// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (c) 2012 Guenter Roeck <linux@roeck-us.net>
 *
 * based on max1668.c
 * Copyright (c) 2011 David George <david.george@ska.ac.za>
 */

#include <linux/bitfield.h>
#include <linux/bits.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/i2c.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/of.h>
#include <linux/regmap.h>
#include <linux/slab.h>

enum chips { max6581, max6602, max6622, max6636, max6689, max6693, max6694,
	     max6697, max6698, max6699 };

/* Report local sensor as temp1 */

static const u8 MAX6697_REG_TEMP[] = {
			0x07, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x08 };
static const u8 MAX6697_REG_TEMP_EXT[] = {
			0x57, 0x09, 0x52, 0x53, 0x54, 0x55, 0x56, 0 };
static const u8 MAX6697_REG_MAX[] = {
			0x17, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x18 };
static const u8 MAX6697_REG_CRIT[] = {
			0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27 };

#define MAX6697_REG_MIN			0x30
/*
 * Map device tree / internal register bit map to chip bit map.
 * Applies to alert register and over-temperature register.
 */

#define MAX6697_EXTERNAL_MASK_DT	GENMASK(7, 1)
#define MAX6697_LOCAL_MASK_DT		BIT(0)
#define MAX6697_EXTERNAL_MASK_CHIP	GENMASK(6, 0)
#define MAX6697_LOCAL_MASK_CHIP		BIT(7)

/* alert - local channel is in bit 6 */
#define MAX6697_ALERT_MAP_BITS(reg)	((((reg) & 0x7e) >> 1) | \
				 (((reg) & 0x01) << 6) | ((reg) & 0x80))

/* over-temperature - local channel is in bit 7 */
#define MAX6697_OVERT_MAP_BITS(reg)	\
	(FIELD_PREP(MAX6697_EXTERNAL_MASK_CHIP, FIELD_GET(MAX6697_EXTERNAL_MASK_DT, reg)) | \
	 FIELD_PREP(MAX6697_LOCAL_MASK_CHIP, FIELD_GET(MAX6697_LOCAL_MASK_DT, reg)))

#define MAX6697_REG_STAT_ALARM		0x44
#define MAX6697_REG_STAT_CRIT		0x45
#define MAX6697_REG_STAT_FAULT		0x46
#define MAX6697_REG_STAT_MIN_ALARM	0x47

#define MAX6697_REG_CONFIG		0x41
#define MAX6581_CONF_EXTENDED		BIT(1)
#define MAX6693_CONF_BETA		BIT(2)
#define MAX6697_CONF_RESISTANCE		BIT(3)
#define MAX6697_CONF_TIMEOUT		BIT(5)
#define MAX6697_REG_ALERT_MASK		0x42
#define MAX6697_REG_OVERT_MASK		0x43

#define MAX6581_REG_RESISTANCE		0x4a
#define MAX6581_REG_IDEALITY		0x4b
#define MAX6581_REG_IDEALITY_SELECT	0x4c
#define MAX6581_REG_OFFSET		0x4d
#define MAX6581_REG_OFFSET_SELECT	0x4e
#define MAX6581_OFFSET_MIN		-31750
#define MAX6581_OFFSET_MAX		31750

#define MAX6697_CONV_TIME		156	/* ms per channel, worst case */

struct max6697_chip_data {
	int channels;
	u32 have_ext;
	u32 have_crit;
	u32 have_fault;
	u8 valid_conf;
};

struct max6697_data {
	struct regmap *regmap;

	enum chips type;
	const struct max6697_chip_data *chip;

	int temp_offset;	/* in degrees C */

	struct mutex update_lock;

