/*
 * drivers/input/touchscreen/hx8526.c
 *
 * Copyright (C) 2004-2012, Ambarella, Inc.
 *	Zhenwu Xue <zwxue@ambarella.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.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/i2c/hx8526.h>

#ifdef	CONFIG_DEBUG_TOUCHSCREEN
#define HX8526_DEBUG(format, arg...)	printk(format , ## arg)
#else
#define HX8526_DEBUG(format, arg...)
#endif

#define	MAX_Z		16
#define MAX_FINGERS	4

typedef enum {
	HX_X0_HI		= 0x00,
	HX_X0_LO,
	HX_Y0_HI,
	HX_Y0_LO,
	HX_X1_HI,
	HX_X1_LO,
	HX_Y1_HI,
	HX_Y1_LO,
	HX_X2_HI,
	HX_X2_LO,
	HX_Y2_HI,
	HX_Y2_LO,
	HX_X3_HI,
	HX_X3_LO,
	HX_Y3_HI,
	HX_Y3_LO,

	HX_SLEEP_OUT		= 0x81,
	HX_SENSE_ON		= 0x83,
	HX_READ_ALL_EVENT	= 0x86,
} hx8526_sub_addr_t;

#define NUM_DATA			24

struct hx8526 {
	char				phys[32];
	struct input_dev		*input;
	struct i2c_client		*client;
	struct workqueue_struct 	*workqueue;
	struct work_struct		report_worker;
	u8				reg_data[NUM_DATA];
	int				irq;
	struct hx8526_fix_data		fix;
	int				(*get_pendown_state)(void);
	void				(*clear_penirq)(void);
};

static int hx8526_reg_init(struct hx8526 *hx)
{
	u8	data[2];

	if(i2c_smbus_write_i2c_block_data(hx->client, HX_SLEEP_OUT, 0, data)) {
		printk("I2C Error: %s\n", __func__);
		return -EIO;
	}

	mdelay(1);
	data[0] = 0x02;
	if(i2c_smbus_write_i2c_block_data(hx->client, 0x42, 1, data)) {
		printk("I2C Error: %s\n", __func__);
		return -EIO;
	}

	mdelay(200);
	data[0] = 0x02;
	if(i2c_smbus_write_i2c_block_data(hx->client, 0x35, 1, data)) {
		printk("I2C Error: %s\n", __func__);
		return -EIO;
	}

	mdelay(1);
	data[0] = 0x0f;
	data[1] = 0x53;
	if(i2c_smbus_write_i2c_block_data(hx->client, 0x36, 2, data)) {
		printk("I2C Error: %s\n", __func__);
		return -EIO;
	}

	mdelay(1);
	data[0] = 0x04;
	data[1] = 0x02;
	if(i2c_smbus_write_i2c_block_data(hx->client, 0xdd, 2, data)) {
		printk("I2C Error: %s\n", __func__);
		return -EIO;
	}

	mdelay(1);
	if(i2c_smbus_write_i2c_block_data(hx->client, HX_SENSE_ON, 0, data)) {
		printk("I2C Error: %s\n", __func__);
		return -EIO;
	}

	return 0;
}

static inline int hx8526_read_all(struct hx8526 *hx)
{
	if (i2c_smbus_read_i2c_block_data(hx->client,
		HX_READ_ALL_EVENT, NUM_DATA, hx->reg_data) != NUM_DATA) {
		printk("I2C Error: %s\n", __func__);
		return -EIO;
	} else {
		return 0;
	}
}

static void hx8526_send_event(struct hx8526 *hx)
{
	struct input_dev	*input = hx->input;
	u8			i, finger;
	static int		prev_touch = 0;
	static int		curr_touch = 0;
	int			event = 0;

	switch (hx->reg_data[20]) {
	case 0xf1:
	case 0xf2:
	case 0xf3:
	case 0xf4:
		curr_touch = hx->reg_data[20] & 0x0f;
		break;

	default:
		curr_touch = 0;
		break;
	}

	/* Button Pressed */
	if (!prev_touch && curr_touch) {
		input_report_key(input, BTN_TOUCH, curr_touch);
		HX8526_DEBUG("Finger Pressed\n");
	}

