/* Texas Instruments TMP102 SMBus temperature sensor driver
 *
 * Copyright (C) 2010 Steven King <sfking@fdwdc.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., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA
 */

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

#define	DRIVER_NAME "tmp102"

enum tmp102_sensors {
	TMP102 = 0x00,
	TMP108 = 0x01
};

/* tmp102 config */
#define	TMP102_TEMP_REG			0x00
#define	TMP102_CONF_REG			0x01
/* note: these bit definitions are byte swapped */
#define		TMP102_CONF_SD		0x0100
#define		TMP102_CONF_TM		0x0200
#define		TMP102_CONF_POL		0x0400
#define		TMP102_CONF_F0		0x0800
#define		TMP102_CONF_F1		0x1000
#define		TMP102_CONF_R0		0x2000
#define		TMP102_CONF_R1		0x4000
#define		TMP102_CONF_OS		0x8000
#define		TMP102_CONF_EM		0x0010
#define		TMP102_CONF_AL		0x0020
#define		TMP102_CONF_CR0		0x0040
#define		TMP102_CONF_CR1		0x0080
#define	TMP102_TLOW_REG			0x02
#define	TMP102_THIGH_REG		0x03

#define TMP102_CONFIG  		(TMP102_CONF_TM | TMP102_CONF_EM | TMP102_CONF_CR1)
#define TMP102_CONFIG_RD_ONLY 	(TMP102_CONF_R0 | TMP102_CONF_R1 | TMP102_CONF_AL)

/* tmp108 config */

#define TMP108_TEMP_REG			0x00
#define TMP108_CONF_REG			0x01
#define TMP108_TLOW_REG			0x02
#define TMP108_THIGH_REG		0x03
/* note: these bit definitions are byte swapped */
#define TMP108_CONF_M0			0x0100
#define TMP108_CONF_M1			0x0200
#define TMP108_CONF_LC			0x0400
#define TMP108_CONF_FL			0x0800
#define TMP108_CONF_FH			0x1000
#define TMP108_CONF_CR0			0x2000
#define TMP108_CONF_CR1			0x4000
#define TMP108_CONF_ID			0x8000
#define TMP108_CONF_POL			0x0080
#define TMP108_CONF_HYS1    		0x0020
#define TMP108_CONF_HYS0    		0x0010
#define TMP108_CONF_SD		(TMP108_CONF_M1)
#define TMP108_CONFIG		(TMP108_CONF_CR1 | TMP108_CONF_M1 | TMP108_CONF_HYS0)


struct tmp_sensor_info {
	enum tmp102_sensors kind;
	u16 config;
	u16 conf_reg;
	u16 temp_reg_low;
	u16 temp_reg_high;
	u16 shutdown_cmd;
};

struct tmp_ops {
	int (*reg_to_mC)(s16);
	u16 (*mC_to_reg)(int);
};
struct tmp102 {
	struct i2c_client *client;
	struct device *hwmon_dev;
	struct mutex lock;
	u16 config_orig;
	unsigned long last_update;
	int temp[3];
	const struct tmp_ops *ops;
	const struct tmp_sensor_info *sensor_info;
};

static const struct tmp_sensor_info tmp_sensor_info_table[] = {
	[TMP102] = {
		.kind = TMP102,
		.config = TMP102_CONFIG,
		.conf_reg = TMP102_CONF_REG,
		.temp_reg_low = TMP102_TLOW_REG,
		.temp_reg_high = TMP102_THIGH_REG,
		.shutdown_cmd = TMP102_CONF_SD,
	},
	[TMP108] = {
		.kind = TMP108,
		.config = TMP108_CONFIG,
		.conf_reg = TMP108_CONF_REG,
		.temp_reg_low = TMP108_TLOW_REG,
		.temp_reg_high = TMP108_THIGH_REG,
		.shutdown_cmd = TMP108_CONF_SD,
	},
};


/* same registers for tmp102 and tmp108 */
static const u8 tmp102_reg[] = {
	TMP102_TEMP_REG,
	TMP102_TLOW_REG,
	TMP102_THIGH_REG,
};

/* convert left adjusted 13-bit TMP102 register value to milliCelsius */
static inline int tmp102_reg_to_mC(s16 val)
{
	return ((val & ~0x01) * 1000) / 128;
}

/* convert milliCelsius to left adjusted 13-bit TMP102 register value */
static inline u16 tmp102_mC_to_reg(int val)
{
	return (val * 128) / 1000;
}

/* convert left adjusted 12-bit TMP108 register value to milliCelsius */
static inline int tmp108_reg_to_mC(s16 val)
{
	return (val  * 1000) / 256;
}

