custom_sensor *new_custom;
> +	u8 index, n_entries, tbl = 0;
> +	struct device *dev = &st->spi->dev;
> +	/*
> +	 * For custom steinhart, the full u32 is taken. For all the others
> +	 * the MSB is discarded.
> +	 */
> +	const u8 n_size = (is_steinhart == true) ? 4 : 3;
> +
> +	n_entries = of_property_count_elems_of_size(np, "adi,custom-sensor",
> +						sizeof(u64));
> +	/* n_entries must be an even number */
> +	if (!n_entries || (n_entries % 2) != 0) {
> +		dev_err(dev, "Number of entries either 0 or not even\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	new_custom = devm_kzalloc(dev, sizeof(*new_custom), GFP_KERNEL);
> +	if (!new_custom)
> +		return ERR_PTR(-ENOMEM);
> +
> +	new_custom->size = n_entries * n_size;
> +	/* check Steinhart size */
> +	if (is_steinhart && new_custom->size != LTC2983_CUSTOM_STEINHART_SIZE) {
> +		dev_err(dev, "Steinhart sensors size(%zu) must be 24",
> +							new_custom->size);
> +		return ERR_PTR(-EINVAL);
> +	}
> +	/* Check space on the table. */
> +	if (st->custom_table_size + new_custom->size >
> +	    (LTC2983_CUST_SENS_TBL_END_REG -
> +	     LTC2983_CUST_SENS_TBL_START_REG) + 1) {
> +		dev_err(dev, "No space left(%d) for new custom sensor(%zu)",
> +				st->custom_table_size, new_custom->size);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	/* allocate the table */
> +	new_custom->table = devm_kzalloc(dev, new_custom->size, GFP_KERNEL);
> +	if (!new_custom->table)
> +		return ERR_PTR(-ENOMEM);
> +
> +	for (index = 0; index < n_entries; index++) {
> +		u64 temp = 0, j;
> +
> +		of_property_read_u64_index(np, "adi,custom-sensor", index,
> +					   &temp);
> +		/*
> +		 * Steinhart sensors are configured with raw values in the
> +		 * devicetree. For the other sensors we must convert the
> +		 * value to raw. The odd index's correspond to temperarures
> +		 * and always have 1/1024 of resolution. Temperatures also
> +		 * come in kelvin, so signed values is not possible
> +		 */
> +		if (!is_steinhart) {
> +			if ((index % 2) != 0)
> +				temp = __convert_to_raw(temp, 1024);
> +			else if (has_signed && (s64)temp < 0)
> +				temp = __convert_to_raw_sign(temp, resolution);
> +			else
> +				temp = __convert_to_raw(temp, resolution);
> +		}
> +
> +		for (j = 0; j < n_size; j++)
> +			new_custom->table[tbl++] =
> +				temp >> (8 * (n_size - j - 1));
> +	}
> +
> +	new_custom->is_steinhart = is_steinhart;
> +	/*
> +	 * This is done to first add all the steinhart sensors to the table,
> +	 * in order to maximize the table usage. If we mix adding steinhart
> +	 * with the other sensors, we might have to do some roundup to make
> +	 * sure that sensor_addr - 0x250(start address) is a multiple of 4
> +	 * (for steinhart), and a multiple of 6 for all the other sensors.
> +	 * Since we have const 24 bytes for steinhart sensors and 24 is
> +	 * also a multiple of 6, we guarantee that the first non-steinhart
> +	 * sensor will sit in a correct address without the need of filling
> +	 * addresses.
> +	 */
> +	if (is_steinhart) {
> +		new_custom->offset = st->custom_table_size /
> +					LTC2983_CUSTOM_STEINHART_ENTRY_SZ;
> +		st->custom_table_size += new_custom->size;
> +	} else {
> +		/* mark as unset. This is checked later on the assign phase */
> +		new_custom->offset = -1;
> +	}
> +
> +	return new_custom;
> +}
> +
> +static int ltc2983_thermocouple_fault_handler(const struct ltc2983_data *st,
> +					      const u32 result)
> +{
> +	return __ltc2983_fault_handler(st, result,
> +				       LTC2983_THERMOCOUPLE_HARD_FAULT_MASK,
> +				       LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK);
> +}
> +
> +static int ltc2983_common_fault_handler(const struct ltc2983_data *st,
> +					const u32 result)
> +{
> +	return __ltc2983_fault_handler(st, result,
> +				       LTC2983_COMMON_HARD_FAULT_MASK,
> +				       LTC2983_COMMON_SOFT_FAULT_MASK);
> +}
> +
> +static int ltc2983_thermocouple_assign_chan(struct ltc2983_data *st,
> +				const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_thermocouple *thermo = to_thermocouple(sensor);
> +	u32 chan_val;
> +
> +	chan_val = LTC2983_CHAN_ASSIGN(thermo->cold_junction_chan);
> +	chan_val |= LTC2983_THERMOCOUPLE_CFG(thermo->sensor_config);
> +
> +	if (thermo->custom) {
> +		int ret;
> +
> +		ret = __ltc2983_chan_custom_sensor_assign(st, thermo->custom,
> +							  &chan_val);
> +		if (ret)
> +			return ret;
> +	}
> +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> +}
> +
> +static int ltc2983_rtd_assign_chan(struct ltc2983_data *st,
> +				   const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_rtd *rtd = to_rtd(sensor);
> +	u32 chan_val;
> +
> +	chan_val = LTC2983_CHAN_ASSIGN(rtd->r_sense_chan);
> +	chan_val |= LTC2983_RTD_CFG(rtd->sensor_config);
> +	chan_val |= LTC2983_RTD_EXC_CURRENT(rtd->excitation_current);
> +	chan_val |= LTC2983_RTD_CURVE(rtd->rtd_curve);
> +
> +	if (rtd->custom) {
> +		int ret;
> +
> +		ret = __ltc2983_chan_custom_sensor_assign(st, rtd->custom,
> +							  &chan_val);
> +		if (ret)
> +			return ret;
> +	}
> +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> +}
> +
> +static int ltc2983_thermistor_assign_chan(struct ltc2983_data *st,
> +					  const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_thermistor *thermistor = to_thermistor(sensor);
> +	u32 chan_val;
> +
> +	chan_val = LTC2983_CHAN_ASSIGN(thermistor->r_sense_chan);
> +	chan_val |= LTC2983_THERMISTOR_CFG(thermistor->sensor_config);
> +	chan_val |=
> +		LTC2983_THERMISTOR_EXC_CURRENT(thermistor->excitation_current);
> +
> +	if (thermistor->custom) {
> +		int ret;
> +
> +		ret = __ltc2983_chan_custom_sensor_assign(st,
> +							  thermistor->custom,
> +							  &chan_val);
> +		if (ret)
> +			return ret;
> +	}
> +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> +}
> +
> +static int ltc2983_diode_assign_chan(struct ltc2983_data *st,
> +				     const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_diode *diode = to_diode(sensor);
> +	u32 chan_val;
> +
> +	chan_val = LTC2983_DIODE_CFG(diode->sensor_config);
> +	chan_val |= LTC2983_DIODE_EXC_CURRENT(diode->excitation_current);
> +	chan_val |= LTC2983_DIODE_IDEAL_FACTOR(diode->ideal_factor_value);
> +
> +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> +}
> +
> +static int ltc2983_r_sense_assign_chan(struct ltc2983_data *st,
> +				       const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_rsense *rsense = to_rsense(sensor);
> +	u32 chan_val;
> +
> +	chan_val = LTC2983_R_SENSE_VAL(rsense->r_sense_val);
> +
> +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> +}
> +
> +static int ltc2983_adc_assign_chan(struct ltc2983_data *st,
> +				   const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_adc *adc = to_adc(sensor);
> +	u32 chan_val;
> +
> +	chan_val = LTC2983_ADC_SINGLE_ENDED(adc->single_ended);
> +
> +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> +}
> +
> +static struct ltc2983_sensor *ltc2983_thermocouple_new(
> +					const struct device_node *child,
> +					struct ltc2983_data *st,
> +					const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_thermocouple *thermo;
> +	struct device_node *phandle;
> +
> +	thermo = devm_kzalloc(&st->spi->dev, sizeof(*thermo), GFP_KERNEL);
> +	if (!thermo)
> +		return ERR_PTR(-ENOMEM);
> +
> +	of_property_read_u32(child, "adi,sensor-config",
> +				 &thermo->sensor_config);
> +	/* validate channel index */
> +	if (!(thermo->sensor_config & LTC2983_THERMOCOUPLE_DIFF_MASK) &&
> +	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> +		dev_err(&st->spi->dev,
> +			"Invalid chann:%d for differential thermocouple",
> +								sensor->chan);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	phandle = of_parse_phandle(child, "adi,cold-junction-handle", 0);
> +	if (phandle) {
> +		int ret;
> +
> +		ret = of_property_read_u32(phandle, "reg",
> +					   &thermo->cold_junction_chan);
> +		if (ret) {
> +			/*
> +			 * This would be catched later but we can just return
> +			 * the error right away.
> +			 */
> +			dev_err(&st->spi->dev, "Property reg must be given\n");
> +			of_node_put(phandle);
> +			return ERR_PTR(-EINVAL);
> +		}
> +	}
> +
> +	/* check custom sensor */
> +	if (sensor->type == LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
> +		thermo->custom = __ltc2983_custom_sensor_new(st, child, false,
> +							     16384, true);
> +		if (IS_ERR(thermo->custom)) {
> +			of_node_put(phandle);
> +			return ERR_CAST(thermo->custom);
> +		}
> +	}
> +
> +	/* set common parameters */
> +	thermo->sensor.name = "thermocouple";
> +	thermo->sensor.fault_handler = ltc2983_thermocouple_fault_handler;
> +	thermo->sensor.assign_chan = ltc2983_thermocouple_assign_chan;
> +
> +	of_node_put(phandle);
> +	return &thermo->sensor;
> +}
> +
> +static struct ltc2983_sensor *ltc2983_rtd_new(const struct device_node *child,
> +					  struct ltc2983_data *st,
> +					  const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_rtd *rtd;
> +	int ret = 0;
> +	struct device *dev = &st->spi->dev;
> +	struct device_node *phandle;
> +
> +	rtd = devm_kzalloc(dev, sizeof(*rtd), GFP_KERNEL);
> +	if (!rtd)
> +		return ERR_PTR(-ENOMEM);
> +
> +	phandle = of_parse_phandle(child, "adi,rsense-handle", 0);
> +	if (!phandle) {
> +		dev_err(dev, "Property adi,rsense-handle missing or invalid");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	ret = of_property_read_u32(phandle, "reg",
> +				&rtd->r_sense_chan);

Doesn't look like that lines needs wrapping. Check for similar elsewhere.

> +	if (ret) {
> +		dev_err(dev, "Property reg must be given\n");
> +		goto fail;
> +	}
> +
> +	of_property_read_u32(child, "adi,sensor-config", &rtd->sensor_config);
> +	/*
> +	 * rtd channel indexes are a bit more complicated to validate.
> +	 * For 4wire RTD with rotation, the channel selection cannot be
> +	 * >=19 since the chann + 1 is used in this configuration.
> +	 * For 4wire RTDs with kelvin rsense, the rsense channel cannot be
> +	 * <=1 since chanel - 1 and channel - 2 are used.
> +	 */
> +	if (rtd->sensor_config & LTC2983_RTD_4_WIRE_MASK) {
> +		/* 4-wire */
> +		u8 min = LTC2983_DIFFERENTIAL_CHAN_MIN,
> +			max = LTC2983_MAX_CHANNELS_NR;
> +
> +		if (rtd->sensor_config & LTC2983_RTD_ROTATION_MASK)
> +			max = LTC2983_MAX_CHANNELS_NR - 1;
> +
> +		if (((rtd->sensor_config & LTC2983_RTD_KELVIN_R_SENSE_MASK)
> +		     == LTC2983_RTD_KELVIN_R_SENSE_MASK) &&
> +		    (rtd->r_sense_chan <=  min)) {
> +			/* kelvin rsense*/
> +			dev_err(dev,
> +				"Invalid rsense chann:%d to use in kelvin rsense",
> +							rtd->r_sense_chan);
> +
> +			ret = -EINVAL;
> +			goto fail;
> +		}
> +
> +		if (sensor->chan < min || sensor->chan > max) {
> +			dev_err(dev, "Invalid chann:%d for the rtd config",
> +								sensor->chan);
> +
> +			ret = -EINVAL;
> +			goto fail;
> +		}
> +	} else {
> +		/* same as differential case */
> +		if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> +			dev_err(&st->spi->dev,
> +				"Invalid chann:%d for RTD", sensor->chan);
> +
> +			ret = -EINVAL;
> +			goto fail;
> +		}
> +	}
> +
> +	/* check custom sensor */
> +	if (sensor->type == LTC2983_SENSOR_RTD_CUSTOM) {
> +		rtd->custom = __ltc2983_custom_sensor_new(st, child, false,
> +							  2048, false);
> +		if (IS_ERR(rtd->custom)) {
> +			of_node_put(phandle);
> +			return ERR_CAST(rtd->custom);
> +		}
> +	}
> +
> +	/* set common parameters */
> +	rtd->sensor.name = "rtd";
> +	rtd->sensor.fault_handler = ltc2983_common_fault_handler;
> +	rtd->sensor.assign_chan = ltc2983_rtd_assign_chan;
> +
> +	ret = of_property_read_u32(child, "adi,excitation-current",
> +				   &rtd->excitation_current);
> +	if (ret)
> +		/* default to 1uA */
> +		rtd->excitation_current = 1;
> +
> +	of_property_read_u32(child, "adi,rtd-curve", &rtd->rtd_curve);
> +
> +	of_node_put(phandle);
> +	return &rtd->sensor;
> +fail:
> +	of_node_put(phandle);
> +	return ERR_PTR(ret);
> +}
> +
> +static struct ltc2983_sensor *ltc2983_thermistor_new(
> +					const struct device_node *child,
> +					struct ltc2983_data *st,
> +					const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_thermistor *thermistor;
> +	struct device *dev = &st->spi->dev;
> +	struct device_node *phandle;
> +	int ret = 0;
> +
> +	thermistor = devm_kzalloc(dev, sizeof(*thermistor), GFP_KERNEL);
> +	if (!thermistor)
> +		return ERR_PTR(-ENOMEM);
> +
> +	phandle = of_parse_phandle(child, "adi,rsense-handle", 0);
> +	if (!phandle) {
> +		dev_err(dev, "Property adi,rsense-handle missing or invalid");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	ret = of_property_read_u32(phandle, "reg",
> +				   &thermistor->r_sense_chan);
> +	if (ret) {
> +		dev_err(dev, "rsense channel must be configured...\n");
> +		goto fail;
> +	}
> +
> +	of_property_read_u32(child, "adi,sensor-config",
> +			     &thermistor->sensor_config);
> +	/* validate channel index */
> +	if (!(thermistor->sensor_config & LTC2983_THERMISTOR_DIFF_MASK) &&
> +	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> +		dev_err(&st->spi->dev,
> +			"Invalid chann:%d for differential thermistor",
> +								sensor->chan);
> +		ret = -EINVAL;
> +		goto fail;
> +	}
> +
> +	/* check custom sensor */
> +	if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART) {
> +		thermistor->custom = __ltc2983_custom_sensor_new(st, child,
> +			sensor->type == LTC2983_SENSOR_THERMISTOR_STEINHART ?
> +							  true : false, 64,
> +							  false);
> +		if (IS_ERR(thermistor->custom)) {
> +			of_node_put(phandle);
> +			return ERR_CAST(thermistor->custom);
> +		}
> +	}
> +	/* set common parameters */
> +	thermistor->sensor.name = "thermistor";
> +	thermistor->sensor.fault_handler = ltc2983_common_fault_handler;
> +	thermistor->sensor.assign_chan = ltc2983_thermistor_assign_chan;
> +
> +	ret = of_property_read_u32(child, "adi,excitation-current",
> +				   &thermistor->excitation_current);
> +	if (ret)
> +		/* default to auto-range */
> +		thermistor->excitation_current = 0x0c;
> +
> +	of_node_put(phandle);
> +	return &thermistor->sensor;
> +fail:
> +	of_node_put(phandle);
> +	return ERR_PTR(ret);
> +}
> +
> +static struct ltc2983_sensor *ltc2983_diode_new(
> +					const struct device_node *child,
> +					const struct ltc2983_data *st,
> +					const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_diode *diode;
> +	u32 temp = 0;
> +
> +	diode = devm_kzalloc(&st->spi->dev, sizeof(*diode), GFP_KERNEL);
> +	if (!diode)
> +		return ERR_PTR(-ENOMEM);
> +
> +	of_property_read_u32(child, "adi,sensor-config", &diode->sensor_config);
> +	/* validate channel index */
> +	if (!(diode->sensor_config & LTC2983_DIODE_DIFF_MASK) &&
> +	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> +		dev_err(&st->spi->dev,
> +			"Invalid chann:%d for differential thermistor",
> +								sensor->chan);
> +		return ERR_PTR(-EINVAL);
> +	}
> +	/* set common parameters */
> +	diode->sensor.name = "diode";
> +	diode->sensor.fault_handler = ltc2983_common_fault_handler;
> +	diode->sensor.assign_chan = ltc2983_diode_assign_chan;
> +
> +	of_property_read_u32(child, "adi,excitation-current",
> +			     &diode->excitation_current);
> +
> +	of_property_read_u32(child, "adi,ideal-factor-value", &temp);
> +
> +	/* 2^20 resolution */
> +	diode->ideal_factor_value = __convert_to_raw(temp, 1048576);
> +
> +	return &diode->sensor;
> +}
> +
> +static struct ltc2983_sensor *ltc2983_r_sense_new(struct device_node *child,
> +					struct ltc2983_data *st,
> +					const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_rsense *rsense;
> +	int ret;
> +	u64 temp;
> +
> +	rsense = devm_kzalloc(&st->spi->dev, sizeof(*rsense), GFP_KERNEL);
> +	if (!rsense)
> +		return ERR_PTR(-ENOMEM);
> +
> +	/* validate channel index */
> +	if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> +		dev_err(&st->spi->dev, "Invalid chann:%d for r_sense",
> +							sensor->chan);
> +		return ERR_PTR(-EINVAL);
> +	}
> +	/* get raw value */
> +	ret = of_property_read_u64(child, "adi,rsense-val-micro-ohms", &temp);
> +	if (ret) {
> +		dev_err(&st->spi->dev, "Property adi,rsense-val-micro-ohms missing\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	/* 2^10 resolution */
> +	rsense->r_sense_val = __convert_to_raw(temp, 1024);
> +
> +	/* set common parameters */
> +	rsense->sensor.name = "r_sense";
> +	rsense->sensor.assign_chan = ltc2983_r_sense_assign_chan;
> +
> +	return &rsense->sensor;
> +}
> +
> +static struct ltc2983_sensor *ltc2983_adc_new(struct device_node *child,
> +					 struct ltc2983_data *st,
> +					 const struct ltc2983_sensor *sensor)
> +{
> +	struct ltc2983_adc *adc;
> +
> +	adc = devm_kzalloc(&st->spi->dev, sizeof(*adc), GFP_KERNEL);
> +	if (!adc)
> +		return ERR_PTR(-ENOMEM);
> +
> +	if (of_property_read_bool(child, "adi,single-ended"))
> +		adc->single_ended = true;
> +
> +	if (!adc->single_ended &&
> +	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> +		dev_err(&st->spi->dev, "Invalid chan:%d for differential adc\n",
> +								sensor->chan);
> +		return ERR_PTR(-EINVAL);
> +	}
> +	/* set common parameters */
> +	adc->sensor.name = "direct_adc";
> +	adc->sensor.assign_chan = ltc2983_adc_assign_chan;
> +	adc->sensor.fault_handler = ltc2983_common_fault_handler;
> +
> +	return &adc->sensor;
> +}
> +
> +static int ltc2983_chan_read(struct ltc2983_data *st,
> +			const struct ltc2983_sensor *sensor, int *val)
> +{
> +	u32 start_conversion = 0;
> +	int ret;
> +	unsigned long time;
> +	__be32 temp;
> +
> +	/*
> +	 * Do not allow channel readings if device is in sleep state.
> +	 * A read/write on the spi bus would bring the device prematurely
> +	 * out of sleep.
> +	 */
> +	if (st->reset)
> +		return -EPERM;
> +
> +	start_conversion = LTC2983_STATUS_START(true);
> +	start_conversion |= LTC2983_STATUS_CHAN_SEL(sensor->chan);
> +	dev_dbg(&st->spi->dev, "Start conversion on chan:%d, status:%02X\n",
> +		sensor->chan, start_conversion);
> +	/* start conversion */
> +	ret = regmap_write(st->regmap, LTC2983_STATUS_REG, start_conversion);
> +	if (ret)
> +		return ret;
> +
> +	reinit_completion(&st->completion);
> +	/*
> +	 * wait for conversion to complete.
> +	 * 300 ms should be more than enough to complete the conversion.
> +	 * Depending on the sensor configuration, there are 2/3 conversions
> +	 * cycles of 82ms.
> +	 */
> +	time = wait_for_completion_timeout(&st->completion,
> +					   msecs_to_jiffies(300));
> +	if (!time) {
> +		dev_warn(&st->spi->dev, "Conversion timed out\n");
> +		return -ETIMEDOUT;
> +	}
> +
> +	/* read the converted data */
> +	ret = regmap_bulk_read(st->regmap, LTC2983_CHAN_RES_ADDR(sensor->chan),
> +			       &temp, sizeof(temp));
> +	if (ret)
> +		return ret;
> +
> +	*val = __be32_to_cpu(temp);
> +	dev_dbg(&st->spi->dev, "Converted data: 0x%08X (addr:0x%04X)\n", *val,
> +					LTC2983_CHAN_RES_ADDR(sensor->chan));

Probably drop all the dev_dbg stuff unless it is providing information that
isn't otherwise available (from reading channel etc, kprobe / ftrace).

