drivers/iio/addac/ad74115.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2022 Analog Devices, Inc.
 * Author: Cosmin Tanislav <cosmin.tanislav@analog.com>
 */

#include <linux/bitfield.h>
#include <linux/bitops.h>
#include <linux/crc8.h>
#include <linux/device.h>
#include <linux/gpio/driver.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/spi/spi.h>
#include <linux/units.h>

#include <asm/unaligned.h>

#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>

#define AD74115_NAME				"ad74115"

#define AD74115_CH_FUNC_SETUP_REG		0x01

#define AD74115_ADC_CONFIG_REG			0x02
#define AD74115_ADC_CONFIG_CONV2_RATE_MASK	GENMASK(15, 13)
#define AD74115_ADC_CONFIG_CONV1_RATE_MASK	GENMASK(12, 10)
#define AD74115_ADC_CONFIG_CONV2_RANGE_MASK	GENMASK(9, 7)
#define AD74115_ADC_CONFIG_CONV1_RANGE_MASK	GENMASK(6, 4)

#define AD74115_PWR_OPTIM_CONFIG_REG		0x03

#define AD74115_DIN_CONFIG1_REG			0x04
#define AD74115_DIN_COMPARATOR_EN_MASK		BIT(13)
#define AD74115_DIN_SINK_MASK			GENMASK(11, 7)
#define AD74115_DIN_DEBOUNCE_MASK		GENMASK(4, 0)

#define AD74115_DIN_CONFIG2_REG			0x05
#define AD74115_COMP_THRESH_MASK		GENMASK(6, 0)

#define AD74115_OUTPUT_CONFIG_REG		0x06
#define AD74115_OUTPUT_SLEW_EN_MASK		GENMASK(6, 5)
#define AD74115_OUTPUT_SLEW_LIN_STEP_MASK	GENMASK(4, 3)
#define AD74115_OUTPUT_SLEW_LIN_RATE_MASK	GENMASK(2, 1)

#define AD74115_RTD3W4W_CONFIG_REG		0x07

#define AD74115_BURNOUT_CONFIG_REG		0x0a
#define AD74115_BURNOUT_EXT2_EN_MASK		BIT(10)
#define AD74115_BURNOUT_EXT1_EN_MASK		BIT(5)
#define AD74115_BURNOUT_VIOUT_EN_MASK		BIT(0)

#define AD74115_DAC_CODE_REG			0x0b

#define AD74115_DAC_ACTIVE_REG			0x0d

#define AD74115_GPIO_CONFIG_X_REG(x)		(0x35 + (x))
#define AD74115_GPIO_CONFIG_GPI_DATA		BIT(5)
#define AD74115_GPIO_CONFIG_GPO_DATA		BIT(4)
#define AD74115_GPIO_CONFIG_SELECT_MASK		GENMASK(2, 0)

#define AD74115_CHARGE_PUMP_REG			0x3a

#define AD74115_ADC_CONV_CTRL_REG		0x3b
#define AD74115_ADC_CONV_SEQ_MASK		GENMASK(13, 12)

#define AD74115_DIN_COMP_OUT_REG		0x40

#define AD74115_LIVE_STATUS_REG			0x42
#define AD74115_ADC_DATA_RDY_MASK		BIT(3)

#define AD74115_READ_SELECT_REG			0x64

#define AD74115_CMD_KEY_REG			0x78
#define AD74115_CMD_KEY_RESET1			0x15fa
#define AD74115_CMD_KEY_RESET2			0xaf51

#define AD74115_CRC_POLYNOMIAL			0x7
DECLARE_CRC8_TABLE(ad74115_crc8_table);

#define AD74115_ADC_CODE_MAX			((int)GENMASK(15, 0))
#define AD74115_ADC_CODE_HALF			(AD74115_ADC_CODE_MAX / 2)

#define AD74115_DAC_VOLTAGE_MAX			12000
#define AD74115_DAC_CURRENT_MAX			25
#define AD74115_DAC_CODE_MAX			((int)GENMASK(13, 0))
#define AD74115_DAC_CODE_HALF			(AD74115_DAC_CODE_MAX / 2)

#define AD74115_COMP_THRESH_MAX			98

#define AD74115_SENSE_RESISTOR_OHMS		100
#define AD74115_REF_RESISTOR_OHMS		2100

#define AD74115_DIN_SINK_LOW_STEP		120
#define AD74115_DIN_SINK_HIGH_STEP		240
#define AD74115_DIN_SINK_MAX			31

#define AD74115_FRAME_SIZE			4
#define AD74115_GPIO_NUM			4

#define AD74115_CONV_TIME_US			1000000

enum ad74115_dac_ch {
	AD74115_DAC_CH_MAIN,
	AD74115_DAC_CH_COMPARATOR,
};

enum ad74115_adc_ch {
	AD74115_ADC_CH_CONV1,
	AD74115_ADC_CH_CONV2,
	AD74115_ADC_CH_NUM
};

enum ad74115_ch_func {
	AD74115_CH_FUNC_HIGH_IMPEDANCE,
	AD74115_CH_FUNC_VOLTAGE_OUTPUT,
	AD74115_CH_FUNC_CURRENT_OUTPUT,
	AD74115_CH_FUNC_VOLTAGE_INPUT,
	AD74115_CH_FUNC_CURRENT_INPUT_EXT_POWER,
	AD74115_CH_FUNC_CURRENT_INPUT_LOOP_POWER,
	AD74115_CH_FUNC_2_WIRE_RESISTANCE_INPUT,
	AD74115_CH_FUNC_3_4_WIRE_RESISTANCE_INPUT,
	AD74115_CH_FUNC_DIGITAL_INPUT_LOGIC,
	AD74115_CH_FUNC_DIGITAL_INPUT_LOOP_POWER,
	AD74115_CH_FUNC_CURRENT_OUTPUT_HART,
	AD74115_CH_FUNC_CURRENT_INPUT_EXT_POWER_HART,
	AD74115_CH_FUNC_CURRENT_INPUT_LOOP_POWER_HART,
	AD74115_CH_FUNC_MAX = AD74115_CH_FUNC_CURRENT_INPUT_LOOP_POWER_HART,
	AD74115_CH_FUNC_NUM
};

enum ad74115_adc_range {
	AD74115_ADC_RANGE_12V,
	AD74115_ADC_RANGE_12V_BIPOLAR,
	AD74115_ADC_RANGE_2_5V_BIPOLAR,
	AD74115_ADC_RANGE_2_5V_NEG,
	AD74115_ADC_RANGE_2_5V,
	AD74115_ADC_RANGE_0_625V,
	AD74115_ADC_RANGE_104MV_BIPOLAR,
	AD74115_ADC_RANGE_12V_OTHER,
	AD74115_ADC_RANGE_MAX = AD74115_ADC_RANGE_12V_OTHER,
	AD74115_ADC_RANGE_NUM
};

enum ad74115_adc_conv_seq {
	AD74115_ADC_CONV_SEQ_STANDBY = 0b00,
	AD74115_ADC_CONV_SEQ_SINGLE = 0b01,
	AD74115_ADC_CONV_SEQ_CONTINUOUS = 0b10,
};

enum ad74115_din_threshold_mode {
	AD74115_DIN_THRESHOLD_MODE_AVDD,
	AD74115_DIN_THRESHOLD_MODE_FIXED,
	AD74115_DIN_THRESHOLD_MODE_MAX = AD74115_DIN_THRESHOLD_MODE_FIXED,
};

enum ad74115_slew_mode {
	AD74115_SLEW_MODE_DISABLED,
	AD74115_SLEW_MODE_LINEAR,
	AD74115_SLEW_MODE_HART,
};

enum ad74115_slew_step {
	AD74115_SLEW_STEP_0_8_PERCENT,
	AD74115_SLEW_STEP_1_5_PERCENT,
	AD74115_SLEW_STEP_6_1_PERCENT,
	AD74115_SLEW_STEP_22_2_PERCENT,
};

enum ad74115_slew_rate {
	AD74115_SLEW_RATE_4KHZ,
	AD74115_SLEW_RATE_64KHZ,
	AD74115_SLEW_RATE_150KHZ,
	AD74115_SLEW_RATE_240KHZ,
};

enum ad74115_gpio_config {
	AD74115_GPIO_CONFIG_OUTPUT_BUFFERED = 0b010,
	AD74115_GPIO_CONFIG_INPUT = 0b011,
};

enum ad74115_gpio_mode {
	AD74115_GPIO_MODE_LOGIC = 1,
	AD74115_GPIO_MODE_SPECIAL = 2,
};

struct ad74115_channels {
	struct iio_chan_spec		*channels;
	unsigned int			num_channels;
};

struct ad74115_state {
	struct spi_device		*spi;
	struct regmap			*regmap;
	struct iio_trigger		*trig;