/* convert milliCelsius to left adjusted 12-bit TMP108 register value */
static inline u16 tmp108_mC_to_reg(int val)
{
	return (val * 256) / 1000;
}

static const struct tmp_ops tmp102_ops = {
	.reg_to_mC = tmp102_reg_to_mC,
	.mC_to_reg = tmp102_mC_to_reg,
};

static const struct tmp_ops tmp108_ops = {
	.reg_to_mC = tmp108_reg_to_mC,
	.mC_to_reg = tmp108_mC_to_reg,
};

static struct tmp102 *tmp102_update_device(struct device *dev)
{
	struct tmp102 *tmp102 = dev_get_drvdata(dev);
	struct i2c_client *client = tmp102->client;

	mutex_lock(&tmp102->lock);
	if (time_after(jiffies, tmp102->last_update + HZ / 3)) {
		int i;
		for (i = 0; i < ARRAY_SIZE(tmp102->temp); ++i) {
			int status = i2c_smbus_read_word_swapped(client,
								 tmp102_reg[i]);
			if (status > -1)
				tmp102->temp[i] = tmp102->ops->reg_to_mC(status);
		}
		tmp102->last_update = jiffies;
	}
	mutex_unlock(&tmp102->lock);
	return tmp102;
}

static int tmp102_read_temp(void *dev, long *temp)
{
	struct tmp102 *tmp102 = tmp102_update_device(dev);

	*temp = tmp102->temp[0];

	return 0;
}

static ssize_t tmp102_show_temp(struct device *dev,
				struct device_attribute *attr,
				char *buf)
{
	struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
	struct tmp102 *tmp102 = tmp102_update_device(dev);

	return sprintf(buf, "%d\n", tmp102->temp[sda->index]);
}

static ssize_t tmp102_set_temp(struct device *dev,
			       struct device_attribute *attr,
			       const char *buf, size_t count)
{
	struct sensor_device_attribute *sda = to_sensor_dev_attr(attr);
	struct tmp102 *tmp102 = dev_get_drvdata(dev);
	struct i2c_client *client = tmp102->client;
	long val;
	int status;

	if (kstrtol(buf, 10, &val) < 0)
		return -EINVAL;
	val = clamp_val(val, -256000, 255000);

	mutex_lock(&tmp102->lock);
	tmp102->temp[sda->index] = val;
	status = i2c_smbus_write_word_swapped(client, tmp102_reg[sda->index],
					      tmp102->ops->mC_to_reg(val));
	mutex_unlock(&tmp102->lock);
	return status ? : count;
}

static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, tmp102_show_temp, NULL , 0);

static SENSOR_DEVICE_ATTR(temp1_max_hyst, S_IWUSR | S_IRUGO, tmp102_show_temp,
			  tmp102_set_temp, 1);

static SENSOR_DEVICE_ATTR(temp1_max, S_IWUSR | S_IRUGO, tmp102_show_temp,
			  tmp102_set_temp, 2);

static struct attribute *tmp102_attrs[] = {
	&sensor_dev_attr_temp1_input.dev_attr.attr,
	&sensor_dev_attr_temp1_max_hyst.dev_attr.attr,
	&sensor_dev_attr_temp1_max.dev_attr.attr,
	NULL
};
ATTRIBUTE_GROUPS(tmp102);

/* OF table */
static const struct of_device_id tmp102_of_match[] = {
	{ .compatible = "ti,tmp102",  .data = &tmp_sensor_info_table[TMP102] },
	{ .compatible = "ti,tmp108",  .data = &tmp_sensor_info_table[TMP108] },
	{ .compatible = "ti,tmp108a", .data = &tmp_sensor_info_table[TMP108] },
	{ .compatible = "ti,tmp108b", .data = &tmp_sensor_info_table[TMP108] },
	{ .compatible = "ti,tmp108c", .data = &tmp_sensor_info_table[TMP108] },
	{ .compatible = "ti,tmp108d", .data = &tmp_sensor_info_table[TMP108] },
	{ }
};
MODULE_DEVICE_TABLE(of, tmp102_of_ids);


static int tmp102_probe(struct i2c_client *client,
				  const struct i2c_device_id *id)
{
	struct device *dev = &client->dev;
	struct device *hwmon_dev;
	struct tmp102 *tmp102;
	int status;
	const struct of_device_id *match;
	u16 conf_reg;
	u16 config;

	match = of_match_device(tmp102_of_match, dev);
	if (!match) {
		dev_err(dev, "unknown device model\n");
		return -ENODEV;
	}

	if (!i2c_check_functionality(client->adapter,
				     I2C_FUNC_SMBUS_WORD_DATA)) {
		dev_err(dev,
			"adapter doesn't support SMBus word transactions\n");
		return -ENODEV;
	}

	tmp102 = devm_kzalloc(dev, sizeof(*tmp102), GFP_KERNEL);
	if (!tmp102)
		return -ENOMEM;

	tmp102->sensor_info = devm_kzalloc(&client->dev, sizeof(struct tmp_sensor_info), GFP_KERNEL);
	if (!tmp102->sensor_info)
		return -ENOMEM;

	tmp102->sensor_info = (struct tmp_sensor_info *)match->data;

