/*
 * kxsd9.c - KXSD9 Tri-axis Accelerometer hardware monitoring driver
 *
 * Copyright (c) 2008-2009 Samsung Eletronics
 * Authors:
 *	Kim Kyuwon <q1.kim@samsung.com>
 *	Kyungmin Park <kyungmin.park@samsung.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Datasheet: http://www.kionix.com/sensors/accelerometer-products.html
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/gpio.h>
#include <linux/input-polldev.h>
#include <linux/kxsd9.h>

#define KXSD9_XOUT_H		0x00
#define KXSD9_XOUT_L		0x01
#define KXSD9_YOUT_H		0x02
#define KXSD9_YOUT_L		0x03
#define KXSD9_ZOUT_H		0x04
#define KXSD9_ZOUT_L		0x05
#define KXSD9_AUXOUT_H		0x06
#define KXSD9_AUXOUT_L		0x07
#define KXSD9_RESET_WRITE	0x0A
#define KXSD9_CTRL_REGC		0x0C
#define KXSD9_CTRL_REGB		0x0D
#define KXSD9_CTRL_REGA		0x0E

#define KXSD9_RESET_KEY		0xCA

#define KXSD9_REGC_LP2		(1 << 7)
#define KXSD9_REGC_LP1		(1 << 6)
#define KXSD9_REGC_LP0		(1 << 5)
#define KXSD9_REGC_MOTLEV	(1 << 4)
#define KXSD9_REGC_MOTLAT	(1 << 3)
#define KXSD9_REGC_FS1		(1 << 1)
#define KXSD9_REGC_FS0		(1 << 0)

/*
 * 'CLKhld=1' makes KXSD9 hold SCL low during A/D conversions. This may
 * affect the operation of other I2C devices. Thus, I don't think it is
 * good to set CLKhld to 1.
 */
#define KXSD9_REGB_CLKHLD	(1 << 7)
#define KXSD9_REGB_ENABLE	(1 << 6)
#define KXSD9_REGB_MOTIEN	(1 << 2)

#define KXSD9_REGA_MOTI		(1 << 1)

/*
 * Default Full Scale Range: +/-2 g
 * 12-bit Sensitivity : 819 counts/g
 */
#define KXSD9_RANGE_DEFAULT	(KXSD9_REGC_FS1 | KXSD9_REGC_FS0)

/* Default Motion Wake Up Acceleration Threshold: +/-1 g */
#define KXSD9_THRESHOLD_DEFAULT	(KXSD9_REGC_MOTLEV | KXSD9_RANGE_DEFAULT)

/* Default Operational Bandwidth (Filter Corner Frequency): 50Mhz */
#define KXSD9_BW_DEFAULT	(KXSD9_REGC_LP0 | KXSD9_REGC_LP1 |\
				KXSD9_REGC_LP2)

#define MAX_12BIT		((1 << 12) - 1)
#define POLL_INTERVAL_DEFAULT	100

enum input_type {
	INPUT_NONE,
	INPUT_POLL,	/* Polling */
	INPUT_INT,	/* Interrupt */
};

struct kxsd9_sensor {
	struct i2c_client			*client;
	struct device				*dev;
	struct input_polled_dev			*ipdev;
	struct input_dev			*idev;
	struct kxsd9_sensor_platform_data	*pdata;
	struct work_struct			work;
	struct mutex				lock;

	enum input_type				type;
};

static int kxsd9_write_reg(struct i2c_client *client, u8 reg, u8 val)
{
	int ret = i2c_smbus_write_byte_data(client, reg, val);

	if (ret < 0)
		dev_err(&client->dev, "%s: reg 0x%x, val 0x%x, err %d\n",
						__func__, reg, val, ret);
	return ret;
}

static int kxsd9_read_reg(struct i2c_client *client, u8 reg)
{
	int ret = i2c_smbus_read_byte_data(client, reg);

	if (ret < 0)
		dev_err(&client->dev, "%s, reg 0x%x, err %d\n",
						__func__, reg, ret);
	return ret;
}

static void kxsd9_read_xyz(struct i2c_client *client,
						s16 *x, s16 *y, s16 *z)
{
	*x = kxsd9_read_reg(client, KXSD9_XOUT_H) << 4 |
				kxsd9_read_reg(client, KXSD9_XOUT_L) >> 4;