	/*
	 * Synchronize consecutive operations when doing a one-shot
	 * conversion and when updating the ADC samples SPI message.
	 */
	struct mutex			lock;
	struct gpio_chip		gc;
	struct gpio_chip		comp_gc;
	int				irq;

	unsigned int			avdd_mv;
	unsigned long			gpio_valid_mask;
	bool				dac_bipolar;
	bool				dac_hart_slew;
	bool				rtd_mode_4_wire;
	enum ad74115_ch_func		ch_func;
	enum ad74115_din_threshold_mode	din_threshold_mode;

	struct completion		adc_data_completion;
	struct spi_message		adc_samples_msg;
	struct spi_transfer		adc_samples_xfer[AD74115_ADC_CH_NUM + 1];

	/*
	 * DMA (thus cache coherency maintenance) requires the
	 * transfer buffers to live in their own cache lines.
	 */
	u8				reg_tx_buf[AD74115_FRAME_SIZE] __aligned(IIO_DMA_MINALIGN);
	u8				reg_rx_buf[AD74115_FRAME_SIZE];
	u8				adc_samples_tx_buf[AD74115_FRAME_SIZE * AD74115_ADC_CH_NUM];
	u8				adc_samples_rx_buf[AD74115_FRAME_SIZE * AD74115_ADC_CH_NUM];
};

struct ad74115_fw_prop {
	const char			*name;
	bool				is_boolean;
	bool				negate;
	unsigned int			max;
	unsigned int			reg;
	unsigned int			mask;
	const unsigned int		*lookup_tbl;
	unsigned int			lookup_tbl_len;
};

#define AD74115_FW_PROP(_name, _max, _reg, _mask)		\
{								\
	.name = (_name),					\
	.max = (_max),						\
	.reg = (_reg),						\
	.mask = (_mask),					\
}

#define AD74115_FW_PROP_TBL(_name, _tbl, _reg, _mask)		\
{								\
	.name = (_name),					\
	.reg = (_reg),						\
	.mask = (_mask),					\
	.lookup_tbl = (_tbl),					\
	.lookup_tbl_len = ARRAY_SIZE(_tbl),			\
}

#define AD74115_FW_PROP_BOOL(_name, _reg, _mask)		\
{								\
	.name = (_name),					\
	.is_boolean = true,					\
	.reg = (_reg),						\
	.mask = (_mask),					\
}

#define AD74115_FW_PROP_BOOL_NEG(_name, _reg, _mask)		\
{								\
	.name = (_name),					\
	.is_boolean = true,					\
	.negate = true,						\
	.reg = (_reg),						\
	.mask = (_mask),					\
}

static const int ad74115_dac_rate_tbl[] = {
	0,
	4 * 8,
	4 * 15,
	4 * 61,
	4 * 222,
	64 * 8,
	64 * 15,
	64 * 61,
	64 * 222,
	150 * 8,
	150 * 15,
	150 * 61,
	150 * 222,
	240 * 8,
	240 * 15,
	240 * 61,
	240 * 222,
};

static const unsigned int ad74115_dac_rate_step_tbl[][3] = {
	{ AD74115_SLEW_MODE_DISABLED },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_0_8_PERCENT, AD74115_SLEW_RATE_4KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_1_5_PERCENT, AD74115_SLEW_RATE_4KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_6_1_PERCENT, AD74115_SLEW_RATE_4KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_22_2_PERCENT, AD74115_SLEW_RATE_4KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_0_8_PERCENT, AD74115_SLEW_RATE_64KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_1_5_PERCENT, AD74115_SLEW_RATE_64KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_6_1_PERCENT, AD74115_SLEW_RATE_64KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_22_2_PERCENT, AD74115_SLEW_RATE_64KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_0_8_PERCENT, AD74115_SLEW_RATE_150KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_1_5_PERCENT, AD74115_SLEW_RATE_150KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_6_1_PERCENT, AD74115_SLEW_RATE_150KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_22_2_PERCENT, AD74115_SLEW_RATE_150KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_0_8_PERCENT, AD74115_SLEW_RATE_240KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_1_5_PERCENT, AD74115_SLEW_RATE_240KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_6_1_PERCENT, AD74115_SLEW_RATE_240KHZ },
	{ AD74115_SLEW_MODE_LINEAR, AD74115_SLEW_STEP_22_2_PERCENT, AD74115_SLEW_RATE_240KHZ },
};

static const unsigned int ad74115_rtd_excitation_current_ua_tbl[] = {
	250, 500, 750, 1000
};

static const unsigned int ad74115_burnout_current_na_tbl[] = {
	0, 50, 0, 500, 1000, 0, 10000, 0
};

static const unsigned int ad74115_viout_burnout_current_na_tbl[] = {
	0, 0, 0, 0, 1000, 0, 10000, 0
};

static const unsigned int ad74115_gpio_mode_tbl[] = {
	0, 0, 0, 1, 2, 3, 4, 5
};

static const unsigned int ad74115_adc_conv_rate_tbl[] = {
	10, 20, 1200, 4800, 9600
};

static const unsigned int ad74115_debounce_tbl[] = {
	0,     13,    18,    24,    32,    42,    56,    75,
	100,   130,   180,   240,   320,   420,   560,   750,
	1000,  1300,  1800,  2400,  3200,  4200,  5600,  7500,
	10000, 13000, 18000, 24000, 32000, 42000, 56000, 75000,
};

static const unsigned int ad74115_adc_ch_data_regs_tbl[] = {
	[AD74115_ADC_CH_CONV1] = 0x44,
	[AD74115_ADC_CH_CONV2] = 0x46,
};

static const unsigned int ad74115_adc_ch_en_bit_tbl[] = {
	[AD74115_ADC_CH_CONV1] = BIT(0),
	[AD74115_ADC_CH_CONV2] = BIT(1),
};

static const bool ad74115_adc_bipolar_tbl[AD74115_ADC_RANGE_NUM] = {
	[AD74115_ADC_RANGE_12V_BIPOLAR]		= true,
	[AD74115_ADC_RANGE_2_5V_BIPOLAR]	= true,
	[AD74115_ADC_RANGE_104MV_BIPOLAR]	= true,
};

static const unsigned int ad74115_adc_conv_mul_tbl[AD74115_ADC_RANGE_NUM] = {
	[AD74115_ADC_RANGE_12V]			= 12000,
	[AD74115_ADC_RANGE_12V_BIPOLAR]		= 24000,
	[AD74115_ADC_RANGE_2_5V_BIPOLAR]	= 5000,
	[AD74115_ADC_RANGE_2_5V_NEG]		= 2500,
	[AD74115_ADC_RANGE_2_5V]		= 2500,
	[AD74115_ADC_RANGE_0_625V]		= 625,
	[AD74115_ADC_RANGE_104MV_BIPOLAR]	= 208,
	[AD74115_ADC_RANGE_12V_OTHER]		= 12000,
};

static const unsigned int ad74115_adc_gain_tbl[AD74115_ADC_RANGE_NUM][2] = {
	[AD74115_ADC_RANGE_12V]			= { 5, 24 },
	[AD74115_ADC_RANGE_12V_BIPOLAR]		= { 5, 24 },
	[AD74115_ADC_RANGE_2_5V_BIPOLAR]	= { 1, 1 },
	[AD74115_ADC_RANGE_2_5V_NEG]		= { 1, 1 },
	[AD74115_ADC_RANGE_2_5V]		= { 1, 1 },
	[AD74115_ADC_RANGE_0_625V]		= { 4, 1 },
	[AD74115_ADC_RANGE_104MV_BIPOLAR]	= { 24, 1 },
	[AD74115_ADC_RANGE_12V_OTHER]		= { 5, 24 },
};

static const int ad74115_adc_range_tbl[AD74115_ADC_RANGE_NUM][2] = {
	[AD74115_ADC_RANGE_12V]			= { 0,         12000000 },
	[AD74115_ADC_RANGE_12V_BIPOLAR]		= { -12000000, 12000000 },
	[AD74115_ADC_RANGE_2_5V_BIPOLAR]	= { -2500000,  2500000 },
	[AD74115_ADC_RANGE_2_5V_NEG]		= { -2500000,  0 },
	[AD74115_ADC_RANGE_2_5V]		= { 0,         2500000 },
	[AD74115_ADC_RANGE_0_625V]		= { 0,         625000 },
	[AD74115_ADC_RANGE_104MV_BIPOLAR]	= { -104000,   104000 },
	[AD74115_ADC_RANGE_12V_OTHER]		= { 0,         12000000 },
};

static int _ad74115_find_tbl_index(const unsigned int *tbl, unsigned int tbl_len,
				   unsigned int val, unsigned int *index)
{
	unsigned int i;

	for (i = 0; i < tbl_len; i++)
		if (val == tbl[i]) {
			*index = i;
			return 0;
		}

	return -EINVAL;
}

#define ad74115_find_tbl_index(tbl, val, index)	\
	_ad74115_find_tbl_index(tbl, ARRAY_SIZE(tbl), val, index)

static int ad74115_crc(u8 *buf)
{
	return crc8(ad74115_crc8_table, buf, 3, 0);
}

static void ad74115_format_reg_write(u8 reg, u16 val, u8 *buf)
{
	buf[0] = reg;
	put_unaligned_be16(val, &buf[1]);
	buf[3] = ad74115_crc(buf);
}

