/*
   * adt7x10.c - Part of lm_sensors, Linux kernel modules for hardware
   *	 monitoring
   * This driver handles the ADT7410 and compatible digital temperature sensors.
   * Hartmut Knaack <knaack.h@gmx.de> 2012-07-22
   * based on lm75.c by Frodo Looijaard <frodol@dds.nl>
   * and adt7410.c from iio-staging by Sonic Zhang <sonic.zhang@analog.com>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/slab.h>
  #include <linux/jiffies.h>
  #include <linux/hwmon.h>
  #include <linux/hwmon-sysfs.h>
  #include <linux/err.h>
  #include <linux/mutex.h>
  #include <linux/delay.h>
  #include <linux/interrupt.h>
  
  #include "adt7x10.h"
  
  /*
   * ADT7X10 status
   */
  #define ADT7X10_STAT_T_LOW		(1 << 4)
  #define ADT7X10_STAT_T_HIGH		(1 << 5)
  #define ADT7X10_STAT_T_CRIT		(1 << 6)
  #define ADT7X10_STAT_NOT_RDY		(1 << 7)
  
  /*
   * ADT7X10 config
   */
  #define ADT7X10_FAULT_QUEUE_MASK	(1 << 0 | 1 << 1)
  #define ADT7X10_CT_POLARITY		(1 << 2)
  #define ADT7X10_INT_POLARITY		(1 << 3)
  #define ADT7X10_EVENT_MODE		(1 << 4)
  #define ADT7X10_MODE_MASK		(1 << 5 | 1 << 6)
  #define ADT7X10_FULL			(0 << 5 | 0 << 6)
  #define ADT7X10_PD			(1 << 5 | 1 << 6)
  #define ADT7X10_RESOLUTION		(1 << 7)
  
  /*
   * ADT7X10 masks
   */
  #define ADT7X10_T13_VALUE_MASK		0xFFF8
  #define ADT7X10_T_HYST_MASK		0xF
  
  /* straight from the datasheet */
  #define ADT7X10_TEMP_MIN (-55000)
  #define ADT7X10_TEMP_MAX 150000
  
  /* Each client has this additional data */
  struct adt7x10_data {
  	const struct adt7x10_ops *ops;
  	const char		*name;
  	struct device		*hwmon_dev;
  	struct mutex		update_lock;
  	u8			config;
  	u8			oldconfig;
  	bool			valid;		/* true if registers valid */
  	unsigned long		last_updated;	/* In jiffies */
  	s16			temp[4];	/* Register values,
  						   0 = input
  						   1 = high
  						   2 = low
  						   3 = critical */
  	u8			hyst;		/* hysteresis offset */
  };
  
  static int adt7x10_read_byte(struct device *dev, u8 reg)
  {
  	struct adt7x10_data *d = dev_get_drvdata(dev);
  	return d->ops->read_byte(dev, reg);
  }
  
  static int adt7x10_write_byte(struct device *dev, u8 reg, u8 data)
  {
  	struct adt7x10_data *d = dev_get_drvdata(dev);
  	return d->ops->write_byte(dev, reg, data);
  }
  
  static int adt7x10_read_word(struct device *dev, u8 reg)
  {
  	struct adt7x10_data *d = dev_get_drvdata(dev);
  	return d->ops->read_word(dev, reg);
  }
  
  static int adt7x10_write_word(struct device *dev, u8 reg, u16 data)
  {
  	struct adt7x10_data *d = dev_get_drvdata(dev);
  	return d->ops->write_word(dev, reg, data);
  }
  
  static const u8 ADT7X10_REG_TEMP[4] = {
  	ADT7X10_TEMPERATURE,		/* input */
  	ADT7X10_T_ALARM_HIGH,		/* high */
  	ADT7X10_T_ALARM_LOW,		/* low */
  	ADT7X10_T_CRIT,			/* critical */
  };
  
  static irqreturn_t adt7x10_irq_handler(int irq, void *private)
  {
  	struct device *dev = private;
  	int status;
  
  	status = adt7x10_read_byte(dev, ADT7X10_STATUS);
  	if (status < 0)
  		return IRQ_HANDLED;
  
  	if (status & ADT7X10_STAT_T_HIGH)
  		sysfs_notify(&dev->kobj, NULL, "temp1_max_alarm");
  	if (status & ADT7X10_STAT_T_LOW)
  		sysfs_notify(&dev->kobj, NULL, "temp1_min_alarm");
  	if (status & ADT7X10_STAT_T_CRIT)
  		sysfs_notify(&dev->kobj, NULL, "temp1_crit_alarm");
  
