/*
 * MPU3050 Tri-axis gyroscope driver
 *
 * Copyright (C) 2011 Wistron Co.Ltd
 * Joseph Lai <joseph_lai@wistron.com>
 *
 * Trimmed down by Alan Cox <alan@linux.intel.com> to produce this version
 *
 * This is a 'lite' version of the driver, while we consider the right way
 * to present the other features to user space. In particular it requires the
 * device has an IRQ, and it only provides an input interface, so is not much
 * use for device orientation. A fuller version is available from the Meego
 * tree.
 *
 * This program is based on bma023.c.
 *
 * 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; version 2 of the License.
 *
 * 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.,
 * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/platform_device.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/pm_runtime.h>

#define MPU3050_CHIP_ID_REG	0x00
#define MPU3050_CHIP_ID		0x69
#define MPU3050_XOUT_H		0x1D
#define MPU3050_PWR_MGM		0x3E
#define MPU3050_PWR_MGM_POS	6
#define MPU3050_PWR_MGM_MASK	0x40

#define MPU3050_AUTO_DELAY	1000

#define MPU3050_MIN_VALUE	-32768
#define MPU3050_MAX_VALUE	32767

struct axis_data {
	s16 x;
	s16 y;
	s16 z;
};

struct mpu3050_sensor {
	struct i2c_client *client;
	struct device *dev;
	struct input_dev *idev;
};

/**
 *	mpu3050_xyz_read_reg	-	read the axes values
 *	@buffer: provide register addr and get register
 *	@length: length of register
 *
 *	Reads the register values in one transaction or returns a negative
 *	error code on failure.
 */
static int mpu3050_xyz_read_reg(struct i2c_client *client,
			       u8 *buffer, int length)
{
	/*
	 * Annoying we can't make this const because the i2c layer doesn't
	 * declare input buffers const.
	 */
	char cmd = MPU3050_XOUT_H;
	struct i2c_msg msg[] = {
		{
			.addr = client->addr,
			.flags = 0,
			.len = 1,
			.buf = &cmd,
		},
		{
			.addr = client->addr,
			.flags = I2C_M_RD,
			.len = length,
			.buf = buffer,
		},
	};

	return i2c_transfer(client->adapter, msg, 2);
}

/**
 *	mpu3050_read_xyz	-	get co-ordinates from device
 *	@client: i2c address of sensor
 *	@coords: co-ordinates to update
 *
 *	Return the converted X Y and Z co-ordinates from the sensor device
 */
static void mpu3050_read_xyz(struct i2c_client *client,
			     struct axis_data *coords)
{
	u16 buffer[3];

	mpu3050_xyz_read_reg(client, (u8 *)buffer, 6);
	coords->x = be16_to_cpu(buffer[0]);
	coords->y = be16_to_cpu(buffer[1]);
	coords->z = be16_to_cpu(buffer[2]);
	dev_dbg(&client->dev, "%s: x %d, y %d, z %d\n", __func__,
					coords->x, coords->y, coords->z);
}

/**
 *	mpu3050_set_power_mode	-	set the power mode
 *	@client: i2c client for the sensor
 *	@val: value to switch on/off of power, 1: normal power, 0: low power
 *
 *	Put device to normal-power mode or low-power mode.
 */
static void mpu3050_set_power_mode(struct i2c_client *client, u8 val)
{
	u8 value;

	value = i2c_smbus_read_byte_data(client, MPU3050_PWR_MGM);
	value = (value & ~MPU3050_PWR_MGM_MASK) |
		(((val << MPU3050_PWR_MGM_POS) & MPU3050_PWR_MGM_MASK) ^
		 MPU3050_PWR_MGM_MASK);
	i2c_smbus_write_byte_data(client, MPU3050_PWR_MGM, value);
}

/**
 *	mpu3050_input_open	-	called on input event open
 *	@input: input dev of opened device
 *
 *	The input layer calls this function when input event is opened. The
 *	function will push the device to resume. Then, the device is ready
 *	to provide data.
 */
static int mpu3050_input_open(struct input_dev *input)
{
	struct mpu3050_sensor *sensor = input_get_drvdata(input);

	pm_runtime_get(sensor->dev);

	return 0;
}

/**
 *	mpu3050_input_close	-	called on input event close
 *	@input: input dev of closed device
 *
 *	The input layer calls this function when input event is closed. The
 *	function will push the device to suspend.
 */
static void mpu3050_input_close(struct input_dev *input)
{
	struct mpu3050_sensor *sensor = input_get_drvdata(input);

	pm_runtime_put(sensor->dev);
}

/**
 *	mpu3050_interrupt_thread	-	handle an IRQ
 *	@irq: interrupt numner
 *	@data: the sensor
 *
 *	Called by the kernel single threaded after an interrupt occurs. Read
 *	the sensor data and generate an input event for it.
 */
static irqreturn_t mpu3050_interrupt_thread(int irq, void *data)
{
	struct mpu3050_sensor *sensor = data;
	struct axis_data axis;

	mpu3050_read_xyz(sensor->client, &axis);

	input_report_abs(sensor->idev, ABS_X, axis.x);
	input_report_abs(sensor->idev, ABS_Y, axis.y);
	input_report_abs(sensor->idev, ABS_Z, axis.z);
	input_sync(sensor->idev);