#define MAX6697_TEMP_INPUT	0
#define MAX6697_TEMP_EXT	1
#define MAX6697_TEMP_MAX	2
#define MAX6697_TEMP_CRIT	3
	u32 alarms;
};

static const struct max6697_chip_data max6697_chip_data[] = {
	[max6581] = {
		.channels = 8,
		.have_crit = 0xff,
		.have_ext = 0x7f,
		.have_fault = 0xfe,
		.valid_conf = MAX6581_CONF_EXTENDED | MAX6697_CONF_TIMEOUT,
	},
	[max6602] = {
		.channels = 5,
		.have_crit = 0x12,
		.have_ext = 0x02,
		.have_fault = 0x1e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
	},
	[max6622] = {
		.channels = 5,
		.have_crit = 0x12,
		.have_ext = 0x02,
		.have_fault = 0x1e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
	},
	[max6636] = {
		.channels = 7,
		.have_crit = 0x72,
		.have_ext = 0x02,
		.have_fault = 0x7e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
	},
	[max6689] = {
		.channels = 7,
		.have_crit = 0x72,
		.have_ext = 0x02,
		.have_fault = 0x7e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
	},
	[max6693] = {
		.channels = 7,
		.have_crit = 0x72,
		.have_ext = 0x02,
		.have_fault = 0x7e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6693_CONF_BETA |
		  MAX6697_CONF_TIMEOUT,
	},
	[max6694] = {
		.channels = 5,
		.have_crit = 0x12,
		.have_ext = 0x02,
		.have_fault = 0x1e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6693_CONF_BETA |
		  MAX6697_CONF_TIMEOUT,
	},
	[max6697] = {
		.channels = 7,
		.have_crit = 0x72,
		.have_ext = 0x02,
		.have_fault = 0x7e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
	},
	[max6698] = {
		.channels = 7,
		.have_crit = 0x72,
		.have_ext = 0x02,
		.have_fault = 0x0e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
	},
	[max6699] = {
		.channels = 5,
		.have_crit = 0x12,
		.have_ext = 0x02,
		.have_fault = 0x1e,
		.valid_conf = MAX6697_CONF_RESISTANCE | MAX6697_CONF_TIMEOUT,
	},
};

static int max6697_alarm_channel_map(int channel)
{
	switch (channel) {
	case 0:
		return 6;
	case 7:
		return 7;
	default:
		return channel - 1;
	}
}

static int max6697_read(struct device *dev, enum hwmon_sensor_types type,
			u32 attr, int channel, long *val)
{
	unsigned int offset_regs[2] = { MAX6581_REG_OFFSET_SELECT, MAX6581_REG_OFFSET };
	unsigned int temp_regs[2] = { MAX6697_REG_TEMP[channel],
				      MAX6697_REG_TEMP_EXT[channel] };
	struct max6697_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	u8 regdata[2] = { };
	u32 regval;
	int ret;

	switch (attr) {
	case hwmon_temp_input:
		ret = regmap_multi_reg_read(regmap, temp_regs, regdata,
					    data->chip->have_ext & BIT(channel) ? 2 : 1);
		if (ret)
			return ret;
		*val = (((regdata[0] - data->temp_offset) << 3) | (regdata[1] >> 5)) * 125;
		break;
	case hwmon_temp_max:
		ret = regmap_read(regmap, MAX6697_REG_MAX[channel], &regval);
		if (ret)
			return ret;
		*val = ((int)regval - data->temp_offset) * 1000;
		break;
	case hwmon_temp_crit:
		ret = regmap_read(regmap, MAX6697_REG_CRIT[channel], &regval);
		if (ret)
			return ret;
		*val = ((int)regval - data->temp_offset) * 1000;
		break;
	case hwmon_temp_min:
		ret = regmap_read(regmap, MAX6697_REG_MIN, &regval);
		if (ret)
			return ret;
		*val = ((int)regval - data->temp_offset) * 1000;
		break;
	case hwmon_temp_offset:
		ret = regmap_multi_reg_read(regmap, offset_regs, regdata, 2);
		if (ret)
			return ret;

		if (!(regdata[0] & BIT(channel - 1)))
			regdata[1] = 0;