static int ad74115_reg_write(void *context, unsigned int reg, unsigned int val)
{
	struct ad74115_state *st = context;

	ad74115_format_reg_write(reg, val, st->reg_tx_buf);

	return spi_write(st->spi, st->reg_tx_buf, AD74115_FRAME_SIZE);
}

static int ad74115_crc_check(struct ad74115_state *st, u8 *buf)
{
	struct device *dev = &st->spi->dev;
	u8 expected_crc = ad74115_crc(buf);

	if (buf[3] != expected_crc) {
		dev_err(dev, "Bad CRC %02x for %02x%02x%02x, expected %02x\n",
			buf[3], buf[0], buf[1], buf[2], expected_crc);
		return -EINVAL;
	}

	return 0;
}

static int ad74115_reg_read(void *context, unsigned int reg, unsigned int *val)
{
	struct ad74115_state *st = context;
	struct spi_transfer reg_read_xfer[] = {
		{
			.tx_buf = st->reg_tx_buf,
			.len = sizeof(st->reg_tx_buf),
			.cs_change = 1,
		},
		{
			.rx_buf = st->reg_rx_buf,
			.len = sizeof(st->reg_rx_buf),
		},
	};
	int ret;

	ad74115_format_reg_write(AD74115_READ_SELECT_REG, reg, st->reg_tx_buf);

	ret = spi_sync_transfer(st->spi, reg_read_xfer, ARRAY_SIZE(reg_read_xfer));
	if (ret)
		return ret;

	ret = ad74115_crc_check(st, st->reg_rx_buf);
	if (ret)
		return ret;

	*val = get_unaligned_be16(&st->reg_rx_buf[1]);

	return 0;
}

static const struct regmap_config ad74115_regmap_config = {
	.reg_bits = 8,
	.val_bits = 16,
	.reg_read = ad74115_reg_read,
	.reg_write = ad74115_reg_write,
};

static int ad74115_gpio_config_set(struct ad74115_state *st, unsigned int offset,
				   enum ad74115_gpio_config cfg)
{
	return regmap_update_bits(st->regmap, AD74115_GPIO_CONFIG_X_REG(offset),
				  AD74115_GPIO_CONFIG_SELECT_MASK,
				  FIELD_PREP(AD74115_GPIO_CONFIG_SELECT_MASK, cfg));
}

static int ad74115_gpio_init_valid_mask(struct gpio_chip *gc,
					unsigned long *valid_mask,
					unsigned int ngpios)
{
	struct ad74115_state *st = gpiochip_get_data(gc);

	*valid_mask = st->gpio_valid_mask;

	return 0;
}

static int ad74115_gpio_get_direction(struct gpio_chip *gc, unsigned int offset)
{
	struct ad74115_state *st = gpiochip_get_data(gc);
	unsigned int val;
	int ret;

	ret = regmap_read(st->regmap, AD74115_GPIO_CONFIG_X_REG(offset), &val);
	if (ret)
		return ret;

	return FIELD_GET(AD74115_GPIO_CONFIG_SELECT_MASK, val) == AD74115_GPIO_CONFIG_INPUT;
}

static int ad74115_gpio_direction_input(struct gpio_chip *gc, unsigned int offset)
{
	struct ad74115_state *st = gpiochip_get_data(gc);

	return ad74115_gpio_config_set(st, offset, AD74115_GPIO_CONFIG_INPUT);
}

static int ad74115_gpio_direction_output(struct gpio_chip *gc, unsigned int offset,
					 int value)
{
	struct ad74115_state *st = gpiochip_get_data(gc);

	return ad74115_gpio_config_set(st, offset, AD74115_GPIO_CONFIG_OUTPUT_BUFFERED);
}

static int ad74115_gpio_get(struct gpio_chip *gc, unsigned int offset)
{
	struct ad74115_state *st = gpiochip_get_data(gc);
	unsigned int val;
	int ret;

	ret = regmap_read(st->regmap, AD74115_GPIO_CONFIG_X_REG(offset), &val);
	if (ret)
		return ret;

	return FIELD_GET(AD74115_GPIO_CONFIG_GPI_DATA, val);
}

static void ad74115_gpio_set(struct gpio_chip *gc, unsigned int offset, int value)
{
	struct ad74115_state *st = gpiochip_get_data(gc);
	struct device *dev = &st->spi->dev;
	int ret;

	ret = regmap_update_bits(st->regmap, AD74115_GPIO_CONFIG_X_REG(offset),
				 AD74115_GPIO_CONFIG_GPO_DATA,
				 FIELD_PREP(AD74115_GPIO_CONFIG_GPO_DATA, value));
	if (ret)
		dev_err(dev, "Failed to set GPIO %u output value, err: %d\n",
			offset, ret);
}

static int ad74115_set_comp_debounce(struct ad74115_state *st, unsigned int val)
{
	unsigned int len = ARRAY_SIZE(ad74115_debounce_tbl);
	unsigned int i;

	for (i = 0; i < len; i++)
		if (val <= ad74115_debounce_tbl[i])
			break;

	if (i == len)
		i = len - 1;

	return regmap_update_bits(st->regmap, AD74115_DIN_CONFIG1_REG,
				  AD74115_DIN_DEBOUNCE_MASK,
				  FIELD_PREP(AD74115_DIN_DEBOUNCE_MASK, val));
}

static int ad74115_comp_gpio_get_direction(struct gpio_chip *chip,
					   unsigned int offset)
{
	return GPIO_LINE_DIRECTION_IN;
}

static int ad74115_comp_gpio_set_config(struct gpio_chip *chip,
					unsigned int offset,
					unsigned long config)
{
	struct ad74115_state *st = gpiochip_get_data(chip);
	u32 param = pinconf_to_config_param(config);
	u32 arg = pinconf_to_config_argument(config);

	switch (param) {
	case PIN_CONFIG_INPUT_DEBOUNCE:
		return ad74115_set_comp_debounce(st, arg);
	default:
		return -ENOTSUPP;
	}
}

static int ad74115_comp_gpio_get(struct gpio_chip *chip, unsigned int offset)
{
	struct ad74115_state *st = gpiochip_get_data(chip);
	unsigned int val;
	int ret;

	ret = regmap_read(st->regmap, AD74115_DIN_COMP_OUT_REG, &val);
	if (ret)
		return ret;

	return !!val;
}

static irqreturn_t ad74115_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct ad74115_state *st = iio_priv(indio_dev);
	int ret;

	ret = spi_sync(st->spi, &st->adc_samples_msg);
	if (ret)
		goto out;

	iio_push_to_buffers(indio_dev, st->adc_samples_rx_buf);

out:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static irqreturn_t ad74115_adc_data_interrupt(int irq, void *data)
{
	struct iio_dev *indio_dev = data;
	struct ad74115_state *st = iio_priv(indio_dev);

	if (iio_buffer_enabled(indio_dev))
		iio_trigger_poll(st->trig);
	else
		complete(&st->adc_data_completion);

	return IRQ_HANDLED;
}

static int ad74115_set_adc_ch_en(struct ad74115_state *st,
				 enum ad74115_adc_ch channel, bool status)
{
	unsigned int mask = ad74115_adc_ch_en_bit_tbl[channel];

	return regmap_update_bits(st->regmap, AD74115_ADC_CONV_CTRL_REG, mask,
				  status ? mask : 0);
}

static int ad74115_set_adc_conv_seq(struct ad74115_state *st,
				    enum ad74115_adc_conv_seq conv_seq)
{
	return regmap_update_bits(st->regmap, AD74115_ADC_CONV_CTRL_REG,
				  AD74115_ADC_CONV_SEQ_MASK,
				  FIELD_PREP(AD74115_ADC_CONV_SEQ_MASK, conv_seq));
}

static int ad74115_update_scan_mode(struct iio_dev *indio_dev,
				    const unsigned long *active_scan_mask)
{
	struct ad74115_state *st = iio_priv(indio_dev);
	struct spi_transfer *xfer = st->adc_samples_xfer;
	u8 *rx_buf = st->adc_samples_rx_buf;
	u8 *tx_buf = st->adc_samples_tx_buf;
	unsigned int i;
	int ret = 0;

	mutex_lock(&st->lock);

	spi_message_init(&st->adc_samples_msg);

	for_each_clear_bit(i, active_scan_mask, AD74115_ADC_CH_NUM) {
		ret = ad74115_set_adc_ch_en(st, i, false);
		if (ret)
			goto out;
	}

