// SPDX-License-Identifier: GPL-2.0-only
/*
 * Analog Devices AD3552R
 * Digital to Analog converter driver
 *
 * Copyright 2021 Analog Devices Inc.
 */
#include <linux/unaligned.h>
#include <linux/bitfield.h>
#include <linux/device.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iopoll.h>
#include <linux/kernel.h>
#include <linux/spi/spi.h>

#include "ad3552r.h"

struct ad3552r_desc {
	const struct ad3552r_model_data *model_data;
	/* Used to look the spi bus for atomic operations where needed */
	struct mutex		lock;
	struct gpio_desc	*gpio_reset;
	struct gpio_desc	*gpio_ldac;
	struct spi_device	*spi;
	struct ad3552r_ch_data	ch_data[AD3552R_MAX_CH];
	struct iio_chan_spec	channels[AD3552R_MAX_CH + 1];
	unsigned long		enabled_ch;
	unsigned int		num_ch;
};

static u8 _ad3552r_reg_len(u8 addr)
{
	switch (addr) {
	case AD3552R_REG_ADDR_HW_LDAC_16B:
	case AD3552R_REG_ADDR_CH_SELECT_16B:
	case AD3552R_REG_ADDR_SW_LDAC_16B:
	case AD3552R_REG_ADDR_HW_LDAC_24B:
	case AD3552R_REG_ADDR_CH_SELECT_24B:
	case AD3552R_REG_ADDR_SW_LDAC_24B:
		return 1;
	default:
		break;
	}

	if (addr > AD3552R_REG_ADDR_HW_LDAC_24B)
		return 3;
	if (addr > AD3552R_REG_ADDR_HW_LDAC_16B)
		return 2;

	return 1;
}

/* SPI transfer to device */
static int ad3552r_transfer(struct ad3552r_desc *dac, u8 addr, u32 len,
			    u8 *data, bool is_read)
{
	/* Maximum transfer: Addr (1B) + 2 * (Data Reg (3B)) + SW LDAC(1B) */
	u8 buf[8];

	buf[0] = addr & AD3552R_ADDR_MASK;
	buf[0] |= is_read ? AD3552R_READ_BIT : 0;
	if (is_read)
		return spi_write_then_read(dac->spi, buf, 1, data, len);

	memcpy(buf + 1, data, len);
	return spi_write_then_read(dac->spi, buf, len + 1, NULL, 0);
}

static int ad3552r_write_reg(struct ad3552r_desc *dac, u8 addr, u16 val)
{
	u8 reg_len;
	u8 buf[AD3552R_MAX_REG_SIZE] = { 0 };

	reg_len = _ad3552r_reg_len(addr);
	if (reg_len == 2)
		/* Only DAC register are 2 bytes wide */
		val &= AD3552R_MASK_DAC_12B;
	if (reg_len == 1)
		buf[0] = val & 0xFF;
	else
		/* reg_len can be 2 or 3, but 3rd bytes needs to be set to 0 */
		put_unaligned_be16(val, buf);

	return ad3552r_transfer(dac, addr, reg_len, buf, false);
}

static int ad3552r_read_reg(struct ad3552r_desc *dac, u8 addr, u16 *val)
{
	int err;
	u8  reg_len, buf[AD3552R_MAX_REG_SIZE] = { 0 };

	reg_len = _ad3552r_reg_len(addr);
	err = ad3552r_transfer(dac, addr, reg_len, buf, true);
	if (err)
		return err;

	if (reg_len == 1)
		*val = buf[0];
	else
		/* reg_len can be 2 or 3, but only first 2 bytes are relevant */
		*val = get_unaligned_be16(buf);

	return 0;
}

/* Update field of a register, shift val if needed */
static int ad3552r_update_reg_field(struct ad3552r_desc *dac, u8 addr, u16 mask,
				    u16 val)
{
	int ret;
	u16 reg;

	ret = ad3552r_read_reg(dac, addr, &reg);
	if (ret < 0)
		return ret;

	reg &= ~mask;
	reg |= val;