  	return IRQ_HANDLED;
  }
  
  static int adt7x10_temp_ready(struct device *dev)
  {
  	int i, status;
  
  	for (i = 0; i < 6; i++) {
  		status = adt7x10_read_byte(dev, ADT7X10_STATUS);
  		if (status < 0)
  			return status;
  		if (!(status & ADT7X10_STAT_NOT_RDY))
  			return 0;
  		msleep(60);
  	}
  	return -ETIMEDOUT;
  }
  
  static int adt7x10_update_temp(struct device *dev)
  {
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  	int ret = 0;
  
  	mutex_lock(&data->update_lock);
  
  	if (time_after(jiffies, data->last_updated + HZ + HZ / 2)
  	    || !data->valid) {
  		int temp;
  
  		dev_dbg(dev, "Starting update
  ");
  
  		ret = adt7x10_temp_ready(dev); /* check for new value */
  		if (ret)
  			goto abort;
  
  		temp = adt7x10_read_word(dev, ADT7X10_REG_TEMP[0]);
  		if (temp < 0) {
  			ret = temp;
  			dev_dbg(dev, "Failed to read value: reg %d, error %d
  ",
  				ADT7X10_REG_TEMP[0], ret);
  			goto abort;
  		}
  		data->temp[0] = temp;
  		data->last_updated = jiffies;
  		data->valid = true;
  	}
  
  abort:
  	mutex_unlock(&data->update_lock);
  	return ret;
  }
  
  static int adt7x10_fill_cache(struct device *dev)
  {
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  	int ret;
  	int i;
  
  	for (i = 1; i < ARRAY_SIZE(data->temp); i++) {
  		ret = adt7x10_read_word(dev, ADT7X10_REG_TEMP[i]);
  		if (ret < 0) {
  			dev_dbg(dev, "Failed to read value: reg %d, error %d
  ",
  				ADT7X10_REG_TEMP[i], ret);
  			return ret;
  		}
  		data->temp[i] = ret;
  	}
  
  	ret = adt7x10_read_byte(dev, ADT7X10_T_HYST);
  	if (ret < 0) {
  		dev_dbg(dev, "Failed to read value: reg %d, error %d
  ",
  				ADT7X10_T_HYST, ret);
  		return ret;
  	}
  	data->hyst = ret;
  
  	return 0;
  }
  
  static s16 ADT7X10_TEMP_TO_REG(long temp)
  {
  	return DIV_ROUND_CLOSEST(clamp_val(temp, ADT7X10_TEMP_MIN,
  					       ADT7X10_TEMP_MAX) * 128, 1000);
  }
  
  static int ADT7X10_REG_TO_TEMP(struct adt7x10_data *data, s16 reg)
  {
  	/* in 13 bit mode, bits 0-2 are status flags - mask them out */
  	if (!(data->config & ADT7X10_RESOLUTION))
  		reg &= ADT7X10_T13_VALUE_MASK;
  	/*
  	 * temperature is stored in twos complement format, in steps of
  	 * 1/128°C
  	 */
  	return DIV_ROUND_CLOSEST(reg * 1000, 128);
  }
  
  /*-----------------------------------------------------------------------*/
  
  /* sysfs attributes for hwmon */
  
  static ssize_t adt7x10_show_temp(struct device *dev,
  				 struct device_attribute *da,
  				 char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  
  
  	if (attr->index == 0) {
  		int ret;
  
  		ret = adt7x10_update_temp(dev);
  		if (ret)
  			return ret;
  	}
  
  	return sprintf(buf, "%d
  ", ADT7X10_REG_TO_TEMP(data,
  		       data->temp[attr->index]));
  }
  
  static ssize_t adt7x10_set_temp(struct device *dev,
  				struct device_attribute *da,
  				const char *buf, size_t count)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  	int nr = attr->index;
  	long temp;
  	int ret;
  
  	ret = kstrtol(buf, 10, &temp);
  	if (ret)
  		return ret;
  
  	mutex_lock(&data->update_lock);
  	data->temp[nr] = ADT7X10_TEMP_TO_REG(temp);
  	ret = adt7x10_write_word(dev, ADT7X10_REG_TEMP[nr], data->temp[nr]);
  	if (ret)
  		count = ret;
  	mutex_unlock(&data->update_lock);
  	return count;
  }
  
  static ssize_t adt7x10_show_t_hyst(struct device *dev,
  				   struct device_attribute *da,
  				   char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  	int nr = attr->index;
  	int hyst;
  
  	hyst = (data->hyst & ADT7X10_T_HYST_MASK) * 1000;
  
