// SPDX-License-Identifier: GPL-2.0-or-later

  /*

   * Copyright (c) 2011 David George <david.george@ska.ac.za>
   *
   * based on adm1021.c
   * some credit to Christoph Scheurer, but largely a rewrite

   */

  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/i2c.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.h>
  
  /* Addresses to scan */

  static const unsigned short max1668_addr_list[] = {

  	0x18, 0x19, 0x1a, 0x29, 0x2a, 0x2b, 0x4c, 0x4d, 0x4e, I2C_CLIENT_END };
  
  /* max1668 registers */
  
  #define MAX1668_REG_TEMP(nr)	(nr)
  #define MAX1668_REG_STAT1	0x05
  #define MAX1668_REG_STAT2	0x06
  #define MAX1668_REG_MAN_ID	0xfe
  #define MAX1668_REG_DEV_ID	0xff
  
  /* limits */
  
  /* write high limits */
  #define MAX1668_REG_LIMH_WR(nr)	(0x13 + 2 * (nr))
  /* write low limits */
  #define MAX1668_REG_LIML_WR(nr)	(0x14 + 2 * (nr))
  /* read high limits */
  #define MAX1668_REG_LIMH_RD(nr)	(0x08 + 2 * (nr))
  /* read low limits */
  #define MAX1668_REG_LIML_RD(nr)	(0x09 + 2 * (nr))
  
  /* manufacturer and device ID Constants */
  #define MAN_ID_MAXIM		0x4d
  #define DEV_ID_MAX1668		0x3
  #define DEV_ID_MAX1805		0x5
  #define DEV_ID_MAX1989		0xb
  
  /* read only mode module parameter */

  static bool read_only;

  module_param(read_only, bool, 0);
  MODULE_PARM_DESC(read_only, "Don't set any values, read only mode");
  
  enum chips { max1668, max1805, max1989 };
  
  struct max1668_data {

  	struct i2c_client *client;
  	const struct attribute_group *groups[3];

  	enum chips type;
  
  	struct mutex update_lock;
  	char valid;		/* !=0 if following fields are valid */
  	unsigned long last_updated;	/* In jiffies */
  
  	/* 1x local and 4x remote */
  	s8 temp_max[5];
  	s8 temp_min[5];
  	s8 temp[5];
  	u16 alarms;
  };
  
  static struct max1668_data *max1668_update_device(struct device *dev)
  {

  	struct max1668_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;

  	struct max1668_data *ret = data;
  	s32 val;
  	int i;
  
  	mutex_lock(&data->update_lock);
  
  	if (data->valid && !time_after(jiffies,
  			data->last_updated + HZ + HZ / 2))
  		goto abort;
  
  	for (i = 0; i < 5; i++) {
  		val = i2c_smbus_read_byte_data(client, MAX1668_REG_TEMP(i));
  		if (unlikely(val < 0)) {
  			ret = ERR_PTR(val);
  			goto abort;
  		}
  		data->temp[i] = (s8) val;
  
  		val = i2c_smbus_read_byte_data(client, MAX1668_REG_LIMH_RD(i));
  		if (unlikely(val < 0)) {
  			ret = ERR_PTR(val);
  			goto abort;
  		}
  		data->temp_max[i] = (s8) val;
  
  		val = i2c_smbus_read_byte_data(client, MAX1668_REG_LIML_RD(i));
  		if (unlikely(val < 0)) {
  			ret = ERR_PTR(val);
  			goto abort;
  		}
  		data->temp_min[i] = (s8) val;
  	}
  
  	val = i2c_smbus_read_byte_data(client, MAX1668_REG_STAT1);
  	if (unlikely(val < 0)) {
  		ret = ERR_PTR(val);
  		goto abort;
  	}

  	data->alarms = val << 8;

  
  	val = i2c_smbus_read_byte_data(client, MAX1668_REG_STAT2);
  	if (unlikely(val < 0)) {
  		ret = ERR_PTR(val);
  		goto abort;
  	}

  	data->alarms |= val;