	return IRQ_HANDLED;
}

/**
 *	mpu3050_probe	-	device detection callback
 *	@client: i2c client of found device
 *	@id: id match information
 *
 *	The I2C layer calls us when it believes a sensor is present at this
 *	address. Probe to see if this is correct and to validate the device.
 *
 *	If present install the relevant sysfs interfaces and input device.
 */
static int __devinit mpu3050_probe(struct i2c_client *client,
				   const struct i2c_device_id *id)
{
	struct mpu3050_sensor *sensor;
	struct input_dev *idev;
	int ret;
	int error;

	sensor = kzalloc(sizeof(struct mpu3050_sensor), GFP_KERNEL);
	idev = input_allocate_device();
	if (!sensor || !idev) {
		dev_err(&client->dev, "failed to allocate driver data\n");
		error = -ENOMEM;
		goto err_free_mem;
	}

	sensor->client = client;
	sensor->dev = &client->dev;
	sensor->idev = idev;

	mpu3050_set_power_mode(client, 1);
	msleep(10);

	ret = i2c_smbus_read_byte_data(client, MPU3050_CHIP_ID_REG);
	if (ret < 0) {
		dev_err(&client->dev, "failed to detect device\n");
		error = -ENXIO;
		goto err_free_mem;
	}

	if (ret != MPU3050_CHIP_ID) {
		dev_err(&client->dev, "unsupported chip id\n");
		error = -ENXIO;
		goto err_free_mem;
	}

	idev->name = "MPU3050";
	idev->id.bustype = BUS_I2C;
	idev->dev.parent = &client->dev;

	idev->open = mpu3050_input_open;
	idev->close = mpu3050_input_close;

	__set_bit(EV_ABS, idev->evbit);
	input_set_abs_params(idev, ABS_X,
			     MPU3050_MIN_VALUE, MPU3050_MAX_VALUE, 0, 0);
	input_set_abs_params(idev, ABS_Y,
			     MPU3050_MIN_VALUE, MPU3050_MAX_VALUE, 0, 0);
	input_set_abs_params(idev, ABS_Z,
			     MPU3050_MIN_VALUE, MPU3050_MAX_VALUE, 0, 0);

	input_set_drvdata(idev, sensor);

	pm_runtime_set_active(&client->dev);

	error = request_threaded_irq(client->irq,
				     NULL, mpu3050_interrupt_thread,
				     IRQF_TRIGGER_RISING,
				     "mpu_int", sensor);
	if (error) {
		dev_err(&client->dev,
			"can't get IRQ %d, error %d\n", client->irq, error);
		goto err_pm_set_suspended;
	}

	error = input_register_device(idev);
	if (error) {
		dev_err(&client->dev, "failed to register input device\n");
		goto err_free_irq;
	}

	pm_runtime_enable(&client->dev);
	pm_runtime_set_autosuspend_delay(&client->dev, MPU3050_AUTO_DELAY);

	return 0;

err_free_irq:
	free_irq(client->irq, sensor);
err_pm_set_suspended:
	pm_runtime_set_suspended(&client->dev);
err_free_mem:
	input_unregister_device(idev);
	kfree(sensor);
	return error;
}

/**
 *	mpu3050_remove	-	remove a sensor
 *	@client: i2c client of sensor being removed
 *
 *	Our sensor is going away, clean up the resources.
 */
static int __devexit mpu3050_remove(struct i2c_client *client)
{
	struct mpu3050_sensor *sensor = i2c_get_clientdata(client);

	pm_runtime_disable(&client->dev);
	pm_runtime_set_suspended(&client->dev);

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

	return 0;
}

#ifdef CONFIG_PM
/**
 *	mpu3050_suspend		-	called on device suspend
 *	@dev: device being suspended
 *
 *	Put the device into sleep mode before we suspend the machine.
 */
static int mpu3050_suspend(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);

	mpu3050_set_power_mode(client, 0);

	return 0;
}

/**
 *	mpu3050_resume		-	called on device resume
 *	@dev: device being resumed
 *
 *	Put the device into powered mode on resume.
 */
static int mpu3050_resume(struct device *dev)
{
	struct i2c_client *client = to_i2c_client(dev);

	mpu3050_set_power_mode(client, 1);
	msleep(100);  /* wait for gyro chip resume */

	return 0;
}
#endif

static UNIVERSAL_DEV_PM_OPS(mpu3050_pm, mpu3050_suspend, mpu3050_resume, NULL);

static const struct i2c_device_id mpu3050_ids[] = {
	{ "mpu3050", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, mpu3050_ids);

static struct i2c_driver mpu3050_i2c_driver = {
	.driver	= {
		.name	= "mpu3050",
		.owner	= THIS_MODULE,
		.pm	= &mpu3050_pm,
	},
	.probe		= mpu3050_probe,
	.remove		= __devexit_p(mpu3050_remove),
	.id_table	= mpu3050_ids,
};

static int __init mpu3050_init(void)
{
	return i2c_add_driver(&mpu3050_i2c_driver);
}
module_init(mpu3050_init);

static void __exit mpu3050_exit(void)
{
	i2c_del_driver(&mpu3050_i2c_driver);
}
module_exit(mpu3050_exit);

MODULE_AUTHOR("Wistron Corp.");
MODULE_DESCRIPTION("MPU3050 Tri-axis gyroscope driver");
MODULE_LICENSE("GPL");