/* drivers/input/misc/gp2ap110s.c - GP2AP110S00F v1.0.1 proximity sensor driver
 *
 * Copyright (C) 2018 Sharp Corporation
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/input.h>
#include <linux/delay.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/irq.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/wakelock.h>
#include <linux/of_gpio.h>
#include <linux/fs.h>
#include <asm/segment.h>
#include <asm/uaccess.h>
#include <linux/sensor/sensors_core.h>
#include "gp2ap110s.h"

#define DEVICE_NAME              "GP2AP110S"
#define CHIP_DEV_VENDOR 	     "SHARP"
#define MODULE_NAME     	     "proximity_sensor"
#define PROX_READ_NUM   	     40 
#define OFFSET_TUNE_ADC          100
#define PROX_AUTO_OFFSET         0x05
#define MAX_RETRY_TUNE_ADC_COUNT 3
#define FORCE_CLOSE_OFFSET_THD   127
#define FORCE_CLOSE_HIGH_THD     750
#define FORCE_CLOSE_LOW_THD      600

// Settings 1 (Default)
#define LED_REG_VAL_1  0x14 // 10 mA
#define HIGH_THD_1     370
#define LOW_THD_1      260

// (If proximity close detection fails during LCIA test)
#define LED_REG_VAL_2  0x24 // 20 mA
#define HIGH_THD_2	   200
#define LOW_THD_2      170

#define PROX_SETTINGS_FILE_PATH    "/efs/FactoryApp/prox_settings"

static int gp2ap_i2c_read(u8 reg, unsigned char *rbuf, int len, struct i2c_client *client)
{
	int               err = -1;
	struct i2c_msg    i2cMsg[2];
	uint8_t           buff;

	if (client == NULL)
		return -ENODEV;

	i2cMsg[0].addr = client->addr;
	i2cMsg[0].flags = 0;
	i2cMsg[0].len = 1;
	i2cMsg[0].buf = &buff;

	buff = reg;

	i2cMsg[1].addr = client->addr;
	i2cMsg[1].flags = I2C_M_RD;
	i2cMsg[1].len = len;
	i2cMsg[1].buf = rbuf;

	err = i2c_transfer(client->adapter, &i2cMsg[0], 2);
	if (err < 0) {
		SENSOR_ERR("i2c transfer error(%d)!!\n", err);
	}

	return err;
}

static int gp2ap_i2c_write(u8 reg, u8 wbuf, struct i2c_client *client)
{
	int               err = 0;
	struct i2c_msg    i2cMsg;
	unsigned char     buff[2];
	int               retry = 10;

	if (client == NULL || (!client->adapter))
		return -ENODEV;

	buff[0] = reg;
	buff[1] = wbuf;

	i2cMsg.addr = client->addr;
	i2cMsg.flags = 0;
	i2cMsg.len = 2;
	i2cMsg.buf = buff;

	while(retry--) {
		err = i2c_transfer(client->adapter, &i2cMsg, 1);
		SENSOR_INFO("0x%x, 0x%x\n", reg, wbuf);
		if (err >= 0)
			return 0;
	}

	SENSOR_ERR("i2c transfer error(%d)!!\n", err);

	return err;
}

static int gp2ap_write_settings(struct gp2ap_data *data)
{
	struct file *filp = NULL;
	mm_segment_t old_fs;
	int ret = -1;
	char tmp_buf[14] = "";
	char *buf = NULL;

	int led_reg_val, ps_high_th, ps_low_th;

	if (data->prox_settings == 1) {
			led_reg_val = data->led_reg_val_1;
			ps_high_th = data->ps_high_th_1;
			ps_low_th = data->ps_low_th_1;
	} else if (data->prox_settings == 2) {
			led_reg_val = data->led_reg_val_2;
			ps_high_th = data->ps_high_th_2;
			ps_low_th = data->ps_low_th_2;
			data->min_close_offset = MAX_OFFSET;
	}
	
	data->led_reg_val = led_reg_val;

	data->bytes = snprintf(tmp_buf, PAGE_SIZE, "%d,%d,%d",
					led_reg_val, ps_high_th, ps_low_th);

	buf = kzalloc(sizeof(char) * (data->bytes), GFP_KERNEL);
	data->bytes = snprintf(buf, PAGE_SIZE, "%d,%d,%d",
					led_reg_val, ps_high_th, ps_low_th);