  
  	data->last_updated = jiffies;
  	data->valid = 1;
  abort:
  	mutex_unlock(&data->update_lock);
  
  	return ret;
  }
  
  static ssize_t show_temp(struct device *dev,
  			 struct device_attribute *devattr, char *buf)
  {
  	int index = to_sensor_dev_attr(devattr)->index;
  	struct max1668_data *data = max1668_update_device(dev);
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	return sprintf(buf, "%d
  ", data->temp[index] * 1000);
  }
  
  static ssize_t show_temp_max(struct device *dev,
  			     struct device_attribute *devattr, char *buf)
  {
  	int index = to_sensor_dev_attr(devattr)->index;
  	struct max1668_data *data = max1668_update_device(dev);
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	return sprintf(buf, "%d
  ", data->temp_max[index] * 1000);
  }
  
  static ssize_t show_temp_min(struct device *dev,
  			     struct device_attribute *devattr, char *buf)
  {
  	int index = to_sensor_dev_attr(devattr)->index;
  	struct max1668_data *data = max1668_update_device(dev);
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	return sprintf(buf, "%d
  ", data->temp_min[index] * 1000);
  }
  
  static ssize_t show_alarm(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
  	int index = to_sensor_dev_attr(attr)->index;
  	struct max1668_data *data = max1668_update_device(dev);
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	return sprintf(buf, "%u
  ", (data->alarms >> index) & 0x1);
  }

  static ssize_t show_fault(struct device *dev,
  			  struct device_attribute *devattr, char *buf)
  {
  	int index = to_sensor_dev_attr(devattr)->index;
  	struct max1668_data *data = max1668_update_device(dev);
  
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	return sprintf(buf, "%u
  ",
  		       (data->alarms & (1 << 12)) && data->temp[index] == 127);
  }

  static ssize_t set_temp_max(struct device *dev,
  			    struct device_attribute *devattr,
  			    const char *buf, size_t count)
  {
  	int index = to_sensor_dev_attr(devattr)->index;

  	struct max1668_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;

  	long temp;
  	int ret;
  
  	ret = kstrtol(buf, 10, &temp);
  	if (ret < 0)
  		return ret;
  
  	mutex_lock(&data->update_lock);

  	data->temp_max[index] = clamp_val(temp/1000, -128, 127);

  	ret = i2c_smbus_write_byte_data(client,

  					MAX1668_REG_LIMH_WR(index),

  					data->temp_max[index]);
  	if (ret < 0)
  		count = ret;

  	mutex_unlock(&data->update_lock);
  
  	return count;
  }
  
  static ssize_t set_temp_min(struct device *dev,
  			    struct device_attribute *devattr,
  			    const char *buf, size_t count)
  {
  	int index = to_sensor_dev_attr(devattr)->index;

  	struct max1668_data *data = dev_get_drvdata(dev);
  	struct i2c_client *client = data->client;

  	long temp;
  	int ret;
  
  	ret = kstrtol(buf, 10, &temp);
  	if (ret < 0)
  		return ret;
  
  	mutex_lock(&data->update_lock);

  	data->temp_min[index] = clamp_val(temp/1000, -128, 127);

  	ret = i2c_smbus_write_byte_data(client,

  					MAX1668_REG_LIML_WR(index),

  					data->temp_min[index]);
  	if (ret < 0)
  		count = ret;

  	mutex_unlock(&data->update_lock);
  