	/*
	 * The read select register is used to select which register's value
	 * will be sent by the slave on the next SPI frame.
	 *
	 * Create an SPI message that, on each step, writes to the read select
	 * register to select the ADC result of the next enabled channel, and
	 * reads the ADC result of the previous enabled channel.
	 *
	 * Example:
	 * W: [WCH1] [WCH2] [WCH2] [WCH3] [    ]
	 * R: [    ] [RCH1] [RCH2] [RCH3] [RCH4]
	 */
	for_each_set_bit(i, active_scan_mask, AD74115_ADC_CH_NUM) {
		ret = ad74115_set_adc_ch_en(st, i, true);
		if (ret)
			goto out;

		if (xfer == st->adc_samples_xfer)
			xfer->rx_buf = NULL;
		else
			xfer->rx_buf = rx_buf;

		xfer->tx_buf = tx_buf;
		xfer->len = AD74115_FRAME_SIZE;
		xfer->cs_change = 1;

		ad74115_format_reg_write(AD74115_READ_SELECT_REG,
					 ad74115_adc_ch_data_regs_tbl[i], tx_buf);

		spi_message_add_tail(xfer, &st->adc_samples_msg);

		tx_buf += AD74115_FRAME_SIZE;
		if (xfer != st->adc_samples_xfer)
			rx_buf += AD74115_FRAME_SIZE;
		xfer++;
	}

	xfer->rx_buf = rx_buf;
	xfer->tx_buf = NULL;
	xfer->len = AD74115_FRAME_SIZE;
	xfer->cs_change = 0;

	spi_message_add_tail(xfer, &st->adc_samples_msg);

out:
	mutex_unlock(&st->lock);

	return ret;
}

static int ad74115_buffer_postenable(struct iio_dev *indio_dev)
{
	struct ad74115_state *st = iio_priv(indio_dev);

	return ad74115_set_adc_conv_seq(st, AD74115_ADC_CONV_SEQ_CONTINUOUS);
}

static int ad74115_buffer_predisable(struct iio_dev *indio_dev)
{
	struct ad74115_state *st = iio_priv(indio_dev);
	unsigned int i;
	int ret;

	mutex_lock(&st->lock);

	ret = ad74115_set_adc_conv_seq(st, AD74115_ADC_CONV_SEQ_STANDBY);
	if (ret)
		goto out;

	/*
	 * update_scan_mode() is not called in the disable path, disable all
	 * channels here.
	 */
	for (i = 0; i < AD74115_ADC_CH_NUM; i++) {
		ret = ad74115_set_adc_ch_en(st, i, false);
		if (ret)
			goto out;
	}

out:
	mutex_unlock(&st->lock);

	return ret;
}

static const struct iio_buffer_setup_ops ad74115_buffer_ops = {
	.postenable = &ad74115_buffer_postenable,
	.predisable = &ad74115_buffer_predisable,
};

static const struct iio_trigger_ops ad74115_trigger_ops = {
	.validate_device = iio_trigger_validate_own_device,
};

static int ad74115_get_adc_rate(struct ad74115_state *st,
				enum ad74115_adc_ch channel, int *val)
{
	unsigned int i;
	int ret;

	ret = regmap_read(st->regmap, AD74115_ADC_CONFIG_REG, &i);
	if (ret)
		return ret;

	if (channel == AD74115_ADC_CH_CONV1)
		i = FIELD_GET(AD74115_ADC_CONFIG_CONV1_RATE_MASK, i);
	else
		i = FIELD_GET(AD74115_ADC_CONFIG_CONV2_RATE_MASK, i);

	*val = ad74115_adc_conv_rate_tbl[i];

	return IIO_VAL_INT;
}

static int _ad74115_get_adc_code(struct ad74115_state *st,
				 enum ad74115_adc_ch channel, int *val)
{
	unsigned int uval;
	int ret;

	reinit_completion(&st->adc_data_completion);

	ret = ad74115_set_adc_ch_en(st, channel, true);
	if (ret)
		return ret;

	ret = ad74115_set_adc_conv_seq(st, AD74115_ADC_CONV_SEQ_SINGLE);
	if (ret)
		return ret;

	if (st->irq) {
		ret = wait_for_completion_timeout(&st->adc_data_completion,
						  msecs_to_jiffies(1000));
		if (!ret)
			return -ETIMEDOUT;
	} else {
		unsigned int regval, wait_time;
		int rate;

		ret = ad74115_get_adc_rate(st, channel, &rate);
		if (ret < 0)
			return ret;

		wait_time = DIV_ROUND_CLOSEST(AD74115_CONV_TIME_US, rate);

		ret = regmap_read_poll_timeout(st->regmap, AD74115_LIVE_STATUS_REG,
					       regval, regval & AD74115_ADC_DATA_RDY_MASK,
					       wait_time, 5 * wait_time);
		if (ret)
			return ret;

		/*
		 * The ADC_DATA_RDY bit is W1C.
		 * See datasheet page 98, Table 62. Bit Descriptions for
		 * LIVE_STATUS.
		 * Although the datasheet mentions that the bit will auto-clear
		 * when writing to the ADC_CONV_CTRL register, this does not
		 * seem to happen.
		 */
		ret = regmap_write_bits(st->regmap, AD74115_LIVE_STATUS_REG,
					AD74115_ADC_DATA_RDY_MASK,
					FIELD_PREP(AD74115_ADC_DATA_RDY_MASK, 1));
		if (ret)
			return ret;
	}

	ret = regmap_read(st->regmap, ad74115_adc_ch_data_regs_tbl[channel], &uval);
	if (ret)
		return ret;

	ret = ad74115_set_adc_conv_seq(st, AD74115_ADC_CONV_SEQ_STANDBY);
	if (ret)
		return ret;

	ret = ad74115_set_adc_ch_en(st, channel, false);
	if (ret)
		return ret;

	*val = uval;

	return IIO_VAL_INT;
}

static int ad74115_get_adc_code(struct iio_dev *indio_dev,
				enum ad74115_adc_ch channel, int *val)
{
	struct ad74115_state *st = iio_priv(indio_dev);
	int ret;

	ret = iio_device_claim_direct_mode(indio_dev);
	if (ret)
		return ret;

	mutex_lock(&st->lock);
	ret = _ad74115_get_adc_code(st, channel, val);
	mutex_unlock(&st->lock);

	iio_device_release_direct_mode(indio_dev);

	return ret;
}

static int ad74115_adc_code_to_resistance(int code, int *val, int *val2)
{
	if (code == AD74115_ADC_CODE_MAX)
		code--;

	*val = code * AD74115_REF_RESISTOR_OHMS;
	*val2 = AD74115_ADC_CODE_MAX - code;

	return IIO_VAL_FRACTIONAL;
}

static int ad74115_set_dac_code(struct ad74115_state *st,
				enum ad74115_dac_ch channel, int val)
{
	if (val < 0)
		return -EINVAL;

	if (channel == AD74115_DAC_CH_COMPARATOR) {
		if (val > AD74115_COMP_THRESH_MAX)
			return -EINVAL;

		return regmap_update_bits(st->regmap, AD74115_DIN_CONFIG2_REG,
					  AD74115_COMP_THRESH_MASK,
					  FIELD_PREP(AD74115_COMP_THRESH_MASK, val));
	}

	if (val > AD74115_DAC_CODE_MAX)
		return -EINVAL;

	return regmap_write(st->regmap, AD74115_DAC_CODE_REG, val);
}

static int ad74115_get_dac_code(struct ad74115_state *st,
				enum ad74115_dac_ch channel, int *val)
{
	unsigned int uval;
	int ret;

	if (channel == AD74115_DAC_CH_COMPARATOR)
		return -EINVAL;

	ret = regmap_read(st->regmap, AD74115_DAC_ACTIVE_REG, &uval);
	if (ret)
		return ret;

	*val = uval;

	return IIO_VAL_INT;
}

static int ad74115_set_adc_rate(struct ad74115_state *st,
				enum ad74115_adc_ch channel, int val)
{
	unsigned int i;
	int ret;

	ret = ad74115_find_tbl_index(ad74115_adc_conv_rate_tbl, val, &i);
	if (ret)
		return ret;

	if (channel == AD74115_ADC_CH_CONV1)
		return regmap_update_bits(st->regmap, AD74115_ADC_CONFIG_REG,
					  AD74115_ADC_CONFIG_CONV1_RATE_MASK,
					  FIELD_PREP(AD74115_ADC_CONFIG_CONV1_RATE_MASK, i));

	return regmap_update_bits(st->regmap, AD74115_ADC_CONFIG_REG,
				  AD74115_ADC_CONFIG_CONV2_RATE_MASK,
				  FIELD_PREP(AD74115_ADC_CONFIG_CONV2_RATE_MASK, i));
}

static int ad74115_get_dac_rate(struct ad74115_state *st, int *val)
{
	unsigned int i, en_val, step_val, rate_val, tmp;
	int ret;

	ret = regmap_read(st->regmap, AD74115_OUTPUT_CONFIG_REG, &tmp);
	if (ret)
		return ret;

	en_val = FIELD_GET(AD74115_OUTPUT_SLEW_EN_MASK, tmp);
	step_val = FIELD_GET(AD74115_OUTPUT_SLEW_LIN_STEP_MASK, tmp);
	rate_val = FIELD_GET(AD74115_OUTPUT_SLEW_LIN_RATE_MASK, tmp);

	for (i = 0; i < ARRAY_SIZE(ad74115_dac_rate_step_tbl); i++)
		if (en_val == ad74115_dac_rate_step_tbl[i][0] &&
		    step_val == ad74115_dac_rate_step_tbl[i][1] &&
		    rate_val == ad74115_dac_rate_step_tbl[i][2])
			break;

	if (i == ARRAY_SIZE(ad74115_dac_rate_step_tbl))
		return -EINVAL;