> +
> +	if (!(LTC2983_RES_VALID_MASK & *val)) {
> +		dev_err(&st->spi->dev, "Invalid conversion detected\n");
> +		return -EIO;
> +	}
> +
> +	ret = sensor->fault_handler(st, *val);
> +	if (ret)
> +		return ret;
> +
> +	*val = sign_extend32((*val) & LTC2983_DATA_MASK, LTC2983_DATA_SIGN_BIT);
> +	return 0;
> +}
> +
> +static int ltc2983_read_raw(struct iio_dev *indio_dev,
> +			    struct iio_chan_spec const *chan,
> +			    int *val, int *val2, long mask)
> +{
> +	struct ltc2983_data *st = iio_priv(indio_dev);
> +	int ret;
> +
> +	/* sanity check */
> +	if (chan->address >= st->num_channels) {
> +		dev_err(&st->spi->dev, "Invalid chan address:%ld",
> +							chan->address);
> +		return -EINVAL;
> +	}
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		mutex_lock(&st->lock);
> +		ret = ltc2983_chan_read(st, st->sensors[chan->address], val);
> +		mutex_unlock(&st->lock);
> +		return ret ?: IIO_VAL_INT;
> +	case IIO_CHAN_INFO_SCALE:
> +		switch (chan->type) {
> +		case IIO_TEMP:
> +			*val = 1;
> +			/* 2^10 */
> +			*val2 = 1024;
> +			return IIO_VAL_FRACTIONAL;
> +		case IIO_VOLTAGE:
> +			*val = 1;
> +			/* 2^21 */
> +			*val2 = 2097152;
> +			return IIO_VAL_FRACTIONAL;
> +		default:
> +			return -EINVAL;
> +		}
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int ltc2983_reg_access(struct iio_dev *indio_dev,
> +			      unsigned int reg,
> +			      unsigned int writeval,
> +			      unsigned int *readval)
> +{
> +	struct ltc2983_data *st = iio_priv(indio_dev);
> +
> +	/* check comment in ltc2983_chan_read() */
> +	if (st->reset)
> +		return -EPERM;
> +
> +	if (readval)
> +		return regmap_read(st->regmap, reg, readval);
> +	else
> +		return regmap_write(st->regmap, reg, writeval);
> +}
> +
> +static irqreturn_t ltc2983_irq_handler(int irq, void *data)
> +{
> +	struct ltc2983_data *st = data;
> +
> +	complete(&st->completion);
> +	return IRQ_HANDLED;
> +}
> +
> +#define LTC2983_CHAN(__type, index, __address, ext_name) ({ \
> +	struct iio_chan_spec __chan = { \
> +		.type = __type, \
> +		.indexed = 1, \
> +		.channel = index, \
> +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> +		.address = __address, \
> +		.extend_name = ext_name, \
> +	}; \
> +	__chan; \
> +})
> +
> +static int ltc2983_parse_dt(struct ltc2983_data *st)
> +{
> +	struct device_node *child;
> +	struct device *dev = &st->spi->dev;
> +	int ret = 0, chan = 0, channel_avail_mask = 0;
> +
> +	if (!of_property_read_bool(dev->of_node, "adi,temperature-celcius"))
> +		st->temp_farenheit = true;
> +
> +	of_property_read_u32(dev->of_node, "adi,mux-delay-config",
> +			     &st->mux_delay_config);
> +
> +	of_property_read_u32(dev->of_node, "adi,filter-notch-freq",
> +			     &st->filter_notch_freq);
> +
> +	st->num_channels = of_get_available_child_count(dev->of_node);
> +	st->sensors = devm_kcalloc(dev, st->num_channels, sizeof(*st->sensors),
> +				   GFP_KERNEL);
> +	if (!st->sensors)
> +		return -ENOMEM;
> +
> +	st->iio_channels = st->num_channels;
> +	for_each_available_child_of_node(dev->of_node, child) {
> +		struct ltc2983_sensor sensor;
> +
> +		ret = of_property_read_u32(child, "reg", &sensor.chan);
> +		if (ret) {
> +			dev_err(dev, "reg property must given for child nodes\n");
> +			return ret;
> +		}
> +
> +		/* check if we have a valid channel */
> +		if (sensor.chan < LTC2983_MIN_CHANNELS_NR ||
> +		    sensor.chan > LTC2983_MAX_CHANNELS_NR) {
> +			dev_err(dev,
> +				"chan:%d must be from 1 to 20\n", sensor.chan);
> +			return -EINVAL;
> +		} else if (channel_avail_mask & BIT(sensor.chan)) {
> +			dev_err(dev, "chan:%d already in use\n", sensor.chan);
> +			return -EINVAL;
> +		}
> +
> +		ret = of_property_read_u32(child, "adi,sensor-type",
> +					       &sensor.type);
> +		if (ret) {
> +			dev_err(dev,
> +				"adi,sensor-type property must given for child nodes\n");
> +			return ret;
> +		}
> +
> +		dev_dbg(dev, "Create new sensor, type %u, chann %u",
> +								sensor.type,
> +								sensor.chan);
> +
> +		if (sensor.type >= LTC2983_SENSOR_THERMOCOUPLE &&
> +		    sensor.type <= LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
> +			st->sensors[chan] = ltc2983_thermocouple_new(child, st,
> +								     &sensor);
> +		} else if (sensor.type >= LTC2983_SENSOR_RTD &&
> +			   sensor.type <= LTC2983_SENSOR_RTD_CUSTOM) {
> +			st->sensors[chan] = ltc2983_rtd_new(child, st, &sensor);
> +		} else if (sensor.type >= LTC2983_SENSOR_THERMISTOR &&
> +			   sensor.type <= LTC2983_SENSOR_THERMISTOR_CUSTOM) {
> +			st->sensors[chan] = ltc2983_thermistor_new(child, st,
> +								   &sensor);
> +		} else if (sensor.type == LTC2983_SENSOR_DIODE) {
> +			st->sensors[chan] = ltc2983_diode_new(child, st,
> +							      &sensor);
> +		} else if (sensor.type == LTC2983_SENSOR_SENSE_RESISTOR) {
> +			st->sensors[chan] = ltc2983_r_sense_new(child, st,
> +								&sensor);
> +			/* don't add rsense to iio */
> +			st->iio_channels--;
> +		} else if (sensor.type == LTC2983_SENSOR_DIRECT_ADC) {
> +			st->sensors[chan] = ltc2983_adc_new(child, st, &sensor);
> +		} else {
> +			dev_err(dev, "Unknown sensor type %d\n", sensor.type);
> +			return -EINVAL;
> +		}
> +
> +		if (IS_ERR(st->sensors[chan])) {
> +			dev_err(dev, "Failed to create sensor %ld",
> +						PTR_ERR(st->sensors[chan]));
> +			return PTR_ERR(st->sensors[chan]);
> +		}
> +		/* set generic sensor parameters */
> +		st->sensors[chan]->chan = sensor.chan;
> +		st->sensors[chan]->type = sensor.type;
> +
> +		channel_avail_mask |= BIT(sensor.chan);
> +		chan++;
> +	}
> +	/* allocate iio_chan array */

This last block isn't really about parsing the DT, perhaps drop it out of
here?

> +	st->iio_chan = devm_kzalloc(dev,
> +				    st->iio_channels * sizeof(*st->iio_chan),
> +				    GFP_KERNEL);
> +	if (!st->iio_chan)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
> +static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
> +{
> +	u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0;
> +	u32 global_cfg = 0;
> +	int ret;
> +	unsigned long time;
> +
> +	/* make sure the device is up */
> +	time = wait_for_completion_timeout(&st->completion,
> +					    msecs_to_jiffies(250));
> +	if (!time) {
> +		dev_err(&st->spi->dev, "Device startup timed out\n");
> +		return -ETIMEDOUT;
> +	}

Blank line here, slightly helps readability be clearly separating the
error handling path from normal flow.

> +	/* set generic global cfg and mux delay */

Not sure this comment adds anything not obvious from the code.  Comments
like this are always at risk of 'rotting' over time, so better to not
put them if they don't bring significant value.

> +	global_cfg = LTC2983_NOTCH_FREQ(st->filter_notch_freq);
> +	global_cfg |= LTC2983_TEMP_UNITS(st->temp_farenheit);
> +	regmap_write(st->regmap, LTC2983_GLOBAL_CONFIG_REG, global_cfg);
> +	regmap_write(st->regmap, LTC2983_MUX_CONFIG_REG, st->mux_delay_config);
> +	/* setup channels */

This comment also not stating anything non obvious.

> +	for (chan = 0; chan < st->num_channels; chan++) {
> +		u32 chan_type = 0, *iio_chan;
> +
> +		ret = st->sensors[chan]->assign_chan(st, st->sensors[chan]);
> +		if (ret)
> +			return ret;
> +		/*
> +		 * The assign_iio flag is necessary for when the device is
> +		 * coming out of sleep. In that case, we just need to
> +		 * re-configure the device channels.
> +		 * We also don't assign iio channels for rsense.
> +		 */
> +		if (st->sensors[chan]->type == LTC2983_SENSOR_SENSE_RESISTOR ||
> +		    !assign_iio)
> +			continue;
> +
> +		/* assign iio channel */
> +		if (st->sensors[chan]->type != LTC2983_SENSOR_DIRECT_ADC) {
> +			chan_type = IIO_TEMP;
> +			iio_chan = &iio_chan_t;
> +		} else {
> +			chan_type = IIO_VOLTAGE;
> +			iio_chan = &iio_chan_v;
> +		}
> +
> +		/*
> +		 * add chan as the iio .address so that, we can directly
> +		 * reference the sensor given the iio_chan_spec
> +		 */
> +		st->iio_chan[iio_idx++] = LTC2983_CHAN(chan_type, (*iio_chan)++,
> +						       chan,
> +						       st->sensors[chan]->name);
> +	}
> +
> +	return 0;
> +}
> +
> +static const struct regmap_range ltc2983_reg_ranges[] = {
> +	regmap_reg_range(LTC2983_STATUS_REG, LTC2983_STATUS_REG),
> +	regmap_reg_range(LTC2983_TEMP_RES_START_REG, LTC2983_TEMP_RES_END_REG),
> +	regmap_reg_range(LTC2983_GLOBAL_CONFIG_REG, LTC2983_GLOBAL_CONFIG_REG),
> +	regmap_reg_range(LTC2983_MULT_CHANNEL_START_REG,
> +			 LTC2983_MULT_CHANNEL_END_REG),
> +	regmap_reg_range(LTC2983_MUX_CONFIG_REG, LTC2983_MUX_CONFIG_REG),
> +	regmap_reg_range(LTC2983_CHAN_ASSIGN_START_REG,
> +			 LTC2983_CHAN_ASSIGN_END_REG),
> +	regmap_reg_range(LTC2983_CUST_SENS_TBL_START_REG,
> +			 LTC2983_CUST_SENS_TBL_END_REG),
> +};
> +
> +static const struct regmap_access_table ltc2983_reg_table = {
> +	.yes_ranges = ltc2983_reg_ranges,
> +	.n_yes_ranges = ARRAY_SIZE(ltc2983_reg_ranges),
> +};

Blank line here.

> +/*
> + *  The reg_bits are actually 12 but the device needs the first *complete*
> + *  byte for the command (R/W).
> + */
> +static const struct regmap_config ltc2983_regmap_config = {
> +	.reg_bits = 24,
> +	.val_bits = 8,
> +	.wr_table = &ltc2983_reg_table,
> +	.rd_table = &ltc2983_reg_table,
> +	.read_flag_mask = GENMASK(1, 0),
> +	.write_flag_mask = BIT(1),
> +};
> +
> +static const struct  iio_info ltc2983_iio_info = {
> +	.read_raw = ltc2983_read_raw,
> +	.debugfs_reg_access = ltc2983_reg_access,
> +};
> +
> +static int ltc2983_probe(struct spi_device *spi)
> +{
> +	struct ltc2983_data *st;
> +	struct iio_dev *indio_dev;
> +	const char *name = spi_get_device_id(spi)->name;
> +	int ret;
> +
> +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> +	if (!indio_dev)
> +		return -ENOMEM;
> +
> +	st = iio_priv(indio_dev);
> +
> +	st->regmap = devm_regmap_init_spi(spi, &ltc2983_regmap_config);
> +	if (IS_ERR(st->regmap)) {
> +		dev_err(&spi->dev, "Failed to initialize regmap\n");
> +		return PTR_ERR(st->regmap);
> +	}
> +
> +	mutex_init(&st->lock);
> +	init_completion(&st->completion);
> +	st->spi = spi;
> +	spi_set_drvdata(spi, st);
> +
> +	ret = ltc2983_parse_dt(st);
> +	if (ret)
> +		return ret;
> +	/*
> +	 * let's request the irq now so it is used to sync the device
> +	 * startup in ltc2983_setup()
> +	 */
> +	ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
> +					ltc2983_irq_handler, IRQF_ONESHOT |
> +					IRQF_TRIGGER_RISING, name, st);
> +	if (ret) {
> +		dev_err(&spi->dev, "failed to request an irq, %d", ret);
> +		return ret;
> +	}
> +
> +	ret = ltc2983_setup(st, true);
> +	if (ret)
> +		return ret;
> +
> +	indio_dev->dev.parent = &spi->dev;
> +	indio_dev->name = name;
> +	indio_dev->num_channels = st->iio_channels;
> +	indio_dev->channels = st->iio_chan;
> +	indio_dev->modes = INDIO_DIRECT_MODE;
> +	indio_dev->info = &ltc2983_iio_info;
> +
> +	return devm_iio_device_register(&spi->dev, indio_dev);
> +}
> +
> +static int __maybe_unused ltc2983_resume(struct device *dev)
> +{
> +	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
> +	int ret;
> +
> +	mutex_lock(&st->lock);
> +	/* dummy read to bring the device out of sleep */
> +	regmap_read(st->regmap, LTC2983_STATUS_REG, &ret);
> +	/* we need to re-assign the channels */
> +	ret = ltc2983_setup(st, false);
> +	st->reset = false;
> +	mutex_unlock(&st->lock);
> +
> +	return ret;
> +}
> +
> +static int __maybe_unused ltc2983_suspend(struct device *dev)
> +{
> +	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
> +	int ret;
> +
> +	mutex_lock(&st->lock);
> +	ret = regmap_write(st->regmap, LTC2983_STATUS_REG, LTC2983_SLEEP);
> +	st->reset = true;

Naming seems a bit odd. The register field is called sleep, but we call
it reset internally?

> +	mutex_unlock(&st->lock);
> +
> +	return ret;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(ltc2983_pm_ops, ltc2983_suspend, ltc2983_resume);
> +
> +static const struct spi_device_id ltc2983_id_table[] = {
> +	{ "ltc2983" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(spi, ltc2983_id_table);
> +
> +static const struct of_device_id ltc2983_of_match[] = {
> +	{ .compatible = "adi,ltc2983" },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, ltc2983_id_table);
> +
> +static struct spi_driver ltc2983_driver = {
> +	.driver = {
> +		.name = "ltc2983",
> +		.of_match_table = ltc2983_of_match,
> +		.pm = &ltc2983_pm_ops,
> +	},
> +	.probe = ltc2983_probe,
> +	.id_table = ltc2983_id_table,
> +};
> +
> +module_spi_driver(ltc2983_driver);
> +
> +MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
> +MODULE_DESCRIPTION("Analog Devices LTC2983 SPI Temperature sensors");
> +MODULE_LICENSE("GPL");


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 1/2] iio: temperature: Add support for LTC2983
  2019-09-15 11:27 ` [PATCH 1/2] iio: temperature: Add support for LTC2983 Jonathan Cameron
@ 2019-09-16  9:37   ` Sa, Nuno
  2019-09-21 17:02     ` Jonathan Cameron
  0 siblings, 1 reply; 11+ messages in thread
From: Sa, Nuno @ 2019-09-16  9:37 UTC (permalink / raw)
  To: jic23
  Cc: robh+dt, mark.rutland, devicetree, knaack.h, linux-iio, pmeerw, lars

Hi Jonathan,

Thanks for the review.
Comments inline.