  	return count;
  }
  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL, 0);
  static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_temp_max,
  				set_temp_max, 0);
  static SENSOR_DEVICE_ATTR(temp1_min, S_IRUGO, show_temp_min,
  				set_temp_min, 0);
  static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, show_temp, NULL, 1);
  static SENSOR_DEVICE_ATTR(temp2_max, S_IRUGO, show_temp_max,
  				set_temp_max, 1);
  static SENSOR_DEVICE_ATTR(temp2_min, S_IRUGO, show_temp_min,
  				set_temp_min, 1);
  static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, show_temp, NULL, 2);
  static SENSOR_DEVICE_ATTR(temp3_max, S_IRUGO, show_temp_max,
  				set_temp_max, 2);
  static SENSOR_DEVICE_ATTR(temp3_min, S_IRUGO, show_temp_min,
  				set_temp_min, 2);
  static SENSOR_DEVICE_ATTR(temp4_input, S_IRUGO, show_temp, NULL, 3);
  static SENSOR_DEVICE_ATTR(temp4_max, S_IRUGO, show_temp_max,
  				set_temp_max, 3);
  static SENSOR_DEVICE_ATTR(temp4_min, S_IRUGO, show_temp_min,
  				set_temp_min, 3);
  static SENSOR_DEVICE_ATTR(temp5_input, S_IRUGO, show_temp, NULL, 4);
  static SENSOR_DEVICE_ATTR(temp5_max, S_IRUGO, show_temp_max,
  				set_temp_max, 4);
  static SENSOR_DEVICE_ATTR(temp5_min, S_IRUGO, show_temp_min,
  				set_temp_min, 4);
  
  static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 14);
  static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, show_alarm, NULL, 13);
  static SENSOR_DEVICE_ATTR(temp2_min_alarm, S_IRUGO, show_alarm, NULL, 7);
  static SENSOR_DEVICE_ATTR(temp2_max_alarm, S_IRUGO, show_alarm, NULL, 6);
  static SENSOR_DEVICE_ATTR(temp3_min_alarm, S_IRUGO, show_alarm, NULL, 5);
  static SENSOR_DEVICE_ATTR(temp3_max_alarm, S_IRUGO, show_alarm, NULL, 4);
  static SENSOR_DEVICE_ATTR(temp4_min_alarm, S_IRUGO, show_alarm, NULL, 3);
  static SENSOR_DEVICE_ATTR(temp4_max_alarm, S_IRUGO, show_alarm, NULL, 2);
  static SENSOR_DEVICE_ATTR(temp5_min_alarm, S_IRUGO, show_alarm, NULL, 1);
  static SENSOR_DEVICE_ATTR(temp5_max_alarm, S_IRUGO, show_alarm, NULL, 0);

  static SENSOR_DEVICE_ATTR(temp2_fault, S_IRUGO, show_fault, NULL, 1);
  static SENSOR_DEVICE_ATTR(temp3_fault, S_IRUGO, show_fault, NULL, 2);
  static SENSOR_DEVICE_ATTR(temp4_fault, S_IRUGO, show_fault, NULL, 3);
  static SENSOR_DEVICE_ATTR(temp5_fault, S_IRUGO, show_fault, NULL, 4);

  /* Attributes common to MAX1668, MAX1989 and MAX1805 */
  static struct attribute *max1668_attribute_common[] = {
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_min.dev_attr.attr,
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp2_max.dev_attr.attr,
  	&sensor_dev_attr_temp2_min.dev_attr.attr,
  	&sensor_dev_attr_temp2_input.dev_attr.attr,
  	&sensor_dev_attr_temp3_max.dev_attr.attr,
  	&sensor_dev_attr_temp3_min.dev_attr.attr,
  	&sensor_dev_attr_temp3_input.dev_attr.attr,
  
  	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp2_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp3_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp3_min_alarm.dev_attr.attr,

  
  	&sensor_dev_attr_temp2_fault.dev_attr.attr,
  	&sensor_dev_attr_temp3_fault.dev_attr.attr,

  	NULL
  };
  
  /* Attributes not present on MAX1805 */
  static struct attribute *max1668_attribute_unique[] = {
  	&sensor_dev_attr_temp4_max.dev_attr.attr,
  	&sensor_dev_attr_temp4_min.dev_attr.attr,
  	&sensor_dev_attr_temp4_input.dev_attr.attr,
  	&sensor_dev_attr_temp5_max.dev_attr.attr,
  	&sensor_dev_attr_temp5_min.dev_attr.attr,
  	&sensor_dev_attr_temp5_input.dev_attr.attr,
  
  	&sensor_dev_attr_temp4_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp4_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp5_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp5_min_alarm.dev_attr.attr,