	/* Button Released */
	if (prev_touch && !curr_touch) {
		event = 1;
		input_report_abs(input, ABS_PRESSURE, 0);
		input_report_key(input, BTN_TOUCH, 0);
		input_report_abs(input, ABS_MT_TOUCH_MAJOR, 0);
		input_mt_sync(input);
		HX8526_DEBUG("Finger Released\n\n\n");
	}

	for (i = 0, finger = 0; i < MAX_FINGERS; i++) {
		u8	xh, xl, yh, yl;
		u32	x, y;

		xh	= hx->reg_data[HX_X0_HI + 4 * i];
		xl	= hx->reg_data[HX_X0_LO + 4 * i];
		yh	= hx->reg_data[HX_Y0_HI + 4 * i];
		yl	= hx->reg_data[HX_Y0_LO + 4 * i];

		if (xh == 0xff && xl == 0xff && yh == 0xff && yl == 0xff) {
			continue;
		} else {
			finger++;
		}

		xh	= xh & 0x0f;
		yh	= yh & 0x0f;
		x	= (xh << 8) | xl;
		y	= (yh << 8) | yl;
		HX8526_DEBUG("Finger%d Raw: (%d, %d)\n", finger, x, y);

		if (x < hx->fix.x_min) {
			x = hx->fix.x_min;
		}
		if (x > hx->fix.x_max) {
			x = hx->fix.x_max;
		}
		if (y < hx->fix.y_min) {
			y = hx->fix.y_min;
		}
		if (y > hx->fix.y_max) {
			y = hx->fix.y_max;
		}

		if (hx->fix.x_invert) {
			x = hx->fix.x_max - x + hx->fix.x_min;
		}

		if (hx->fix.y_invert) {
			y = hx->fix.y_max - y + hx->fix.y_min;
		}

		event	= 1;
		if (finger == 1) {
			input_report_abs(input, ABS_PRESSURE, MAX_Z);
			input_report_abs(input, ABS_X, x);
			input_report_abs(input, ABS_Y, y);
		}

		input_report_abs(input, ABS_MT_TOUCH_MAJOR, MAX_Z);
		input_report_abs(input, ABS_MT_POSITION_X, x);
		input_report_abs(input, ABS_MT_POSITION_Y, y);
		input_mt_sync(input);
		HX8526_DEBUG("Finger%d Calibrated: (%d, %d)\n", finger, x, y);
	}

	if (event)
		input_sync(input);
	prev_touch = curr_touch;
}

static irqreturn_t hx8526_irq(int irq, void *handle)
{
	struct hx8526 *hx = handle;

	if (hx->get_pendown_state && !hx->get_pendown_state())
		goto hx8526_irq_exit;

	if (hx->clear_penirq) {
		hx->clear_penirq();
	}

	queue_work(hx->workqueue, &hx->report_worker);

hx8526_irq_exit:
	return IRQ_HANDLED;
}

static void hx8526_report_worker(struct work_struct *work)
{
	struct hx8526	*hx;

	hx = container_of(work, struct hx8526, report_worker);

	hx8526_read_all(hx);
	hx8526_send_event(hx);
}

static int hx8526_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
{
	struct input_dev 		*input_dev;
	struct hx8526 			*hx;
	struct hx8526_platform_data	*pdata;
	int				err;

	pdata = client->dev.platform_data;
	if (!pdata) {
		dev_err(&client->dev, "platform data is required!\n");
		return -EINVAL;
	}
	pdata->init_platform_hw();

	if (!i2c_check_functionality(client->adapter,
		I2C_FUNC_SMBUS_WRITE_BYTE_DATA | I2C_FUNC_SMBUS_WRITE_BYTE |
		I2C_FUNC_SMBUS_READ_BYTE))
		return -EIO;

