Re: [PATCH v4 1/2] iio: temperature: Add support for LTC2983

Jonathan Cameron
2019-10-12T11:04:36Z

On Fri, 11 Oct 2019 10:40:37 +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>

There are a few mostly stylistic little bits inline. If you don't need
to do a v5 for the binding, I'll probably just apply this and tidy
them up whilst doing so.

If it looks like I've lost the driver, feel free to poke me in a few
weeks time!

Great stuff,

Thanks,

Jonathan

> ---
> Changes in v2:
> * Added some needed blank lines (for readability);
> * Allocate iio_chan in the setup() function;
> * Rename reset to sleep;
> * Remove unneeded dev_dbg calls;
> * Remove unneeded line wrapping;
> * Remove unneeded comments;
> * Remove extend_names. Use the standard ABI;
> * Adapt the scales to report in millivolt and milli degrees;
> * Adapt the of_property readings to the renaming of the properties;
> * For custom thermistors, excitation-current cannot be set to Auto range.
>
> Changes in v3:
> * Use normal `devm_request_irq`;
> * Handle and decode the new devicetree properties for sensor configuration.
>
> Changes in v4:
> * Add 'select REGMAP_SPI';
> * Use `____cacheline_aligned` for regmap_bulk_read();
> * Read rsense value as u32 (due to dt bindings change);
> * __ltc2983_custom_sensor_new(): new argument to identify the property name;
> * __ltc2983_custom_sensor_new(): uses u32 api to read steinhart values;
> * Drop sleep flag and calls to mutex_* in suspend/resume;
> * Add error handling for regmap calls in setup();
> * Drop temp_farenheit boolean.
>
> MAINTAINERS | 7 +
> drivers/iio/temperature/Kconfig | 11 +
> drivers/iio/temperature/Makefile | 1 +
> drivers/iio/temperature/ltc2983.c | 1557 +++++++++++++++++++++++++++++
> 4 files changed, 1576 insertions(+)
> create mode 100644 drivers/iio/temperature/ltc2983.c
>
> 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..e1ccb4003015 100644
> --- a/drivers/iio/temperature/Kconfig
> +++ b/drivers/iio/temperature/Kconfig
> @@ -4,6 +4,17 @@
> #
> menu "Temperature sensors"
>
> +config LTC2983
> + tristate "Analog Devices Multi-Sensor Digital Temperature Measurement System"
> + depends on SPI
> + select REGMAP_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..9532cbe06574
> --- /dev/null
> +++ b/drivers/iio/temperature/ltc2983.c
> @@ -0,0 +1,1557 @@
> +// 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_THERMOCOUPLE_SGL(x) \
> + FIELD_PREP(LTC2983_THERMOCOUPLE_DIFF_MASK, x)
> +#define LTC2983_THERMOCOUPLE_OC_CURR_MASK GENMASK(1, 0)
> +#define LTC2983_THERMOCOUPLE_OC_CURR(x) \
> + FIELD_PREP(LTC2983_THERMOCOUPLE_OC_CURR_MASK, x)
> +#define LTC2983_THERMOCOUPLE_OC_CHECK_MASK BIT(2)
> +#define LTC2983_THERMOCOUPLE_OC_CHECK(x) \
> + FIELD_PREP(LTC2983_THERMOCOUPLE_OC_CHECK_MASK, x)
> +
> +#define LTC2983_THERMISTOR_DIFF_MASK BIT(2)
> +#define LTC2983_THERMISTOR_SGL(x) \
> + FIELD_PREP(LTC2983_THERMISTOR_DIFF_MASK, x)
> +#define LTC2983_THERMISTOR_R_SHARE_MASK BIT(1)
> +#define LTC2983_THERMISTOR_R_SHARE(x) \
> + FIELD_PREP(LTC2983_THERMISTOR_R_SHARE_MASK, x)
> +#define LTC2983_THERMISTOR_C_ROTATE_MASK BIT(0)
> +#define LTC2983_THERMISTOR_C_ROTATE(x) \
> + FIELD_PREP(LTC2983_THERMISTOR_C_ROTATE_MASK, x)
> +
> +#define LTC2983_DIODE_DIFF_MASK BIT(2)
> +#define LTC2983_DIODE_SGL(x) \
> + FIELD_PREP(LTC2983_DIODE_DIFF_MASK, x)
> +#define LTC2983_DIODE_3_CONV_CYCLE_MASK BIT(1)
> +#define LTC2983_DIODE_3_CONV_CYCLE(x) \
> + FIELD_PREP(LTC2983_DIODE_3_CONV_CYCLE_MASK, x)
> +#define LTC2983_DIODE_AVERAGE_ON_MASK BIT(0)
> +#define LTC2983_DIODE_AVERAGE_ON(x) \
> + FIELD_PREP(LTC2983_DIODE_AVERAGE_ON_MASK, x)
> +
> +#define LTC2983_RTD_4_WIRE_MASK BIT(3)
> +#define LTC2983_RTD_ROTATION_MASK BIT(1)
> +#define LTC2983_RTD_C_ROTATE(x) \
> + FIELD_PREP(LTC2983_RTD_ROTATION_MASK, x)
> +#define LTC2983_RTD_KELVIN_R_SENSE_MASK GENMASK(3, 2)
> +#define LTC2983_RTD_N_WIRES_MASK GENMASK(3, 2)
> +#define LTC2983_RTD_N_WIRES(x) \
> + FIELD_PREP(LTC2983_RTD_N_WIRES_MASK, x)
> +#define LTC2983_RTD_R_SHARE_MASK BIT(0)
> +#define LTC2983_RTD_R_SHARE(x) \
> + FIELD_PREP(LTC2983_RTD_R_SHARE_MASK, 1)
> +
> +#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;
> + /*
> + * DMA (thus cache coherency maintenance) requires the
> + * transfer buffers to live in their own cache lines.
> + * Holds the converted temperature
> + */
> + __be32 temp ____cacheline_aligned;
> +};
> +
> +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);
> + /* 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 reg:0x%04X, val:0x%08X\n", 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 char *propname,