Nuno Sá

On Sun, 2019-09-15 at 12:27 +0100, Jonathan Cameron wrote:
> 
> On Mon, 9 Sep 2019 16:45:49 +0200
> Nuno Sá <nuno.sa@analog.com> wrote:
> 
> > The LTC2983 is a Multi-Sensor High Accuracy Digital Temperature
> > Measurement System. It measures a wide variety of temperature
> > sensors and
> > digitally outputs the result, in °C or °F, with 0.1°C accuracy and
> > 0.001°C resolution. It can measure the temperature of all standard
> > thermocouples (type B,E,J,K,N,S,R,T), standard 2-,3-,4-wire RTDs,
> > thermistors and diodes.
> > 
> > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> Some comments inline.  Main concern is around the interface, rest is
> minor
> stuff.
> 
> Jonathan
> 
> > ---
> >  .../testing/sysfs-bus-iio-temperature-ltc2983 |   43 +
> >  MAINTAINERS                                   |    7 +
> >  drivers/iio/temperature/Kconfig               |   10 +
> >  drivers/iio/temperature/Makefile              |    1 +
> >  drivers/iio/temperature/ltc2983.c             | 1327
> > +++++++++++++++++
> >  5 files changed, 1388 insertions(+)
> >  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-
> > temperature-ltc2983
> >  create mode 100644 drivers/iio/temperature/ltc2983.c
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-temperature-
> > ltc2983 b/Documentation/ABI/testing/sysfs-bus-iio-temperature-
> > ltc2983
> > new file mode 100644
> > index 000000000000..3ad3440c0986
> > --- /dev/null
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983
> > @@ -0,0 +1,43 @@
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_therm
> > istor_raw
> For each of these, I presume we know which type of device is attached
> at any time?
> Using the channel naming to convey this (and I assume the fact that
> different
> conversions need to be done in userspace?) is a bit messy.  If we
> need
> to convey the channel type, then a separate in_tempY_mode attribute
> may make more
> sense.  That would keep this ABI 'closer' to standard. Software that
> just logs
> an unprocessed value could just work for example.
> 
> I'm not sure I've totally understood what is going on here though.
> 
So, the `extend_name` does not really bring any functional advantage.
It was just an easy way for someone to know which kind of sensor the
channel was referring to. In terms of conversions, all the work is done
by the part for all the different sensor's and the scale is the same
for all of them. So, I can just drop the extended name and use standard
ABI if you prefer?

> > +KernelVersion:
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Reads the raw (unscaled no bias removal etc)
> > temperature from
> > +		channel Y. The value is returned by a Thermistor sensor
> > measurement.
> > +		Units after application of scale are degrees Celsius or
> > Fahrenheit
> > +		depending on the device configuration.
> > +
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_therm
> > ocouple_raw
> > +KernelVersion:
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Reads the raw (unscaled no bias removal etc)
> > temperature from
> > +		channel Y. The value is returned by a Thermocouple
> > sensor measurement.
> > +		Units after application of scale are degrees Celsius or
> > Fahrenheit
> > +		depending on the device configuration.
> > +
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_rtd_r
> > aw
> > +KernelVersion:
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Reads the raw (unscaled no bias removal etc)
> > temperature from
> > +		channel Y. The value is returned by a RTD sensor
> > measurement.
> > +		Units after application of scale are degrees Celsius or
> > Fahrenheit
> > +		depending on the device configuration.
> > +
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_diode
> > _raw
> > +KernelVersion:
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Reads the raw (unscaled no bias removal etc)
> > temperature from
> > +		channel Y. The value is returned by a Diode sensor
> > measurement.
> > +		Units after application of scale are degrees Celsius or
> > Fahrenheit
> > +		depending on the device configuration.
> > +
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_voltageY_di
> > rect_adc_raw
> > +KernelVersion:
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Reads the raw (unscaled no bias removal etc) voltage
> > from
> > +		channel Y. The value is returned by a direct ADC
> > measurement.
> > +		Units after application of scale are Volts.
> 
> What is the extended name adding?

The same as before. But here I see that it does not make sense having
the extended name because if it's voltage then we know it's a direct
adc reading. I will drop it.