	hx = kzalloc(sizeof(struct hx8526), GFP_KERNEL);
	input_dev = input_allocate_device();
	if (!hx || !input_dev) {
		err = -ENOMEM;
		goto err_free_mem;
	}

	hx->client = client;
	i2c_set_clientdata(client, hx);
	hx->input = input_dev;
	hx->get_pendown_state = pdata->get_pendown_state;
	hx->clear_penirq = pdata->clear_penirq;
	snprintf(hx->phys, sizeof(hx->phys),
		 "%s/input0", dev_name(&client->dev));

	err = hx8526_reg_init(hx);
	if (err)
		goto err_free_mem;

	hx->fix	= pdata->fix[HX8526_FAMILY_0];

	err = hx8526_read_all(hx);
	if (err)
		goto err_free_mem;

	input_dev->name = "Synaptics HX8526 Touchscreen";
	input_dev->phys = hx->phys;
	input_dev->id.bustype = BUS_I2C;
	set_bit(EV_SYN, input_dev->evbit);
	set_bit(EV_KEY, input_dev->evbit);
	set_bit(BTN_TOUCH, input_dev->keybit);
	set_bit(EV_ABS, input_dev->evbit);

	input_set_abs_params(input_dev, ABS_PRESSURE, 0, MAX_Z, 0, 0);
	input_set_abs_params(input_dev, ABS_X, hx->fix.x_min, hx->fix.x_max, 0, 0);
	input_set_abs_params(input_dev, ABS_Y, hx->fix.y_min, hx->fix.y_max, 0, 0);

	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, MAX_Z, 0, 0);
	input_set_abs_params(input_dev, ABS_MT_POSITION_X, hx->fix.x_min, hx->fix.x_max, 0, 0);
	input_set_abs_params(input_dev, ABS_MT_POSITION_Y, hx->fix.y_min, hx->fix.y_max, 0, 0);

	hx->workqueue = create_singlethread_workqueue("hx8526");
	INIT_WORK(&hx->report_worker, hx8526_report_worker);

	hx->irq = client->irq;
	err = request_irq(hx->irq, hx8526_irq, IRQF_TRIGGER_FALLING,
			client->dev.driver->name, hx);
	if (err < 0) {
		dev_err(&client->dev, "irq %d busy?\n", hx->irq);
		goto err_free_mem;
	}

	err = input_register_device(input_dev);
	if (err)
		goto err_free_irq;

	return 0;

 err_free_irq:
	free_irq(hx->irq, hx);
 err_free_mem:
	input_free_device(input_dev);
	kfree(hx);
	return err;
}

static int hx8526_remove(struct i2c_client *client)
{
	struct hx8526			*hx = i2c_get_clientdata(client);
	struct hx8526_platform_data	*pdata = client->dev.platform_data;

	pdata->exit_platform_hw();
	destroy_workqueue(hx->workqueue);
	free_irq(hx->irq, hx);
	input_unregister_device(hx->input);
	kfree(hx);

	return 0;
}

static struct i2c_device_id hx8526_idtable[] = {
	{ "hx8526", 0 },
	{ }
};

MODULE_DEVICE_TABLE(i2c, hx8526_idtable);

static struct i2c_driver hx8526_driver = {
	.driver = {
		.owner	= THIS_MODULE,
		.name	= "hx8526"
	},
	.id_table	= hx8526_idtable,
	.probe		= hx8526_probe,
	.remove		= hx8526_remove,
};

static int __init hx8526_init(void)
{
	return i2c_add_driver(&hx8526_driver);
}

static void __exit hx8526_exit(void)
{
	i2c_del_driver(&hx8526_driver);
}

module_init(hx8526_init);
module_exit(hx8526_exit);

MODULE_AUTHOR("Zhenwu Xue <zwxue@ambarella.com>");
MODULE_DESCRIPTION("HiMax HX8526 TouchScreen Driver");
MODULE_LICENSE("GPL");