	*y = kxsd9_read_reg(client, KXSD9_YOUT_H) << 4 |
				kxsd9_read_reg(client, KXSD9_YOUT_L) >> 4;

	*z = kxsd9_read_reg(client, KXSD9_ZOUT_H) << 4 |
				kxsd9_read_reg(client, KXSD9_ZOUT_L) >> 4;
}

static void kxsd9_set_bits(struct i2c_client *client, u8 reg, u8 bits, int on)
{
	struct kxsd9_sensor *sensor = i2c_get_clientdata(client);
	int val;

	mutex_lock(&sensor->lock);
	if (on)
		val = kxsd9_read_reg(client, reg) | bits;
	else
		val = kxsd9_read_reg(client, reg) & ~bits;
	kxsd9_write_reg(client, reg, (u8)val);
	mutex_unlock(&sensor->lock);
}

static int kxsd9_read_bit(struct i2c_client *client, u8 reg, u8 bit)
{
	struct kxsd9_sensor *sensor = i2c_get_clientdata(client);
	int val;

	mutex_lock(&sensor->lock);
	val = kxsd9_read_reg(client, reg) & bit;
	mutex_unlock(&sensor->lock);

	return !!val;
}

static ssize_t kxsd9_show_xyz(struct device *dev,
				struct device_attribute *attr, char *buf)
{
	struct kxsd9_sensor *sensor = dev_get_drvdata(dev);
	s16 x, y, z;

	x = y = z = 0;
	kxsd9_read_xyz(sensor->client, &x, &y, &z);

	return sprintf(buf, "%d, %d, %d\n", x, y, z);
}
static SENSOR_DEVICE_ATTR(xyz, S_IRUGO, kxsd9_show_xyz, NULL, 0);

#define KXSD9_SET_REGISTER(_name, _reg)					\
static ssize_t kxsd9_store_##_name(struct device *dev,			\
	struct device_attribute *attr, const char *buf, size_t count)	\
{									\
	struct kxsd9_sensor *sensor = dev_get_drvdata(dev);		\
	unsigned long val;						\
	int ret = strict_strtoul(buf, 16, &val);			\
	if (ret)							\
		return ret;						\
	mutex_lock(&sensor->lock);					\
	kxsd9_write_reg(sensor->client, KXSD9_CTRL_##_reg, (u8) val);	\
	mutex_unlock(&sensor->lock);					\
	return count;							\
}									\
static SENSOR_DEVICE_ATTR(_name, S_IRUGO | S_IWUSR,			\
					NULL, kxsd9_store_##_name, 0);

KXSD9_SET_REGISTER(regc, REGC);
KXSD9_SET_REGISTER(regb, REGB);

#define KXSD9_CONTROL_BIT(_reg, _bit)					\
static ssize_t kxsd9_show_##_bit(struct device *dev,			\
			struct device_attribute *attr, char *buf)	\
{									\
	struct kxsd9_sensor *sensor = dev_get_drvdata(dev);		\
	int ret = kxsd9_read_bit(sensor->client, KXSD9_CTRL_##_reg,	\
						KXSD9_##_reg##_##_bit);	\
	return sprintf(buf, "%d\n", ret);				\
}									\
static ssize_t kxsd9_store_##_bit(struct device *dev,			\
	struct device_attribute *attr, const char *buf, size_t count)	\
{									\
	struct kxsd9_sensor *sensor = dev_get_drvdata(dev);		\
	unsigned long val;						\
	int ret = strict_strtoul(buf, 10, &val);			\
	if (ret)							\
		return ret;						\
	kxsd9_set_bits(sensor->client, KXSD9_CTRL_##_reg,		\
					KXSD9_##_reg##_##_bit, val);	\
	return count;							\
}									\
static SENSOR_DEVICE_ATTR(_bit, S_IRUGO | S_IWUSR,			\
			kxsd9_show_##_bit, kxsd9_store_##_bit, 0);