	return ad3552r_write_reg(dac, addr, reg);
}

#define AD3552R_CH_DAC(_idx) ((struct iio_chan_spec) {		\
	.type = IIO_VOLTAGE,					\
	.output = true,						\
	.indexed = true,					\
	.channel = _idx,					\
	.scan_index = _idx,					\
	.scan_type = {						\
		.sign = 'u',					\
		.realbits = 16,					\
		.storagebits = 16,				\
		.endianness = IIO_BE,				\
	},							\
	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |		\
				BIT(IIO_CHAN_INFO_SCALE) |	\
				BIT(IIO_CHAN_INFO_ENABLE) |	\
				BIT(IIO_CHAN_INFO_OFFSET),	\
})

static int ad3552r_read_raw(struct iio_dev *indio_dev,
			    struct iio_chan_spec const *chan,
			    int *val,
			    int *val2,
			    long mask)
{
	struct ad3552r_desc *dac = iio_priv(indio_dev);
	u16 tmp_val;
	int err;
	u8 ch = chan->channel;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		mutex_lock(&dac->lock);
		err = ad3552r_read_reg(dac, AD3552R_REG_ADDR_CH_DAC_24B(ch),
				       &tmp_val);
		mutex_unlock(&dac->lock);
		if (err < 0)
			return err;
		*val = tmp_val;
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_ENABLE:
		mutex_lock(&dac->lock);
		err = ad3552r_read_reg(dac, AD3552R_REG_ADDR_POWERDOWN_CONFIG,
				       &tmp_val);
		mutex_unlock(&dac->lock);
		if (err < 0)
			return err;
		*val = !((tmp_val & AD3552R_MASK_CH_DAC_POWERDOWN(ch)) >>
			  __ffs(AD3552R_MASK_CH_DAC_POWERDOWN(ch)));
		return IIO_VAL_INT;
	case IIO_CHAN_INFO_SCALE:
		*val = dac->ch_data[ch].scale_int;
		*val2 = dac->ch_data[ch].scale_dec;
		return IIO_VAL_INT_PLUS_MICRO;
	case IIO_CHAN_INFO_OFFSET:
		*val = dac->ch_data[ch].offset_int;
		*val2 = dac->ch_data[ch].offset_dec;
		return IIO_VAL_INT_PLUS_MICRO;
	default:
		return -EINVAL;
	}
}

static int ad3552r_write_raw(struct iio_dev *indio_dev,
			     struct iio_chan_spec const *chan,
			     int val,
			     int val2,
			     long mask)
{
	struct ad3552r_desc *dac = iio_priv(indio_dev);
	int err;

	mutex_lock(&dac->lock);
	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		err = ad3552r_write_reg(dac,
					AD3552R_REG_ADDR_CH_DAC_24B(chan->channel),
					val);
		break;
	case IIO_CHAN_INFO_ENABLE:
		if (chan->channel == 0)
			val = FIELD_PREP(AD3552R_MASK_CH_DAC_POWERDOWN(0), !val);
		else
			val = FIELD_PREP(AD3552R_MASK_CH_DAC_POWERDOWN(1), !val);

		err = ad3552r_update_reg_field(dac, AD3552R_REG_ADDR_POWERDOWN_CONFIG,
					       AD3552R_MASK_CH_DAC_POWERDOWN(chan->channel),
					       val);
		break;
	default:
		err = -EINVAL;
		break;
	}
	mutex_unlock(&dac->lock);

	return err;
}

static const struct iio_info ad3552r_iio_info = {
	.read_raw = ad3552r_read_raw,
	.write_raw = ad3552r_write_raw
};

static int32_t ad3552r_trigger_hw_ldac(struct gpio_desc *ldac)
{
	gpiod_set_value_cansleep(ldac, 0);
	usleep_range(AD3552R_LDAC_PULSE_US, AD3552R_LDAC_PULSE_US + 10);
	gpiod_set_value_cansleep(ldac, 1);