	SENSOR_INFO("tmp_buf=%s, buf=%s, bytes=%d\n", tmp_buf, buf, data->bytes);

	old_fs = get_fs();
	set_fs(KERNEL_DS);

	filp = filp_open(PROX_SETTINGS_FILE_PATH,
			O_CREAT | O_TRUNC | O_RDWR | O_SYNC, 0666);

	if (filp == NULL) {
		SENSOR_INFO("filp is NULL\n");
		return ret;
	}

	if (IS_ERR(filp)) {
		set_fs(old_fs);
		ret = PTR_ERR(filp);
		SENSOR_ERR("Can't open prox settings file (%d)\n", ret);
		return ret;
	}

	ret = vfs_write(filp, buf, data->bytes, &filp->f_pos);
	if (ret != data->bytes) {
		SENSOR_ERR("Can't write the prox settings data to file, ret=%d\n", ret);
		ret = -EIO;
	}

	filp_close(filp, current->files);
	set_fs(old_fs);

	msleep(150);

	SENSOR_INFO("Done, ret=%d\n", ret);

	return ret;
}

static int gp2ap_read_settings(struct gp2ap_data *data)
{
	struct file *filp = NULL;
	mm_segment_t old_fs;
	int ret = -1;

	char *buf = kzalloc(sizeof(char) * (data->bytes), GFP_KERNEL);

	old_fs = get_fs();
	set_fs(KERNEL_DS);

	filp = filp_open(PROX_SETTINGS_FILE_PATH, O_RDONLY, 0);
	if (IS_ERR(filp)) {
		set_fs(old_fs);
		ret = PTR_ERR(filp);
		SENSOR_ERR("Can't open prox settings file (%d)\n", ret);
		return ret;
	}

	ret = vfs_read(filp, buf, data->bytes, &filp->f_pos);
	if (ret <= 0) {
		SENSOR_ERR("Can't read the prox settings data from file, bytes=%d\n", ret);
		ret = -EIO;
	} else {
		sscanf(buf, "%d,%d,%d", &data->led_reg_val, &data->ps_high_th, &data->ps_low_th);
		SENSOR_INFO("led_reg_val=%d, ps_high_th=%d, ps_low_th=%d\n",
							data->led_reg_val, data->ps_high_th, data->ps_low_th);
	}

	SENSOR_INFO("buf=%s\n", buf);

	filp_close(filp, current->files);
	set_fs(old_fs);

	SENSOR_INFO("Done, ret=%d\n", ret);

	return ret;
}

static void gp2ap_StartMeasurement(struct gp2ap_data *data)
{
	u8    wdata;
	wdata = 0xA0;

	gp2ap_i2c_write(REG_COM1, wdata, data->client);
}

static void gp2ap_StopMeasurement(struct gp2ap_data *data)
{
	u8    wdata;
	wdata = 0x00;

	gp2ap_i2c_write(REG_COM1, wdata, data->client);
	gp2ap_i2c_write(REG_COM2, wdata, data->client);
}

static int gp2ap_get_proximity_adc(struct gp2ap_data *data)
{
	u8 value[2];
	int ret;

	ret = gp2ap_i2c_read(REG_D0_LSB, value, sizeof(value), data->client);
	if (ret < 0) {
		SENSOR_ERR("fail, ret=%d\n", ret);
		return ret;
	}

	return (value[0] | (value[1] << 8));
}

static void gp2ap_InitData(struct gp2ap_data *data)
{
	u8    wdata;
	u8    offset;
	int   adc = 0;

	gp2ap_i2c_read(REG_DYNAMIC_CAL_RESULT, &offset, sizeof(offset), data->client);
	SENSOR_INFO("offset=%d\n", offset);