		*val = sign_extend32(regdata[1], 7) * 250;
		break;
	case hwmon_temp_fault:
		ret = regmap_read(regmap, MAX6697_REG_STAT_FAULT, &regval);
		if (ret)
			return ret;
		if (data->type == max6581)
			*val = !!(regval & BIT(channel - 1));
		else
			*val = !!(regval & BIT(channel));
		break;
	case hwmon_temp_crit_alarm:
		ret = regmap_read(regmap, MAX6697_REG_STAT_CRIT, &regval);
		if (ret)
			return ret;
		/*
		 * In the MAX6581 datasheet revision 0 to 3, the local channel
		 * overtemperature status is reported in bit 6 of register 0x45,
		 * and the overtemperature status for remote channel 7 is
		 * reported in bit 7. In Revision 4 and later, the local channel
		 * overtemperature status is reported in bit 7, and the remote
		 * channel 7 overtemperature status is reported in bit 6. A real
		 * chip was found to match the functionality documented in
		 * Revision 4 and later.
		 */
		*val = !!(regval & BIT(channel ? channel - 1 : 7));
		break;
	case hwmon_temp_max_alarm:
		ret = regmap_read(regmap, MAX6697_REG_STAT_ALARM, &regval);
		if (ret)
			return ret;
		*val = !!(regval & BIT(max6697_alarm_channel_map(channel)));
		break;
	case hwmon_temp_min_alarm:
		ret = regmap_read(regmap, MAX6697_REG_STAT_MIN_ALARM, &regval);
		if (ret)
			return ret;
		*val = !!(regval & BIT(max6697_alarm_channel_map(channel)));
		break;
	default:
		return -EOPNOTSUPP;
	}
	return 0;
}

static int max6697_write(struct device *dev, enum hwmon_sensor_types type,
			 u32 attr, int channel, long val)
{
	struct max6697_data *data = dev_get_drvdata(dev);
	struct regmap *regmap = data->regmap;
	int ret;

	switch (attr) {
	case hwmon_temp_max:
		val = clamp_val(val, -1000000, 1000000);	/* prevent underflow */
		val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
		val = clamp_val(val, 0, data->type == max6581 ? 255 : 127);
		return regmap_write(regmap, MAX6697_REG_MAX[channel], val);
	case hwmon_temp_crit:
		val = clamp_val(val, -1000000, 1000000);	/* prevent underflow */
		val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
		val = clamp_val(val, 0, data->type == max6581 ? 255 : 127);
		return regmap_write(regmap, MAX6697_REG_CRIT[channel], val);
	case hwmon_temp_min:
		val = clamp_val(val, -1000000, 1000000);	/* prevent underflow */
		val = DIV_ROUND_CLOSEST(val, 1000) + data->temp_offset;
		val = clamp_val(val, 0, 255);
		return regmap_write(regmap, MAX6697_REG_MIN, val);
	case hwmon_temp_offset:
		mutex_lock(&data->update_lock);
		val = clamp_val(val, MAX6581_OFFSET_MIN, MAX6581_OFFSET_MAX);
		val = DIV_ROUND_CLOSEST(val, 250);
		if (!val) {	/* disable this (and only this) channel */
			ret = regmap_clear_bits(regmap, MAX6581_REG_OFFSET_SELECT,
						BIT(channel - 1));
		} else {
			/* enable channel and update offset */
			ret = regmap_set_bits(regmap, MAX6581_REG_OFFSET_SELECT,
					      BIT(channel - 1));
			if (ret)
				goto unlock;
			ret = regmap_write(regmap, MAX6581_REG_OFFSET, val);
		}
unlock:
		mutex_unlock(&data->update_lock);
		return ret;
	default:
		return -EOPNOTSUPP;
	}
}

static umode_t max6697_is_visible(const void *_data, enum hwmon_sensor_types type,
				  u32 attr, int channel)
{
	const struct max6697_data *data = _data;
	const struct max6697_chip_data *chip = data->chip;

	if (channel >= chip->channels)
		return 0;

	switch (attr) {
	case hwmon_temp_max:
		return 0644;
	case hwmon_temp_input:
	case hwmon_temp_max_alarm:
		return 0444;
	case hwmon_temp_min:
		if (data->type == max6581)
			return channel ? 0444 : 0644;
		break;
	case hwmon_temp_min_alarm:
		if (data->type == max6581)
			return 0444;
		break;
	case hwmon_temp_crit:
		if (chip->have_crit & BIT(channel))
			return 0644;
		break;
	case hwmon_temp_crit_alarm:
		if (chip->have_crit & BIT(channel))
			return 0444;
		break;
	case hwmon_temp_fault:
		if (chip->have_fault & BIT(channel))
			return 0444;
		break;
	case hwmon_temp_offset:
		if (data->type == max6581 && channel)
			return 0644;
		break;
	default:
		break;
	}
	return 0;
}