> in_voltageY_raw already tells you it's the raw voltage from channel
> y.
> 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index f0c03740b9fb..14a256e785ca 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -9491,6 +9491,13 @@ S:	Maintained
> >  F:	Documentation/devicetree/bindings/iio/dac/ltc1660.txt
> >  F:	drivers/iio/dac/ltc1660.c
> >  
> > +LTC2983 IIO TEMPERATURE DRIVER
> > +M:	Nuno Sá <nuno.sa@analog.com>
> > +W:	http://ez.analog.com/community/linux-device-drivers
> > +L:	linux-iio@vger.kernel.org
> > +S:	Supported
> > +F:	drivers/iio/temperature/ltc2983.c
> > +
> >  LTC4261 HARDWARE MONITOR DRIVER
> >  M:	Guenter Roeck <linux@roeck-us.net>
> >  L:	linux-hwmon@vger.kernel.org
> > diff --git a/drivers/iio/temperature/Kconfig
> > b/drivers/iio/temperature/Kconfig
> > index 737faa0901fe..04b5a67b593c 100644
> > --- a/drivers/iio/temperature/Kconfig
> > +++ b/drivers/iio/temperature/Kconfig
> > @@ -4,6 +4,16 @@
> >  #
> >  menu "Temperature sensors"
> >  
> > +config LTC2983
> > +	tristate "Analog Devices Multi-Sensor Digital Temperature
> > Measurement System"
> > +	depends on SPI
> > +	help
> > +	  Say yes here to build support for the LTC2983 Multi-Sensor
> > +	  high accuracy digital temperature measurement system.
> > +
> > +	  To compile this driver as a module, choose M here: the module
> > +	  will be called ltc2983.
> > +
> >  config MAXIM_THERMOCOUPLE
> >  	tristate "Maxim thermocouple sensors"
> >  	depends on SPI
> > diff --git a/drivers/iio/temperature/Makefile
> > b/drivers/iio/temperature/Makefile
> > index baca4776ca0d..d6b850b0cf63 100644
> > --- a/drivers/iio/temperature/Makefile
> > +++ b/drivers/iio/temperature/Makefile
> > @@ -3,6 +3,7 @@
> >  # Makefile for industrial I/O temperature drivers
> >  #
> >  
> > +obj-$(CONFIG_LTC2983) += ltc2983.o
> >  obj-$(CONFIG_HID_SENSOR_TEMP) += hid-sensor-temperature.o
> >  obj-$(CONFIG_MAXIM_THERMOCOUPLE) += maxim_thermocouple.o
> >  obj-$(CONFIG_MAX31856) += max31856.o
> > diff --git a/drivers/iio/temperature/ltc2983.c
> > b/drivers/iio/temperature/ltc2983.c
> > new file mode 100644
> > index 000000000000..2d97b5019e3b
> > --- /dev/null
> > +++ b/drivers/iio/temperature/ltc2983.c
> > @@ -0,0 +1,1327 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Analog Devices LTC2983 Multi-Sensor Digital Temperature
> > Measurement System
> > + * driver
> > + *
> > + * Copyright 2019 Analog Devices Inc.
> > + */
> > +#include <linux/bitfield.h>
> > +#include <linux/completion.h>
> > +#include <linux/device.h>
> > +#include <linux/kernel.h>
> > +#include <linux/iio/iio.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/list.h>
> > +#include <linux/module.h>
> > +#include <linux/of_gpio.h>
> > +#include <linux/regmap.h>
> > +#include <linux/spi/spi.h>
> > +
> > +/* register map */
> > +#define LTC2983_STATUS_REG			0x0000
> > +#define LTC2983_TEMP_RES_START_REG		0x0010
> > +#define LTC2983_TEMP_RES_END_REG		0x005F
> > +#define LTC2983_GLOBAL_CONFIG_REG		0x00F0
> > +#define LTC2983_MULT_CHANNEL_START_REG		0x00F4
> > +#define LTC2983_MULT_CHANNEL_END_REG		0x00F7
> > +#define LTC2983_MUX_CONFIG_REG			0x00FF
> > +#define LTC2983_CHAN_ASSIGN_START_REG		0x0200
> > +#define LTC2983_CHAN_ASSIGN_END_REG		0x024F
> > +#define LTC2983_CUST_SENS_TBL_START_REG		0x0250
> > +#define LTC2983_CUST_SENS_TBL_END_REG		0x03CF
> > +
> > +#define LTC2983_DIFFERENTIAL_CHAN_MIN		2
> > +#define LTC2983_MAX_CHANNELS_NR			20
> > +#define LTC2983_MIN_CHANNELS_NR			1
> > +#define LTC2983_SLEEP				0x97
> > +#define LTC2983_CUSTOM_STEINHART_SIZE		24
> > +#define LTC2983_CUSTOM_SENSOR_ENTRY_SZ		6
> > +#define LTC2983_CUSTOM_STEINHART_ENTRY_SZ	4
> > +
> > +#define LTC2983_CHAN_START_ADDR(chan) \
> > +			(((chan - 1) * 4) +
> > LTC2983_CHAN_ASSIGN_START_REG)
> > +#define LTC2983_CHAN_RES_ADDR(chan) \
> > +			(((chan - 1) * 4) + LTC2983_TEMP_RES_START_REG)
> > +#define LTC2983_THERMOCOUPLE_DIFF_MASK		BIT(3)
> > +#define LTC2983_THERMISTOR_DIFF_MASK		BIT(2)
> > +#define LTC2983_DIODE_DIFF_MASK			BIT(2)
> > +#define LTC2983_RTD_4_WIRE_MASK			BIT(3)
> > +#define LTC2983_RTD_ROTATION_MASK		BIT(1)
> > +#define LTC2983_RTD_KELVIN_R_SENSE_MASK		GENMASK(3, 2)
> > +
> > +#define LTC2983_COMMON_HARD_FAULT_MASK	GENMASK(31, 30)
> > +#define LTC2983_COMMON_SOFT_FAULT_MASK	GENMASK(27, 25)
> > +
> > +#define	LTC2983_STATUS_START_MASK	BIT(7)
> > +#define	LTC2983_STATUS_START(x)		FIELD_PREP(LTC2983_
> > STATUS_START_MASK, x)
> > +
> > +#define	LTC2983_STATUS_CHAN_SEL_MASK	GENMASK(4, 0)
> > +#define	LTC2983_STATUS_CHAN_SEL(x) \
> > +				FIELD_PREP(LTC2983_STATUS_CHAN_SEL_MASK
> > , x)
> > +
> > +#define LTC2983_TEMP_UNITS_MASK		BIT(2)
> > +#define LTC2983_TEMP_UNITS(x)		FIELD_PREP(LTC2983_TEMP
> > _UNITS_MASK, x)
> > +
> > +#define LTC2983_NOTCH_FREQ_MASK		GENMASK(1, 0)
> > +#define LTC2983_NOTCH_FREQ(x)		FIELD_PREP(LTC2983_NOTC
> > H_FREQ_MASK, x)
> > +
> > +#define LTC2983_RES_VALID_MASK		BIT(24)
> > +#define LTC2983_DATA_MASK		GENMASK(23, 0)
> > +#define LTC2983_DATA_SIGN_BIT		23
> > +
> > +#define LTC2983_CHAN_TYPE_MASK		GENMASK(31, 27)
> > +#define LTC2983_CHAN_TYPE(x)		FIELD_PREP(LTC2983_CHAN
> > _TYPE_MASK, x)
> > +
> > +/* cold junction for thermocouples and rsense for rtd's and
> > thermistor's */
> > +#define LTC2983_CHAN_ASSIGN_MASK	GENMASK(26, 22)
> > +#define LTC2983_CHAN_ASSIGN(x)		FIELD_PREP(LTC2983_CHAN
> > _ASSIGN_MASK, x)
> > +
> > +#define LTC2983_CUSTOM_LEN_MASK		GENMASK(5, 0)
> > +#define LTC2983_CUSTOM_LEN(x)		FIELD_PREP(LTC2983_CUST
> > OM_LEN_MASK, x)
> > +
> > +#define LTC2983_CUSTOM_ADDR_MASK	GENMASK(11, 6)
> > +#define LTC2983_CUSTOM_ADDR(x)		FIELD_PREP(LTC2983_CUST
> > OM_ADDR_MASK, x)
> > +
> > +#define LTC2983_THERMOCOUPLE_CFG_MASK	GENMASK(21, 18)
> > +#define LTC2983_THERMOCOUPLE_CFG(x) \
> > +				FIELD_PREP(LTC2983_THERMOCOUPLE_CFG_MAS
> > K, x)
> > +#define LTC2983_THERMOCOUPLE_HARD_FAULT_MASK	GENMASK(31, 29)
> > +#define LTC2983_THERMOCOUPLE_SOFT_FAULT_MASK	GENMASK(28, 25)
> > +
> > +#define LTC2983_RTD_CFG_MASK		GENMASK(21, 18)
> > +#define LTC2983_RTD_CFG(x)		FIELD_PREP(LTC2983_RTD_CFG_MASK
> > , x)
> > +#define LTC2983_RTD_EXC_CURRENT_MASK	GENMASK(17, 14)
> > +#define LTC2983_RTD_EXC_CURRENT(x) \
> > +				FIELD_PREP(LTC2983_RTD_EXC_CURRENT_MASK
> > , x)
> > +#define LTC2983_RTD_CURVE_MASK		GENMASK(13, 12)
> > +#define LTC2983_RTD_CURVE(x)		FIELD_PREP(LTC2983_RTD_
> > CURVE_MASK, x)
> > +
> > +#define LTC2983_THERMISTOR_CFG_MASK	GENMASK(21, 19)
> > +#define LTC2983_THERMISTOR_CFG(x) \
> > +				FIELD_PREP(LTC2983_THERMISTOR_CFG_MASK,
> > x)
> > +#define LTC2983_THERMISTOR_EXC_CURRENT_MASK	GENMASK(18, 15)
> > +#define LTC2983_THERMISTOR_EXC_CURRENT(x) \
> > +			FIELD_PREP(LTC2983_THERMISTOR_EXC_CURRENT_MASK,
> > x)
> > +
> > +#define LTC2983_DIODE_CFG_MASK		GENMASK(26, 24)
> > +#define LTC2983_DIODE_CFG(x)		FIELD_PREP(LTC2983_DIOD
> > E_CFG_MASK, x)
> > +#define LTC2983_DIODE_EXC_CURRENT_MASK	GENMASK(23, 22)
> > +#define LTC2983_DIODE_EXC_CURRENT(x) \
> > +				FIELD_PREP(LTC2983_DIODE_EXC_CURRENT_MA
> > SK, x)
> > +#define LTC2983_DIODE_IDEAL_FACTOR_MASK	GENMASK(21, 0)
> > +#define LTC2983_DIODE_IDEAL_FACTOR(x) \
> > +				FIELD_PREP(LTC2983_DIODE_IDEAL_FACTOR_M
> > ASK, x)
> > +
> > +#define LTC2983_R_SENSE_VAL_MASK	GENMASK(26, 0)
> > +#define LTC2983_R_SENSE_VAL(x)		FIELD_PREP(LTC2983_R_SE
> > NSE_VAL_MASK, x)
> > +
> > +#define LTC2983_ADC_SINGLE_ENDED_MASK	BIT(26)
> > +#define LTC2983_ADC_SINGLE_ENDED(x) \
> > +				FIELD_PREP(LTC2983_ADC_SINGLE_ENDED_MAS
> > K, x)
> > +
> > +enum {
> > +	LTC2983_SENSOR_THERMOCOUPLE = 1,
> > +	LTC2983_SENSOR_THERMOCOUPLE_CUSTOM = 9,
> > +	LTC2983_SENSOR_RTD = 10,
> > +	LTC2983_SENSOR_RTD_CUSTOM = 18,
> > +	LTC2983_SENSOR_THERMISTOR = 19,
> > +	LTC2983_SENSOR_THERMISTOR_STEINHART = 26,
> > +	LTC2983_SENSOR_THERMISTOR_CUSTOM = 27,
> > +	LTC2983_SENSOR_DIODE = 28,
> > +	LTC2983_SENSOR_SENSE_RESISTOR = 29,
> > +	LTC2983_SENSOR_DIRECT_ADC = 30,
> > +};
> > +
> > +#define to_thermocouple(_sensor) \
> > +		container_of(_sensor, struct ltc2983_thermocouple,
> > sensor)
> > +
> > +#define to_rtd(_sensor) \
> > +		container_of(_sensor, struct ltc2983_rtd, sensor)
> > +
> > +#define to_thermistor(_sensor) \
> > +		container_of(_sensor, struct ltc2983_thermistor,
> > sensor)
> > +
> > +#define to_diode(_sensor) \
> > +		container_of(_sensor, struct ltc2983_diode, sensor)
> > +
> > +#define to_rsense(_sensor) \
> > +		container_of(_sensor, struct ltc2983_rsense, sensor)
> > +
> > +#define to_adc(_sensor) \
> > +		container_of(_sensor, struct ltc2983_adc, sensor)
> > +
> > +struct ltc2983_data {
> > +	struct regmap *regmap;
> > +	struct spi_device *spi;
> > +	struct mutex lock;
> > +	struct completion completion;
> > +	struct iio_chan_spec *iio_chan;
> > +	struct ltc2983_sensor **sensors;
> > +	u32 mux_delay_config;
> > +	u32 filter_notch_freq;
> > +	u16 custom_table_size;
> > +	u8 num_channels;
> > +	u8 iio_channels;
> > +	bool temp_farenheit;
> > +	bool reset;
> > +};
> > +
> > +struct ltc2983_sensor {
> > +	int (*fault_handler)(const struct ltc2983_data *st, const u32
> > result);
> > +	int (*assign_chan)(struct ltc2983_data *st,
> > +			   const struct ltc2983_sensor *sensor);
> > +	const char *name;
> > +	/* specifies the sensor channel */
> > +	u32 chan;
> > +	/* sensor type */
> > +	u32 type;
> > +};
> > +
> > +struct ltc2983_custom_sensor {
> > +	/* raw table sensor data */
> > +	u8 *table;
> > +	size_t size;
> > +	/* address offset */
> > +	s8 offset;
> > +	bool is_steinhart;
> > +};
> > +
> > +struct ltc2983_thermocouple {
> > +	struct ltc2983_sensor sensor;
> > +	struct ltc2983_custom_sensor *custom;
> > +	u32 sensor_config;
> > +	u32 cold_junction_chan;
> > +};
> > +
> > +struct ltc2983_rtd {
> > +	struct ltc2983_sensor sensor;
> > +	struct ltc2983_custom_sensor *custom;
> > +	u32 sensor_config;
> > +	u32 r_sense_chan;
> > +	u32 excitation_current;
> > +	u32 rtd_curve;
> > +};
> > +
> > +struct ltc2983_thermistor {
> > +	struct ltc2983_sensor sensor;
> > +	struct ltc2983_custom_sensor *custom;
> > +	u32 sensor_config;
> > +	u32 r_sense_chan;
> > +	u32 excitation_current;
> > +};
> > +
> > +struct ltc2983_diode {
> > +	struct ltc2983_sensor sensor;
> > +	u32 sensor_config;
> > +	u32 excitation_current;
> > +	u32 ideal_factor_value;
> > +};
> > +
> > +struct ltc2983_rsense {
> > +	struct ltc2983_sensor sensor;
> > +	u32 r_sense_val;
> > +};
> > +
> > +struct ltc2983_adc {
> > +	struct ltc2983_sensor sensor;
> > +	bool single_ended;
> > +};
> > +
> > +/*
> > + * Convert to Q format numbers. These number's are integers where
> > + * the number of integer and fractional bits are specified. The
> > resolution
> > + * is given by 1/@resolution and tell us the number of fractional
> > bits. For
> > + * instance a resolution of 2^-10 means we have 10 fractional
> > bits.
> > + */
> > +static u32 __convert_to_raw(const u64 val, const u32 resolution)
> > +{
> > +	u64 __res = val * resolution;
> > +
> > +	/* all values are multiplied by 1000000 to remove the fraction
> > */
> > +	do_div(__res, 1000000);
> > +
> > +	return __res;
> > +}
> > +
> > +static u32 __convert_to_raw_sign(const u64 val, const u32
> > resolution)
> > +{
> > +	s64 __res = -(s32)val;
> > +
> > +	__res = __convert_to_raw(__res, resolution);
> > +
> > +	return (u32)-__res;
> > +}
> > +
> > +static int __ltc2983_fault_handler(const struct ltc2983_data *st,
> > +				   const u32 result, const u32
> > hard_mask,
> > +				   const u32 soft_mask)
> > +{
> > +	const struct device *dev = &st->spi->dev;
> > +
> > +	if (result & hard_mask) {
> > +		dev_err(dev, "Invalid conversion: Sensor HARD
> > fault\n");
> > +		return -EIO;
> > +	} else if (result & soft_mask) {
> > +		/* just print a warning */
> > +		dev_warn(dev, "Suspicious conversion: Sensor SOFT
> > fault\n");
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static int __ltc2983_chan_assign_common(const struct ltc2983_data
> > *st,
> > +					const struct ltc2983_sensor
> > *sensor,
> > +					u32 chan_val)
> > +{
> > +	u32 reg = LTC2983_CHAN_START_ADDR(sensor->chan);
> > +	__be32 __chan_val;
> > +
> > +	chan_val |= LTC2983_CHAN_TYPE(sensor->type);
> > +	dev_dbg(&st->spi->dev, "Assign %s, reg:0x%04X, val:0x%08X\n",
> > +							sensor->name,
> > +							reg, chan_val);
> > +	__chan_val = cpu_to_be32(chan_val);
> > +	return regmap_bulk_write(st->regmap, reg, &__chan_val,
> > +				 sizeof(__chan_val));
> > +}
> > +
> > +static int __ltc2983_chan_custom_sensor_assign(struct ltc2983_data
> > *st,
> > +					  struct ltc2983_custom_sensor
> > *custom,
> > +					  u32 *chan_val)
> > +{
> > +	u32 reg;
> > +	u8 mult = custom->is_steinhart ?
> > LTC2983_CUSTOM_STEINHART_ENTRY_SZ :
> > +		LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
> > +	const struct device *dev = &st->spi->dev;
> > +	/*
> > +	 * custom->size holds the raw size of the table. However, when
> > +	 * configuring the sensor channel, we must write the number of
> > +	 * entries of the table minus 1. For steinhart sensors 0 is
> > written
> > +	 * since the size is constant!
> > +	 */
> > +	const u8 len = custom->is_steinhart ? 0 :
> > +		(custom->size / LTC2983_CUSTOM_SENSOR_ENTRY_SZ) - 1;
> > +	/*
> > +	 * Check if the offset was assigned already. It should be for
> > steinhart
> > +	 * sensors. When coming from sleep, it should be assigned for
> > all.
> > +	 */
> > +	if (custom->offset < 0) {
> > +		/*
> > +		 * This needs to be done again here because, from the
> > moment
> > +		 * when this test was done (successfully) for this
> > custom
> > +		 * sensor, a steinhart sensor might have been added
> > changing
> > +		 * custom_table_size...
> > +		 */
> > +		if (st->custom_table_size + custom->size >
> > +		    (LTC2983_CUST_SENS_TBL_END_REG -
> > +		     LTC2983_CUST_SENS_TBL_START_REG) + 1) {
> > +			dev_err(dev,
> > +				"Not space left(%d) for new custom
> > sensor(%zu)",
> > +							st-
> > >custom_table_size,
> > +							custom->size);
> > +			return -EINVAL;
> > +		}
> > +
> > +		custom->offset = st->custom_table_size /
> > +					LTC2983_CUSTOM_SENSOR_ENTRY_SZ;
> > +		st->custom_table_size += custom->size;
> > +	}
> > +
> > +	reg = (custom->offset * mult) +
> > LTC2983_CUST_SENS_TBL_START_REG;
> > +
> > +	*chan_val |= LTC2983_CUSTOM_LEN(len);
> > +	*chan_val |= LTC2983_CUSTOM_ADDR(custom->offset);
> > +	dev_dbg(dev, "Assign custom sensor, reg:0x%04X, off:%d,
> > sz:%zu",
> > +							reg, custom-
> > >offset,
> > +							custom->size);
> > +	/* write custom sensor table */
> > +	return regmap_bulk_write(st->regmap, reg, custom->table,
> > custom->size);
> > +}
> > +
> > +static struct ltc2983_custom_sensor *__ltc2983_custom_sensor_new(
> > +						struct ltc2983_data
> > *st,
> > +						const struct
> > device_node *np,
> > +						const bool
> > is_steinhart,
> > +						const u32 resolution,
> > +						const bool has_signed)
> > +{
> > +	struct ltc2983_custom_sensor *new_custom;
> > +	u8 index, n_entries, tbl = 0;
> > +	struct device *dev = &st->spi->dev;
> > +	/*
> > +	 * For custom steinhart, the full u32 is taken. For all the
> > others
> > +	 * the MSB is discarded.
> > +	 */
> > +	const u8 n_size = (is_steinhart == true) ? 4 : 3;
> > +
> > +	n_entries = of_property_count_elems_of_size(np, "adi,custom-
> > sensor",
> > +						sizeof(u64));
> > +	/* n_entries must be an even number */
> > +	if (!n_entries || (n_entries % 2) != 0) {
> > +		dev_err(dev, "Number of entries either 0 or not
> > even\n");
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +
> > +	new_custom = devm_kzalloc(dev, sizeof(*new_custom),
> > GFP_KERNEL);
> > +	if (!new_custom)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	new_custom->size = n_entries * n_size;
> > +	/* check Steinhart size */
> > +	if (is_steinhart && new_custom->size !=
> > LTC2983_CUSTOM_STEINHART_SIZE) {
> > +		dev_err(dev, "Steinhart sensors size(%zu) must be 24",
> > +							new_custom-
> > >size);
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +	/* Check space on the table. */
> > +	if (st->custom_table_size + new_custom->size >
> > +	    (LTC2983_CUST_SENS_TBL_END_REG -
> > +	     LTC2983_CUST_SENS_TBL_START_REG) + 1) {
> > +		dev_err(dev, "No space left(%d) for new custom
> > sensor(%zu)",
> > +				st->custom_table_size, new_custom-
> > >size);
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +
> > +	/* allocate the table */
> > +	new_custom->table = devm_kzalloc(dev, new_custom->size,
> > GFP_KERNEL);
> > +	if (!new_custom->table)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	for (index = 0; index < n_entries; index++) {
> > +		u64 temp = 0, j;
> > +
> > +		of_property_read_u64_index(np, "adi,custom-sensor",
> > index,
> > +					   &temp);
> > +		/*
> > +		 * Steinhart sensors are configured with raw values in
> > the
> > +		 * devicetree. For the other sensors we must convert
> > the
> > +		 * value to raw. The odd index's correspond to
> > temperarures
> > +		 * and always have 1/1024 of resolution. Temperatures
> > also
> > +		 * come in kelvin, so signed values is not possible
> > +		 */
> > +		if (!is_steinhart) {
> > +			if ((index % 2) != 0)
> > +				temp = __convert_to_raw(temp, 1024);
> > +			else if (has_signed && (s64)temp < 0)
> > +				temp = __convert_to_raw_sign(temp,
> > resolution);
> > +			else
> > +				temp = __convert_to_raw(temp,
> > resolution);
> > +		}
> > +
> > +		for (j = 0; j < n_size; j++)
> > +			new_custom->table[tbl++] =
> > +				temp >> (8 * (n_size - j - 1));
> > +	}
> > +
> > +	new_custom->is_steinhart = is_steinhart;
> > +	/*
> > +	 * This is done to first add all the steinhart sensors to the
> > table,
> > +	 * in order to maximize the table usage. If we mix adding
> > steinhart
> > +	 * with the other sensors, we might have to do some roundup to
> > make
> > +	 * sure that sensor_addr - 0x250(start address) is a multiple
> > of 4
> > +	 * (for steinhart), and a multiple of 6 for all the other
> > sensors.
> > +	 * Since we have const 24 bytes for steinhart sensors and 24 is
> > +	 * also a multiple of 6, we guarantee that the first non-
> > steinhart
> > +	 * sensor will sit in a correct address without the need of
> > filling
> > +	 * addresses.
> > +	 */
> > +	if (is_steinhart) {
> > +		new_custom->offset = st->custom_table_size /
> > +					LTC2983_CUSTOM_STEINHART_ENTRY_
> > SZ;
> > +		st->custom_table_size += new_custom->size;
> > +	} else {
> > +		/* mark as unset. This is checked later on the assign
> > phase */
> > +		new_custom->offset = -1;
> > +	}
> > +
> > +	return new_custom;
> > +}
> > +
> > +static int ltc2983_thermocouple_fault_handler(const struct
> > ltc2983_data *st,
> > +					      const u32 result)
> > +{
> > +	return __ltc2983_fault_handler(st, result,
> > +				       LTC2983_THERMOCOUPLE_HARD_FAULT_
> > MASK,
> > +				       LTC2983_THERMOCOUPLE_SOFT_FAULT_
> > MASK);
> > +}
> > +
> > +static int ltc2983_common_fault_handler(const struct ltc2983_data
> > *st,
> > +					const u32 result)
> > +{
> > +	return __ltc2983_fault_handler(st, result,
> > +				       LTC2983_COMMON_HARD_FAULT_MASK,
> > +				       LTC2983_COMMON_SOFT_FAULT_MASK);
> > +}
> > +
> > +static int ltc2983_thermocouple_assign_chan(struct ltc2983_data
> > *st,
> > +				const struct ltc2983_sensor *sensor)
> > +{
> > +	struct ltc2983_thermocouple *thermo = to_thermocouple(sensor);
> > +	u32 chan_val;
> > +
> > +	chan_val = LTC2983_CHAN_ASSIGN(thermo->cold_junction_chan);
> > +	chan_val |= LTC2983_THERMOCOUPLE_CFG(thermo->sensor_config);
> > +
> > +	if (thermo->custom) {
> > +		int ret;
> > +
> > +		ret = __ltc2983_chan_custom_sensor_assign(st, thermo-
> > >custom,
> > +							  &chan_val);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> > +}
> > +
> > +static int ltc2983_rtd_assign_chan(struct ltc2983_data *st,
> > +				   const struct ltc2983_sensor *sensor)
> > +{
> > +	struct ltc2983_rtd *rtd = to_rtd(sensor);
> > +	u32 chan_val;
> > +
> > +	chan_val = LTC2983_CHAN_ASSIGN(rtd->r_sense_chan);
> > +	chan_val |= LTC2983_RTD_CFG(rtd->sensor_config);
> > +	chan_val |= LTC2983_RTD_EXC_CURRENT(rtd->excitation_current);
> > +	chan_val |= LTC2983_RTD_CURVE(rtd->rtd_curve);
> > +
> > +	if (rtd->custom) {
> > +		int ret;
> > +
> > +		ret = __ltc2983_chan_custom_sensor_assign(st, rtd-
> > >custom,
> > +							  &chan_val);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> > +}
> > +
> > +static int ltc2983_thermistor_assign_chan(struct ltc2983_data *st,
> > +					  const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_thermistor *thermistor = to_thermistor(sensor);
> > +	u32 chan_val;
> > +
> > +	chan_val = LTC2983_CHAN_ASSIGN(thermistor->r_sense_chan);
> > +	chan_val |= LTC2983_THERMISTOR_CFG(thermistor->sensor_config);
> > +	chan_val |=
> > +		LTC2983_THERMISTOR_EXC_CURRENT(thermistor-
> > >excitation_current);
> > +
> > +	if (thermistor->custom) {
> > +		int ret;
> > +
> > +		ret = __ltc2983_chan_custom_sensor_assign(st,
> > +							  thermistor-
> > >custom,
> > +							  &chan_val);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> > +}
> > +
> > +static int ltc2983_diode_assign_chan(struct ltc2983_data *st,
> > +				     const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_diode *diode = to_diode(sensor);
> > +	u32 chan_val;
> > +
> > +	chan_val = LTC2983_DIODE_CFG(diode->sensor_config);
> > +	chan_val |= LTC2983_DIODE_EXC_CURRENT(diode-
> > >excitation_current);
> > +	chan_val |= LTC2983_DIODE_IDEAL_FACTOR(diode-
> > >ideal_factor_value);
> > +
> > +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> > +}
> > +
> > +static int ltc2983_r_sense_assign_chan(struct ltc2983_data *st,
> > +				       const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_rsense *rsense = to_rsense(sensor);
> > +	u32 chan_val;
> > +
> > +	chan_val = LTC2983_R_SENSE_VAL(rsense->r_sense_val);
> > +
> > +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> > +}
> > +
> > +static int ltc2983_adc_assign_chan(struct ltc2983_data *st,
> > +				   const struct ltc2983_sensor *sensor)
> > +{
> > +	struct ltc2983_adc *adc = to_adc(sensor);
> > +	u32 chan_val;
> > +
> > +	chan_val = LTC2983_ADC_SINGLE_ENDED(adc->single_ended);
> > +
> > +	return __ltc2983_chan_assign_common(st, sensor, chan_val);
> > +}
> > +
> > +static struct ltc2983_sensor *ltc2983_thermocouple_new(
> > +					const struct device_node
> > *child,
> > +					struct ltc2983_data *st,
> > +					const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_thermocouple *thermo;
> > +	struct device_node *phandle;
> > +
> > +	thermo = devm_kzalloc(&st->spi->dev, sizeof(*thermo),
> > GFP_KERNEL);
> > +	if (!thermo)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	of_property_read_u32(child, "adi,sensor-config",
> > +				 &thermo->sensor_config);
> > +	/* validate channel index */
> > +	if (!(thermo->sensor_config & LTC2983_THERMOCOUPLE_DIFF_MASK)
> > &&
> > +	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> > +		dev_err(&st->spi->dev,
> > +			"Invalid chann:%d for differential
> > thermocouple",
> > +								sensor-
> > >chan);
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +
> > +	phandle = of_parse_phandle(child, "adi,cold-junction-handle",
> > 0);
> > +	if (phandle) {
> > +		int ret;
> > +
> > +		ret = of_property_read_u32(phandle, "reg",
> > +					   &thermo-
> > >cold_junction_chan);
> > +		if (ret) {
> > +			/*
> > +			 * This would be catched later but we can just
> > return
> > +			 * the error right away.
> > +			 */
> > +			dev_err(&st->spi->dev, "Property reg must be
> > given\n");
> > +			of_node_put(phandle);
> > +			return ERR_PTR(-EINVAL);
> > +		}
> > +	}
> > +
> > +	/* check custom sensor */
> > +	if (sensor->type == LTC2983_SENSOR_THERMOCOUPLE_CUSTOM) {
> > +		thermo->custom = __ltc2983_custom_sensor_new(st, child,
> > false,
> > +							     16384,
> > true);
> > +		if (IS_ERR(thermo->custom)) {
> > +			of_node_put(phandle);
> > +			return ERR_CAST(thermo->custom);
> > +		}
> > +	}
> > +
> > +	/* set common parameters */
> > +	thermo->sensor.name = "thermocouple";
> > +	thermo->sensor.fault_handler =
> > ltc2983_thermocouple_fault_handler;
> > +	thermo->sensor.assign_chan = ltc2983_thermocouple_assign_chan;
> > +
> > +	of_node_put(phandle);
> > +	return &thermo->sensor;
> > +}
> > +
> > +static struct ltc2983_sensor *ltc2983_rtd_new(const struct
> > device_node *child,
> > +					  struct ltc2983_data *st,
> > +					  const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_rtd *rtd;
> > +	int ret = 0;
> > +	struct device *dev = &st->spi->dev;
> > +	struct device_node *phandle;
> > +
> > +	rtd = devm_kzalloc(dev, sizeof(*rtd), GFP_KERNEL);
> > +	if (!rtd)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	phandle = of_parse_phandle(child, "adi,rsense-handle", 0);
> > +	if (!phandle) {
> > +		dev_err(dev, "Property adi,rsense-handle missing or
> > invalid");
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +
> > +	ret = of_property_read_u32(phandle, "reg",
> > +				&rtd->r_sense_chan);
> 
> Doesn't look like that lines needs wrapping. Check for similar
> elsewhere.

ack.