	if(data->handle_high_offset) {
		data->ps_high_th = data->force_close_thd_high;
		data->ps_low_th = data->force_close_thd_low;
		data->handle_high_offset = false;
		SENSOR_INFO("Tune High th: high %d, low %d\n", data->ps_high_th, data->ps_low_th);
	} else {
		if (!data->pre_test) {
			if (offset >= OFFSET_TUNE_ADC &&
    				data->tune_adc_count < MAX_RETRY_TUNE_ADC_COUNT) {
    				adc = gp2ap_get_proximity_adc(data);
					if(adc < 0) {
						data->tune_adc_count++;
						return;
					}
    				wdata = (adc+ 1280)/256;
    				SENSOR_INFO("Tune ADC: adc %d, wdata 0x%x\n", adc, wdata);
    				if(wdata > 0x0D)
					wdata = 0x0D;
    				data->handle_high_offset = true;
    				data->high_offset = (u16)wdata * 16;
    				gp2ap_i2c_write(0x8D, wdata, data->client);
    				data->tune_adc_count++;
    				return;
			}
		}
	}

	wdata = 0x00;    				     gp2ap_i2c_write(0x81, wdata, data->client);
	wdata = 0x02;    				     gp2ap_i2c_write(0x82, wdata, data->client);
	wdata = 0x13;   				     gp2ap_i2c_write(0x83, wdata, data->client);
	wdata = 0x10;    				     gp2ap_i2c_write(0x85, wdata, data->client);
	wdata = data->led_reg_val;		     gp2ap_i2c_write(0x86, wdata, data->client);
	wdata = 0x20;    				     gp2ap_i2c_write(0x87, wdata, data->client);
	wdata = (u8)data->ps_low_th;         gp2ap_i2c_write(0x88, wdata, data->client);
	wdata = (u8)(data->ps_low_th >> 8);    gp2ap_i2c_write(0x89, wdata, data->client);
	wdata = (u8)data->ps_high_th;        gp2ap_i2c_write(0x8A, wdata, data->client);
	wdata = (u8)(data->ps_high_th >> 8);   gp2ap_i2c_write(0x8B, wdata, data->client);

	wdata = 0x88;    gp2ap_i2c_write(0x8E, wdata, data->client);
	wdata = 0x10;    gp2ap_i2c_write(0xB1, wdata, data->client);
	wdata = 0x02;    gp2ap_i2c_write(0xF0, wdata, data->client);
	wdata = 0x01;    gp2ap_i2c_write(0xF1, wdata, data->client);
}

static void gp2ap_InitDataDynamicCalibration(struct gp2ap_data *data)
{
	u8    wdata;

	SENSOR_INFO("led_reg_val=%d", data->led_reg_val);

	wdata = 0x00;    				gp2ap_i2c_write(0x81, wdata, data->client);
	wdata = 0x12;    				gp2ap_i2c_write(0x82, wdata, data->client);
	wdata = 0x10;    				gp2ap_i2c_write(0x83, wdata, data->client);
	wdata = 0x10;   				gp2ap_i2c_write(0x85, wdata, data->client);
	wdata = data->led_reg_val;		gp2ap_i2c_write(0x86, wdata, data->client);
	wdata = 0x70;    				gp2ap_i2c_write(0x87, wdata, data->client);
	wdata = 0x00;   				gp2ap_i2c_write(0x88, wdata, data->client);
	wdata = 0x00;    				gp2ap_i2c_write(0x89, wdata, data->client);
	wdata = 0x00;    				gp2ap_i2c_write(0x8A, wdata, data->client);
	wdata = 0x00;    				gp2ap_i2c_write(0x8B, wdata, data->client);
	wdata = 0x88;    				gp2ap_i2c_write(0x8E, wdata, data->client);
	wdata = 0x10;    				gp2ap_i2c_write(0xB1, wdata, data->client);
	wdata = 0x01;    				gp2ap_i2c_write(0xC1, wdata, data->client);
	wdata = 0x21;    				gp2ap_i2c_write(0xC2, wdata, data->client);
	wdata = 0x02;    				gp2ap_i2c_write(0xF0, wdata, data->client);
	wdata = 0x01;    				gp2ap_i2c_write(0xF1, wdata, data->client);
}

static ssize_t ps_enable_show(struct device *dev,
					struct device_attribute *attr,
						char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	int                 enabled;