  	/*
  	 * hysteresis is stored as a 4 bit offset in the device, convert it
  	 * to an absolute value
  	 */
  	if (nr == 2)	/* min has positive offset, others have negative */
  		hyst = -hyst;
  	return sprintf(buf, "%d
  ",
  		       ADT7X10_REG_TO_TEMP(data, data->temp[nr]) - hyst);
  }
  
  static ssize_t adt7x10_set_t_hyst(struct device *dev,
  				  struct device_attribute *da,
  				  const char *buf, size_t count)
  {
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  	int limit, ret;
  	long hyst;
  
  	ret = kstrtol(buf, 10, &hyst);
  	if (ret)
  		return ret;
  	/* convert absolute hysteresis value to a 4 bit delta value */
  	limit = ADT7X10_REG_TO_TEMP(data, data->temp[1]);
  	hyst = clamp_val(hyst, ADT7X10_TEMP_MIN, ADT7X10_TEMP_MAX);
  	data->hyst = clamp_val(DIV_ROUND_CLOSEST(limit - hyst, 1000),
  				   0, ADT7X10_T_HYST_MASK);
  	ret = adt7x10_write_byte(dev, ADT7X10_T_HYST, data->hyst);
  	if (ret)
  		return ret;
  
  	return count;
  }
  
  static ssize_t adt7x10_show_alarm(struct device *dev,
  				  struct device_attribute *da,
  				  char *buf)
  {
  	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
  	int ret;
  
  	ret = adt7x10_read_byte(dev, ADT7X10_STATUS);
  	if (ret < 0)
  		return ret;
  
  	return sprintf(buf, "%d
  ", !!(ret & attr->index));
  }
  
  static ssize_t adt7x10_show_name(struct device *dev,
  				 struct device_attribute *da,
  				 char *buf)
  {
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  
  	return sprintf(buf, "%s
  ", data->name);
  }
  
  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, adt7x10_show_temp, NULL, 0);
  static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO,
  			  adt7x10_show_temp, adt7x10_set_temp, 1);
  static SENSOR_DEVICE_ATTR(temp1_min, S_IWUSR | S_IRUGO,
  			  adt7x10_show_temp, adt7x10_set_temp, 2);
  static SENSOR_DEVICE_ATTR(temp1_crit, S_IWUSR | S_IRUGO,
  			  adt7x10_show_temp, adt7x10_set_temp, 3);
  static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO,
  			  adt7x10_show_t_hyst, adt7x10_set_t_hyst, 1);
  static SENSOR_DEVICE_ATTR(temp1_min_hyst, S_IRUGO,
  			  adt7x10_show_t_hyst, NULL, 2);
  static SENSOR_DEVICE_ATTR(temp1_crit_hyst, S_IRUGO,
  			  adt7x10_show_t_hyst, NULL, 3);
  static SENSOR_DEVICE_ATTR(temp1_min_alarm, S_IRUGO, adt7x10_show_alarm,
  			  NULL, ADT7X10_STAT_T_LOW);
  static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, adt7x10_show_alarm,
  			  NULL, ADT7X10_STAT_T_HIGH);
  static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, adt7x10_show_alarm,
  			  NULL, ADT7X10_STAT_T_CRIT);
  static DEVICE_ATTR(name, S_IRUGO, adt7x10_show_name, NULL);
  
  static struct attribute *adt7x10_attributes[] = {
  	&sensor_dev_attr_temp1_input.dev_attr.attr,
  	&sensor_dev_attr_temp1_max.dev_attr.attr,
  	&sensor_dev_attr_temp1_min.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp1_min_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
  	&sensor_dev_attr_temp1_min_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
  	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
  	NULL
  };
  
  static const struct attribute_group adt7x10_group = {
  	.attrs = adt7x10_attributes,
  };
  
  int adt7x10_probe(struct device *dev, const char *name, int irq,
  		  const struct adt7x10_ops *ops)
  {
  	struct adt7x10_data *data;
  	int ret;
  