	*val = ad74115_dac_rate_tbl[i];

	return IIO_VAL_INT;
}

static int ad74115_set_dac_rate(struct ad74115_state *st, int val)
{
	unsigned int i, en_val, step_val, rate_val, mask, tmp;
	int ret;

	ret = ad74115_find_tbl_index(ad74115_dac_rate_tbl, val, &i);
	if (ret)
		return ret;

	en_val = ad74115_dac_rate_step_tbl[i][0];
	step_val = ad74115_dac_rate_step_tbl[i][1];
	rate_val = ad74115_dac_rate_step_tbl[i][2];

	mask = AD74115_OUTPUT_SLEW_EN_MASK;
	mask |= AD74115_OUTPUT_SLEW_LIN_STEP_MASK;
	mask |= AD74115_OUTPUT_SLEW_LIN_RATE_MASK;

	tmp = FIELD_PREP(AD74115_OUTPUT_SLEW_EN_MASK, en_val);
	tmp |= FIELD_PREP(AD74115_OUTPUT_SLEW_LIN_STEP_MASK, step_val);
	tmp |= FIELD_PREP(AD74115_OUTPUT_SLEW_LIN_RATE_MASK, rate_val);

	return regmap_update_bits(st->regmap, AD74115_OUTPUT_CONFIG_REG, mask, tmp);
}

static int ad74115_get_dac_scale(struct ad74115_state *st,
				 struct iio_chan_spec const *chan,
				 int *val, int *val2)
{
	if (chan->channel == AD74115_DAC_CH_MAIN) {
		if (chan->type == IIO_VOLTAGE) {
			*val = AD74115_DAC_VOLTAGE_MAX;

			if (st->dac_bipolar)
				*val *= 2;

		} else {
			*val = AD74115_DAC_CURRENT_MAX;
		}

		*val2 = AD74115_DAC_CODE_MAX;
	} else {
		if (st->din_threshold_mode == AD74115_DIN_THRESHOLD_MODE_AVDD) {
			*val = 196 * st->avdd_mv;
			*val2 = 10 * AD74115_COMP_THRESH_MAX;
		} else {
			*val = 49000;
			*val2 = AD74115_COMP_THRESH_MAX;
		}
	}

	return IIO_VAL_FRACTIONAL;
}

static int ad74115_get_dac_offset(struct ad74115_state *st,
				  struct iio_chan_spec const *chan, int *val)
{
	if (chan->channel == AD74115_DAC_CH_MAIN) {
		if (chan->type == IIO_VOLTAGE && st->dac_bipolar)
			*val = -AD74115_DAC_CODE_HALF;
		else
			*val = 0;
	} else {
		if (st->din_threshold_mode == AD74115_DIN_THRESHOLD_MODE_AVDD)
			*val = -48;
		else
			*val = -38;
	}

	return IIO_VAL_INT;
}

static int ad74115_get_adc_range(struct ad74115_state *st,
				 enum ad74115_adc_ch channel, unsigned int *val)
{
	int ret;

	ret = regmap_read(st->regmap, AD74115_ADC_CONFIG_REG, val);
	if (ret)
		return ret;

	if (channel == AD74115_ADC_CH_CONV1)
		*val = FIELD_GET(AD74115_ADC_CONFIG_CONV1_RANGE_MASK, *val);
	else
		*val = FIELD_GET(AD74115_ADC_CONFIG_CONV2_RANGE_MASK, *val);

	return 0;
}

static int ad74115_get_adc_resistance_scale(struct ad74115_state *st,
					    unsigned int range,
					    int *val, int *val2)
{
	*val = ad74115_adc_gain_tbl[range][1] * AD74115_REF_RESISTOR_OHMS;
	*val2 = ad74115_adc_gain_tbl[range][0];

	if (ad74115_adc_bipolar_tbl[range])
		*val2 *= AD74115_ADC_CODE_HALF;
	else
		*val2 *= AD74115_ADC_CODE_MAX;

	return IIO_VAL_FRACTIONAL;
}

static int ad74115_get_adc_scale(struct ad74115_state *st,
				 struct iio_chan_spec const *chan,
				 int *val, int *val2)
{
	unsigned int range;
	int ret;

	ret = ad74115_get_adc_range(st, chan->channel, &range);
	if (ret)
		return ret;

	if (chan->type == IIO_RESISTANCE)
		return ad74115_get_adc_resistance_scale(st, range, val, val2);

	*val = ad74115_adc_conv_mul_tbl[range];
	*val2 = AD74115_ADC_CODE_MAX;

	if (chan->type == IIO_CURRENT)
		*val2 *= AD74115_SENSE_RESISTOR_OHMS;

	return IIO_VAL_FRACTIONAL;
}

static int ad74115_get_adc_resistance_offset(struct ad74115_state *st,
					     unsigned int range,
					     int *val, int *val2)
{
	unsigned int d = 10 * AD74115_REF_RESISTOR_OHMS
			 * ad74115_adc_gain_tbl[range][1];

	*val = 5;

	if (ad74115_adc_bipolar_tbl[range])
		*val -= AD74115_ADC_CODE_HALF;

	*val *= d;

	if (!st->rtd_mode_4_wire) {
		/* Add 0.2 Ohm to the final result for 3-wire RTD. */
		unsigned int v = 2 * ad74115_adc_gain_tbl[range][0];

		if (ad74115_adc_bipolar_tbl[range])
			v *= AD74115_ADC_CODE_HALF;
		else
			v *= AD74115_ADC_CODE_MAX;

		*val += v;
	}

	*val2 = d;

	return IIO_VAL_FRACTIONAL;
}

static int ad74115_get_adc_offset(struct ad74115_state *st,
				  struct iio_chan_spec const *chan,
				  int *val, int *val2)
{
	unsigned int range;
	int ret;

	ret = ad74115_get_adc_range(st, chan->channel, &range);
	if (ret)
		return ret;

	if (chan->type == IIO_RESISTANCE)
		return ad74115_get_adc_resistance_offset(st, range, val, val2);

	if (ad74115_adc_bipolar_tbl[range])
		*val = -AD74115_ADC_CODE_HALF;
	else if (range == AD74115_ADC_RANGE_2_5V_NEG)
		*val = -AD74115_ADC_CODE_MAX;
	else
		*val = 0;

	return IIO_VAL_INT;
}

static int ad74115_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val, int *val2, long info)
{
	struct ad74115_state *st = iio_priv(indio_dev);
	int ret;

	switch (info) {
	case IIO_CHAN_INFO_RAW:
		if (chan->output)
			return ad74115_get_dac_code(st, chan->channel, val);

		return ad74115_get_adc_code(indio_dev, chan->channel, val);
	case IIO_CHAN_INFO_PROCESSED:
		ret = ad74115_get_adc_code(indio_dev, chan->channel, val);
		if (ret)
			return ret;

		return ad74115_adc_code_to_resistance(*val, val, val2);
	case IIO_CHAN_INFO_SCALE:
		if (chan->output)
			return ad74115_get_dac_scale(st, chan, val, val2);

		return ad74115_get_adc_scale(st, chan, val, val2);
	case IIO_CHAN_INFO_OFFSET:
		if (chan->output)
			return ad74115_get_dac_offset(st, chan, val);

		return ad74115_get_adc_offset(st, chan, val, val2);
	case IIO_CHAN_INFO_SAMP_FREQ:
		if (chan->output)
			return ad74115_get_dac_rate(st, val);

		return ad74115_get_adc_rate(st, chan->channel, val);
	default:
		return -EINVAL;
	}
}

static int ad74115_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan, int val, int val2,
			     long info)
{
	struct ad74115_state *st = iio_priv(indio_dev);

	switch (info) {
	case IIO_CHAN_INFO_RAW:
		if (!chan->output)
			return -EINVAL;

		return ad74115_set_dac_code(st, chan->channel, val);
	case IIO_CHAN_INFO_SAMP_FREQ:
		if (chan->output)
			return ad74115_set_dac_rate(st, val);

		return ad74115_set_adc_rate(st, chan->channel, val);
	default:
		return -EINVAL;
	}
}

static int ad74115_read_avail(struct iio_dev *indio_dev,
			      struct iio_chan_spec const *chan,
			      const int **vals, int *type, int *length, long info)
{
	switch (info) {
	case IIO_CHAN_INFO_SAMP_FREQ:
		if (chan->output) {
			*vals = ad74115_dac_rate_tbl;
			*length = ARRAY_SIZE(ad74115_dac_rate_tbl);
		} else {
			*vals = ad74115_adc_conv_rate_tbl;
			*length = ARRAY_SIZE(ad74115_adc_conv_rate_tbl);
		}