> + 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;
> + const u8 e_size = (is_steinhart == true) ? sizeof(u32) : sizeof(u64);
> +
> + n_entries = of_property_count_elems_of_size(np, propname, e_size);
> + /* 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;
> + /*
> + * 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) {
> + of_property_read_u64_index(np, propname, index, &temp);
> +
> + 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);
> + } else {
> + of_property_read_u32_index(np, propname, index,
> + (u32 *)&temp);
> + }
> +
> + 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;
> + u32 oc_current;
> + int ret;
> +
> + thermo = devm_kzalloc(&st->spi->dev, sizeof(*thermo), GFP_KERNEL);
> + if (!thermo)
> + return ERR_PTR(-ENOMEM);
> +
> + if (of_property_read_bool(child, "adi,single-ended"))
> + thermo->sensor_config = LTC2983_THERMOCOUPLE_SGL(1);
> +
> + ret = of_property_read_u32(child, "adi,sensor-oc-current-microamp",
> + &oc_current);
> + if (!ret) {
> + switch (oc_current) {
> + case 10:
> + thermo->sensor_config |=
> + LTC2983_THERMOCOUPLE_OC_CURR(0);
> + break;
> + case 100:
> + thermo->sensor_config |=
> + LTC2983_THERMOCOUPLE_OC_CURR(1);
> + break;
> + case 500:
> + thermo->sensor_config |=
> + LTC2983_THERMOCOUPLE_OC_CURR(2);
> + break;
> + case 1000:
> + thermo->sensor_config |=
> + LTC2983_THERMOCOUPLE_OC_CURR(3);
> + break;
> + default:
> + dev_err(&st->spi->dev,
> + "Invalid open circuit current:%u", oc_current);
> + return ERR_PTR(-EINVAL);
> + }
> +
> + thermo->sensor_config |= LTC2983_THERMOCOUPLE_OC_CHECK(1);
> + }
> + /* 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) {
> + const char *propname = "adi,custom-thermocouple";
> +
> + thermo->custom = __ltc2983_custom_sensor_new(st, child,
> + propname, false,
> + 16384, true);
> + if (IS_ERR(thermo->custom)) {
> + of_node_put(phandle);
> + return ERR_CAST(thermo->custom);
> + }
> + }
> +
> + /* set common parameters */
> + 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;
> + u32 excitation_current = 0, n_wires = 0;
> +
> + 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;
> + }
> +
> + ret = of_property_read_u32(child, "adi,number-of-wires", &n_wires);
> + if (!ret) {
> + switch (n_wires) {
> + case 2:
> + rtd->sensor_config = LTC2983_RTD_N_WIRES(0);
> + break;
> + case 3:
> + rtd->sensor_config = LTC2983_RTD_N_WIRES(1);
> + break;
> + case 4:
> + rtd->sensor_config = LTC2983_RTD_N_WIRES(2);
> + break;
> + case 5:
> + /* 4 wires, Kelvin Rsense */
> + rtd->sensor_config = LTC2983_RTD_N_WIRES(3);
> + break;
> + default:
> + dev_err(dev, "Invalid number of wires:%u\n", n_wires);
> + ret = -EINVAL;
> + goto fail;
> + }
> + }
> +
> + if (of_property_read_bool(child, "adi,rsense-share")) {
> + /* Current rotation is only available with rsense sharing */
> + if (of_property_read_bool(child, "adi,current-rotate")) {
> + if (n_wires == 2 || n_wires == 3) {
> + dev_err(dev,
> + "Rotation not allowed for 2/3 Wire RTDs");
> + ret = -EINVAL;
> + goto fail;
> + }
> + rtd->sensor_config |= LTC2983_RTD_C_ROTATE(1);
> + } else {
> + rtd->sensor_config |= LTC2983_RTD_R_SHARE(1);
> + }
> + }
> + /*
> + * 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,
> + "adi,custom-rtd",
> + false, 2048, false);
> + if (IS_ERR(rtd->custom)) {
> + of_node_put(phandle);
> + return ERR_CAST(rtd->custom);
> + }
> + }
> +
> + /* set common parameters */
> + 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-microamp",
> + &excitation_current);
> + if (ret) {
> + /* default to 5uA */
> + rtd->excitation_current = 1;
> + } else {
> + switch (excitation_current) {
> + case 5:
> + rtd->excitation_current = 0x01;
> + break;
> + case 10:
> + rtd->excitation_current = 0x02;
> + break;
> + case 25:
> + rtd->excitation_current = 0x03;
> + break;
> + case 50:
> + rtd->excitation_current = 0x04;
> + break;
> + case 100:
> + rtd->excitation_current = 0x05;
> + break;
> + case 250:
> + rtd->excitation_current = 0x06;
> + break;
> + case 500:
> + rtd->excitation_current = 0x07;
> + break;
> + case 1000:
> + rtd->excitation_current = 0x08;
> + break;
> + default:
> + dev_err(&st->spi->dev,
> + "Invalid value for excitation current(%u)",
> + excitation_current);
> + ret = -EINVAL;
> + goto fail;
> + }
> + }
> +
> + 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;
> + u32 excitation_current = 0;
> + 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;
> + }
> +
> + if (of_property_read_bool(child, "adi,single-ended")) {