> > +	if (ret) {
> > +		dev_err(dev, "Property reg must be given\n");
> > +		goto fail;
> > +	}
> > +
> > +	of_property_read_u32(child, "adi,sensor-config", &rtd-
> > >sensor_config);
> > +	/*
> > +	 * rtd channel indexes are a bit more complicated to validate.
> > +	 * For 4wire RTD with rotation, the channel selection cannot be
> > +	 * >=19 since the chann + 1 is used in this configuration.
> > +	 * For 4wire RTDs with kelvin rsense, the rsense channel cannot
> > be
> > +	 * <=1 since chanel - 1 and channel - 2 are used.
> > +	 */
> > +	if (rtd->sensor_config & LTC2983_RTD_4_WIRE_MASK) {
> > +		/* 4-wire */
> > +		u8 min = LTC2983_DIFFERENTIAL_CHAN_MIN,
> > +			max = LTC2983_MAX_CHANNELS_NR;
> > +
> > +		if (rtd->sensor_config & LTC2983_RTD_ROTATION_MASK)
> > +			max = LTC2983_MAX_CHANNELS_NR - 1;
> > +
> > +		if (((rtd->sensor_config &
> > LTC2983_RTD_KELVIN_R_SENSE_MASK)
> > +		     == LTC2983_RTD_KELVIN_R_SENSE_MASK) &&
> > +		    (rtd->r_sense_chan <=  min)) {
> > +			/* kelvin rsense*/
> > +			dev_err(dev,
> > +				"Invalid rsense chann:%d to use in
> > kelvin rsense",
> > +							rtd-
> > >r_sense_chan);
> > +
> > +			ret = -EINVAL;
> > +			goto fail;
> > +		}
> > +
> > +		if (sensor->chan < min || sensor->chan > max) {
> > +			dev_err(dev, "Invalid chann:%d for the rtd
> > config",
> > +								sensor-
> > >chan);
> > +
> > +			ret = -EINVAL;
> > +			goto fail;
> > +		}
> > +	} else {
> > +		/* same as differential case */
> > +		if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> > +			dev_err(&st->spi->dev,
> > +				"Invalid chann:%d for RTD", sensor-
> > >chan);
> > +
> > +			ret = -EINVAL;
> > +			goto fail;
> > +		}
> > +	}
> > +
> > +	/* check custom sensor */
> > +	if (sensor->type == LTC2983_SENSOR_RTD_CUSTOM) {
> > +		rtd->custom = __ltc2983_custom_sensor_new(st, child,
> > false,
> > +							  2048, false);
> > +		if (IS_ERR(rtd->custom)) {
> > +			of_node_put(phandle);
> > +			return ERR_CAST(rtd->custom);
> > +		}
> > +	}
> > +
> > +	/* set common parameters */
> > +	rtd->sensor.name = "rtd";
> > +	rtd->sensor.fault_handler = ltc2983_common_fault_handler;
> > +	rtd->sensor.assign_chan = ltc2983_rtd_assign_chan;
> > +
> > +	ret = of_property_read_u32(child, "adi,excitation-current",
> > +				   &rtd->excitation_current);
> > +	if (ret)
> > +		/* default to 1uA */
> > +		rtd->excitation_current = 1;
> > +
> > +	of_property_read_u32(child, "adi,rtd-curve", &rtd->rtd_curve);
> > +
> > +	of_node_put(phandle);
> > +	return &rtd->sensor;
> > +fail:
> > +	of_node_put(phandle);
> > +	return ERR_PTR(ret);
> > +}
> > +
> > +static struct ltc2983_sensor *ltc2983_thermistor_new(
> > +					const struct device_node
> > *child,
> > +					struct ltc2983_data *st,
> > +					const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_thermistor *thermistor;
> > +	struct device *dev = &st->spi->dev;
> > +	struct device_node *phandle;
> > +	int ret = 0;
> > +
> > +	thermistor = devm_kzalloc(dev, sizeof(*thermistor),
> > GFP_KERNEL);
> > +	if (!thermistor)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	phandle = of_parse_phandle(child, "adi,rsense-handle", 0);
> > +	if (!phandle) {
> > +		dev_err(dev, "Property adi,rsense-handle missing or
> > invalid");
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +
> > +	ret = of_property_read_u32(phandle, "reg",
> > +				   &thermistor->r_sense_chan);
> > +	if (ret) {
> > +		dev_err(dev, "rsense channel must be configured...\n");
> > +		goto fail;
> > +	}
> > +
> > +	of_property_read_u32(child, "adi,sensor-config",
> > +			     &thermistor->sensor_config);
> > +	/* validate channel index */
> > +	if (!(thermistor->sensor_config & LTC2983_THERMISTOR_DIFF_MASK)
> > &&
> > +	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> > +		dev_err(&st->spi->dev,
> > +			"Invalid chann:%d for differential thermistor",
> > +								sensor-
> > >chan);
> > +		ret = -EINVAL;
> > +		goto fail;
> > +	}
> > +
> > +	/* check custom sensor */
> > +	if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART) {
> > +		thermistor->custom = __ltc2983_custom_sensor_new(st,
> > child,
> > +			sensor->type ==
> > LTC2983_SENSOR_THERMISTOR_STEINHART ?
> > +							  true : false,
> > 64,
> > +							  false);
> > +		if (IS_ERR(thermistor->custom)) {
> > +			of_node_put(phandle);
> > +			return ERR_CAST(thermistor->custom);
> > +		}
> > +	}
> > +	/* set common parameters */
> > +	thermistor->sensor.name = "thermistor";
> > +	thermistor->sensor.fault_handler =
> > ltc2983_common_fault_handler;
> > +	thermistor->sensor.assign_chan =
> > ltc2983_thermistor_assign_chan;
> > +
> > +	ret = of_property_read_u32(child, "adi,excitation-current",
> > +				   &thermistor->excitation_current);
> > +	if (ret)
> > +		/* default to auto-range */
> > +		thermistor->excitation_current = 0x0c;
> > +
> > +	of_node_put(phandle);
> > +	return &thermistor->sensor;
> > +fail:
> > +	of_node_put(phandle);
> > +	return ERR_PTR(ret);
> > +}
> > +
> > +static struct ltc2983_sensor *ltc2983_diode_new(
> > +					const struct device_node
> > *child,
> > +					const struct ltc2983_data *st,
> > +					const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_diode *diode;
> > +	u32 temp = 0;
> > +
> > +	diode = devm_kzalloc(&st->spi->dev, sizeof(*diode),
> > GFP_KERNEL);
> > +	if (!diode)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	of_property_read_u32(child, "adi,sensor-config", &diode-
> > >sensor_config);
> > +	/* validate channel index */
> > +	if (!(diode->sensor_config & LTC2983_DIODE_DIFF_MASK) &&
> > +	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> > +		dev_err(&st->spi->dev,
> > +			"Invalid chann:%d for differential thermistor",
> > +								sensor-
> > >chan);
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +	/* set common parameters */
> > +	diode->sensor.name = "diode";
> > +	diode->sensor.fault_handler = ltc2983_common_fault_handler;
> > +	diode->sensor.assign_chan = ltc2983_diode_assign_chan;
> > +
> > +	of_property_read_u32(child, "adi,excitation-current",
> > +			     &diode->excitation_current);
> > +
> > +	of_property_read_u32(child, "adi,ideal-factor-value", &temp);
> > +
> > +	/* 2^20 resolution */
> > +	diode->ideal_factor_value = __convert_to_raw(temp, 1048576);
> > +
> > +	return &diode->sensor;
> > +}
> > +
> > +static struct ltc2983_sensor *ltc2983_r_sense_new(struct
> > device_node *child,
> > +					struct ltc2983_data *st,
> > +					const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_rsense *rsense;
> > +	int ret;
> > +	u64 temp;
> > +
> > +	rsense = devm_kzalloc(&st->spi->dev, sizeof(*rsense),
> > GFP_KERNEL);
> > +	if (!rsense)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	/* validate channel index */
> > +	if (sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> > +		dev_err(&st->spi->dev, "Invalid chann:%d for r_sense",
> > +							sensor->chan);
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +	/* get raw value */
> > +	ret = of_property_read_u64(child, "adi,rsense-val-micro-ohms",
> > &temp);
> > +	if (ret) {
> > +		dev_err(&st->spi->dev, "Property adi,rsense-val-micro-
> > ohms missing\n");
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +
> > +	/* 2^10 resolution */
> > +	rsense->r_sense_val = __convert_to_raw(temp, 1024);
> > +
> > +	/* set common parameters */
> > +	rsense->sensor.name = "r_sense";
> > +	rsense->sensor.assign_chan = ltc2983_r_sense_assign_chan;
> > +
> > +	return &rsense->sensor;
> > +}
> > +
> > +static struct ltc2983_sensor *ltc2983_adc_new(struct device_node
> > *child,
> > +					 struct ltc2983_data *st,
> > +					 const struct ltc2983_sensor
> > *sensor)
> > +{
> > +	struct ltc2983_adc *adc;
> > +
> > +	adc = devm_kzalloc(&st->spi->dev, sizeof(*adc), GFP_KERNEL);
> > +	if (!adc)
> > +		return ERR_PTR(-ENOMEM);
> > +
> > +	if (of_property_read_bool(child, "adi,single-ended"))
> > +		adc->single_ended = true;
> > +
> > +	if (!adc->single_ended &&
> > +	    sensor->chan < LTC2983_DIFFERENTIAL_CHAN_MIN) {
> > +		dev_err(&st->spi->dev, "Invalid chan:%d for
> > differential adc\n",
> > +								sensor-
> > >chan);
> > +		return ERR_PTR(-EINVAL);
> > +	}
> > +	/* set common parameters */
> > +	adc->sensor.name = "direct_adc";
> > +	adc->sensor.assign_chan = ltc2983_adc_assign_chan;
> > +	adc->sensor.fault_handler = ltc2983_common_fault_handler;
> > +
> > +	return &adc->sensor;
> > +}
> > +
> > +static int ltc2983_chan_read(struct ltc2983_data *st,
> > +			const struct ltc2983_sensor *sensor, int *val)
> > +{
> > +	u32 start_conversion = 0;
> > +	int ret;
> > +	unsigned long time;
> > +	__be32 temp;
> > +
> > +	/*
> > +	 * Do not allow channel readings if device is in sleep state.
> > +	 * A read/write on the spi bus would bring the device
> > prematurely
> > +	 * out of sleep.
> > +	 */
> > +	if (st->reset)
> > +		return -EPERM;
> > +
> > +	start_conversion = LTC2983_STATUS_START(true);
> > +	start_conversion |= LTC2983_STATUS_CHAN_SEL(sensor->chan);
> > +	dev_dbg(&st->spi->dev, "Start conversion on chan:%d,
> > status:%02X\n",
> > +		sensor->chan, start_conversion);
> > +	/* start conversion */
> > +	ret = regmap_write(st->regmap, LTC2983_STATUS_REG,
> > start_conversion);
> > +	if (ret)
> > +		return ret;
> > +
> > +	reinit_completion(&st->completion);
> > +	/*
> > +	 * wait for conversion to complete.
> > +	 * 300 ms should be more than enough to complete the
> > conversion.
> > +	 * Depending on the sensor configuration, there are 2/3
> > conversions
> > +	 * cycles of 82ms.
> > +	 */
> > +	time = wait_for_completion_timeout(&st->completion,
> > +					   msecs_to_jiffies(300));
> > +	if (!time) {
> > +		dev_warn(&st->spi->dev, "Conversion timed out\n");
> > +		return -ETIMEDOUT;
> > +	}
> > +
> > +	/* read the converted data */
> > +	ret = regmap_bulk_read(st->regmap,
> > LTC2983_CHAN_RES_ADDR(sensor->chan),
> > +			       &temp, sizeof(temp));
> > +	if (ret)
> > +		return ret;
> > +
> > +	*val = __be32_to_cpu(temp);
> > +	dev_dbg(&st->spi->dev, "Converted data: 0x%08X
> > (addr:0x%04X)\n", *val,
> > +					LTC2983_CHAN_RES_ADDR(sensor-
> > >chan));
> 
> Probably drop all the dev_dbg stuff unless it is providing
> information that
> isn't otherwise available (from reading channel etc, kprobe /
> ftrace).

ack.

> > +
> > +	if (!(LTC2983_RES_VALID_MASK & *val)) {
> > +		dev_err(&st->spi->dev, "Invalid conversion
> > detected\n");
> > +		return -EIO;
> > +	}
> > +
> > +	ret = sensor->fault_handler(st, *val);
> > +	if (ret)
> > +		return ret;
> > +
> > +	*val = sign_extend32((*val) & LTC2983_DATA_MASK,
> > LTC2983_DATA_SIGN_BIT);
> > +	return 0;
> > +}
> > +
> > +static int ltc2983_read_raw(struct iio_dev *indio_dev,
> > +			    struct iio_chan_spec const *chan,
> > +			    int *val, int *val2, long mask)
> > +{
> > +	struct ltc2983_data *st = iio_priv(indio_dev);
> > +	int ret;
> > +
> > +	/* sanity check */
> > +	if (chan->address >= st->num_channels) {
> > +		dev_err(&st->spi->dev, "Invalid chan address:%ld",
> > +							chan->address);
> > +		return -EINVAL;
> > +	}
> > +	switch (mask) {
> > +	case IIO_CHAN_INFO_RAW:
> > +		mutex_lock(&st->lock);
> > +		ret = ltc2983_chan_read(st, st->sensors[chan->address], 
> > val);
> > +		mutex_unlock(&st->lock);
> > +		return ret ?: IIO_VAL_INT;
> > +	case IIO_CHAN_INFO_SCALE:
> > +		switch (chan->type) {
> > +		case IIO_TEMP:
> > +			*val = 1;
> > +			/* 2^10 */
> > +			*val2 = 1024;
> > +			return IIO_VAL_FRACTIONAL;
> > +		case IIO_VOLTAGE:
> > +			*val = 1;
> > +			/* 2^21 */
> > +			*val2 = 2097152;
> > +			return IIO_VAL_FRACTIONAL;
> > +		default:
> > +			return -EINVAL;
> > +		}
> > +	}
> > +
> > +	return -EINVAL;
> > +}
> > +
> > +static int ltc2983_reg_access(struct iio_dev *indio_dev,
> > +			      unsigned int reg,
> > +			      unsigned int writeval,
> > +			      unsigned int *readval)
> > +{
> > +	struct ltc2983_data *st = iio_priv(indio_dev);
> > +
> > +	/* check comment in ltc2983_chan_read() */
> > +	if (st->reset)
> > +		return -EPERM;
> > +
> > +	if (readval)
> > +		return regmap_read(st->regmap, reg, readval);
> > +	else
> > +		return regmap_write(st->regmap, reg, writeval);
> > +}
> > +
> > +static irqreturn_t ltc2983_irq_handler(int irq, void *data)
> > +{
> > +	struct ltc2983_data *st = data;
> > +
> > +	complete(&st->completion);
> > +	return IRQ_HANDLED;
> > +}
> > +
> > +#define LTC2983_CHAN(__type, index, __address, ext_name) ({ \
> > +	struct iio_chan_spec __chan = { \
> > +		.type = __type, \
> > +		.indexed = 1, \
> > +		.channel = index, \
> > +		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
> > +		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
> > +		.address = __address, \
> > +		.extend_name = ext_name, \
> > +	}; \
> > +	__chan; \
> > +})
> > +
> > +static int ltc2983_parse_dt(struct ltc2983_data *st)
> > +{
> > +	struct device_node *child;
> > +	struct device *dev = &st->spi->dev;
> > +	int ret = 0, chan = 0, channel_avail_mask = 0;
> > +
> > +	if (!of_property_read_bool(dev->of_node, "adi,temperature-
> > celcius"))
> > +		st->temp_farenheit = true;
> > +
> > +	of_property_read_u32(dev->of_node, "adi,mux-delay-config",
> > +			     &st->mux_delay_config);
> > +
> > +	of_property_read_u32(dev->of_node, "adi,filter-notch-freq",
> > +			     &st->filter_notch_freq);
> > +
> > +	st->num_channels = of_get_available_child_count(dev->of_node);
> > +	st->sensors = devm_kcalloc(dev, st->num_channels, sizeof(*st-
> > >sensors),
> > +				   GFP_KERNEL);
> > +	if (!st->sensors)
> > +		return -ENOMEM;
> > +
> > +	st->iio_channels = st->num_channels;
> > +	for_each_available_child_of_node(dev->of_node, child) {
> > +		struct ltc2983_sensor sensor;
> > +
> > +		ret = of_property_read_u32(child, "reg", &sensor.chan);
> > +		if (ret) {
> > +			dev_err(dev, "reg property must given for child
> > nodes\n");
> > +			return ret;
> > +		}
> > +
> > +		/* check if we have a valid channel */
> > +		if (sensor.chan < LTC2983_MIN_CHANNELS_NR ||
> > +		    sensor.chan > LTC2983_MAX_CHANNELS_NR) {
> > +			dev_err(dev,
> > +				"chan:%d must be from 1 to 20\n",
> > sensor.chan);
> > +			return -EINVAL;
> > +		} else if (channel_avail_mask & BIT(sensor.chan)) {
> > +			dev_err(dev, "chan:%d already in use\n",
> > sensor.chan);
> > +			return -EINVAL;
> > +		}
> > +
> > +		ret = of_property_read_u32(child, "adi,sensor-type",
> > +					       &sensor.type);
> > +		if (ret) {
> > +			dev_err(dev,
> > +				"adi,sensor-type property must given
> > for child nodes\n");
> > +			return ret;
> > +		}
> > +
> > +		dev_dbg(dev, "Create new sensor, type %u, chann %u",
> > +								sensor.
> > type,
> > +								sensor.
> > chan);
> > +
> > +		if (sensor.type >= LTC2983_SENSOR_THERMOCOUPLE &&
> > +		    sensor.type <= LTC2983_SENSOR_THERMOCOUPLE_CUSTOM)
> > {
> > +			st->sensors[chan] =
> > ltc2983_thermocouple_new(child, st,
> > +								     &s
> > ensor);
> > +		} else if (sensor.type >= LTC2983_SENSOR_RTD &&
> > +			   sensor.type <= LTC2983_SENSOR_RTD_CUSTOM) {
> > +			st->sensors[chan] = ltc2983_rtd_new(child, st,
> > &sensor);
> > +		} else if (sensor.type >= LTC2983_SENSOR_THERMISTOR &&
> > +			   sensor.type <=
> > LTC2983_SENSOR_THERMISTOR_CUSTOM) {
> > +			st->sensors[chan] =
> > ltc2983_thermistor_new(child, st,
> > +								   &sen
> > sor);
> > +		} else if (sensor.type == LTC2983_SENSOR_DIODE) {
> > +			st->sensors[chan] = ltc2983_diode_new(child,
> > st,
> > +							      &sensor);
> > +		} else if (sensor.type ==
> > LTC2983_SENSOR_SENSE_RESISTOR) {
> > +			st->sensors[chan] = ltc2983_r_sense_new(child,
> > st,
> > +								&sensor
> > );
> > +			/* don't add rsense to iio */
> > +			st->iio_channels--;
> > +		} else if (sensor.type == LTC2983_SENSOR_DIRECT_ADC) {
> > +			st->sensors[chan] = ltc2983_adc_new(child, st,
> > &sensor);
> > +		} else {
> > +			dev_err(dev, "Unknown sensor type %d\n",
> > sensor.type);
> > +			return -EINVAL;
> > +		}
> > +
> > +		if (IS_ERR(st->sensors[chan])) {
> > +			dev_err(dev, "Failed to create sensor %ld",
> > +						PTR_ERR(st-
> > >sensors[chan]));
> > +			return PTR_ERR(st->sensors[chan]);
> > +		}
> > +		/* set generic sensor parameters */
> > +		st->sensors[chan]->chan = sensor.chan;
> > +		st->sensors[chan]->type = sensor.type;
> > +
> > +		channel_avail_mask |= BIT(sensor.chan);
> > +		chan++;
> > +	}
> > +	/* allocate iio_chan array */
> 
> This last block isn't really about parsing the DT, perhaps drop it
> out of
> here?
Hmm that is true. I can just allocate the iio_chan array in the setup
function.
> > +	st->iio_chan = devm_kzalloc(dev,
> > +				    st->iio_channels * sizeof(*st-
> > >iio_chan),
> > +				    GFP_KERNEL);
> > +	if (!st->iio_chan)
> > +		return -ENOMEM;
> > +
> > +	return 0;
> > +}
> > +
> > +static int ltc2983_setup(struct ltc2983_data *st, bool assign_iio)
> > +{
> > +	u32 iio_chan_t = 0, iio_chan_v = 0, chan, iio_idx = 0;
> > +	u32 global_cfg = 0;
> > +	int ret;
> > +	unsigned long time;
> > +
> > +	/* make sure the device is up */
> > +	time = wait_for_completion_timeout(&st->completion,
> > +					    msecs_to_jiffies(250));
> > +	if (!time) {
> > +		dev_err(&st->spi->dev, "Device startup timed out\n");
> > +		return -ETIMEDOUT;
> > +	}
> 
> Blank line here, slightly helps readability be clearly separating the
> error handling path from normal flow.
ack.
> > +	/* set generic global cfg and mux delay */
> 
> Not sure this comment adds anything not obvious from the
> code.  Comments
> like this are always at risk of 'rotting' over time, so better to not
> put them if they don't bring significant value.
> 
I will drop it.
> > +	global_cfg = LTC2983_NOTCH_FREQ(st->filter_notch_freq);
> > +	global_cfg |= LTC2983_TEMP_UNITS(st->temp_farenheit);
> > +	regmap_write(st->regmap, LTC2983_GLOBAL_CONFIG_REG,
> > global_cfg);
> > +	regmap_write(st->regmap, LTC2983_MUX_CONFIG_REG, st-
> > >mux_delay_config);
> > +	/* setup channels */
> 
> This comment also not stating anything non obvious.
I will drop it.
> > +	for (chan = 0; chan < st->num_channels; chan++) {
> > +		u32 chan_type = 0, *iio_chan;
> > +
> > +		ret = st->sensors[chan]->assign_chan(st, st-
> > >sensors[chan]);
> > +		if (ret)
> > +			return ret;
> > +		/*
> > +		 * The assign_iio flag is necessary for when the device
> > is
> > +		 * coming out of sleep. In that case, we just need to
> > +		 * re-configure the device channels.
> > +		 * We also don't assign iio channels for rsense.
> > +		 */
> > +		if (st->sensors[chan]->type ==
> > LTC2983_SENSOR_SENSE_RESISTOR ||
> > +		    !assign_iio)
> > +			continue;
> > +
> > +		/* assign iio channel */
> > +		if (st->sensors[chan]->type !=
> > LTC2983_SENSOR_DIRECT_ADC) {
> > +			chan_type = IIO_TEMP;
> > +			iio_chan = &iio_chan_t;
> > +		} else {
> > +			chan_type = IIO_VOLTAGE;
> > +			iio_chan = &iio_chan_v;
> > +		}
> > +
> > +		/*
> > +		 * add chan as the iio .address so that, we can
> > directly
> > +		 * reference the sensor given the iio_chan_spec
> > +		 */
> > +		st->iio_chan[iio_idx++] = LTC2983_CHAN(chan_type,
> > (*iio_chan)++,
> > +						       chan,
> > +						       st-
> > >sensors[chan]->name);
> > +	}
> > +
> > +	return 0;
> > +}
> > +
> > +static const struct regmap_range ltc2983_reg_ranges[] = {
> > +	regmap_reg_range(LTC2983_STATUS_REG, LTC2983_STATUS_REG),
> > +	regmap_reg_range(LTC2983_TEMP_RES_START_REG,
> > LTC2983_TEMP_RES_END_REG),
> > +	regmap_reg_range(LTC2983_GLOBAL_CONFIG_REG,
> > LTC2983_GLOBAL_CONFIG_REG),
> > +	regmap_reg_range(LTC2983_MULT_CHANNEL_START_REG,
> > +			 LTC2983_MULT_CHANNEL_END_REG),
> > +	regmap_reg_range(LTC2983_MUX_CONFIG_REG,
> > LTC2983_MUX_CONFIG_REG),
> > +	regmap_reg_range(LTC2983_CHAN_ASSIGN_START_REG,
> > +			 LTC2983_CHAN_ASSIGN_END_REG),
> > +	regmap_reg_range(LTC2983_CUST_SENS_TBL_START_REG,
> > +			 LTC2983_CUST_SENS_TBL_END_REG),
> > +};
> > +
> > +static const struct regmap_access_table ltc2983_reg_table = {
> > +	.yes_ranges = ltc2983_reg_ranges,
> > +	.n_yes_ranges = ARRAY_SIZE(ltc2983_reg_ranges),
> > +};
> 
> Blank line here.
ack.
> > +/*
> > + *  The reg_bits are actually 12 but the device needs the first
> > *complete*
> > + *  byte for the command (R/W).
> > + */
> > +static const struct regmap_config ltc2983_regmap_config = {
> > +	.reg_bits = 24,
> > +	.val_bits = 8,
> > +	.wr_table = &ltc2983_reg_table,
> > +	.rd_table = &ltc2983_reg_table,
> > +	.read_flag_mask = GENMASK(1, 0),
> > +	.write_flag_mask = BIT(1),
> > +};
> > +
> > +static const struct  iio_info ltc2983_iio_info = {
> > +	.read_raw = ltc2983_read_raw,
> > +	.debugfs_reg_access = ltc2983_reg_access,
> > +};
> > +
> > +static int ltc2983_probe(struct spi_device *spi)
> > +{
> > +	struct ltc2983_data *st;
> > +	struct iio_dev *indio_dev;
> > +	const char *name = spi_get_device_id(spi)->name;
> > +	int ret;
> > +
> > +	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
> > +	if (!indio_dev)
> > +		return -ENOMEM;
> > +
> > +	st = iio_priv(indio_dev);
> > +
> > +	st->regmap = devm_regmap_init_spi(spi, &ltc2983_regmap_config);
> > +	if (IS_ERR(st->regmap)) {
> > +		dev_err(&spi->dev, "Failed to initialize regmap\n");
> > +		return PTR_ERR(st->regmap);
> > +	}
> > +
> > +	mutex_init(&st->lock);
> > +	init_completion(&st->completion);
> > +	st->spi = spi;
> > +	spi_set_drvdata(spi, st);
> > +
> > +	ret = ltc2983_parse_dt(st);
> > +	if (ret)
> > +		return ret;
> > +	/*
> > +	 * let's request the irq now so it is used to sync the device
> > +	 * startup in ltc2983_setup()
> > +	 */
> > +	ret = devm_request_threaded_irq(&spi->dev, spi->irq, NULL,
> > +					ltc2983_irq_handler,
> > IRQF_ONESHOT |
> > +					IRQF_TRIGGER_RISING, name, st);
> > +	if (ret) {
> > +		dev_err(&spi->dev, "failed to request an irq, %d",
> > ret);
> > +		return ret;
> > +	}
> > +
> > +	ret = ltc2983_setup(st, true);
> > +	if (ret)
> > +		return ret;
> > +
> > +	indio_dev->dev.parent = &spi->dev;
> > +	indio_dev->name = name;
> > +	indio_dev->num_channels = st->iio_channels;
> > +	indio_dev->channels = st->iio_chan;
> > +	indio_dev->modes = INDIO_DIRECT_MODE;
> > +	indio_dev->info = &ltc2983_iio_info;
> > +
> > +	return devm_iio_device_register(&spi->dev, indio_dev);
> > +}
> > +
> > +static int __maybe_unused ltc2983_resume(struct device *dev)
> > +{
> > +	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
> > +	int ret;
> > +
> > +	mutex_lock(&st->lock);
> > +	/* dummy read to bring the device out of sleep */
> > +	regmap_read(st->regmap, LTC2983_STATUS_REG, &ret);
> > +	/* we need to re-assign the channels */
> > +	ret = ltc2983_setup(st, false);
> > +	st->reset = false;
> > +	mutex_unlock(&st->lock);
> > +
> > +	return ret;
> > +}
> > +
> > +static int __maybe_unused ltc2983_suspend(struct device *dev)
> > +{
> > +	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
> > +	int ret;
> > +
> > +	mutex_lock(&st->lock);
> > +	ret = regmap_write(st->regmap, LTC2983_STATUS_REG,
> > LTC2983_SLEEP);
> > +	st->reset = true;
> 
> Naming seems a bit odd. The register field is called sleep, but we
> call
> it reset internally?
I agree. Something like `suspend` or `sleep` for the boolean would be
ok?
> > +	mutex_unlock(&st->lock);
> > +
> > +	return ret;
> > +}
> > +
> > +static SIMPLE_DEV_PM_OPS(ltc2983_pm_ops, ltc2983_suspend,
> > ltc2983_resume);
> > +
> > +static const struct spi_device_id ltc2983_id_table[] = {
> > +	{ "ltc2983" },
> > +	{},
> > +};
> > +MODULE_DEVICE_TABLE(spi, ltc2983_id_table);
> > +
> > +static const struct of_device_id ltc2983_of_match[] = {
> > +	{ .compatible = "adi,ltc2983" },
> > +	{},
> > +};
> > +MODULE_DEVICE_TABLE(of, ltc2983_id_table);
> > +
> > +static struct spi_driver ltc2983_driver = {
> > +	.driver = {
> > +		.name = "ltc2983",
> > +		.of_match_table = ltc2983_of_match,
> > +		.pm = &ltc2983_pm_ops,
> > +	},
> > +	.probe = ltc2983_probe,
> > +	.id_table = ltc2983_id_table,
> > +};
> > +
> > +module_spi_driver(ltc2983_driver);
> > +
> > +MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
> > +MODULE_DESCRIPTION("Analog Devices LTC2983 SPI Temperature
> > sensors");
> > +MODULE_LICENSE("GPL");


