/*
 * i5500_temp - Driver for Intel 5500/5520/X58 chipset thermal sensor
 *
 * Copyright (C) 2012, 2014 Jean Delvare <jdelvare@suse.de>
 *
 * 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.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/pci.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>

/* Register definitions from datasheet */
#define REG_TSTHRCATA	0xE2
#define REG_TSCTRL	0xE8
#define REG_TSTHRRPEX	0xEB
#define REG_TSTHRLO	0xEC
#define REG_TSTHRHI	0xEE
#define REG_CTHINT	0xF0
#define REG_TSFSC	0xF3
#define REG_CTSTS	0xF4
#define REG_TSTHRRQPI	0xF5
#define REG_CTCTRL	0xF7
#define REG_TSTIMER	0xF8

struct i5500_temp_data {
	struct device *hwmon_dev;
	const char *name;
};

/*
 * Sysfs stuff
 */

/* Sensor resolution : 0.5 degree C */
static ssize_t show_temp(struct device *dev,
			 struct device_attribute *devattr, char *buf)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	long temp;
	u16 tsthrhi;
	s8 tsfsc;

	pci_read_config_word(pdev, REG_TSTHRHI, &tsthrhi);
	pci_read_config_byte(pdev, REG_TSFSC, &tsfsc);
	temp = ((long)tsthrhi - tsfsc) * 500;

	return sprintf(buf, "%ld\n", temp);
}

static ssize_t show_thresh(struct device *dev,
			   struct device_attribute *devattr, char *buf)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	int reg = to_sensor_dev_attr(devattr)->index;
	long temp;
	u16 tsthr;

	pci_read_config_word(pdev, reg, &tsthr);
	temp = tsthr * 500;

	return sprintf(buf, "%ld\n", temp);
}

static ssize_t show_alarm(struct device *dev,
			  struct device_attribute *devattr, char *buf)
{
	struct pci_dev *pdev = to_pci_dev(dev);
	int nr = to_sensor_dev_attr(devattr)->index;
	u8 ctsts;

	pci_read_config_byte(pdev, REG_CTSTS, &ctsts);
	return sprintf(buf, "%u\n", (unsigned int)ctsts & (1 << nr));
}

static ssize_t show_name(struct device *dev, struct device_attribute
			 *devattr, char *buf)
{
	struct i5500_temp_data *data = dev_get_drvdata(dev);

	return sprintf(buf, "%s\n", data->name);
}

static DEVICE_ATTR(temp1_input, S_IRUGO, show_temp, NULL);
static SENSOR_DEVICE_ATTR(temp1_crit, S_IRUGO, show_thresh, NULL, 0xE2);
static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IRUGO, show_thresh, NULL, 0xEC);
static SENSOR_DEVICE_ATTR(temp1_max, S_IRUGO, show_thresh, NULL, 0xEE);
static SENSOR_DEVICE_ATTR(temp1_crit_alarm, S_IRUGO, show_alarm, NULL, 0);
static SENSOR_DEVICE_ATTR(temp1_max_alarm, S_IRUGO, show_alarm, NULL, 1);
static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);

static struct attribute *i5500_temp_attributes[] = {
	&dev_attr_temp1_input.attr,
	&sensor_dev_attr_temp1_crit.dev_attr.attr,
	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	&sensor_dev_attr_temp1_crit_alarm.dev_attr.attr,
	&sensor_dev_attr_temp1_max_alarm.dev_attr.attr,
	&dev_attr_name.attr,
	NULL
};

static const struct attribute_group i5500_temp_group = {
	.attrs = i5500_temp_attributes,
};

static const struct pci_device_id i5500_temp_ids[] = {
	{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, 0x3438) },
	{ 0 },
};

MODULE_DEVICE_TABLE(pci, i5500_temp_ids);

static int i5500_temp_probe(struct pci_dev *pdev,
			    const struct pci_device_id *id)
{
	int err;
	struct i5500_temp_data *data;

	data = kzalloc(sizeof(struct i5500_temp_data), GFP_KERNEL);
	if (!data) {
		err = -ENOMEM;
		goto exit;
	}

	data->name = "intel5500";
	dev_set_drvdata(&pdev->dev, data);

	err = pci_enable_device(pdev);
	if (err) {
		dev_err(&pdev->dev, "Failed to enable device\n");
		goto exit_free;
	}

	/* Register sysfs hooks */
	err = sysfs_create_group(&pdev->dev.kobj, &i5500_temp_group);
	if (err)
		goto exit_free;

	data->hwmon_dev = hwmon_device_register(&pdev->dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto exit_remove;
	}

	return 0;

 exit_remove:
	sysfs_remove_group(&pdev->dev.kobj, &i5500_temp_group);
 exit_free:
	kfree(data);
 exit:
	return err;
}

static void i5500_temp_remove(struct pci_dev *pdev)
{
	struct i5500_temp_data *data = dev_get_drvdata(&pdev->dev);

	hwmon_device_unregister(data->hwmon_dev);
	sysfs_remove_group(&pdev->dev.kobj, &i5500_temp_group);
	kfree(data);
}

static struct pci_driver i5500_temp_driver = {
	.name = "i5500_temp",
	.id_table = i5500_temp_ids,
	.probe = i5500_temp_probe,
	.remove = i5500_temp_remove,
};

static int __init i5500_temp_init(void)
{
	return pci_register_driver(&i5500_temp_driver);
}

static void __exit i5500_temp_exit(void)
{
	pci_unregister_driver(&i5500_temp_driver);
}

MODULE_AUTHOR("Jean Delvare <jdelvare@suse.de>");
MODULE_DESCRIPTION("Intel 5500/5520/X58 chipset thermal sensor driver");
MODULE_LICENSE("GPL");

module_init(i5500_temp_init)
module_exit(i5500_temp_exit)