> + thermistor->sensor_config = LTC2983_THERMISTOR_SGL(1);
> + } else if (of_property_read_bool(child, "adi,rsense-share")) {
> + /* rotation is only possible if sharing rsense */
> + if (of_property_read_bool(child, "adi,current-rotate"))
> + thermistor->sensor_config =
> + LTC2983_THERMISTOR_C_ROTATE(1);
> + else
> + thermistor->sensor_config =
> + LTC2983_THERMISTOR_R_SHARE(1);
> + }
> + /* 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) {
> + bool steinhart = false;
> + const char *propname;
> +
> + if (sensor->type == LTC2983_SENSOR_THERMISTOR_STEINHART) {
> + steinhart = true;
> + propname = "adi,custom-steinhart";
> + } else {
> + propname = "adi,custom-thermistor";
> + }
> +
> + thermistor->custom = __ltc2983_custom_sensor_new(st, child,
> + propname,
> + steinhart,
> + 64, false);
> + if (IS_ERR(thermistor->custom)) {
> + of_node_put(phandle);
> + return ERR_CAST(thermistor->custom);
> + }
> + }
> + /* set common parameters */
> + 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-nanoamp",
> + &excitation_current);
> + if (ret) {
> + /* Auto range is not allowed for custom sensors */
> + if (sensor->type >= LTC2983_SENSOR_THERMISTOR_STEINHART)
> + /* default to 1uA */
> + thermistor->excitation_current = 0x03;
> + else
> + /* default to auto-range */
> + thermistor->excitation_current = 0x0c;
> + } else {
> + switch (excitation_current) {
> + case 0:
> + /* auto range */
> + if (sensor->type >=
> + LTC2983_SENSOR_THERMISTOR_STEINHART) {
> + dev_err(&st->spi->dev,
> + "Auto Range not allowed for custom sensors\n");
> + ret = -EINVAL;
> + goto fail;
> + }
> + thermistor->excitation_current = 0x0c;
> + break;
> + case 250:
> + thermistor->excitation_current = 0x01;
> + break;
> + case 500:
> + thermistor->excitation_current = 0x02;
> + break;
> + case 1000:
> + thermistor->excitation_current = 0x03;
> + break;
> + case 5000:
> + thermistor->excitation_current = 0x04;
> + break;
> + case 10000:
> + thermistor->excitation_current = 0x05;
> + break;
> + case 25000:
> + thermistor->excitation_current = 0x06;
> + break;
> + case 50000:
> + thermistor->excitation_current = 0x07;
> + break;
> + case 100000:
> + thermistor->excitation_current = 0x08;
> + break;
> + case 250000:
> + thermistor->excitation_current = 0x09;
> + break;
> + case 500000:
> + thermistor->excitation_current = 0x0a;
> + break;
> + case 1000000:
> + thermistor->excitation_current = 0x0b;
> + break;
> + default:
> + dev_err(&st->spi->dev,
> + "Invalid value for excitation current(%u)",
> + excitation_current);
> + ret = -EINVAL;
> + goto fail;
> + }
> + }
> +
> + 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, excitation_current = 0;
> + int ret;
> +
> + diode = devm_kzalloc(&st->spi->dev, sizeof(*diode), GFP_KERNEL);
> + if (!diode)
> + return ERR_PTR(-ENOMEM);
> +
> + if (of_property_read_bool(child, "adi,single-ended"))
> + diode->sensor_config = LTC2983_DIODE_SGL(1);
> +
> + if (of_property_read_bool(child, "adi,three-conversion-cycles"))
> + diode->sensor_config |= LTC2983_DIODE_3_CONV_CYCLE(1);
> +
> + if (of_property_read_bool(child, "adi,average-on"))
> + diode->sensor_config |= LTC2983_DIODE_AVERAGE_ON(1);
> +
> + /* 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.fault_handler = ltc2983_common_fault_handler;
> + diode->sensor.assign_chan = ltc2983_diode_assign_chan;
> +
> + ret = of_property_read_u32(child, "adi,excitation-current-microamp",
> + &excitation_current);
> + if (!ret) {
> + switch (excitation_current) {
> + case 10:
> + diode->excitation_current = 0x00;
> + break;
> + case 20:
> + diode->excitation_current = 0x01;
> + break;
> + case 40:
> + diode->excitation_current = 0x02;
> + break;
> + case 80:
> + diode->excitation_current = 0x03;
> + break;
> + default:
> + dev_err(&st->spi->dev,
> + "Invalid value for excitation current(%u)",
> + excitation_current);
> + return ERR_PTR(-EINVAL);
> + }
> + }
> +
> + 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;
> + u32 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);
> + }
> +
> + ret = of_property_read_u32(child, "adi,rsense-val-milli-ohms", &temp);
> + if (ret) {
> + dev_err(&st->spi->dev, "Property adi,rsense-val-milli-ohms missing\n");
> + return ERR_PTR(-EINVAL);
> + }
> + /*
> + * Times 1000 because we have milli-ohms and __convert_to_raw
> + * expects scales of 1000000 which are used for all other
> + * properties.
> + * 2^10 resolution
> + */
> + rsense->r_sense_val = __convert_to_raw((u64)temp * 1000, 1024);
> +
> + /* set common parameters */
> + 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);