	return 0;
}

static int ad3552r_write_all_channels(struct ad3552r_desc *dac, u8 *data)
{
	int err, len;
	u8 addr, buff[AD3552R_MAX_CH * AD3552R_MAX_REG_SIZE + 1];

	addr = AD3552R_REG_ADDR_CH_INPUT_24B(1);
	/* CH1 */
	memcpy(buff, data + 2, 2);
	buff[2] = 0;
	/* CH0 */
	memcpy(buff + 3, data, 2);
	buff[5] = 0;
	len = 6;
	if (!dac->gpio_ldac) {
		/* Software LDAC */
		buff[6] = AD3552R_MASK_ALL_CH;
		++len;
	}
	err = ad3552r_transfer(dac, addr, len, buff, false);
	if (err)
		return err;

	if (dac->gpio_ldac)
		return ad3552r_trigger_hw_ldac(dac->gpio_ldac);

	return 0;
}

static int ad3552r_write_codes(struct ad3552r_desc *dac, u32 mask, u8 *data)
{
	int err;
	u8 addr, buff[AD3552R_MAX_REG_SIZE];

	if (mask == AD3552R_MASK_ALL_CH) {
		if (memcmp(data, data + 2, 2) != 0)
			return ad3552r_write_all_channels(dac, data);

		addr = AD3552R_REG_ADDR_INPUT_PAGE_MASK_24B;
	} else {
		addr = AD3552R_REG_ADDR_CH_INPUT_24B(__ffs(mask));
	}

	memcpy(buff, data, 2);
	buff[2] = 0;
	err = ad3552r_transfer(dac, addr, 3, data, false);
	if (err)
		return err;

	if (dac->gpio_ldac)
		return ad3552r_trigger_hw_ldac(dac->gpio_ldac);

	return ad3552r_write_reg(dac, AD3552R_REG_ADDR_SW_LDAC_24B, mask);
}

static irqreturn_t ad3552r_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
	struct iio_dev *indio_dev = pf->indio_dev;
	struct iio_buffer *buf = indio_dev->buffer;
	struct ad3552r_desc *dac = iio_priv(indio_dev);
	/* Maximum size of a scan */
	u8 buff[AD3552R_MAX_CH * AD3552R_MAX_REG_SIZE] = { };
	int err;

	err = iio_pop_from_buffer(buf, buff);
	if (err)
		goto end;

	mutex_lock(&dac->lock);
	ad3552r_write_codes(dac, *indio_dev->active_scan_mask, buff);
	mutex_unlock(&dac->lock);
end:
	iio_trigger_notify_done(indio_dev->trig);

	return IRQ_HANDLED;
}

static int ad3552r_check_scratch_pad(struct ad3552r_desc *dac)
{
	const u16 val1 = AD3552R_SCRATCH_PAD_TEST_VAL1;
	const u16 val2 = AD3552R_SCRATCH_PAD_TEST_VAL2;
	u16 val;
	int err;

	err = ad3552r_write_reg(dac, AD3552R_REG_ADDR_SCRATCH_PAD, val1);
	if (err < 0)
		return err;

	err = ad3552r_read_reg(dac, AD3552R_REG_ADDR_SCRATCH_PAD, &val);
	if (err < 0)
		return err;

	if (val1 != val)
		return -ENODEV;

	err = ad3552r_write_reg(dac, AD3552R_REG_ADDR_SCRATCH_PAD, val2);
	if (err < 0)
		return err;

	err = ad3552r_read_reg(dac, AD3552R_REG_ADDR_SCRATCH_PAD, &val);
	if (err < 0)
		return err;

	if (val2 != val)
		return -ENODEV;

	return 0;
}

struct reg_addr_pool {
	struct ad3552r_desc *dac;
	u8		    addr;
};

static int ad3552r_read_reg_wrapper(struct reg_addr_pool *addr)
{
	int err;
	u16 val;

	err = ad3552r_read_reg(addr->dac, addr->addr, &val);
	if (err)
		return err;