/* Return 0 if detection is successful, -ENODEV otherwise */
static const struct hwmon_channel_info * const max6697_info[] = {
	HWMON_CHANNEL_INFO(temp,
			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM,
			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
			   HWMON_T_FAULT | HWMON_T_OFFSET,
			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
			   HWMON_T_FAULT | HWMON_T_OFFSET,
			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
			   HWMON_T_FAULT | HWMON_T_OFFSET,
			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
			   HWMON_T_FAULT | HWMON_T_OFFSET,
			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
			   HWMON_T_FAULT | HWMON_T_OFFSET,
			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
			   HWMON_T_FAULT | HWMON_T_OFFSET,
			   HWMON_T_INPUT | HWMON_T_MAX | HWMON_T_CRIT |
			   HWMON_T_MAX_ALARM | HWMON_T_CRIT_ALARM |
			   HWMON_T_MIN | HWMON_T_MIN_ALARM |
			   HWMON_T_FAULT | HWMON_T_OFFSET),
	NULL
};

static const struct hwmon_ops max6697_hwmon_ops = {
	.is_visible = max6697_is_visible,
	.read = max6697_read,
	.write = max6697_write,
};

static const struct hwmon_chip_info max6697_chip_info = {
	.ops = &max6697_hwmon_ops,
	.info = max6697_info,
};

static int max6697_config_of(struct device_node *node, struct max6697_data *data)
{
	const struct max6697_chip_data *chip = data->chip;
	struct regmap *regmap = data->regmap;
	int ret, confreg;
	u32 vals[2];

	confreg = 0;
	if (of_property_read_bool(node, "smbus-timeout-disable") &&
	    (chip->valid_conf & MAX6697_CONF_TIMEOUT)) {
		confreg |= MAX6697_CONF_TIMEOUT;
	}
	if (of_property_read_bool(node, "extended-range-enable") &&
	    (chip->valid_conf & MAX6581_CONF_EXTENDED)) {
		confreg |= MAX6581_CONF_EXTENDED;
		data->temp_offset = 64;
	}
	if (of_property_read_bool(node, "beta-compensation-enable") &&
	    (chip->valid_conf & MAX6693_CONF_BETA)) {
		confreg |= MAX6693_CONF_BETA;
	}

	if (of_property_read_u32(node, "alert-mask", vals))
		vals[0] = 0;
	ret = regmap_write(regmap, MAX6697_REG_ALERT_MASK,
			   MAX6697_ALERT_MAP_BITS(vals[0]));
	if (ret)
		return ret;

	if (of_property_read_u32(node, "over-temperature-mask", vals))
		vals[0] = 0;
	ret = regmap_write(regmap, MAX6697_REG_OVERT_MASK,
			   MAX6697_OVERT_MAP_BITS(vals[0]));
	if (ret)
		return ret;

	if (data->type != max6581) {
		if (of_property_read_bool(node, "resistance-cancellation") &&
		    chip->valid_conf & MAX6697_CONF_RESISTANCE) {
			confreg |= MAX6697_CONF_RESISTANCE;
		}
	} else {
		if (of_property_read_u32(node, "resistance-cancellation", &vals[0])) {
			if (of_property_read_bool(node, "resistance-cancellation"))
				vals[0] = 0xfe;
			else
				vals[0] = 0;
		}

		vals[0] &= 0xfe;
		ret = regmap_write(regmap, MAX6581_REG_RESISTANCE, vals[0] >> 1);
		if (ret < 0)
			return ret;

		if (of_property_read_u32_array(node, "transistor-ideality", vals, 2)) {
			vals[0] = 0;
			vals[1] = 0;
		}

		ret = regmap_write(regmap, MAX6581_REG_IDEALITY, vals[1]);
		if (ret < 0)
			return ret;
		ret = regmap_write(regmap, MAX6581_REG_IDEALITY_SELECT,
				   (vals[0] & 0xfe) >> 1);
		if (ret < 0)
			return ret;
	}
	return regmap_write(regmap, MAX6697_REG_CONFIG, confreg);
}

static int max6697_init_chip(struct device_node *np, struct max6697_data *data)
{
	unsigned int reg;
	int ret;