		*type = IIO_VAL_INT;

		return IIO_AVAIL_LIST;
	default:
		return -EINVAL;
	}
}

static int ad74115_reg_access(struct iio_dev *indio_dev, unsigned int reg,
			      unsigned int writeval, unsigned int *readval)
{
	struct ad74115_state *st = iio_priv(indio_dev);

	if (readval)
		return regmap_read(st->regmap, reg, readval);

	return regmap_write(st->regmap, reg, writeval);
}

static const struct iio_info ad74115_info = {
	.read_raw = ad74115_read_raw,
	.write_raw = ad74115_write_raw,
	.read_avail = ad74115_read_avail,
	.update_scan_mode = ad74115_update_scan_mode,
	.debugfs_reg_access = ad74115_reg_access,
};

#define AD74115_DAC_CHANNEL(_type, index)				\
	{								\
		.type = (_type),					\
		.channel = (index),					\
		.indexed = 1,						\
		.output = 1,						\
		.scan_index = -1,					\
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW)		\
				      | BIT(IIO_CHAN_INFO_SCALE)	\
				      | BIT(IIO_CHAN_INFO_OFFSET),	\
	}

#define _AD74115_ADC_CHANNEL(_type, index, extra_mask_separate)		\
	{								\
		.type = (_type),					\
		.channel = (index),					\
		.indexed = 1,						\
		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW)		\
				      | BIT(IIO_CHAN_INFO_SAMP_FREQ)	\
				      | (extra_mask_separate),		\
		.info_mask_separate_available =				\
					BIT(IIO_CHAN_INFO_SAMP_FREQ),	\
		.scan_index = index,					\
		.scan_type = {						\
			.sign = 'u',					\
			.realbits = 16,					\
			.storagebits = 32,				\
			.shift = 8,					\
			.endianness = IIO_BE,				\
		},							\
	}

#define AD74115_ADC_CHANNEL(_type, index)				\
	_AD74115_ADC_CHANNEL(_type, index, BIT(IIO_CHAN_INFO_SCALE)	\
					   | BIT(IIO_CHAN_INFO_OFFSET))

static struct iio_chan_spec ad74115_voltage_input_channels[] = {
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV1),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV2),
};

static struct iio_chan_spec ad74115_voltage_output_channels[] = {
	AD74115_DAC_CHANNEL(IIO_VOLTAGE, AD74115_DAC_CH_MAIN),
	AD74115_ADC_CHANNEL(IIO_CURRENT, AD74115_ADC_CH_CONV1),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV2),
};

static struct iio_chan_spec ad74115_current_input_channels[] = {
	AD74115_ADC_CHANNEL(IIO_CURRENT, AD74115_ADC_CH_CONV1),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV2),
};

static struct iio_chan_spec ad74115_current_output_channels[] = {
	AD74115_DAC_CHANNEL(IIO_CURRENT, AD74115_DAC_CH_MAIN),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV1),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV2),
};

static struct iio_chan_spec ad74115_2_wire_resistance_input_channels[] = {
	_AD74115_ADC_CHANNEL(IIO_RESISTANCE, AD74115_ADC_CH_CONV1,
			     BIT(IIO_CHAN_INFO_PROCESSED)),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV2),
};

static struct iio_chan_spec ad74115_3_4_wire_resistance_input_channels[] = {
	AD74115_ADC_CHANNEL(IIO_RESISTANCE, AD74115_ADC_CH_CONV1),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV2),
};

static struct iio_chan_spec ad74115_digital_input_logic_channels[] = {
	AD74115_DAC_CHANNEL(IIO_VOLTAGE, AD74115_DAC_CH_COMPARATOR),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV1),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV2),
};

static struct iio_chan_spec ad74115_digital_input_loop_channels[] = {
	AD74115_DAC_CHANNEL(IIO_CURRENT, AD74115_DAC_CH_MAIN),
	AD74115_DAC_CHANNEL(IIO_VOLTAGE, AD74115_DAC_CH_COMPARATOR),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV1),
	AD74115_ADC_CHANNEL(IIO_VOLTAGE, AD74115_ADC_CH_CONV2),
};

#define _AD74115_CHANNELS(_channels)			\
	{						\
		.channels = _channels,			\
		.num_channels = ARRAY_SIZE(_channels),	\
	}

#define AD74115_CHANNELS(name) \
	_AD74115_CHANNELS(ad74115_ ## name ## _channels)

static const struct ad74115_channels ad74115_channels_map[AD74115_CH_FUNC_NUM] = {
	[AD74115_CH_FUNC_HIGH_IMPEDANCE] = AD74115_CHANNELS(voltage_input),
	[AD74115_CH_FUNC_VOLTAGE_INPUT] = AD74115_CHANNELS(voltage_input),

	[AD74115_CH_FUNC_VOLTAGE_OUTPUT] = AD74115_CHANNELS(voltage_output),

	[AD74115_CH_FUNC_CURRENT_INPUT_EXT_POWER] = AD74115_CHANNELS(current_input),
	[AD74115_CH_FUNC_CURRENT_INPUT_LOOP_POWER] = AD74115_CHANNELS(current_input),
	[AD74115_CH_FUNC_CURRENT_INPUT_EXT_POWER_HART] = AD74115_CHANNELS(current_input),
	[AD74115_CH_FUNC_CURRENT_INPUT_LOOP_POWER_HART] = AD74115_CHANNELS(current_input),

	[AD74115_CH_FUNC_CURRENT_OUTPUT] = AD74115_CHANNELS(current_output),
	[AD74115_CH_FUNC_CURRENT_OUTPUT_HART] = AD74115_CHANNELS(current_output),

	[AD74115_CH_FUNC_2_WIRE_RESISTANCE_INPUT] = AD74115_CHANNELS(2_wire_resistance_input),
	[AD74115_CH_FUNC_3_4_WIRE_RESISTANCE_INPUT] = AD74115_CHANNELS(3_4_wire_resistance_input),

	[AD74115_CH_FUNC_DIGITAL_INPUT_LOGIC] = AD74115_CHANNELS(digital_input_logic),

	[AD74115_CH_FUNC_DIGITAL_INPUT_LOOP_POWER] = AD74115_CHANNELS(digital_input_loop),
};

#define AD74115_GPIO_MODE_FW_PROP(i)					\
{									\
	.name = "adi,gpio" __stringify(i) "-mode",			\
	.reg = AD74115_GPIO_CONFIG_X_REG(i),				\
	.mask = AD74115_GPIO_CONFIG_SELECT_MASK,			\
	.lookup_tbl = ad74115_gpio_mode_tbl,				\
	.lookup_tbl_len = ARRAY_SIZE(ad74115_gpio_mode_tbl),		\
}

static const struct ad74115_fw_prop ad74115_gpio_mode_fw_props[] = {
	AD74115_GPIO_MODE_FW_PROP(0),
	AD74115_GPIO_MODE_FW_PROP(1),
	AD74115_GPIO_MODE_FW_PROP(2),
	AD74115_GPIO_MODE_FW_PROP(3),
};

static const struct ad74115_fw_prop ad74115_din_threshold_mode_fw_prop =
	AD74115_FW_PROP_BOOL("adi,digital-input-threshold-mode-fixed",
			     AD74115_DIN_CONFIG2_REG, BIT(7));

static const struct ad74115_fw_prop ad74115_dac_bipolar_fw_prop =
	AD74115_FW_PROP_BOOL("adi,dac-bipolar", AD74115_OUTPUT_CONFIG_REG, BIT(7));

static const struct ad74115_fw_prop ad74115_ch_func_fw_prop =
	AD74115_FW_PROP("adi,ch-func", AD74115_CH_FUNC_MAX,
			AD74115_CH_FUNC_SETUP_REG, GENMASK(3, 0));

static const struct ad74115_fw_prop ad74115_rtd_mode_fw_prop =
	AD74115_FW_PROP_BOOL("adi,4-wire-rtd", AD74115_RTD3W4W_CONFIG_REG, BIT(3));

static const struct ad74115_fw_prop ad74115_din_range_fw_prop =
	AD74115_FW_PROP_BOOL("adi,digital-input-sink-range-high",
			     AD74115_DIN_CONFIG1_REG, BIT(12));

static const struct ad74115_fw_prop ad74115_ext2_burnout_current_fw_prop =
	AD74115_FW_PROP_TBL("adi,ext2-burnout-current-nanoamp",
			    ad74115_burnout_current_na_tbl,
			    AD74115_BURNOUT_CONFIG_REG, GENMASK(14, 12));

static const struct ad74115_fw_prop ad74115_ext1_burnout_current_fw_prop =
	AD74115_FW_PROP_TBL("adi,ext1-burnout-current-nanoamp",
			    ad74115_burnout_current_na_tbl,
			    AD74115_BURNOUT_CONFIG_REG, GENMASK(9, 7));

static const struct ad74115_fw_prop ad74115_viout_burnout_current_fw_prop =
	AD74115_FW_PROP_TBL("adi,viout-burnout-current-nanoamp",
			    ad74115_viout_burnout_current_na_tbl,
			    AD74115_BURNOUT_CONFIG_REG, GENMASK(4, 2));

static const struct ad74115_fw_prop ad74115_fw_props[] = {
	AD74115_FW_PROP("adi,conv2-mux", 3,
			AD74115_ADC_CONFIG_REG, GENMASK(3, 2)),