	return val;
}

static int ad3552r_reset(struct ad3552r_desc *dac)
{
	struct reg_addr_pool addr;
	int ret;
	int val;

	dac->gpio_reset = devm_gpiod_get_optional(&dac->spi->dev, "reset",
						  GPIOD_OUT_LOW);
	if (IS_ERR(dac->gpio_reset))
		return dev_err_probe(&dac->spi->dev, PTR_ERR(dac->gpio_reset),
				     "Error while getting gpio reset");

	if (dac->gpio_reset) {
		/* Perform hardware reset */
		usleep_range(10, 20);
		gpiod_set_value_cansleep(dac->gpio_reset, 1);
	} else {
		/* Perform software reset if no GPIO provided */
		ret = ad3552r_update_reg_field(dac,
					       AD3552R_REG_ADDR_INTERFACE_CONFIG_A,
					       AD3552R_MASK_SOFTWARE_RESET,
					       AD3552R_MASK_SOFTWARE_RESET);
		if (ret < 0)
			return ret;

	}

	addr.dac = dac;
	addr.addr = AD3552R_REG_ADDR_INTERFACE_CONFIG_B;
	ret = readx_poll_timeout(ad3552r_read_reg_wrapper, &addr, val,
				 val == AD3552R_DEFAULT_CONFIG_B_VALUE ||
				 val < 0,
				 5000, 50000);
	if (val < 0)
		ret = val;
	if (ret) {
		dev_err(&dac->spi->dev, "Error while resetting");
		return ret;
	}

	ret = readx_poll_timeout(ad3552r_read_reg_wrapper, &addr, val,
				 !(val & AD3552R_MASK_INTERFACE_NOT_READY) ||
				 val < 0,
				 5000, 50000);
	if (val < 0)
		ret = val;
	if (ret) {
		dev_err(&dac->spi->dev, "Error while resetting");
		return ret;
	}

	/* Clear reset error flag, see ad3552r manual, rev B table 38. */
	ret = ad3552r_write_reg(dac, AD3552R_REG_ADDR_ERR_STATUS,
				AD3552R_MASK_RESET_STATUS);
	if (ret)
		return ret;

	return ad3552r_update_reg_field(dac,
					AD3552R_REG_ADDR_INTERFACE_CONFIG_A,
					AD3552R_MASK_ADDR_ASCENSION,
					FIELD_PREP(AD3552R_MASK_ADDR_ASCENSION, val));
}

static int ad3552r_configure_custom_gain(struct ad3552r_desc *dac,
					 struct fwnode_handle *child,
					 u32 ch)
{
	struct device *dev = &dac->spi->dev;
	int err;
	u8 addr;
	u16 reg;

	err = ad3552r_get_custom_gain(dev, child,
				      &dac->ch_data[ch].p,
				      &dac->ch_data[ch].n,
				      &dac->ch_data[ch].rfb,
				      &dac->ch_data[ch].gain_offset);
	if (err)
		return err;

	dac->ch_data[ch].range_override = 1;

	addr = AD3552R_REG_ADDR_CH_GAIN(ch);
	err = ad3552r_write_reg(dac, addr,
				abs((s32)dac->ch_data[ch].gain_offset) &
				AD3552R_MASK_CH_OFFSET_BITS_0_7);
	if (err)
		return dev_err_probe(dev, err, "Error writing register\n");

	reg = ad3552r_calc_custom_gain(dac->ch_data[ch].p, dac->ch_data[ch].n,
				       dac->ch_data[ch].gain_offset);

	err = ad3552r_write_reg(dac, addr, reg);
	if (err)
		return dev_err_probe(dev, err, "Error writing register\n");

	return 0;
}

static int ad3552r_configure_device(struct ad3552r_desc *dac)
{
	struct device *dev = &dac->spi->dev;
	int err, cnt = 0;
	u32 val, ch;

	dac->gpio_ldac = devm_gpiod_get_optional(dev, "ldac", GPIOD_OUT_HIGH);
	if (IS_ERR(dac->gpio_ldac))
		return dev_err_probe(dev, PTR_ERR(dac->gpio_ldac),
				     "Error getting gpio ldac");