	/*
	 * Don't touch configuration if there is no devicetree configuration.
	 * If that is the case, use the current chip configuration.
	 */
	if (!np) {
		struct regmap *regmap = data->regmap;

		ret = regmap_read(regmap, MAX6697_REG_CONFIG, &reg);
		if (ret < 0)
			return ret;
		if (data->type == max6581) {
			if (reg & MAX6581_CONF_EXTENDED)
				data->temp_offset = 64;
			ret = regmap_read(regmap, MAX6581_REG_RESISTANCE, &reg);
		}
	} else {
		ret = max6697_config_of(np, data);
	}

	return ret;
}

static bool max6697_volatile_reg(struct device *dev, unsigned int reg)
{
	switch (reg) {
	case 0x00 ... 0x09:	/* temperature high bytes */
	case 0x44 ... 0x47:	/* status */
	case 0x51 ... 0x58:	/* temperature low bytes */
		return true;
	default:
		return false;
	}
}

static bool max6697_writeable_reg(struct device *dev, unsigned int reg)
{
	return reg != 0x0a && reg != 0x0f && !max6697_volatile_reg(dev, reg);
}

static const struct regmap_config max6697_regmap_config = {
	.reg_bits = 8,
	.val_bits = 8,
	.max_register = 0x58,
	.writeable_reg = max6697_writeable_reg,
	.volatile_reg = max6697_volatile_reg,
	.cache_type = REGCACHE_MAPLE,
};

static int max6697_probe(struct i2c_client *client)
{
	struct device *dev = &client->dev;
	struct max6697_data *data;
	struct device *hwmon_dev;
	struct regmap *regmap;
	int err;

	regmap = regmap_init_i2c(client, &max6697_regmap_config);
	if (IS_ERR(regmap))
		return PTR_ERR(regmap);

	data = devm_kzalloc(dev, sizeof(struct max6697_data), GFP_KERNEL);
	if (!data)
		return -ENOMEM;

	data->regmap = regmap;
	data->type = (uintptr_t)i2c_get_match_data(client);
	data->chip = &max6697_chip_data[data->type];
	mutex_init(&data->update_lock);

	err = max6697_init_chip(client->dev.of_node, data);
	if (err)
		return err;

	hwmon_dev = devm_hwmon_device_register_with_info(dev, client->name, data,
							 &max6697_chip_info, NULL);
	return PTR_ERR_OR_ZERO(hwmon_dev);
}

static const struct i2c_device_id max6697_id[] = {
	{ "max6581", max6581 },
	{ "max6602", max6602 },
	{ "max6622", max6622 },
	{ "max6636", max6636 },
	{ "max6689", max6689 },
	{ "max6693", max6693 },
	{ "max6694", max6694 },
	{ "max6697", max6697 },
	{ "max6698", max6698 },
	{ "max6699", max6699 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, max6697_id);

static const struct of_device_id __maybe_unused max6697_of_match[] = {
	{
		.compatible = "maxim,max6581",
		.data = (void *)max6581
	},
	{
		.compatible = "maxim,max6602",
		.data = (void *)max6602
	},
	{
		.compatible = "maxim,max6622",
		.data = (void *)max6622
	},
	{
		.compatible = "maxim,max6636",
		.data = (void *)max6636
	},
	{
		.compatible = "maxim,max6689",
		.data = (void *)max6689
	},
	{
		.compatible = "maxim,max6693",
		.data = (void *)max6693
	},
	{
		.compatible = "maxim,max6694",
		.data = (void *)max6694
	},
	{
		.compatible = "maxim,max6697",
		.data = (void *)max6697
	},
	{
		.compatible = "maxim,max6698",
		.data = (void *)max6698
	},
	{
		.compatible = "maxim,max6699",
		.data = (void *)max6699
	},
	{ },
};
MODULE_DEVICE_TABLE(of, max6697_of_match);

static struct i2c_driver max6697_driver = {
	.driver = {
		.name	= "max6697",
		.of_match_table = of_match_ptr(max6697_of_match),
	},
	.probe = max6697_probe,
	.id_table = max6697_id,
};

module_i2c_driver(max6697_driver);

MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("MAX6697 temperature sensor driver");
MODULE_LICENSE("GPL");