KXSD9_CONTROL_BIT(REGB, MOTIEN);
KXSD9_CONTROL_BIT(REGB, ENABLE);

static struct attribute *kxsd9_attributes[] = {
	&sensor_dev_attr_xyz.dev_attr.attr,
	&sensor_dev_attr_regc.dev_attr.attr,
	&sensor_dev_attr_regb.dev_attr.attr,
	&sensor_dev_attr_MOTIEN.dev_attr.attr,
	&sensor_dev_attr_ENABLE.dev_attr.attr,
	NULL
};

static const struct attribute_group kxsd9_group = {
	.attrs	= kxsd9_attributes,
};

static void kxsd9_report_abs(struct kxsd9_sensor *sensor,
						struct input_dev *idev)
{
	s16 x, y, z;

	x = y = z = 0;

	mutex_lock(&sensor->lock);

	kxsd9_read_xyz(sensor->client, &x, &y, &z);

	input_report_abs(idev, ABS_X, x);
	input_report_abs(idev, ABS_Y, y);
	input_report_abs(idev, ABS_Z, z);

	input_sync(idev);

	mutex_unlock(&sensor->lock);
}

static void kxsd9_work(struct work_struct *work)
{
	struct kxsd9_sensor *sensor =
			container_of(work, struct kxsd9_sensor, work);
	s16 x, y, z;
	int ret;

	kxsd9_read_xyz(sensor->client, &x, &y, &z);

	/* The MOT pin can be cleared by reading CTRL_REGA. */
	ret = kxsd9_read_bit(sensor->client, KXSD9_CTRL_REGA, KXSD9_REGA_MOTI);
	if (!ret)
		dev_err(&sensor->client->dev, "MOTI bit is not set\n");

	/*
	 * To re-enter low power motion wakeup mode, reset the MOTIen bit to 1
	 */
	kxsd9_set_bits(sensor->client, KXSD9_CTRL_REGB, KXSD9_REGB_MOTIEN, 1);

	kxsd9_report_abs(sensor, sensor->idev);

	enable_irq(sensor->client->irq);
}

static irqreturn_t kxsd9_irq(int irq, void *dev_id)
{
	struct kxsd9_sensor *sensor = (struct kxsd9_sensor *) dev_id;

	if (!work_pending(&sensor->work)) {
		disable_irq_nosync(irq);
		schedule_work(&sensor->work);
	} else
		dev_err(&sensor->client->dev, "work_pending\n");

	return IRQ_HANDLED;
}

static void kxsd9_initialize(struct kxsd9_sensor *sensor)
{
	/*
	 * The reset time of the KXSD9 accelerometer takes about 11 msec.
	 * So write proper register values at first instead of resetting kxsd9.
	 */

	kxsd9_write_reg(sensor->client, KXSD9_CTRL_REGC,
		KXSD9_BW_DEFAULT | KXSD9_THRESHOLD_DEFAULT
		| KXSD9_REGC_MOTLAT);
	kxsd9_write_reg(sensor->client, KXSD9_CTRL_REGB,
		KXSD9_REGB_ENABLE | KXSD9_REGB_MOTIEN);
}

static void kxsd9_ipdev_poll(struct input_polled_dev *dev)
{
	struct kxsd9_sensor *sensor = dev->private;
	struct input_dev *idev = dev->input;

	kxsd9_report_abs(sensor, idev);
}

static void kxsd9_initialize_input_device(struct input_dev *idev,
						struct i2c_client *client)
{
	idev->name = "KXSD9 Accel";
	idev->id.bustype = BUS_I2C;
	idev->dev.parent = &client->dev;