	SENSOR_INFO("ps_enable_show: %d\n", data->ps_enabled);
	enabled = data->ps_enabled;
	return sprintf(buf, "%d", enabled);
}


static void gp2ap_ps_setting(struct gp2ap_data *data)
{
	int ret = 0;
	SENSOR_INFO("\n");
	if (data->prox_settings == 0) {
		ret = gp2ap_read_settings(data);
		if (ret > 0) {
	    		if (data->ps_high_th == data->ps_high_th_2)
	    				data->prox_settings = 2;
	    			else
	    				data->prox_settings = 1;

	    			SENSOR_INFO("Applied File prox_settings=%d, led_reg_val=%d, high_thd=%d, low_thd=%d\n",
	    				data->prox_settings, data->led_reg_val, data->ps_high_th, data->ps_low_th);
			} else {
	    			data->prox_settings = 1;
	    			data->led_reg_val = data->led_reg_val_1;
	    			data->ps_high_th = data->ps_high_th_1;
	    			data->ps_low_th = data->ps_low_th_1;

	    			SENSOR_INFO("Applied prox_settings=%d, led_reg_val=%d, high_thd=%d, low_thd=%d\n",
	    				data->prox_settings, data->led_reg_val, data->ps_high_th, data->ps_low_th);
	 		}
	} else if (data->prox_settings == 1) {
		data->led_reg_val = data->led_reg_val_1;
		data->ps_high_th = data->ps_high_th_1;
		data->ps_low_th = data->ps_low_th_1;
		
	    	SENSOR_INFO("led_reg_val=%d, high_thd=%d, low_thd=%d\n",
	    		data->led_reg_val, data->ps_high_th, data->ps_low_th);
		
	} else if (data->prox_settings == 2) {
		data->led_reg_val = data->led_reg_val_2;
		data->ps_high_th = data->ps_high_th_2;
		data->ps_low_th = data->ps_low_th_2;

	    	SENSOR_INFO("led_reg_val=%d, high_thd=%d, low_thd=%d\n",
	    		data->led_reg_val, data->ps_high_th, data->ps_low_th);		
	}
}

static int gp2ap_ps_onoff(u8 onoff, struct gp2ap_data *data)
{
	SENSOR_INFO("onoff= %d\n", onoff);

	if (onoff) {
		gp2ap_ps_setting(data);
		if (data->dynamic_calib_enabled) {
			gp2ap_InitDataDynamicCalibration(data);
			data->dynamic_calib_done = 0;

			gp2ap_StartMeasurement(data);

			msleep(50);

			data->dynamic_calib_done = 1;
			SENSOR_INFO("dynamic calibration done\n");

			if(data->zero_detect)
				data->zero_detect = 0;

			gp2ap_InitData(data);
		} else {
			gp2ap_InitData(data);
		}
		gp2ap_StartMeasurement(data);
	} else {
		gp2ap_StopMeasurement(data);
	}

	return 0;
}

static ssize_t gp2ap_ps_enable_store(struct device *dev,
					struct device_attribute *attr, const char *buf, size_t size)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	bool new_value;

	if (sysfs_streq(buf, "1"))
		new_value = true;
	else if (sysfs_streq(buf, "0"))
		new_value = false;
	else {
		SENSOR_ERR("invalid value %d\n", *buf);
		return size;
	}

	mutex_lock(&data->mutex_enable);