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation
  2019-09-15 11:07     ` Jonathan Cameron
@ 2019-09-16 15:20       ` Sa, Nuno
  2019-09-17  1:09         ` Rob Herring
  0 siblings, 1 reply; 11+ messages in thread
From: Sa, Nuno @ 2019-09-16 15:20 UTC (permalink / raw)
  To: robh, jic23; +Cc: mark.rutland, devicetree, knaack.h, linux-iio, pmeerw, lars

Hi Rob and Jonathan,

Some comments/questions inline.

Nuno Sá

On Sun, 2019-09-15 at 12:07 +0100, Jonathan Cameron wrote:
> 
> On Fri, 13 Sep 2019 15:36:21 +0100
> Rob Herring <robh@kernel.org> wrote:
> 
> > On Mon, Sep 09, 2019 at 04:45:50PM +0200, Nuno Sá wrote:
> > > Document the LTC2983 temperature sensor devicetree bindings.
> > > 
> > > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > > ---
> > >  .../bindings/iio/temperature/adi,ltc2983.yaml | 442
> > > ++++++++++++++++++
> > >  MAINTAINERS                                   |   1 +
> > >  2 files changed, 443 insertions(+)
> > >  create mode 100644
> > > Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yam
> > > l
> > > 
> > > diff --git
> > > a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > aml
> > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > aml
> > > new file mode 100644
> > > index 000000000000..2b468b3ed177
> > > --- /dev/null
> > > +++
> > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > aml
> > > @@ -0,0 +1,442 @@
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +%YAML 1.2
> > > +---
> > > +$id: 
> > > http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
> > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > +
> > > +title: Analog Devices LTC2983 Multi-sensor Temperature system
> > > +
> > > +maintainers:
> > > +  - Nuno Sá <nuno.sa@analog.com>
> > > +
> > > +description: |
> > > +  Analog Devices LTC2983 Multi-Sensor Digital Temperature
> > > Measurement System
> > > +  
> > > https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
> > > +
> > > +properties:
> > > +  compatible:
> > > +    enum:
> > > +      - adi,ltc2983
> > > +
> > > +  reg:
> > > +    maxItems: 1
> > > +
> > > +  interrupts:
> > > +    maxItems: 1
> > > +
> > > +  adi,temperature-celcius:
> > > +    description:
> > > +      If this property is present, the temperature is reported
> > > in Celsius.
> > > +    type: boolean
> > > +    maxItems: 1  
> > 
> > It's a boolean, not an array so 'maxItems' doesn't make sense.
> > 
> > Running 'make dt_binding_check' should tell you this. You may need
> > to 
> > update dt-schema install though.

Rob, I'm having some issues with `make dt_binding_check`. I updated dt-
schema and I get this when run it:

...
"ruamel.yaml.constructor.DuplicateKeyError: while constructing a
mapping
  in "<unicode string>", line 4, column 1
found duplicate key "patternProperties" with value "{}" (original
value: "{}")
  in "<unicode string>", line 113, column 1"

If you want, I can paste the complete traceback in a following email.
However I could use `dt-doc-validate
Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml`
directly by doing a manual change in `dt-doc-validate `. I changed the
call `testtree = dtschema.load(filename, line_number=line_number,
duplicate_keys=False)` to `testtree = dtschema.load(filename,
line_number=line_number, duplicate_keys=True)`. Is this something
already known? I would not be surprised if it is some problem in my
environment. However, I even tried this in a clean docker container
based on ubuntu 18.04 and got the same behavior.
 
> > > +
> > > +  adi,mux-delay-config:
> > > +    description:
> > > +      The LTC2983 performs 2 or 3 internal conversion cycles per
> > > temperature result.
> > > +      Each conversion cycle is performed with different
> > > excitation and input multiplexer
> > > +      configurations. Prior to each conversion, these excitation
> > > circuits and input
> > > +      switch configurations are changed and an internal 1ms
> > > delay ensures settling prior
> > > +      to the conversion cycle in most cases. An extra delay can
> > > be configured using this
> > > +      property. The value written here is multiplied by 100us.
> 
> Make this adi,mux-delay-config-us and state it is rounded to nearest
> 100us.
> 
> > > +    allOf:
> > > +      - $ref: /schemas/types.yaml#/definitions/uint32
> > > +      - maximum: 255
> > > +        maxItems: 1  
> > 
> > Drop this.
> > 
> > > +
> > > +  adi,filter-notch-freq:
> > > +    description:
> > > +      Set's the default setting of the digital filter. The
> > > default is simultaneous
> > > +      50/60Hz rejection.
> > > +    allOf:
> > > +      - $ref: /schemas/types.yaml#/definitions/uint32
> > > +      - enum: [0, 1, 2]
> > > +    maxItems: 1  
> > 
> > Drop this.
> > 
> > > +
> > > +  '#address-cells':
> > > +    const: 1
> > > +
> > > +  '#size-cells':
> > > +    const: 0
> > > +
> > > +patternProperties:
> > > +  "^thermocouple@([1-9]|1[0-9]|20)$":
> > > +    type: object
> > > +    description: Represents a thermocouple sensor which is
> > > connected to one of the device channels.  
> > 
> > Wrap lines at 80 char.
> > 
> > > +
> > > +    properties:
> > > +      reg:
> > > +        description: |
> > > +          The channel number. It can be connected to one of the
> > > 20 channels of the device.
> > > +          Note that, for differential thermocouples, the minimum
> > > is 2.
> > > +        minimum: 1
> > > +        maximum: 20
> > > +        maxItems: 1  
> > 
> > Drop this and pretty much everywhere else that is never an array.
> > 
> > > +
> > > +      adi,sensor-type:
> > > +        description: |
> > > +           Identifies the type of thermocouple connected to the
> > > device.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [1 2 3 4 5 6 7 8]  
> > 
> > Missing commas which may not even parse. Maybe be consistent with 
> > elsewhere and use minimum and maximum.
> > 
> > > +        maxItems: 1
> > > +
> > > +      adi,sensor-config:
> > > +        description: |
> > > +          Raw value which set's the sensor configuration. Look
> > > at table 14 of the
> > > +          datasheet for how to set this value for thermocouples.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - minimum: 1
> > > +          - maximun: 15
> > > +        maxItems: 1
> > > +
> > > +      adi,cold-junction-handle:
> > > +        description: |
> > > +          Phandle which points to a sensor object responsible
> > > for measuring the
> > > +          thermocouple cold junction temperature.
> > > +        $ref: "/schemas/types.yaml#/definitions/phandle"
> > > +        maxItems: 1
> > > +
> > > +      adi,custom-sensor:
> > > +        description: |
> > > +          This is a table, where each entry should be a pair of
> > > voltage(mv)-temperature(K).
> > > +          The entries must be given in nv and uK so that, the
> > > original values must be
> > > +          multiplied by 1000000. For more details look at table
> > > 69 and 70.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/int64-array
> > > +        minItems: 6
> > > +        maxItems: 128
> > > +    required:
> > > +      - reg
> > > +      - adi,sensor-type
> > > +
> > > +patternProperties:
> > > +  "^diode@([1-9]|1[0-9]|20)$":
> > > +    type: object
> > > +    description: Represents a diode sensor which is connected to
> > > one of the device channels.
> > > +
> > > +    properties:
> > > +      reg:
> > > +        description:
> > > +          The channel number. It can be connected to one of the
> > > 20 channels of the device.
> > > +          Note that, for differential diodes, the minimum is 2.
> > > +        minimum: 1
> > > +        maximum: 20
> > > +        maxItems: 1
> > > +
> > > +      adi,sensor-type:
> > > +        description: |
> > > +          Identifies the sensor as a diode.
> > > +        const: 28
> > > +        maxItems: 1
> > > +
> > > +      adi,sensor-config:
> > > +        description: |
> > > +          Raw value which set's the sensor configuration. Look
> > > at table 17 of the
> > > +          datasheet for how to set this value for diodes.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [0 1 2 3 4 5 6 7]
> > > +        maxItems: 1
> > > +
> > > +      adi,excitation-current:
> > > +        description: |
> > > +          This property controls the magnitude of the excitation
> > > current applied
> > > +          to the diode. Look at table 19 of the datasheet for
> > > more info.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [0 1 2 3]
> > > +        maxItems: 1
> > > +
> > > +      adi,ideal-factor-value:
> > > +        description: |
> > > +          This property sets the diode ideality factor. The real
> > > value must be
> > > +          multiplied by 1000000 to remove the fractional part.
> > > For more information
> > > +          look at table 20 of the datasheet.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +        maxItems: 1
> > > +
> > > +    required:
> > > +      - reg
> > > +      - adi,sensor-type
> > > +
> > > +patternProperties:
> > > +  "^rtd@([2-9]|1[0-9]|20)$":
> > > +    type: object
> > > +    description: Represents a rtd sensor which is connected to
> > > one of the device channels.
> > > +
> > > +    properties:
> > > +      reg:
> > > +        description: |
> > > +          The channel number. It can be connected to one of the
> > > 20 channels of the device.
> > > +        minimum: 2
> > > +        maximum: 20
> > > +        maxItems: 1  
> > 
> > As this is pretty much the same for all child nodes, make a pattern
> > that 
> > matches all child nodes and put this there rather than duplicating
> > it. 
> > Then you only need 'minimum: 2' in the cases needing that.

I'm not sure I'm following your point here. So it's better to clarify
it before sending a v2. Do you mean to add something like:

patternProperties:
  "^(thermocouple|diode|rtd|thermistor|adc|rsense)@([1-9]|1[0-9]|20)$"
    type: object
    
    properties:
      reg:
       description: |
         The channel number. It can be connected to one of the 20      
channels of the device.
       minimum: 1
       maximum: 20

And then, for instance, for a RTD I would have:

patternProperties:
  "^rtd@([2-9]|1[0-9]|20)$"
    
    ...
    
    properties:
      reg:
       minimum: 2
    
    ...

Would this also make sense, or it's not really necessary?

patternProperties:
  "^thermocouple@([1-9]|1[0-9]|20)$"
    type: object
    
    ...
     
    properties:
      reg:
       description: For differential thermocouples, the minimum is 2.

    ...
 
Am I understanding it correctly?
> > > +thermistor
> > > +      adi,sensor-type:
> > > +        description: |
> > > +          Identifies the type of RTD connected to the device.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [10 11 12 13 14 15 16 17]
> > > +        maxItems: 1
> > > +
> > > +      adi,rsense-handle:
> > > +        description: |
> > > +          Phandle pointing to a rsense object associated with
> > > this RTD.
> > > +        $ref: "/schemas/types.yaml#/definitions/phandle"
> > > +        maxItems: 1
> > > +
> > > +      adi,sensor-config:
> > > +        description: |
> > > +          Raw value which set's the sensor configuration. Look
> > > at table 28 of the
> > > +          datasheet for how to set this value for RTD's.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [0 1 4 5 8 9 10 12 13 14]
> > > +        maxItems: 1
> > > +
> > > +      adi,excitation-current:
> > > +        description: |
> > > +          This property controls the magnitude of the excitation
> > > current applied
> > > +          to the RTD. Look at table 29 of the datasheet for more
> > > info.
> 
> Any way we can make this real units?  Can list valid value here.

For RTD's and diodes, it is possible to have it with real units.
However, for thermistors it's not really doable since, for instance,
for them we have an "Auto Range" setting. So, I just wanted to be
consistent through all sensors having excitation-current configuration.
Do you prefer to have it in real units where possible?

> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [1 2 3 4 5 6 7 8]
> > > +        maxItems: 1
> > > +
> > > +      adi,rtd-curve:
> > > +        description: |
> > > +          This property set the RTD curve used and the
> > > corresponding Callendar-Van
> > > +          Dusen constants. Look at table 30 of the datasheet.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [0 1 2 3]
> > > +        maxItems: 1
> > > +
> > > +      adi,custom-sensor:
> > > +        description: |
> > > +          This is a table, where each entry should be a pair of
> > > resistance(ohm)-temperature(K).
> > > +          The entries added here are in uohm and uK. For more
> > > details values look at table 74 and 75.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint64-array
> > > +        minItems: 6
> > > +        maxItems: 128
> > > +    required:
> > > +      - reg
> > > +      - adi,sensor-type
> > > +      - adi,rsense-handle
> > > +
> > > +patternProperties:
> > > +  "^thermistor@([1-9]|1[0-9]|20)$":
> > > +    type: object
> > > +    description: Represents a thermistor sensor which is
> > > connected to one of the device channels.
> > > +
> > > +    properties:
> > > +      reg:
> > > +        description: |
> > > +          The channel number. It can be connected to one of the
> > > 20 channels of the device.
> > > +          Note that, for differential thermistors, the minimum
> > > is 2.
> > > +        minimum: 1
> > > +        maximum: 20
> > > +        maxItems: 1
> > > +
> > > +      adi,sensor-type:
> > > +        description: |
> > > +          Identifies the type of thermistor connected to the
> > > device.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [19 20 21 22 23 24 25]
> > > +        maxItems: 1
> > > +
> > > +      adi,rsense-handle:
> > > +        description: |
> > > +          Phandle pointing to a rsense object associated with
> > > this thermistor.
> > > +        $ref: "/schemas/types.yaml#/definitions/phandle"
> > > +        maxItems: 1
> > > +
> > > +      adi,sensor-config:
> > > +        description: |
> > > +          Raw value which set's the sensor configuration. Look
> > > at table 52 of the
> > > +          datasheet for how to set this value for thermistors.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > +          - enum: [0 1 2 4]
> > > +        maxItems: 1
> > > +
> > > +      adi,excitation-current:
> > > +        description: |
> > > +          This property controls the magnitude of the excitation
> > > current applied
> > > +          to the thermistor. Look at table 53 of the datasheet
> > > for more info.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint32-array
> > > +          - enum: [1 2 3 4 5 6 7 8 9 10 11 12]
> > > +        maxItems: 1
> > > +
> > > +      adi,custom-sensor:
> > > +        description: |
> > > +          This is a table, where each entry should be a pair of
> > > resistance(ohm)-temperature(K).
> > > +          The entries added here are in uohm and uK only for
> > > custom thermistors.
> > > +          For more details look at table 78 and 79.
> > > +          Steinhart-Hart coefficients are also supported and can
> > > be programmed into the
> > > +          device memory using this property. For Steinhart
> > > sensors, this table has a constant
> > > +          size of 6 entries (defining the coefficients) and the
> > > values are given in the raw format.
> > > +          Look at table 82 for more information.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint64-array
> > > +        minItems: 6
> > > +        maxItems: 128
> > > +    required:
> > > +      - reg
> > > +      - adi,sensor-type
> > > +      - adi,rsense-handle
> > > +
> > > +patternProperties:
> > > +  "^adc@([1-9]|1[0-9]|20)$":
> > > +    type: object
> > > +    description: Represents a channel which is being used as a
> > > direct adc.
> > > +
> > > +    properties:
> > > +      reg:
> > > +        description: |
> > > +          The channel number. It can be connected to one of the
> > > 20 channels of the device.
> > > +          Note that, for differential adc's, the minimum is 2.
> > > +        minimum: 1
> > > +        maximum: 20
> > > +        maxItems: 1
> > > +
> > > +      adi,sensor-type:
> > > +        description: |
> > > +          Identifies the sensor as a direct adc.
> > > +        const: 30
> > > +        maxItems: 1
> > > +
> > > +      adi,single-ended:
> > > +        description: |
> > > +          Boolean property which set's the adc as single-ended.
> > > +        type: boolean
> > > +
> > > +    required:
> > > +      - reg
> > > +      - adi,sensor-type
> > > +
> > > +patternProperties:
> > > +  "^rsense@([2-9]|1[0-9]|20)$":
> > > +    type: object
> > > +    description: |
> > > +      Represents a rsense which is connected to one of the
> > > device channels.
> > > +      Rsense are used by thermistors and RTD's.
> > > +
> > > +    properties:
> > > +      reg:
> > > +        description: |
> > > +          The channel number. It can be connected to one of the
> > > 20 channels of the device.
> > > +        minimum: 2
> > > +        maximum: 20
> > > +        maxItems: 1
> > > +
> > > +      adi,sensor-type:
> > > +        description: |
> > > +          Identifies the sensor as a rsense.
> > > +        const: 29
> > > +        maxItems: 1
> > > +
> > > +      adi,rsense-val-micro-ohms:
> > > +        description: |
> > > +          Sets the value of the sense resistor. Look at table 20
> > > of the datasheet
> > > +          for information.
> > > +        allOf:
> > > +          - $ref: /schemas/types.yaml#/definitions/uint64
> > > +        maxItems: 1
> > > +
> > > +    required:
> > > +      - reg
> > > +      - adi,sensor-type
> > > +      - adi, rsense-val
> > > +
> > > +required:
> > > +  - compatible
> > > +  - reg
> > > +  - interrupts
> > > +
> > > +examples:
> > > +  - |
> > > +    #include <dt-bindings/interrupt-controller/irq.h>
> > > +    spi0 {
> > > +        #address-cells = <1>;
> > > +        #size-cells = <0>;
> > > +
> > > +        sensor_ltc2983: ltc2983@0 {
> > > +                compatible = "adi,ltc2983";
> > > +                reg = <0>;
> > > +
> > > +                #address-cells = <1>;
> > > +                #size-cells = <0>;
> > > +
> > > +                adi,temperature-celcius;
> > > +                interrupts = <20 IRQ_TYPE_EDGE_RISING>;
> > > +                interrupt-parent = <&gpio>;
> > > +
> > > +                thermocouple@18 {
> > > +                        reg = <18>;
> > > +                        adi,sensor-type = <8>; //Type B
> > > +                        adi,sensor-config = <1>; //Differential,
> > > open-circuit current
> > > +                        adi,cold-junction-handle = <&diode5>;
> > > +                };
> > > +
> > > +                diode5: diode@5 {
> > > +                        reg = <5>;
> > > +                        adi,sensor-type = <28>;
> > > +                };
> > > +
> > > +                rsense2: rsense@2 {
> > > +                        reg = <2>;
> > > +                        adi,sensor-type = <29>;
> > > +                        adi,rsense-val-micro-ohms = /bits/ 64
> > > <1200000000>; //1.2Kohms
> > > +                };
> > > +
> > > +                rtd@14 {
> > > +                        reg = <14>;
> > > +                        adi,sensor-type = <15>; //PT1000
> > > +                        /*2-wire, internal gnd, no current
> > > rotation*/
> > > +                        adi,sensor-config = <1>;
> > > +                        adi,excitation-current = <7>; //500uA
> > > +                        adi,rsense-handle = <&rsense2>;
> > > +                };
> > > +
> > > +                adc@10 {
> > > +                        reg = <10>;
> > > +                        adi,sensor-type = <30>;
> > > +                        adi,single-ended;
> > > +                };
> > > +
> > > +                thermistor@12 {
> > > +                        reg = <12>;
> > > +                        adi,sensor-type = <26>; //Steinhart
> > > +                        adi,rsense-handle = <&rsense2>;
> > > +                        adi,custom-sensor = /bits/ 64
> > > <0x00F371EC 0x12345678
> > > +                                        0x2C0F8733 0x10018C66
> > > 0xA0FEACCD
> > > +                                        0x90021D99>; //6 entries
> > > +                };
> > > +
> > > +                thermocouple@20 {
> > > +                        reg = <20>;
> > > +                        adi,sensor-type = <9>; //custom
> > > thermocouple
> > > +                        adi,sensor-config = <8>; //single-ended
> > > +                        adi,custom-sensor = /bits/ 64
> > > +                                 <(-50220000) 0
> > > +                                  (-30200000) 99100000
> > > +                                  (-5300000) 135400000
> > > +                                  0 273150000
> > > +                                  40200000 361200000
> > > +                                  55300000 522100000
> > > +                                  88300000 720300000
> > > +                                  132200000 811200000
> > > +                                  188700000 922500000
> > > +                                  460400000 1000000000>; //10
> > > pairs
> > > +               };
> > > +
> > > +        };
> > > +    };
> > > +...
> > > diff --git a/MAINTAINERS b/MAINTAINERS
> > > index 14a256e785ca..f747a9dc27f5 100644
> > > --- a/MAINTAINERS
> > > +++ b/MAINTAINERS
> > > @@ -9497,6 +9497,7 @@ W:	
> > > http://ez.analog.com/community/linux-device-drivers
> > >  L:	linux-iio@vger.kernel.org
> > >  S:	Supported
> > >  F:	drivers/iio/temperature/ltc2983.c
> > > +F:	Documentation/devicetree/bindings/iio/temperature/adi,l
> > > tc2983.yaml
> > >  
> > >  LTC4261 HARDWARE MONITOR DRIVER
> > >  M:	Guenter Roeck <linux@roeck-us.net>
> > > -- 
> > > 2.23.0
> > >   

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation
  2019-09-16 15:20       ` Sa, Nuno
@ 2019-09-17  1:09         ` Rob Herring
  2019-09-17  8:35           ` Sa, Nuno
  0 siblings, 1 reply; 11+ messages in thread
From: Rob Herring @ 2019-09-17  1:09 UTC (permalink / raw)
  To: Sa, Nuno
  Cc: jic23, mark.rutland, devicetree, knaack.h, linux-iio, pmeerw, lars

On Mon, Sep 16, 2019 at 10:20 AM Sa, Nuno <Nuno.Sa@analog.com> wrote:
>
> Hi Rob and Jonathan,
>
> Some comments/questions inline.
>
> Nuno Sá
>
> On Sun, 2019-09-15 at 12:07 +0100, Jonathan Cameron wrote:
> >
> > On Fri, 13 Sep 2019 15:36:21 +0100
> > Rob Herring <robh@kernel.org> wrote:
> >
> > > On Mon, Sep 09, 2019 at 04:45:50PM +0200, Nuno Sá wrote:
> > > > Document the LTC2983 temperature sensor devicetree bindings.
> > > >
> > > > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > > > ---
> > > >  .../bindings/iio/temperature/adi,ltc2983.yaml | 442
> > > > ++++++++++++++++++
> > > >  MAINTAINERS                                   |   1 +
> > > >  2 files changed, 443 insertions(+)
> > > >  create mode 100644
> > > > Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yam
> > > > l
> > > >
> > > > diff --git
> > > > a/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > > aml
> > > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > > aml
> > > > new file mode 100644
> > > > index 000000000000..2b468b3ed177
> > > > --- /dev/null
> > > > +++
> > > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.y
> > > > aml
> > > > @@ -0,0 +1,442 @@
> > > > +# SPDX-License-Identifier: GPL-2.0
> > > > +%YAML 1.2
> > > > +---
> > > > +$id:
> > > > http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
> > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > +
> > > > +title: Analog Devices LTC2983 Multi-sensor Temperature system
> > > > +
> > > > +maintainers:
> > > > +  - Nuno Sá <nuno.sa@analog.com>
> > > > +
> > > > +description: |
> > > > +  Analog Devices LTC2983 Multi-Sensor Digital Temperature
> > > > Measurement System
> > > > +
> > > > https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
> > > > +
> > > > +properties:
> > > > +  compatible:
> > > > +    enum:
> > > > +      - adi,ltc2983
> > > > +
> > > > +  reg:
> > > > +    maxItems: 1
> > > > +
> > > > +  interrupts:
> > > > +    maxItems: 1
> > > > +
> > > > +  adi,temperature-celcius:
> > > > +    description:
> > > > +      If this property is present, the temperature is reported
> > > > in Celsius.
> > > > +    type: boolean
> > > > +    maxItems: 1
> > >
> > > It's a boolean, not an array so 'maxItems' doesn't make sense.
> > >
> > > Running 'make dt_binding_check' should tell you this. You may need
> > > to
> > > update dt-schema install though.
>
> Rob, I'm having some issues with `make dt_binding_check`. I updated dt-
> schema and I get this when run it:
>
> ...
> "ruamel.yaml.constructor.DuplicateKeyError: while constructing a
> mapping
>   in "<unicode string>", line 4, column 1
> found duplicate key "patternProperties" with value "{}" (original
> value: "{}")
>   in "<unicode string>", line 113, column 1"

Simply drop all but the first 'patternProperties'. You can have
multiple patterns under one.

>
> If you want, I can paste the complete traceback in a following email.
> However I could use `dt-doc-validate
> Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml`
> directly by doing a manual change in `dt-doc-validate `. I changed the
> call `testtree = dtschema.load(filename, line_number=line_number,
> duplicate_keys=False)` to `testtree = dtschema.load(filename,
> line_number=line_number, duplicate_keys=True)`. Is this something
> already known? I would not be surprised if it is some problem in my
> environment. However, I even tried this in a clean docker container
> based on ubuntu 18.04 and got the same behavior.

[...]

> > > > +patternProperties:
> > > > +  "^rtd@([2-9]|1[0-9]|20)$":
> > > > +    type: object
> > > > +    description: Represents a rtd sensor which is connected to
> > > > one of the device channels.
> > > > +
> > > > +    properties:
> > > > +      reg:
> > > > +        description: |
> > > > +          The channel number. It can be connected to one of the
> > > > 20 channels of the device.
> > > > +        minimum: 2
> > > > +        maximum: 20
> > > > +        maxItems: 1
> > >
> > > As this is pretty much the same for all child nodes, make a pattern
> > > that
> > > matches all child nodes and put this there rather than duplicating
> > > it.
> > > Then you only need 'minimum: 2' in the cases needing that.
>
> I'm not sure I'm following your point here. So it's better to clarify
> it before sending a v2. Do you mean to add something like:
>
> patternProperties:
>   "^(thermocouple|diode|rtd|thermistor|adc|rsense)@([1-9]|1[0-9]|20)$"

Just ".*@([1-9]|1[0-9]|20)$" is fine.

>     type: object
>
>     properties:
>       reg:
>        description: |
>          The channel number. It can be connected to one of the 20
> channels of the device.
>        minimum: 1
>        maximum: 20
>
> And then, for instance, for a RTD I would have:
>
> patternProperties:
>   "^rtd@([2-9]|1[0-9]|20)$"

You've already defined the unit-address format above, so '^rtd@.*'
would be sufficient here.

>
>     ...
>
>     properties:
>       reg:
>        minimum: 2
>
>     ...
>
> Would this also make sense, or it's not really necessary?

Yes, makes sense.

>
> patternProperties:
>   "^thermocouple@([1-9]|1[0-9]|20)$"
>     type: object
>
>     ...
>
>     properties:
>       reg:
>        description: For differential thermocouples, the minimum is 2.

Why do you have a constraint in free form text here?

>
>     ...
>
> Am I understanding it correctly?
> > > > +thermistor
> > > > +      adi,sensor-type:
> > > > +        description: |
> > > > +          Identifies the type of RTD connected to the device.
> > > > +        allOf:
> > > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > > +          - enum: [10 11 12 13 14 15 16 17]
> > > > +        maxItems: 1
> > > > +
> > > > +      adi,rsense-handle:
> > > > +        description: |
> > > > +          Phandle pointing to a rsense object associated with
> > > > this RTD.
> > > > +        $ref: "/schemas/types.yaml#/definitions/phandle"
> > > > +        maxItems: 1
> > > > +
> > > > +      adi,sensor-config:
> > > > +        description: |
> > > > +          Raw value which set's the sensor configuration. Look
> > > > at table 28 of the
> > > > +          datasheet for how to set this value for RTD's.
> > > > +        allOf:
> > > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > > +          - enum: [0 1 4 5 8 9 10 12 13 14]
> > > > +        maxItems: 1
> > > > +
> > > > +      adi,excitation-current:
> > > > +        description: |
> > > > +          This property controls the magnitude of the excitation
> > > > current applied
> > > > +          to the RTD. Look at table 29 of the datasheet for more
> > > > info.
> >
> > Any way we can make this real units?  Can list valid value here.
>
> For RTD's and diodes, it is possible to have it with real units.
> However, for thermistors it's not really doable since, for instance,
> for them we have an "Auto Range" setting. So, I just wanted to be
> consistent through all sensors having excitation-current configuration.
> Do you prefer to have it in real units where possible?

That's the preference if it makes sense. I have no idea what an RTD is
to comment further.