That parameter should be aligned with the open bracket.

> + return ERR_PTR(-EINVAL);
> + }
> + /* set common parameters */
> + 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;
> +
> + 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),
> + &st->temp, sizeof(st->temp));
> + if (ret)
> + return ret;
> +
> + *val = __be32_to_cpu(st->temp);
> +
> + 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);

Odd indent.

> + 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;
Would have preferred separate error handling.
if (ret)
return ret;

return IIO_VAL_INT;

> + case IIO_CHAN_INFO_SCALE:
> + switch (chan->type) {
> + case IIO_TEMP:
> + /* value in milli degrees */
> + *val = 1000;
> + /* 2^10 */
> + *val2 = 1024;
> + return IIO_VAL_FRACTIONAL;
> + case IIO_VOLTAGE:
> + /* value in millivolt */
> + *val = 1000;
> + /* 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);
> +
> + 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) ({ \
> + 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, \
> + }; \
> + __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;
> +
> + of_property_read_u32(dev->of_node, "adi,mux-delay-config-us",
> + &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++;
> + }
> +
> + 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;
> + 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;
> + }
> +
> + st->iio_chan = devm_kzalloc(&st->spi->dev,
> + st->iio_channels * sizeof(*st->iio_chan),
> + GFP_KERNEL);
> +

Bit a stylistic inconsistency here on whether you have a blank line
before error checks or not. I might tweak that when applying depending
on how fussy I feel.

> + if (!st->iio_chan)
> + return -ENOMEM;
> +
> + ret = regmap_update_bits(st->regmap, LTC2983_GLOBAL_CONFIG_REG,
> + LTC2983_NOTCH_FREQ_MASK,
> + LTC2983_NOTCH_FREQ(st->filter_notch_freq));
> + if (ret)
> + return ret;
> +
> + ret = regmap_write(st->regmap, LTC2983_MUX_CONFIG_REG,
> + st->mux_delay_config);
> + if (ret)
> + return ret;
> +
> + 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);
> + }
> +
> + 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_irq(&spi->dev, spi->irq, ltc2983_irq_handler,
> + 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 dummy;
> +
> + /* dummy read to bring the device out of sleep */
> + regmap_read(st->regmap, LTC2983_STATUS_REG, &dummy);
> + /* we need to re-assign the channels */
> + return ltc2983_setup(st, false);
> +}
> +
> +static int __maybe_unused ltc2983_suspend(struct device *dev)
> +{
> + struct ltc2983_data *st = spi_get_drvdata(to_spi_device(dev));
> +
> + return regmap_write(st->regmap, LTC2983_STATUS_REG, LTC2983_SLEEP);
> +}
> +
> +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");