	AD74115_FW_PROP_BOOL_NEG("adi,sense-agnd-buffer-low-power",
				 AD74115_PWR_OPTIM_CONFIG_REG, BIT(4)),
	AD74115_FW_PROP_BOOL_NEG("adi,lf-buffer-low-power",
				 AD74115_PWR_OPTIM_CONFIG_REG, BIT(3)),
	AD74115_FW_PROP_BOOL_NEG("adi,hf-buffer-low-power",
				 AD74115_PWR_OPTIM_CONFIG_REG, BIT(2)),
	AD74115_FW_PROP_BOOL_NEG("adi,ext2-buffer-low-power",
				 AD74115_PWR_OPTIM_CONFIG_REG, BIT(1)),
	AD74115_FW_PROP_BOOL_NEG("adi,ext1-buffer-low-power",
				 AD74115_PWR_OPTIM_CONFIG_REG, BIT(0)),

	AD74115_FW_PROP_BOOL("adi,comparator-invert",
			     AD74115_DIN_CONFIG1_REG, BIT(14)),
	AD74115_FW_PROP_BOOL("adi,digital-input-debounce-mode-counter-reset",
			     AD74115_DIN_CONFIG1_REG, BIT(6)),

	AD74115_FW_PROP_BOOL("adi,digital-input-unbuffered",
			     AD74115_DIN_CONFIG2_REG, BIT(10)),
	AD74115_FW_PROP_BOOL("adi,digital-input-short-circuit-detection",
			     AD74115_DIN_CONFIG2_REG, BIT(9)),
	AD74115_FW_PROP_BOOL("adi,digital-input-open-circuit-detection",
			     AD74115_DIN_CONFIG2_REG, BIT(8)),

	AD74115_FW_PROP_BOOL("adi,dac-current-limit-low",
			     AD74115_OUTPUT_CONFIG_REG, BIT(0)),

	AD74115_FW_PROP_BOOL("adi,3-wire-rtd-excitation-swap",
			     AD74115_RTD3W4W_CONFIG_REG, BIT(2)),
	AD74115_FW_PROP_TBL("adi,rtd-excitation-current-microamp",
			    ad74115_rtd_excitation_current_ua_tbl,
			    AD74115_RTD3W4W_CONFIG_REG, GENMASK(1, 0)),

	AD74115_FW_PROP_BOOL("adi,ext2-burnout-current-polarity-sourcing",
			     AD74115_BURNOUT_CONFIG_REG, BIT(11)),
	AD74115_FW_PROP_BOOL("adi,ext1-burnout-current-polarity-sourcing",
			     AD74115_BURNOUT_CONFIG_REG, BIT(6)),
	AD74115_FW_PROP_BOOL("adi,viout-burnout-current-polarity-sourcing",
			     AD74115_BURNOUT_CONFIG_REG, BIT(1)),

	AD74115_FW_PROP_BOOL("adi,charge-pump",
			     AD74115_CHARGE_PUMP_REG, BIT(0)),
};

static int ad74115_apply_fw_prop(struct ad74115_state *st,
				 const struct ad74115_fw_prop *prop, u32 *retval)
{
	struct device *dev = &st->spi->dev;
	u32 val = 0;
	int ret;

	if (prop->is_boolean) {
		val = device_property_read_bool(dev, prop->name);
	} else {
		ret = device_property_read_u32(dev, prop->name, &val);
		if (ret && prop->lookup_tbl)
			val = prop->lookup_tbl[0];
	}

	*retval = val;

	if (prop->negate)
		val = !val;

	if (prop->lookup_tbl)
		ret = _ad74115_find_tbl_index(prop->lookup_tbl,
					      prop->lookup_tbl_len, val, &val);
	else if (prop->max && val > prop->max)
		ret = -EINVAL;
	else
		ret = 0;

	if (ret)
		return dev_err_probe(dev, -EINVAL,
				     "Invalid value %u for prop %s\n",
				     val, prop->name);

	WARN(!prop->mask, "Prop %s mask is empty\n", prop->name);

	val = (val << __ffs(prop->mask)) & prop->mask;

	return regmap_update_bits(st->regmap, prop->reg, prop->mask, val);
}

static int ad74115_setup_adc_conv2_range(struct ad74115_state *st)
{
	unsigned int tbl_len = ARRAY_SIZE(ad74115_adc_range_tbl);
	const char *prop_name = "adi,conv2-range-microvolt";
	s32 vals[2] = {
		ad74115_adc_range_tbl[0][0],
		ad74115_adc_range_tbl[0][1],
	};
	struct device *dev = &st->spi->dev;
	unsigned int i;

	device_property_read_u32_array(dev, prop_name, vals, 2);

	for (i = 0; i < tbl_len; i++)
		if (vals[0] == ad74115_adc_range_tbl[i][0] &&
		    vals[1] == ad74115_adc_range_tbl[i][1])
			break;

	if (i == tbl_len)
		return dev_err_probe(dev, -EINVAL,
				     "Invalid value %d, %d for prop %s\n",
				     vals[0], vals[1], prop_name);

	return regmap_update_bits(st->regmap, AD74115_ADC_CONFIG_REG,
				  AD74115_ADC_CONFIG_CONV2_RANGE_MASK,
				  FIELD_PREP(AD74115_ADC_CONFIG_CONV2_RANGE_MASK, i));
}

static int ad74115_setup_iio_channels(struct iio_dev *indio_dev)
{
	struct ad74115_state *st = iio_priv(indio_dev);
	struct device *dev = &st->spi->dev;
	struct iio_chan_spec *channels;

	channels = devm_kcalloc(dev, sizeof(*channels),
				indio_dev->num_channels, GFP_KERNEL);
	if (!channels)
		return -ENOMEM;

	indio_dev->channels = channels;

	memcpy(channels, ad74115_channels_map[st->ch_func].channels,
	       sizeof(*channels) * ad74115_channels_map[st->ch_func].num_channels);

	if (channels[0].output && channels[0].channel == AD74115_DAC_CH_MAIN &&
	    channels[0].type == IIO_VOLTAGE && !st->dac_hart_slew) {
		channels[0].info_mask_separate |= BIT(IIO_CHAN_INFO_SAMP_FREQ);
		channels[0].info_mask_separate_available |= BIT(IIO_CHAN_INFO_SAMP_FREQ);
	}

	return 0;
}

static int ad74115_setup_gpio_chip(struct ad74115_state *st)
{
	struct device *dev = &st->spi->dev;

	if (!st->gpio_valid_mask)
		return 0;

	st->gc = (struct gpio_chip) {
		.owner = THIS_MODULE,
		.label = AD74115_NAME,
		.base = -1,
		.ngpio = AD74115_GPIO_NUM,
		.parent = dev,
		.can_sleep = true,
		.init_valid_mask = ad74115_gpio_init_valid_mask,
		.get_direction = ad74115_gpio_get_direction,
		.direction_input = ad74115_gpio_direction_input,
		.direction_output = ad74115_gpio_direction_output,
		.get = ad74115_gpio_get,
		.set = ad74115_gpio_set,
	};

	return devm_gpiochip_add_data(dev, &st->gc, st);
}

static int ad74115_setup_comp_gpio_chip(struct ad74115_state *st)
{
	struct device *dev = &st->spi->dev;
	u32 val;
	int ret;

	ret = regmap_read(st->regmap, AD74115_DIN_CONFIG1_REG, &val);
	if (ret)
		return ret;

	if (!(val & AD74115_DIN_COMPARATOR_EN_MASK))
		return 0;

	st->comp_gc = (struct gpio_chip) {
		.owner = THIS_MODULE,
		.label = AD74115_NAME,
		.base = -1,
		.ngpio = 1,
		.parent = dev,
		.can_sleep = true,
		.get_direction = ad74115_comp_gpio_get_direction,
		.get = ad74115_comp_gpio_get,
		.set_config = ad74115_comp_gpio_set_config,
	};

	return devm_gpiochip_add_data(dev, &st->comp_gc, st);
}

static int ad74115_setup(struct iio_dev *indio_dev)
{
	struct ad74115_state *st = iio_priv(indio_dev);
	struct device *dev = &st->spi->dev;
	u32 val, din_range_high;
	unsigned int i;
	int ret;

	ret = ad74115_apply_fw_prop(st, &ad74115_ch_func_fw_prop, &val);
	if (ret)
		return ret;

	indio_dev->num_channels += ad74115_channels_map[val].num_channels;
	st->ch_func = val;

	ret = ad74115_setup_adc_conv2_range(st);
	if (ret)
		return ret;

	val = device_property_read_bool(dev, "adi,dac-hart-slew");
	if (val) {
		st->dac_hart_slew = val;

		ret = regmap_update_bits(st->regmap, AD74115_OUTPUT_CONFIG_REG,
					 AD74115_OUTPUT_SLEW_EN_MASK,
					 FIELD_PREP(AD74115_OUTPUT_SLEW_EN_MASK,
						    AD74115_SLEW_MODE_HART));
		if (ret)
			return ret;
	}