	if (tmp102->sensor_info->kind == TMP108) {
		tmp102->ops = &tmp108_ops;
	} else {
		tmp102->ops = &tmp102_ops;
	}

	i2c_set_clientdata(client, tmp102);
	tmp102->client = client;

	conf_reg = tmp102->sensor_info->conf_reg;
	config = tmp102->sensor_info->config;

	status = i2c_smbus_read_word_swapped(client, conf_reg);
	if (status < 0) {
		dev_err(dev, "error reading config register\n");
		return status;
	}
	tmp102->config_orig = status;
	status = i2c_smbus_write_word_swapped(client, conf_reg, config);
	if (status < 0) {
		dev_err(dev, "error writing config register\n");
		goto fail_restore_config;
	}
	status = i2c_smbus_read_word_swapped(client, conf_reg);
	if (status < 0) {
		dev_err(dev, "error reading config register\n");
		goto fail_restore_config;
	}
	if (tmp102->sensor_info->kind == TMP102) {
		status &= ~TMP102_CONFIG_RD_ONLY;
	}
	if (status != config) {
		dev_err(dev, "config settings did not stick\n");
		status = -ENODEV;
		goto fail_restore_config;
	}
	tmp102->last_update = jiffies - HZ;
	mutex_init(&tmp102->lock);

	hwmon_dev = hwmon_device_register_with_groups(dev, client->name,
						      tmp102, tmp102_groups);
	if (IS_ERR(hwmon_dev)) {
		dev_dbg(dev, "unable to register hwmon device\n");
		status = PTR_ERR(hwmon_dev);
		goto fail_restore_config;
	}
	tmp102->hwmon_dev = hwmon_dev;

	dev_info(dev, "initialized\n");

	return 0;

fail_restore_config:
	i2c_smbus_write_word_swapped(client, TMP102_CONF_REG,
				     tmp102->config_orig);
	return status;
}

static int tmp102_remove(struct i2c_client *client)
{
	struct tmp102 *tmp102 = i2c_get_clientdata(client);
	u16 conf_reg = tmp102->sensor_info->conf_reg;
	u16 shutdown_cmd = tmp102->sensor_info->shutdown_cmd;

	hwmon_device_unregister(tmp102->hwmon_dev);

	/* Stop monitoring if device was stopped originally */
	if (tmp102->config_orig & shutdown_cmd) {
		int config;

		config = i2c_smbus_read_word_swapped(client, conf_reg);
		if (config >= 0)
			i2c_smbus_write_word_swapped(client, conf_reg,
						     config | shutdown_cmd);
	}

	return 0;
}

#ifdef CONFIG_PM
/* Power management for tmp102 and tmp108 */
static int tmp102_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct tmp102 *tmp102 = i2c_get_clientdata(client);
	u16 conf_reg = tmp102->sensor_info->conf_reg;
	u16 shutdown_cmd = tmp102->sensor_info->shutdown_cmd;
	int config;

	config = i2c_smbus_read_word_swapped(client, conf_reg);
	if (config < 0)
		return config;

	config |= shutdown_cmd;
	return i2c_smbus_write_word_swapped(client, conf_reg, config);
}

static int tmp102_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);
	struct tmp102 *tmp102 = i2c_get_clientdata(client);
	u16 conf_reg = tmp102->sensor_info->conf_reg;
	u16 shutdown_cmd = tmp102->sensor_info->shutdown_cmd;
	int config;

	config = i2c_smbus_read_word_swapped(client, conf_reg);
	if (config < 0)
		return config;

	config &= ~(shutdown_cmd);
	return i2c_smbus_write_word_swapped(client, conf_reg, config);
}

static const struct dev_pm_ops tmp102_dev_pm_ops = {
	.suspend	= tmp102_suspend,
	.resume		= tmp102_resume,
};

#define TMP102_DEV_PM_OPS (&tmp102_dev_pm_ops)
#else
#define	TMP102_DEV_PM_OPS NULL
#endif /* CONFIG_PM */

static const struct i2c_device_id tmp102_id[] = {
	{ "tmp102",  TMP102 },
	{ "tmp108",  TMP108 },
	{ "tmp108a", TMP108 },
	{ "tmp108b", TMP108 },
	{ "tmp108c", TMP108 },
	{ "tmp108d", TMP108 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, tmp102_id);

static struct i2c_driver tmp102_driver = {
	.driver.name	= DRIVER_NAME,
	.driver.pm	= TMP102_DEV_PM_OPS,
	.driver.of_match_table = of_match_ptr(tmp102_of_match),
	.probe		= tmp102_probe,
	.remove		= tmp102_remove,
	.id_table	= tmp102_id,
};

module_i2c_driver(tmp102_driver);

MODULE_AUTHOR("Steven King <sfking@fdwdc.com>");
MODULE_DESCRIPTION("Texas Instruments TMP102 temperature sensor driver");
MODULE_LICENSE("GPL");