	SENSOR_INFO("new= %d, ps_enabled= %d\n",
		new_value, data->ps_enabled);

	if (!data->ps_enabled && new_value) {
		gp2ap_i2c_write(0x8D, 0, data->client);
		data->ps_distance = 1;
		data->zero_detect = 0;
		data->ps_enabled = new_value;
		data->tune_adc_count = 0;
		data->handle_high_offset = false;
		data->high_offset = 0;
		mutex_lock(&data->mutex_ps_onoff);
		gp2ap_ps_onoff(1, data);
		mutex_unlock(&data->mutex_ps_onoff);

		if(data->tune_adc_count > 0 && data->tune_adc_count < MAX_RETRY_TUNE_ADC_COUNT) {
			SENSOR_INFO("Restart sensor, data->tune_adc_count=%d\n", data->tune_adc_count);
			mutex_lock(&data->mutex_ps_onoff);
			gp2ap_ps_onoff(0, data);
			gp2ap_ps_onoff(1, data);
			mutex_unlock(&data->mutex_ps_onoff);
		}

		enable_irq_wake(data->ps_irq);
		enable_irq(data->ps_irq);
		schedule_delayed_work(&data->offset_work, msecs_to_jiffies(OFFSET_TUNE_DELAY));

		SENSOR_INFO("proximity_sensor enable!! \n");
	} else if (data->ps_enabled && !new_value) {
		disable_irq_wake(data->ps_irq);
		disable_irq(data->ps_irq);

		cancel_delayed_work_sync(&data->offset_work);
		mutex_lock(&data->mutex_ps_onoff);
		gp2ap_ps_onoff(0, data);
		mutex_unlock(&data->mutex_ps_onoff);
		data->ps_distance = 1;
		data->ps_enabled = new_value;

		SENSOR_INFO("proximity_sensor disable!! \n");
	}

	mutex_unlock(&data->mutex_enable);

	return size;
}

static DEVICE_ATTR(enable, 0664, ps_enable_show, gp2ap_ps_enable_store);

static struct attribute *ps_attributes[] =
{
	&dev_attr_enable.attr,
	NULL
};

static struct attribute_group ps_attribute_group =
{
	.attrs = ps_attributes
};

static int ps_input_init(struct gp2ap_data *data)
{
	struct input_dev *dev;
	int err = 0;

	/* Create the input device */
	dev = input_allocate_device();
	if (!dev) {
		SENSOR_ERR("%s, input_allocate_device error!!\n", __func__);
		return -ENOMEM;
	}

	dev->name = MODULE_NAME;
	dev->id.bustype = BUS_I2C;
	input_set_drvdata(dev, data);
	input_set_capability(dev, EV_ABS, ABS_DISTANCE);
	input_set_abs_params(dev, ABS_DISTANCE, 0, 1, 0, 0);

	err = input_register_device(dev);

	if (err < 0) {
		input_free_device(dev);
		SENSOR_INFO("%s, input_register_device error(%d)!!\n", __func__, err);
		return err;
	}

	err = sensors_create_symlink(&dev->dev.kobj, dev->name);

	if (err < 0) {
		SENSOR_ERR("create sysfs symlink error\n");
		input_unregister_device(dev);
		return err;
	}

	err = sysfs_create_group(&dev->dev.kobj, &ps_attribute_group);
	if (err) {
		SENSOR_INFO("sysfs_create_group failed[%s]\n", dev->name);
		return err;
	}

	data->ps_input_dev = dev;

	return err;
}

void gp2ap_update_min_close_offset(struct gp2ap_data *data)
{
	u8 offset;
	u8 rdata_d0[2];
	u16 ps_count;

	gp2ap_i2c_read(REG_DYNAMIC_CAL_RESULT, &offset, sizeof(offset), data->client);
	gp2ap_i2c_read(REG_D0_LSB, rdata_d0, sizeof(rdata_d0), data->client);
	ps_count = (rdata_d0[1] << 8) | rdata_d0[0];

	if (data->high_offset + offset + OFFSET_DELTA < data->min_close_offset)
		data->min_close_offset = data->high_offset + offset + OFFSET_DELTA;

	SENSOR_INFO(":%u %u %u %u\n", ps_count, offset, data->high_offset, data->min_close_offset);
}

irqreturn_t gp2ap_ps_irq_handler(int irq, void *id_data)
{
	struct gp2ap_data *data = id_data;
	u8 val;

	val = gpio_get_value(data->p_out);