	/* Let's use idev->open, idev->close later */

	input_set_abs_params(idev, ABS_X, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(idev, ABS_Y, 0, MAX_12BIT, 0, 0);
	input_set_abs_params(idev, ABS_Z, 0, MAX_12BIT, 0, 0);

	set_bit(EV_ABS, idev->evbit);
}

static int kxsd9_register_polled_input_device(struct kxsd9_sensor *sensor)
{
	struct kxsd9_sensor_platform_data *pdata = sensor->pdata;
	struct i2c_client *client = sensor->client;
	struct input_polled_dev *ipdev;
	int ret;

	ipdev = sensor->ipdev = input_allocate_polled_device();
	if (!ipdev) {
		dev_err(&client->dev, "fail: allocate poll input device\n");
		ret = -ENOMEM;
		goto failed_quit_polled_input;
	}

	ipdev->private = sensor;
	ipdev->poll = kxsd9_ipdev_poll;
	ipdev->poll_interval = pdata->poll_interval;

	kxsd9_initialize_input_device(ipdev->input, client);

	ret = input_register_polled_device(ipdev);
	if (ret) {
		dev_err(&client->dev, "fail: register to poll input device\n");
		goto failed_free_polled_input;
	}

	sensor->type = INPUT_POLL;

	return 0;

failed_free_polled_input:
	input_free_polled_device(sensor->ipdev);
failed_quit_polled_input:

	return ret;
}

static void kxsd9_unregister_polled_input_devce(struct kxsd9_sensor *sensor)
{
	input_unregister_polled_device(sensor->ipdev);
	input_free_polled_device(sensor->ipdev);

	sensor->type = INPUT_NONE;
}

static int kxsd9_register_interrupt_input_device(struct kxsd9_sensor *sensor)
{
	struct i2c_client *client = sensor->client;
	int ret;

	sensor->idev = input_allocate_device();
	if (!sensor->idev) {
		dev_err(&client->dev, "fail: allocate input device\n");
		ret = -ENOMEM;
		goto failed_quit_interrupt_input;
	}

	kxsd9_initialize_input_device(sensor->idev, client);

	ret = input_register_device(sensor->idev);
	if (ret) {
		dev_err(&client->dev, "fail: register to input device\n");
		goto failed_free_interrupt_input;
	}

	ret = request_irq(client->irq, kxsd9_irq, IRQF_TRIGGER_HIGH,
						"KXSD9 Accel", sensor);
	if (ret) {
		dev_err(&client->dev, "can't get IRQ %d, ret %d\n",
						client->irq, ret);
		goto failed_unregister_input;
	}

	sensor->type = INPUT_INT;

	return 0;

failed_unregister_input:
	input_unregister_device(sensor->idev);
failed_free_interrupt_input:
	input_free_device(sensor->idev);
failed_quit_interrupt_input:

	return ret;
}

static void kxsd9_unregister_interrupt_input_devce(struct kxsd9_sensor *sensor)
{
	struct i2c_client *client = sensor->client;

	free_irq(client->irq, sensor);
	input_unregister_device(sensor->idev);
	input_free_device(sensor->idev);

	sensor->type = INPUT_NONE;
 }

static int kxsd9_unregister_input_device(struct kxsd9_sensor *sensor)
{
	struct i2c_client *client = sensor->client;

	if (sensor->type == INPUT_INT)
		kxsd9_unregister_interrupt_input_devce(sensor);
	else if (sensor->type == INPUT_POLL)
		kxsd9_unregister_polled_input_devce(sensor);
	else
		dev_err(&client->dev, "No input device to unregister\n");

	return 0;
}

static int __devinit kxsd9_probe(struct i2c_client *client,
					const struct i2c_device_id *id)
{
	struct kxsd9_sensor *sensor;
	int ret;

	sensor = kzalloc(sizeof(struct kxsd9_sensor), GFP_KERNEL);
	if (!sensor) {
		dev_err(&client->dev, "failed to allocate driver data\n");
		return -ENOMEM;
	}

	sensor->client = client;
	sensor->pdata = client->dev.platform_data;
	i2c_set_clientdata(client, sensor);