  	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
  	if (!data)
  		return -ENOMEM;
  
  	data->ops = ops;
  	data->name = name;
  
  	dev_set_drvdata(dev, data);
  	mutex_init(&data->update_lock);
  
  	/* configure as specified */
  	ret = adt7x10_read_byte(dev, ADT7X10_CONFIG);
  	if (ret < 0) {
  		dev_dbg(dev, "Can't read config? %d
  ", ret);
  		return ret;
  	}
  	data->oldconfig = ret;
  
  	/*
  	 * Set to 16 bit resolution, continous conversion and comparator mode.
  	 */
  	data->config = data->oldconfig;
  	data->config &= ~(ADT7X10_MODE_MASK | ADT7X10_CT_POLARITY |
  			ADT7X10_INT_POLARITY);
  	data->config |= ADT7X10_FULL | ADT7X10_RESOLUTION | ADT7X10_EVENT_MODE;
  
  	if (data->config != data->oldconfig) {
  		ret = adt7x10_write_byte(dev, ADT7X10_CONFIG, data->config);
  		if (ret)
  			return ret;
  	}
  	dev_dbg(dev, "Config %02x
  ", data->config);
  
  	ret = adt7x10_fill_cache(dev);
  	if (ret)
  		goto exit_restore;
  
  	/* Register sysfs hooks */
  	ret = sysfs_create_group(&dev->kobj, &adt7x10_group);
  	if (ret)
  		goto exit_restore;
  
  	/*
  	 * The I2C device will already have it's own 'name' attribute, but for
  	 * the SPI device we need to register it. name will only be non NULL if
  	 * the device doesn't register the 'name' attribute on its own.
  	 */
  	if (name) {
  		ret = device_create_file(dev, &dev_attr_name);
  		if (ret)
  			goto exit_remove;
  	}
  
  	data->hwmon_dev = hwmon_device_register(dev);
  	if (IS_ERR(data->hwmon_dev)) {
  		ret = PTR_ERR(data->hwmon_dev);
  		goto exit_remove_name;
  	}
  
  	if (irq > 0) {
  		ret = request_threaded_irq(irq, NULL, adt7x10_irq_handler,
  				IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
  				dev_name(dev), dev);
  		if (ret)
  			goto exit_hwmon_device_unregister;
  	}
  
  	return 0;
  
  exit_hwmon_device_unregister:
  	hwmon_device_unregister(data->hwmon_dev);
  exit_remove_name:
  	if (name)
  		device_remove_file(dev, &dev_attr_name);
  exit_remove:
  	sysfs_remove_group(&dev->kobj, &adt7x10_group);
  exit_restore:
  	adt7x10_write_byte(dev, ADT7X10_CONFIG, data->oldconfig);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(adt7x10_probe);
  
  int adt7x10_remove(struct device *dev, int irq)
  {
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  
  	if (irq > 0)
  		free_irq(irq, dev);
  
  	hwmon_device_unregister(data->hwmon_dev);
  	if (data->name)
  		device_remove_file(dev, &dev_attr_name);
  	sysfs_remove_group(&dev->kobj, &adt7x10_group);
  	if (data->oldconfig != data->config)
  		adt7x10_write_byte(dev, ADT7X10_CONFIG, data->oldconfig);
  	return 0;
  }
  EXPORT_SYMBOL_GPL(adt7x10_remove);
  
  #ifdef CONFIG_PM_SLEEP
  
  static int adt7x10_suspend(struct device *dev)
  {
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  
  	return adt7x10_write_byte(dev, ADT7X10_CONFIG,
  		data->config | ADT7X10_PD);
  }
  
  static int adt7x10_resume(struct device *dev)
  {
  	struct adt7x10_data *data = dev_get_drvdata(dev);
  
  	return adt7x10_write_byte(dev, ADT7X10_CONFIG, data->config);
  }
  
  SIMPLE_DEV_PM_OPS(adt7x10_dev_pm_ops, adt7x10_suspend, adt7x10_resume);
  EXPORT_SYMBOL_GPL(adt7x10_dev_pm_ops);
  
  #endif /* CONFIG_PM_SLEEP */
  
  MODULE_AUTHOR("Hartmut Knaack");
  MODULE_DESCRIPTION("ADT7410/ADT7420, ADT7310/ADT7320 common code");
  MODULE_LICENSE("GPL");