	/*1: Far, 0: Near */
	SENSOR_INFO("val:%d en:%d\n", val, data->ps_enabled);
	if(data->ps_enabled)
		schedule_work(&data->ps_int_work);

	return IRQ_HANDLED;
}

static void gp2ap_ps_work_int_func(struct work_struct *work)
{
	struct gp2ap_data *data = container_of((struct work_struct *)work, 
					struct gp2ap_data, ps_int_work);
	char  distance;
	u8 near_far = 1;
	u8    rdata;
	u8    rdata_d0[2];
	u8    offset;

	if (data == NULL)
		return;

	mutex_lock(&data->mutex_interrupt);
	gp2ap_i2c_read(REG_DYNAMIC_CAL_RESULT, &offset, sizeof(offset), data->client);
	gp2ap_i2c_read(0x81, &rdata, sizeof(rdata), data->client);
	if ((rdata & 0x08) == 0x08)
		distance = 0; // Near
	else
		distance = 1; // Far
	if (data->ps_distance != distance) {
		data->ps_distance = distance;
	}

	gp2ap_i2c_read(REG_D0_LSB, rdata_d0, sizeof(rdata_d0), data->client);
	data->ps_count = (rdata_d0[1] << 8) | rdata_d0[0];

	if (data->ps_count >= data->ps_high_th || (data->high_offset + offset >= data->min_close_offset && data->ps_count != 0))
		near_far = 0;
	else if (data->ps_count < data->ps_low_th && (data->high_offset + offset < data->min_close_offset && data->ps_count != 0))
		near_far = 1;

	if (near_far == 0) {
		data->zero_detect = 0;
	}

	SENSOR_INFO("dis:%d near_far:%d count:%d zero:%d\n", 
		data->ps_distance, near_far, data->ps_count,data->zero_detect);

	if ((near_far == 1) && (data->ps_count == 0) && (data->zero_detect == 0)) {
		SENSOR_INFO("zero detection!!!\n");
		data->zero_detect = 1;
		mutex_lock(&data->mutex_ps_onoff);
		disable_irq_wake(data->ps_irq);
		disable_irq(data->ps_irq);
		gp2ap_ps_onoff(0, data);
		gp2ap_ps_onoff(1, data);
		enable_irq_wake(data->ps_irq);
		enable_irq(data->ps_irq);
		mutex_unlock(&data->mutex_ps_onoff);

		if(!offset) {
			gp2ap_i2c_write(0x8D, 0, data->client);
			data->min_close_offset = MAX_OFFSET;
			data->high_offset = 0;
			SENSOR_INFO("offset = 0 , Restart sensor!");
			mutex_lock(&data->mutex_ps_onoff);
			gp2ap_ps_onoff(0, data);
			gp2ap_ps_onoff(1, data);
			mutex_unlock(&data->mutex_ps_onoff);
		}
	} else {
		input_report_abs(data->ps_input_dev, ABS_DISTANCE, near_far);
		input_sync(data->ps_input_dev);
	}
	gp2ap_update_min_close_offset(data);
	mutex_unlock(&data->mutex_interrupt);
}

static int gp2ap_setup_irq(struct gp2ap_data *gp2ap)
{
	int ret;
	ret = gpio_request(gp2ap->p_out, "gpio_proximity_out");

	if (ret < 0) {
		SENSOR_ERR("gpio %d request failed (%d)\n", gp2ap->p_out, ret);
		return ret;
	}

	ret = gpio_direction_input(gp2ap->p_out);
	if (ret < 0) {
		SENSOR_ERR("failed gpio %d as input (%d)\n", gp2ap->p_out, ret);
		goto err_gpio_direction_input;
	}

	gp2ap->ps_irq = gpio_to_irq(gp2ap->p_out);
	ret = request_irq(gp2ap->ps_irq, gp2ap_ps_irq_handler,
			IRQF_TRIGGER_RISING  |  IRQF_TRIGGER_FALLING | IRQF_ONESHOT, "proximity_int", gp2ap);

	if (ret < 0) {
		SENSOR_ERR("request_irq(%d) failed for gpio %d (%d)\n",
			gp2ap->ps_irq, gp2ap->p_out, ret);
		goto err_request_irq;
	}