	/* Detect KXSD9 */
	ret = kxsd9_read_reg(client, KXSD9_CTRL_REGC);
	if (ret < 0) {
		dev_err(&client->dev, "failed to detect device\n");
		goto failed_free;
	} else
		dev_info(&client->dev, "successed to detect device\n");

	/* Initialize KXSD9 */
	kxsd9_initialize(sensor);

	INIT_WORK(&sensor->work, kxsd9_work);
	mutex_init(&sensor->lock);

	ret = sysfs_create_group(&client->dev.kobj, &kxsd9_group);
	if (ret) {
		dev_err(&client->dev, "failed to create kxsd9 attribute group");
		goto failed_free;
	}

	sensor->dev = hwmon_device_register(&client->dev);
	if (IS_ERR(sensor->dev)) {
		dev_err(&client->dev, "failed to register to hwmon device");
		ret = PTR_ERR(sensor->dev);
		goto failed_remove_sysfs;
	}

	if (client->irq > 0)
		ret = kxsd9_register_interrupt_input_device(sensor);
	else
		ret = kxsd9_register_polled_input_device(sensor);
	if (ret)
		goto failed_unregister_hwmon;

	return 0;

failed_unregister_hwmon:
	hwmon_device_unregister(&client->dev);
failed_remove_sysfs:
	sysfs_remove_group(&client->dev.kobj, &kxsd9_group);
failed_free:
	i2c_set_clientdata(client, NULL);
	kfree(sensor);

	return ret;
}

static int __devexit kxsd9_remove(struct i2c_client *client)
{
	struct kxsd9_sensor *sensor = i2c_get_clientdata(client);

	kxsd9_set_bits(client, KXSD9_CTRL_REGB, KXSD9_REGB_ENABLE, 0);
	kxsd9_unregister_input_device(sensor);
	hwmon_device_unregister(&client->dev);
	sysfs_remove_group(&client->dev.kobj, &kxsd9_group);
	i2c_set_clientdata(client, NULL);
	kfree(sensor);

	return 0;
}

static int kxsd9_suspend(struct i2c_client *client, pm_message_t mesg)
{
	disable_irq(client->irq);
	kxsd9_set_bits(client, KXSD9_CTRL_REGB, KXSD9_REGB_ENABLE, 0);

	return 0;
}

static int kxsd9_resume(struct i2c_client *client)
{
	kxsd9_set_bits(client, KXSD9_CTRL_REGB, KXSD9_REGB_ENABLE, 1);
	enable_irq(client->irq);

	return 0;
}

static const struct i2c_device_id kxsd9_id[] = {
	{ "KXSD9", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, kxsd9_id);

static struct i2c_driver kxsd9_i2c_driver = {
	.class		= I2C_CLASS_HWMON,
	.driver	= {
		.name	= "KXSD9",
	},
	.probe		= kxsd9_probe,
	.remove		= __devexit_p(kxsd9_remove),
	.suspend	= kxsd9_suspend,
	.resume		= kxsd9_resume,
	.id_table	= kxsd9_id,
};

static int __init kxsd9_init(void)
{
	return i2c_add_driver(&kxsd9_i2c_driver);
}
module_init(kxsd9_init);

static void __exit kxsd9_exit(void)
{
	i2c_del_driver(&kxsd9_i2c_driver);
}
module_exit(kxsd9_exit);

MODULE_AUTHOR("Kim Kyuwon <q1.kim@samsung.com>");
MODULE_DESCRIPTION("KXSD9 hardware monitoring driver");
MODULE_LICENSE("GPL v2");