	ret = ad74115_apply_fw_prop(st, &ad74115_din_range_fw_prop,
				    &din_range_high);
	if (ret)
		return ret;

	ret = device_property_read_u32(dev, "adi,digital-input-sink-microamp", &val);
	if (!ret) {
		if (din_range_high)
			val = DIV_ROUND_CLOSEST(val, AD74115_DIN_SINK_LOW_STEP);
		else
			val = DIV_ROUND_CLOSEST(val, AD74115_DIN_SINK_HIGH_STEP);

		if (val > AD74115_DIN_SINK_MAX)
			val = AD74115_DIN_SINK_MAX;

		ret = regmap_update_bits(st->regmap, AD74115_DIN_CONFIG1_REG,
					 AD74115_DIN_SINK_MASK,
					 FIELD_PREP(AD74115_DIN_SINK_MASK, val));
		if (ret)
			return ret;
	}

	ret = ad74115_apply_fw_prop(st, &ad74115_din_threshold_mode_fw_prop, &val);
	if (ret)
		return ret;

	if (val == AD74115_DIN_THRESHOLD_MODE_AVDD && !st->avdd_mv)
		return dev_err_probe(dev, -EINVAL,
				     "AVDD voltage is required for digital input threshold mode AVDD\n");

	st->din_threshold_mode = val;

	ret = ad74115_apply_fw_prop(st, &ad74115_dac_bipolar_fw_prop, &val);
	if (ret)
		return ret;

	st->dac_bipolar = val;

	ret = ad74115_apply_fw_prop(st, &ad74115_rtd_mode_fw_prop, &val);
	if (ret)
		return ret;

	st->rtd_mode_4_wire = val;

	ret = ad74115_apply_fw_prop(st, &ad74115_ext2_burnout_current_fw_prop, &val);
	if (ret)
		return ret;

	if (val) {
		ret = regmap_update_bits(st->regmap, AD74115_BURNOUT_CONFIG_REG,
					 AD74115_BURNOUT_EXT2_EN_MASK,
					 FIELD_PREP(AD74115_BURNOUT_EXT2_EN_MASK, 1));
		if (ret)
			return ret;
	}

	ret = ad74115_apply_fw_prop(st, &ad74115_ext1_burnout_current_fw_prop, &val);
	if (ret)
		return ret;

	if (val) {
		ret = regmap_update_bits(st->regmap, AD74115_BURNOUT_CONFIG_REG,
					 AD74115_BURNOUT_EXT1_EN_MASK,
					 FIELD_PREP(AD74115_BURNOUT_EXT1_EN_MASK, 1));
		if (ret)
			return ret;
	}

	ret = ad74115_apply_fw_prop(st, &ad74115_viout_burnout_current_fw_prop, &val);
	if (ret)
		return ret;

	if (val) {
		ret = regmap_update_bits(st->regmap, AD74115_BURNOUT_CONFIG_REG,
					 AD74115_BURNOUT_VIOUT_EN_MASK,
					 FIELD_PREP(AD74115_BURNOUT_VIOUT_EN_MASK, 1));
		if (ret)
			return ret;
	}

	for (i = 0; i < AD74115_GPIO_NUM; i++) {
		ret = ad74115_apply_fw_prop(st, &ad74115_gpio_mode_fw_props[i], &val);
		if (ret)
			return ret;

		if (val == AD74115_GPIO_MODE_LOGIC)
			st->gpio_valid_mask |= BIT(i);
	}

	for (i = 0; i < ARRAY_SIZE(ad74115_fw_props); i++) {
		ret = ad74115_apply_fw_prop(st, &ad74115_fw_props[i], &val);
		if (ret)
			return ret;
	}

	ret = ad74115_setup_gpio_chip(st);
	if (ret)
		return ret;

	ret = ad74115_setup_comp_gpio_chip(st);
	if (ret)
		return ret;

	return ad74115_setup_iio_channels(indio_dev);
}

static int ad74115_reset(struct ad74115_state *st)
{
	struct device *dev = &st->spi->dev;
	struct gpio_desc *reset_gpio;
	int ret;

	reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH);
	if (IS_ERR(reset_gpio))
		return dev_err_probe(dev, PTR_ERR(reset_gpio),
				     "Failed to find reset GPIO\n");

	if (reset_gpio) {
		fsleep(100);

		gpiod_set_value_cansleep(reset_gpio, 0);
	} else {
		ret = regmap_write(st->regmap, AD74115_CMD_KEY_REG,
				   AD74115_CMD_KEY_RESET1);
		if (ret)
			return ret;

		ret = regmap_write(st->regmap, AD74115_CMD_KEY_REG,
				   AD74115_CMD_KEY_RESET2);
		if (ret)
			return ret;
	}

	fsleep(1000);

	return 0;
}

static int ad74115_setup_trigger(struct iio_dev *indio_dev)
{
	struct ad74115_state *st = iio_priv(indio_dev);
	struct device *dev = &st->spi->dev;
	int ret;

	st->irq = fwnode_irq_get_byname(dev_fwnode(dev), "adc_rdy");

	if (st->irq == -EPROBE_DEFER)
		return -EPROBE_DEFER;

	if (st->irq < 0) {
		st->irq = 0;
		return 0;
	}

	ret = devm_request_irq(dev, st->irq, ad74115_adc_data_interrupt,
			       0, AD74115_NAME, indio_dev);
	if (ret)
		return ret;

	st->trig = devm_iio_trigger_alloc(dev, "%s-dev%d", AD74115_NAME,
					  iio_device_id(indio_dev));
	if (!st->trig)
		return -ENOMEM;

	st->trig->ops = &ad74115_trigger_ops;
	iio_trigger_set_drvdata(st->trig, st);

	ret = devm_iio_trigger_register(dev, st->trig);
	if (ret)
		return ret;

	indio_dev->trig = iio_trigger_get(st->trig);

	return 0;
}

static int ad74115_probe(struct spi_device *spi)
{
	static const char * const regulator_names[] = {
		"avcc", "dvcc", "dovdd", "refin",
	};
	struct device *dev = &spi->dev;
	struct ad74115_state *st;
	struct iio_dev *indio_dev;
	int ret;

	indio_dev = devm_iio_device_alloc(dev, sizeof(*st));
	if (!indio_dev)
		return -ENOMEM;

	st = iio_priv(indio_dev);

	st->spi = spi;
	mutex_init(&st->lock);
	init_completion(&st->adc_data_completion);

	indio_dev->name = AD74115_NAME;
	indio_dev->modes = INDIO_DIRECT_MODE;
	indio_dev->info = &ad74115_info;

	ret = devm_regulator_get_enable_read_voltage(dev, "avdd");
	if (ret < 0) {
		/*
		 * Since this is both a power supply and only optionally a
		 * reference voltage, make sure to enable it even when the
		 * voltage is not available.
		 */
		ret = devm_regulator_get_enable(dev, "avdd");
		if (ret)
			return dev_err_probe(dev, ret, "failed to enable avdd\n");
	} else {
		st->avdd_mv = ret / 1000;
	}

	ret = devm_regulator_bulk_get_enable(dev, ARRAY_SIZE(regulator_names),
					     regulator_names);
	if (ret)
		return ret;

	st->regmap = devm_regmap_init(dev, NULL, st, &ad74115_regmap_config);
	if (IS_ERR(st->regmap))
		return PTR_ERR(st->regmap);

	ret = ad74115_reset(st);
	if (ret)
		return ret;

	ret = ad74115_setup(indio_dev);
	if (ret)
		return ret;

	ret = ad74115_setup_trigger(indio_dev);
	if (ret)
		return ret;

	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
					      ad74115_trigger_handler,
					      &ad74115_buffer_ops);
	if (ret)
		return ret;

	return devm_iio_device_register(dev, indio_dev);
}

static int ad74115_unregister_driver(struct spi_driver *spi)
{
	spi_unregister_driver(spi);

	return 0;
}

static int __init ad74115_register_driver(struct spi_driver *spi)
{
	crc8_populate_msb(ad74115_crc8_table, AD74115_CRC_POLYNOMIAL);

	return spi_register_driver(spi);
}

static const struct spi_device_id ad74115_spi_id[] = {
	{ "ad74115h" },
	{ }
};

MODULE_DEVICE_TABLE(spi, ad74115_spi_id);

static const struct of_device_id ad74115_dt_id[] = {
	{ .compatible = "adi,ad74115h" },
	{ }
};
MODULE_DEVICE_TABLE(of, ad74115_dt_id);

static struct spi_driver ad74115_driver = {
	.driver = {
		   .name = "ad74115",
		   .of_match_table = ad74115_dt_id,
	},
	.probe = ad74115_probe,
	.id_table = ad74115_spi_id,
};

module_driver(ad74115_driver,
	      ad74115_register_driver, ad74115_unregister_driver);

MODULE_AUTHOR("Cosmin Tanislav <cosmin.tanislav@analog.com>");
MODULE_DESCRIPTION("Analog Devices AD74115 ADDAC");
MODULE_LICENSE("GPL");