#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>

#define MODULE_NAME		"ltc1695"
#define MODULE_VERSION_STR	"v1.0"

static int speed = 100;
module_param(speed, int, 0644);
MODULE_PARM_DESC(speed, "Fan speed [0:100]%%. Default: 100");

static const unsigned short normal_i2c[] = { 0x74, I2C_CLIENT_END };

struct ltc1695_data {
	struct i2c_client *client;
	struct device *hwmon_dev;
};


static int ltc1695_set_speed(struct i2c_client *client, u8 speed)
{	
	u8 cmd;
	if (speed > 100) {
		return -EINVAL;
	}

	cmd = 0x80 | ((0x3A * speed) / 100);
	return i2c_smbus_write_byte(client, cmd);
}

static ssize_t ltc1695_speed_show(struct device *dev, 
		struct device_attribute *attr, char *buf)
{
	return sprintf(buf, "%u\n", speed);
}

static ssize_t ltc1695_speed_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t size)
{
	ssize_t ret = -EINVAL;
	struct i2c_client *client = to_i2c_client(dev);
	unsigned long val = simple_strtoul(buf, NULL, 0);

	ret = ltc1695_set_speed(client, val);
	if (ret == 0) {
		speed = val;
		ret = size;
	}
	return ret;
}

static DEVICE_ATTR(speed, 0644, ltc1695_speed_show, ltc1695_speed_store);

static int ltc1695_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{	
	int ret;
	struct ltc1695_data *data;

	if (!i2c_check_functionality(client->adapter, 
					I2C_FUNC_SMBUS_BYTE_DATA)) {
		return -ENODEV;
	}

	ret = ltc1695_set_speed(client, speed);
	if (ret != 0) {
		goto error;
	}

	data = kzalloc(sizeof(struct ltc1695_data), GFP_KERNEL);
	if (data == NULL) {
		dev_err(&client->dev, "Failed to allocate device memory !\n");
		return -ENOMEM;
	}

	i2c_set_clientdata(client, data);

	data->client = client;

	ret = device_create_file(&client->dev, &dev_attr_speed);
	if (ret != 0) {
		dev_err(&client->dev, "Failed to create sysfs hook !\n");
		goto error_device_create_file;
	}

	/* Register sysfs hooks */
	//err = sysfs_create_group(&client->dev.kobj, &g760a_group);
	//if (err)
	//	goto error_sysfs_create_group;

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		dev_err(&client->dev, "Failed to register HW monitor device\n" );
		ret = PTR_ERR(data->hwmon_dev);
		goto error_hwmon_device_register;
	}

	dev_info(&client->dev, "Detected LTC1695 chip\n");
	return 0;

error_hwmon_device_register:
	//sysfs_remove_group(&client->dev.kobj, &g760a_group);
	device_remove_file(&client->dev, &dev_attr_speed);
error_device_create_file:
	kfree(data);
	i2c_set_clientdata(client, NULL);
error:
	dev_err(&client->dev, "Probe failed\n");
	return ret;
}

static int ltc1695_remove(struct i2c_client *client)
{

	struct ltc1695_data *data = i2c_get_clientdata(client);

	hwmon_device_unregister(data->hwmon_dev);

	device_remove_file(&client->dev, &dev_attr_speed);

	kfree(data);
	i2c_set_clientdata(client, NULL);
	return 0;
}

static const struct i2c_device_id ltc1695_id[] = {
	{ MODULE_NAME, 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ltc1695_id);

static struct i2c_driver ltc1695_driver = {
	.driver = {
		.name	= MODULE_NAME,
	},
	.probe		= ltc1695_probe,
	.remove		= ltc1695_remove,
	.id_table	= ltc1695_id,
};

static int __init ltc1695_init(void)
{
	return i2c_add_driver(&ltc1695_driver);
}
module_init(ltc1695_init);

static void __exit ltc1695_exit(void)
{
	i2c_del_driver(&ltc1695_driver);
}
module_exit(ltc1695_exit);

MODULE_DESCRIPTION("sysmobts v1 FAN Driver");
MODULE_AUTHOR("Lyrtech RD Inc. <www.lyrtech.com>");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:" MODULE_NAME);