  
  	&sensor_dev_attr_temp4_fault.dev_attr.attr,
  	&sensor_dev_attr_temp5_fault.dev_attr.attr,

  	NULL
  };

  static umode_t max1668_attribute_mode(struct kobject *kobj,

  				     struct attribute *attr, int index)
  {

  	umode_t ret = S_IRUGO;

  	if (read_only)
  		return ret;
  	if (attr == &sensor_dev_attr_temp1_max.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp2_max.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp3_max.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp4_max.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp5_max.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp1_min.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp2_min.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp3_min.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp4_min.dev_attr.attr ||
  	    attr == &sensor_dev_attr_temp5_min.dev_attr.attr)
  		ret |= S_IWUSR;
  	return ret;
  }
  
  static const struct attribute_group max1668_group_common = {
  	.attrs = max1668_attribute_common,
  	.is_visible = max1668_attribute_mode
  };
  
  static const struct attribute_group max1668_group_unique = {
  	.attrs = max1668_attribute_unique,
  	.is_visible = max1668_attribute_mode
  };
  
  /* Return 0 if detection is successful, -ENODEV otherwise */
  static int max1668_detect(struct i2c_client *client,
  			  struct i2c_board_info *info)
  {
  	struct i2c_adapter *adapter = client->adapter;
  	const char *type_name;
  	int man_id, dev_id;
  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  		return -ENODEV;
  
  	/* Check for unsupported part */
  	man_id = i2c_smbus_read_byte_data(client, MAX1668_REG_MAN_ID);
  	if (man_id != MAN_ID_MAXIM)
  		return -ENODEV;
  
  	dev_id = i2c_smbus_read_byte_data(client, MAX1668_REG_DEV_ID);
  	if (dev_id < 0)
  		return -ENODEV;
  
  	type_name = NULL;
  	if (dev_id == DEV_ID_MAX1668)
  		type_name = "max1668";
  	else if (dev_id == DEV_ID_MAX1805)
  		type_name = "max1805";
  	else if (dev_id == DEV_ID_MAX1989)
  		type_name = "max1989";
  
  	if (!type_name)
  		return -ENODEV;
  
  	strlcpy(info->type, type_name, I2C_NAME_SIZE);
  
  	return 0;
  }

  static const struct i2c_device_id max1668_id[];
  
  static int max1668_probe(struct i2c_client *client)

  {
  	struct i2c_adapter *adapter = client->adapter;

  	struct device *dev = &client->dev;
  	struct device *hwmon_dev;

  	struct max1668_data *data;

  
  	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA))
  		return -ENODEV;

  	data = devm_kzalloc(dev, sizeof(struct max1668_data), GFP_KERNEL);

  	if (!data)
  		return -ENOMEM;

  	data->client = client;

  	data->type = i2c_match_id(max1668_id, client)->driver_data;

  	mutex_init(&data->update_lock);

  	/* sysfs hooks */
  	data->groups[0] = &max1668_group_common;

  	if (data->type == max1668 || data->type == max1989)

  		data->groups[1] = &max1668_group_unique;

  	hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
  							   data, data->groups);
  	return PTR_ERR_OR_ZERO(hwmon_dev);

  }
  
  static const struct i2c_device_id max1668_id[] = {
  	{ "max1668", max1668 },
  	{ "max1805", max1805 },
  	{ "max1989", max1989 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, max1668_id);
  
  /* This is the driver that will be inserted */
  static struct i2c_driver max1668_driver = {
  	.class = I2C_CLASS_HWMON,
  	.driver = {
  		  .name	= "max1668",
  		  },

  	.probe_new = max1668_probe,

  	.id_table = max1668_id,
  	.detect	= max1668_detect,
  	.address_list = max1668_addr_list,
  };

  module_i2c_driver(max1668_driver);

  
  MODULE_AUTHOR("David George <david.george@ska.ac.za>");
  MODULE_DESCRIPTION("MAX1668 remote temperature sensor driver");
  MODULE_LICENSE("GPL");