	err = ad3552r_get_ref_voltage(dev, &val);
	if (err < 0)
		return err;

	err = ad3552r_update_reg_field(dac,
				       AD3552R_REG_ADDR_SH_REFERENCE_CONFIG,
				       AD3552R_MASK_REFERENCE_VOLTAGE_SEL,
				       FIELD_PREP(AD3552R_MASK_REFERENCE_VOLTAGE_SEL, val));
	if (err)
		return err;

	err = ad3552r_get_drive_strength(dev, &val);
	if (!err) {
		err = ad3552r_update_reg_field(dac,
					       AD3552R_REG_ADDR_INTERFACE_CONFIG_D,
					       AD3552R_MASK_SDO_DRIVE_STRENGTH,
					       FIELD_PREP(AD3552R_MASK_SDO_DRIVE_STRENGTH, val));
		if (err)
			return err;
	}

	dac->num_ch = device_get_child_node_count(dev);
	if (!dac->num_ch) {
		dev_err(dev, "No channels defined\n");
		return -ENODEV;
	}

	device_for_each_child_node_scoped(dev, child) {
		err = fwnode_property_read_u32(child, "reg", &ch);
		if (err)
			return dev_err_probe(dev, err,
					     "mandatory reg property missing\n");
		if (ch >= dac->model_data->num_hw_channels)
			return dev_err_probe(dev, -EINVAL,
					     "reg must be less than %d\n",
					     dac->model_data->num_hw_channels);

		err = ad3552r_get_output_range(dev, dac->model_data,
					       child, &val);
		if (err && err != -ENOENT)
			return err;

		if (!err) {
			if (ch == 0)
				val = FIELD_PREP(AD3552R_MASK_CH_OUTPUT_RANGE_SEL(0), val);
			else
				val = FIELD_PREP(AD3552R_MASK_CH_OUTPUT_RANGE_SEL(1), val);

			err = ad3552r_update_reg_field(dac,
						       AD3552R_REG_ADDR_CH0_CH1_OUTPUT_RANGE,
						       AD3552R_MASK_CH_OUTPUT_RANGE_SEL(ch),
						       val);
			if (err)
				return err;

			dac->ch_data[ch].range = val;
		} else if (dac->model_data->requires_output_range) {
			return dev_err_probe(dev, -EINVAL,
					     "adi,output-range-microvolt is required for %s\n",
					     dac->model_data->model_name);
		} else {
			err = ad3552r_configure_custom_gain(dac, child, ch);
			if (err)
				return err;
		}

		ad3552r_calc_gain_and_offset(&dac->ch_data[ch], dac->model_data);
		dac->enabled_ch |= BIT(ch);

		if (ch == 0)
			val = FIELD_PREP(AD3552R_MASK_CH(0), 1);
		else
			val = FIELD_PREP(AD3552R_MASK_CH(1), 1);

		err = ad3552r_update_reg_field(dac,
					       AD3552R_REG_ADDR_CH_SELECT_16B,
					       AD3552R_MASK_CH(ch), val);
		if (err < 0)
			return err;

		dac->channels[cnt] = AD3552R_CH_DAC(ch);
		++cnt;

	}

	/* Disable unused channels */
	for_each_clear_bit(ch, &dac->enabled_ch,
			   dac->model_data->num_hw_channels) {
		if (ch == 0)
			val = FIELD_PREP(AD3552R_MASK_CH_AMPLIFIER_POWERDOWN(0), 1);
		else
			val = FIELD_PREP(AD3552R_MASK_CH_AMPLIFIER_POWERDOWN(1), 1);

		err = ad3552r_update_reg_field(dac,
					       AD3552R_REG_ADDR_POWERDOWN_CONFIG,
					       AD3552R_MASK_CH_AMPLIFIER_POWERDOWN(ch),
					       val);
		if (err)
			return err;
	}

	dac->num_ch = cnt;