Rob

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation
  2019-09-17  1:09         ` Rob Herring
@ 2019-09-17  8:35           ` Sa, Nuno
  0 siblings, 0 replies; 11+ messages in thread
From: Sa, Nuno @ 2019-09-17  8:35 UTC (permalink / raw)
  To: robh; +Cc: pmeerw, jic23, devicetree, mark.rutland, knaack.h, linux-iio, lars

On Mon, 2019-09-16 at 20:09 -0500, Rob Herring wrote:
> 
> On Mon, Sep 16, 2019 at 10:20 AM Sa, Nuno <Nuno.Sa@analog.com> wrote:
> > Hi Rob and Jonathan,
> > 
> > Some comments/questions inline.
> > 
> > Nuno Sá
> > 
> > On Sun, 2019-09-15 at 12:07 +0100, Jonathan Cameron wrote:
> > > On Fri, 13 Sep 2019 15:36:21 +0100
> > > Rob Herring <robh@kernel.org> wrote:
> > > 
> > > > On Mon, Sep 09, 2019 at 04:45:50PM +0200, Nuno Sá wrote:
> > > > > Document the LTC2983 temperature sensor devicetree bindings.
> > > > > 
> > > > > Signed-off-by: Nuno Sá <nuno.sa@analog.com>
> > > > > ---
> > > > >  .../bindings/iio/temperature/adi,ltc2983.yaml | 442
> > > > > ++++++++++++++++++
> > > > >  MAINTAINERS                                   |   1 +
> > > > >  2 files changed, 443 insertions(+)
> > > > >  create mode 100644
> > > > > Documentation/devicetree/bindings/iio/temperature/adi,ltc2983
> > > > > .yam
> > > > > l
> > > > > 
> > > > > diff --git
> > > > > a/Documentation/devicetree/bindings/iio/temperature/adi,ltc29
> > > > > 83.y
> > > > > aml
> > > > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc29
> > > > > 83.y
> > > > > aml
> > > > > new file mode 100644
> > > > > index 000000000000..2b468b3ed177
> > > > > --- /dev/null
> > > > > +++
> > > > > b/Documentation/devicetree/bindings/iio/temperature/adi,ltc29
> > > > > 83.y
> > > > > aml
> > > > > @@ -0,0 +1,442 @@
> > > > > +# SPDX-License-Identifier: GPL-2.0
> > > > > +%YAML 1.2
> > > > > +---
> > > > > +$id:
> > > > > http://devicetree.org/schemas/iio/temperature/adi,ltc2983.yaml#
> > > > > +$schema: http://devicetree.org/meta-schemas/core.yaml#
> > > > > +
> > > > > +title: Analog Devices LTC2983 Multi-sensor Temperature
> > > > > system
> > > > > +
> > > > > +maintainers:
> > > > > +  - Nuno Sá <nuno.sa@analog.com>
> > > > > +
> > > > > +description: |
> > > > > +  Analog Devices LTC2983 Multi-Sensor Digital Temperature
> > > > > Measurement System
> > > > > +
> > > > > https://www.analog.com/media/en/technical-documentation/data-sheets/2983fc.pdf
> > > > > +
> > > > > +properties:
> > > > > +  compatible:
> > > > > +    enum:
> > > > > +      - adi,ltc2983
> > > > > +
> > > > > +  reg:
> > > > > +    maxItems: 1
> > > > > +
> > > > > +  interrupts:
> > > > > +    maxItems: 1
> > > > > +
> > > > > +  adi,temperature-celcius:
> > > > > +    description:
> > > > > +      If this property is present, the temperature is
> > > > > reported
> > > > > in Celsius.
> > > > > +    type: boolean
> > > > > +    maxItems: 1
> > > > 
> > > > It's a boolean, not an array so 'maxItems' doesn't make sense.
> > > > 
> > > > Running 'make dt_binding_check' should tell you this. You may
> > > > need
> > > > to
> > > > update dt-schema install though.
> > 
> > Rob, I'm having some issues with `make dt_binding_check`. I updated
> > dt-
> > schema and I get this when run it:
> > 
> > ...
> > "ruamel.yaml.constructor.DuplicateKeyError: while constructing a
> > mapping
> >   in "<unicode string>", line 4, column 1
> > found duplicate key "patternProperties" with value "{}" (original
> > value: "{}")
> >   in "<unicode string>", line 113, column 1"
> 
> Simply drop all but the first 'patternProperties'. You can have
> multiple patterns under one.
> 
Ok, got it.
> > If you want, I can paste the complete traceback in a following
> > email.
> > However I could use `dt-doc-validate
> > Documentation/devicetree/bindings/iio/temperature/adi,ltc2983.yaml`
> > directly by doing a manual change in `dt-doc-validate `. I changed
> > the
> > call `testtree = dtschema.load(filename, line_number=line_number,
> > duplicate_keys=False)` to `testtree = dtschema.load(filename,
> > line_number=line_number, duplicate_keys=True)`. Is this something
> > already known? I would not be surprised if it is some problem in my
> > environment. However, I even tried this in a clean docker container
> > based on ubuntu 18.04 and got the same behavior.
> 
> [...]
> 
> > > > > +patternProperties:
> > > > > +  "^rtd@([2-9]|1[0-9]|20)$":
> > > > > +    type: object
> > > > > +    description: Represents a rtd sensor which is connected
> > > > > to
> > > > > one of the device channels.
> > > > > +
> > > > > +    properties:
> > > > > +      reg:
> > > > > +        description: |
> > > > > +          The channel number. It can be connected to one of
> > > > > the
> > > > > 20 channels of the device.
> > > > > +        minimum: 2
> > > > > +        maximum: 20
> > > > > +        maxItems: 1
> > > > 
> > > > As this is pretty much the same for all child nodes, make a
> > > > pattern
> > > > that
> > > > matches all child nodes and put this there rather than
> > > > duplicating
> > > > it.
> > > > Then you only need 'minimum: 2' in the cases needing that.
> > 
> > I'm not sure I'm following your point here. So it's better to
> > clarify
> > it before sending a v2. Do you mean to add something like:
> > 
> > patternProperties:
> >   "^(thermocouple|diode|rtd|thermistor|adc|rsense)@([1-9]|1[0-
> > 9]|20)$"
> 
> Just ".*@([1-9]|1[0-9]|20)$" is fine.
> 
> >     type: object
> > 
> >     properties:
> >       reg:
> >        description: |
> >          The channel number. It can be connected to one of the 20
> > channels of the device.
> >        minimum: 1
> >        maximum: 20
> > 
> > And then, for instance, for a RTD I would have:
> > 
> > patternProperties:
> >   "^rtd@([2-9]|1[0-9]|20)$"
> 
> You've already defined the unit-address format above, so '^rtd@.*'
> would be sufficient here.

Ack.

> >     ...
> > 
> >     properties:
> >       reg:
> >        minimum: 2
> > 
> >     ...
> > 
> > Would this also make sense, or it's not really necessary?
> 
> Yes, makes sense.
> 
> > patternProperties:
> >   "^thermocouple@([1-9]|1[0-9]|20)$"
> >     type: object
> > 
> >     ...
> > 
> >     properties:
> >       reg:
> >        description: For differential thermocouples, the minimum is
> > 2.
> 
> Why do you have a constraint in free form text here?

There are sensors (like thermocouples) which can be configured as
differential or single-ended. Depending on that the 'reg' minimum value
is 1 or 2. The text was only giving a *note* on that. However I guess I
can just drop it.
 
> >     ...
> > 
> > Am I understanding it correctly?
> > > > > +thermistor
> > > > > +      adi,sensor-type:
> > > > > +        description: |
> > > > > +          Identifies the type of RTD connected to the
> > > > > device.
> > > > > +        allOf:
> > > > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > > > +          - enum: [10 11 12 13 14 15 16 17]
> > > > > +        maxItems: 1
> > > > > +
> > > > > +      adi,rsense-handle:
> > > > > +        description: |
> > > > > +          Phandle pointing to a rsense object associated
> > > > > with
> > > > > this RTD.
> > > > > +        $ref: "/schemas/types.yaml#/definitions/phandle"
> > > > > +        maxItems: 1
> > > > > +
> > > > > +      adi,sensor-config:
> > > > > +        description: |
> > > > > +          Raw value which set's the sensor configuration.
> > > > > Look
> > > > > at table 28 of the
> > > > > +          datasheet for how to set this value for RTD's.
> > > > > +        allOf:
> > > > > +          - $ref: /schemas/types.yaml#/definitions/uint32
> > > > > +          - enum: [0 1 4 5 8 9 10 12 13 14]
> > > > > +        maxItems: 1
> > > > > +
> > > > > +      adi,excitation-current:
> > > > > +        description: |
> > > > > +          This property controls the magnitude of the
> > > > > excitation
> > > > > current applied
> > > > > +          to the RTD. Look at table 29 of the datasheet for
> > > > > more
> > > > > info.
> > > 
> > > Any way we can make this real units?  Can list valid value here.
> > 
> > For RTD's and diodes, it is possible to have it with real units.
> > However, for thermistors it's not really doable since, for
> > instance,
> > for them we have an "Auto Range" setting. So, I just wanted to be
> > consistent through all sensors having excitation-current
> > configuration.
> > Do you prefer to have it in real units where possible?
> 
> That's the preference if it makes sense. I have no idea what an RTD
> is
> to comment further.

Ack. I will come up with some proposal for this on v2.

> Rob


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 1/2] iio: temperature: Add support for LTC2983
  2019-09-16  9:37   ` Sa, Nuno
@ 2019-09-21 17:02     ` Jonathan Cameron
  2019-09-23  7:17       ` Sa, Nuno
  0 siblings, 1 reply; 11+ messages in thread
From: Jonathan Cameron @ 2019-09-21 17:02 UTC (permalink / raw)
  To: Sa, Nuno
  Cc: robh+dt, mark.rutland, devicetree, knaack.h, linux-iio, pmeerw, lars

On Mon, 16 Sep 2019 09:37:18 +0000
"Sa, Nuno" <Nuno.Sa@analog.com> wrote:

> Hi Jonathan,
> 
> Thanks for the review.
> Comments inline.
> 
> Nuno Sá
> 
> On Sun, 2019-09-15 at 12:27 +0100, Jonathan Cameron wrote:
> > 
> > On Mon, 9 Sep 2019 16:45:49 +0200
> > Nuno Sá <nuno.sa@analog.com> wrote:
> >   
> > > The LTC2983 is a Multi-Sensor High Accuracy Digital Temperature
> > > Measurement System. It measures a wide variety of temperature
> > > sensors and
> > > digitally outputs the result, in °C or °F, with 0.1°C accuracy and
> > > 0.001°C resolution. It can measure the temperature of all standard
> > > thermocouples (type B,E,J,K,N,S,R,T), standard 2-,3-,4-wire RTDs,
> > > thermistors and diodes.
> > > 
> > > Signed-off-by: Nuno Sá <nuno.sa@analog.com>  
> > Some comments inline.  Main concern is around the interface, rest is
> > minor
> > stuff.
> > 
> > Jonathan
> >   
> > > ---
> > >  .../testing/sysfs-bus-iio-temperature-ltc2983 |   43 +
> > >  MAINTAINERS                                   |    7 +
> > >  drivers/iio/temperature/Kconfig               |   10 +
> > >  drivers/iio/temperature/Makefile              |    1 +
> > >  drivers/iio/temperature/ltc2983.c             | 1327
> > > +++++++++++++++++
> > >  5 files changed, 1388 insertions(+)
> > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-
> > > temperature-ltc2983
> > >  create mode 100644 drivers/iio/temperature/ltc2983.c
> > > 
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-temperature-
> > > ltc2983 b/Documentation/ABI/testing/sysfs-bus-iio-temperature-
> > > ltc2983
> > > new file mode 100644
> > > index 000000000000..3ad3440c0986
> > > --- /dev/null
> > > +++ b/Documentation/ABI/testing/sysfs-bus-iio-temperature-ltc2983
> > > @@ -0,0 +1,43 @@
> > > +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_therm
> > > istor_raw  
> > For each of these, I presume we know which type of device is attached
> > at any time?
> > Using the channel naming to convey this (and I assume the fact that
> > different
> > conversions need to be done in userspace?) is a bit messy.  If we
> > need
> > to convey the channel type, then a separate in_tempY_mode attribute
> > may make more
> > sense.  That would keep this ABI 'closer' to standard. Software that
> > just logs
> > an unprocessed value could just work for example.
> > 
> > I'm not sure I've totally understood what is going on here though.
> >   
> So, the `extend_name` does not really bring any functional advantage.
> It was just an easy way for someone to know which kind of sensor the
> channel was referring to. In terms of conversions, all the work is done
> by the part for all the different sensor's and the scale is the same
> for all of them. So, I can just drop the extended name and use standard
> ABI if you prefer?

Please do.  It may make sense to add an additional attribute to provide
the info on the type of sensor, but we don't want to do anything that
will create new ABI in the basic read path.


...
> > > +
> > > +static int __maybe_unused ltc2983_suspend(struct device *dev)
> > > +{
> > > +	struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
> > > +	int ret;
> > > +
> > > +	mutex_lock(&st->lock);
> > > +	ret = regmap_write(st->regmap, LTC2983_STATUS_REG,
> > > LTC2983_SLEEP);
> > > +	st->reset = true;  
> > 
> > Naming seems a bit odd. The register field is called sleep, but we
> > call
> > it reset internally?  
> I agree. Something like `suspend` or `sleep` for the boolean would be
> ok?

yes.

> > > +	mutex_unlock(&st->lock);
> > > +
> > > +	return ret;
> > > +}
> > > +
> > > +static SIMPLE_DEV_PM_OPS(ltc2983_pm_ops, ltc2983_suspend,
> > > ltc2983_resume);
> > > +
> > > +static const struct spi_device_id ltc2983_id_table[] = {
> > > +	{ "ltc2983" },
> > > +	{},
> > > +};
> > > +MODULE_DEVICE_TABLE(spi, ltc2983_id_table);
> > > +
> > > +static const struct of_device_id ltc2983_of_match[] = {
> > > +	{ .compatible = "adi,ltc2983" },
> > > +	{},
> > > +};
> > > +MODULE_DEVICE_TABLE(of, ltc2983_id_table);
> > > +
> > > +static struct spi_driver ltc2983_driver = {
> > > +	.driver = {
> > > +		.name = "ltc2983",
> > > +		.of_match_table = ltc2983_of_match,
> > > +		.pm = &ltc2983_pm_ops,
> > > +	},
> > > +	.probe = ltc2983_probe,
> > > +	.id_table = ltc2983_id_table,
> > > +};
> > > +
> > > +module_spi_driver(ltc2983_driver);
> > > +
> > > +MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
> > > +MODULE_DESCRIPTION("Analog Devices LTC2983 SPI Temperature
> > > sensors");
> > > +MODULE_LICENSE("GPL");  
> 


^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH 1/2] iio: temperature: Add support for LTC2983
  2019-09-21 17:02     ` Jonathan Cameron
@ 2019-09-23  7:17       ` Sa, Nuno
  0 siblings, 0 replies; 11+ messages in thread
From: Sa, Nuno @ 2019-09-23  7:17 UTC (permalink / raw)
  To: jic23
  Cc: linux-iio, lars, devicetree, mark.rutland, knaack.h, robh+dt, pmeerw

On Sat, 2019-09-21 at 18:02 +0100, Jonathan Cameron wrote:
> 
> On Mon, 16 Sep 2019 09:37:18 +0000
> "Sa, Nuno" <Nuno.Sa@analog.com> wrote:
> 
> > Hi Jonathan,
> > 
> > Thanks for the review.
> > Comments inline.
> > 
> > Nuno Sá
> > 
> > On Sun, 2019-09-15 at 12:27 +0100, Jonathan Cameron wrote:
> > > On Mon, 9 Sep 2019 16:45:49 +0200
> > > Nuno Sá <nuno.sa@analog.com> wrote:
> > >   
> > > > The LTC2983 is a Multi-Sensor High Accuracy Digital Temperature
> > > > Measurement System. It measures a wide variety of temperature
> > > > sensors and
> > > > digitally outputs the result, in °C or °F, with 0.1°C accuracy
> > > > and
> > > > 0.001°C resolution. It can measure the temperature of all
> > > > standard
> > > > thermocouples (type B,E,J,K,N,S,R,T), standard 2-,3-,4-wire
> > > > RTDs,
> > > > thermistors and diodes.
> > > > 
> > > > Signed-off-by: Nuno Sá <nuno.sa@analog.com>  
> > > Some comments inline.  Main concern is around the interface, rest
> > > is
> > > minor
> > > stuff.
> > > 
> > > Jonathan
> > >   
> > > > ---
> > > >  .../testing/sysfs-bus-iio-temperature-ltc2983 |   43 +
> > > >  MAINTAINERS                                   |    7 +
> > > >  drivers/iio/temperature/Kconfig               |   10 +
> > > >  drivers/iio/temperature/Makefile              |    1 +
> > > >  drivers/iio/temperature/ltc2983.c             | 1327
> > > > +++++++++++++++++
> > > >  5 files changed, 1388 insertions(+)
> > > >  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-
> > > > temperature-ltc2983
> > > >  create mode 100644 drivers/iio/temperature/ltc2983.c
> > > > 
> > > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio-
> > > > temperature-
> > > > ltc2983 b/Documentation/ABI/testing/sysfs-bus-iio-temperature-
> > > > ltc2983
> > > > new file mode 100644
> > > > index 000000000000..3ad3440c0986
> > > > --- /dev/null
> > > > +++ b/Documentation/ABI/testing/sysfs-bus-iio-temperature-
> > > > ltc2983
> > > > @@ -0,0 +1,43 @@
> > > > +What:		/sys/bus/iio/devices/iio:deviceX/in_tempY_therm
> > > > istor_raw  
> > > For each of these, I presume we know which type of device is
> > > attached
> > > at any time?
> > > Using the channel naming to convey this (and I assume the fact
> > > that
> > > different
> > > conversions need to be done in userspace?) is a bit messy.  If we
> > > need
> > > to convey the channel type, then a separate in_tempY_mode
> > > attribute
> > > may make more
> > > sense.  That would keep this ABI 'closer' to standard. Software
> > > that
> > > just logs
> > > an unprocessed value could just work for example.
> > > 
> > > I'm not sure I've totally understood what is going on here
> > > though.
> > >   
> > So, the `extend_name` does not really bring any functional
> > advantage.
> > It was just an easy way for someone to know which kind of sensor
> > the
> > channel was referring to. In terms of conversions, all the work is
> > done
> > by the part for all the different sensor's and the scale is the
> > same
> > for all of them. So, I can just drop the extended name and use
> > standard
> > ABI if you prefer?
> 
> Please do.  It may make sense to add an additional attribute to
> provide
> the info on the type of sensor, but we don't want to do anything that
> will create new ABI in the basic read path.

There is already a v2 that I've sent last week which drops the
`extend_name`. I guess we would need the type of sensor plus the
channel number. Either way, I guess that can be added later if someone
actually needs it.

> ...
> > > > +
> > > > +static int __maybe_unused ltc2983_suspend(struct device *dev)
> > > > +{
> > > > +	struct ltc2983_data *st =
> > > > spi_get_drvdata(to_spi_device(dev));
> > > > +	int ret;
> > > > +
> > > > +	mutex_lock(&st->lock);
> > > > +	ret = regmap_write(st->regmap, LTC2983_STATUS_REG,
> > > > LTC2983_SLEEP);
> > > > +	st->reset = true;  
> > > 
> > > Naming seems a bit odd. The register field is called sleep, but
> > > we
> > > call
> > > it reset internally?  
> > I agree. Something like `suspend` or `sleep` for the boolean would
> > be
> > ok?
> 
> yes.

Renamed to `sleep`.

> > > > +	mutex_unlock(&st->lock);
> > > > +
> > > > +	return ret;
> > > > +}
> > > > +
> > > > +static SIMPLE_DEV_PM_OPS(ltc2983_pm_ops, ltc2983_suspend,
> > > > ltc2983_resume);
> > > > +
> > > > +static const struct spi_device_id ltc2983_id_table[] = {
> > > > +	{ "ltc2983" },
> > > > +	{},
> > > > +};
> > > > +MODULE_DEVICE_TABLE(spi, ltc2983_id_table);
> > > > +
> > > > +static const struct of_device_id ltc2983_of_match[] = {
> > > > +	{ .compatible = "adi,ltc2983" },
> > > > +	{},
> > > > +};
> > > > +MODULE_DEVICE_TABLE(of, ltc2983_id_table);
> > > > +
> > > > +static struct spi_driver ltc2983_driver = {
> > > > +	.driver = {
> > > > +		.name = "ltc2983",
> > > > +		.of_match_table = ltc2983_of_match,
> > > > +		.pm = &ltc2983_pm_ops,
> > > > +	},
> > > > +	.probe = ltc2983_probe,
> > > > +	.id_table = ltc2983_id_table,
> > > > +};
> > > > +
> > > > +module_spi_driver(ltc2983_driver);
> > > > +
> > > > +MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>");
> > > > +MODULE_DESCRIPTION("Analog Devices LTC2983 SPI Temperature
> > > > sensors");
> > > > +MODULE_LICENSE("GPL");  


^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2019-09-23  7:18 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-09-09 14:45 [PATCH 1/2] iio: temperature: Add support for LTC2983 Nuno Sá
2019-09-09 14:45 ` [PATCH 2/2] dt-bindings: iio: Add ltc2983 documentation Nuno Sá
2019-09-13 14:36   ` Rob Herring
2019-09-15 11:07     ` Jonathan Cameron
2019-09-16 15:20       ` Sa, Nuno
2019-09-17  1:09         ` Rob Herring
2019-09-17  8:35           ` Sa, Nuno
2019-09-15 11:27 ` [PATCH 1/2] iio: temperature: Add support for LTC2983 Jonathan Cameron
2019-09-16  9:37   ` Sa, Nuno
2019-09-21 17:02     ` Jonathan Cameron
2019-09-23  7:17       ` Sa, Nuno

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