	return 0;
}

static int ad3552r_init(struct ad3552r_desc *dac)
{
	int err;
	u16 val, id;

	err = ad3552r_reset(dac);
	if (err) {
		dev_err(&dac->spi->dev, "Reset failed\n");
		return err;
	}

	err = ad3552r_check_scratch_pad(dac);
	if (err) {
		dev_err(&dac->spi->dev, "Scratch pad test failed\n");
		return err;
	}

	err = ad3552r_read_reg(dac, AD3552R_REG_ADDR_PRODUCT_ID_L, &val);
	if (err) {
		dev_err(&dac->spi->dev, "Fail read PRODUCT_ID_L\n");
		return err;
	}

	id = val;
	err = ad3552r_read_reg(dac, AD3552R_REG_ADDR_PRODUCT_ID_H, &val);
	if (err) {
		dev_err(&dac->spi->dev, "Fail read PRODUCT_ID_H\n");
		return err;
	}

	id |= val << 8;
	if (id != dac->model_data->chip_id) {
		dev_err(&dac->spi->dev, "Product id not matching\n");
		return -ENODEV;
	}

	return ad3552r_configure_device(dac);
}

static int ad3552r_probe(struct spi_device *spi)
{
	struct ad3552r_desc *dac;
	struct iio_dev *indio_dev;
	int err;

	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*dac));
	if (!indio_dev)
		return -ENOMEM;

	dac = iio_priv(indio_dev);
	dac->spi = spi;
	dac->model_data = spi_get_device_match_data(spi);
	if (!dac->model_data)
		return -EINVAL;

	mutex_init(&dac->lock);

	err = ad3552r_init(dac);
	if (err)
		return err;

	/* Config triggered buffer device */
	indio_dev->name = dac->model_data->model_name;
	indio_dev->dev.parent = &spi->dev;
	indio_dev->info = &ad3552r_iio_info;
	indio_dev->num_channels = dac->num_ch;
	indio_dev->channels = dac->channels;
	indio_dev->modes = INDIO_DIRECT_MODE;

	err = devm_iio_triggered_buffer_setup_ext(&indio_dev->dev, indio_dev, NULL,
						  &ad3552r_trigger_handler,
						  IIO_BUFFER_DIRECTION_OUT,
						  NULL,
						  NULL);
	if (err)
		return err;

	return devm_iio_device_register(&spi->dev, indio_dev);
}

static const struct spi_device_id ad3552r_id[] = {
	{
		.name = "ad3541r",
		.driver_data = (kernel_ulong_t)&ad3541r_model_data
	},
	{
		.name = "ad3542r",
		.driver_data = (kernel_ulong_t)&ad3542r_model_data
	},
	{
		.name = "ad3551r",
		.driver_data = (kernel_ulong_t)&ad3551r_model_data
	},
	{
		.name = "ad3552r",
		.driver_data = (kernel_ulong_t)&ad3552r_model_data
	},
	{ }
};
MODULE_DEVICE_TABLE(spi, ad3552r_id);

static const struct of_device_id ad3552r_of_match[] = {
	{ .compatible = "adi,ad3541r", .data = &ad3541r_model_data },
	{ .compatible = "adi,ad3542r", .data = &ad3542r_model_data },
	{ .compatible = "adi,ad3551r", .data = &ad3551r_model_data },
	{ .compatible = "adi,ad3552r", .data = &ad3552r_model_data },
	{ }
};
MODULE_DEVICE_TABLE(of, ad3552r_of_match);

static struct spi_driver ad3552r_driver = {
	.driver = {
		.name = "ad3552r",
		.of_match_table = ad3552r_of_match,
	},
	.probe = ad3552r_probe,
	.id_table = ad3552r_id
};
module_spi_driver(ad3552r_driver);

MODULE_AUTHOR("Mihail Chindris <mihail.chindris@analog.com>");
MODULE_DESCRIPTION("Analog Device AD3552R DAC");
MODULE_LICENSE("GPL v2");
MODULE_IMPORT_NS("IIO_AD3552R");