	SENSOR_INFO("request_irq(%d) success (%d)\n", gp2ap->ps_irq, gp2ap->p_out);

	disable_irq(gp2ap->ps_irq);

	goto done;
err_request_irq:
err_gpio_direction_input:
	gpio_free(gp2ap->p_out);
done:
	return ret;
}

static ssize_t name_read(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%s\n", DEVICE_NAME);
}

static ssize_t vendor_read(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	return snprintf(buf, PAGE_SIZE, "%s\n", CHIP_DEV_VENDOR);
}

static ssize_t proximity_register_read_show(struct device *dev,
		struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);

	u8 reg = 0;
	int offset = 0;
	u8 val = 0;

	for (reg = 0x80; reg <= 0x8E; reg++) {
		gp2ap_i2c_read(reg, &val, sizeof(val), data->client);
		SENSOR_INFO("Read Reg: 0x%2x Value: 0x%2x\n", reg, val);
		offset += snprintf(buf + offset, PAGE_SIZE - offset,
			"Reg: 0x%2x Value: 0x%2x\n", reg, val);
	}

	for (reg = 0x90; reg <= 0x91; reg++) {
		gp2ap_i2c_read(reg, &val, sizeof(val), data->client);
		SENSOR_INFO("Read Reg: 0x%2x Value: 0x%2x\n", reg, val);
		offset += snprintf(buf + offset, PAGE_SIZE - offset,
			"Reg: 0x%2x Value: 0x%2x\n", reg, val);
	}

	gp2ap_i2c_read(0xA0, &val, sizeof(val), data->client);
	SENSOR_INFO("Read Reg: 0x%2x Value: 0x%2x\n", reg, val);
	offset += snprintf(buf + offset, PAGE_SIZE - offset,
		"Reg: 0x%2x Value: 0x%2x\n", reg, val);

	gp2ap_i2c_read(0xB1, &val, sizeof(val), data->client);
	SENSOR_INFO("Read Reg: 0x%2x Value: 0x%2x\n", reg, val);
	offset += snprintf(buf + offset, PAGE_SIZE - offset,
		"Reg: 0x%2x Value: 0x%2x\n", reg, val);

	for (reg = 0xC0; reg <= 0xC2; reg++) {
		gp2ap_i2c_read(reg, &val, sizeof(val), data->client);
		SENSOR_INFO("Read Reg: 0x%2x Value: 0x%2x\n", reg, val);
		offset += snprintf(buf + offset, PAGE_SIZE - offset,
			"Reg: 0x%2x Value: 0x%2x\n", reg, val);
	}

	for (reg = 0xF0; reg <= 0xF1; reg++) {
		gp2ap_i2c_read(reg, &val, sizeof(val), data->client);
		SENSOR_INFO("Read Reg: 0x%2x Value: 0x%2x\n", reg, val);
		offset += snprintf(buf + offset, PAGE_SIZE - offset,
			"Reg: 0x%2x Value: 0x%2x\n", reg, val);
	}

	return offset;
}

static ssize_t proximity_register_write_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);

	unsigned int reg, val;
	int ret;

	if (sscanf(buf, "%2x,%2x", &reg, &val) != 2) {
		SENSOR_ERR("invalid value\n");
		return count;
	}

	ret = gp2ap_i2c_write(reg, val, data->client);
	if(ret < 0)
		SENSOR_ERR("failed %d\n", ret);
	else
		SENSOR_INFO("Register(0x%2x) data(0x%2x)\n", reg, val);

    return count;
}

static ssize_t proximity_cal_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	s8 value;

	gp2ap_i2c_read(REG_DYNAMIC_CAL_RESULT, &value, sizeof(value), data->client);
	
	return snprintf(buf, PAGE_SIZE, "%d,%d,%d\n",
		value, data->ps_high_th, data->ps_low_th);
}

static ssize_t proximity_cal_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t size)
{
	//for LCiA ADC Check sequence
	SENSOR_INFO("\n");
	return size;
}

static ssize_t proximity_thresh_high_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);

	SENSOR_INFO("%d\n", data->ps_high_th);

	return scnprintf(buf, PAGE_SIZE, "%d\n", data->ps_high_th);
}

static ssize_t proximity_thresh_high_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t size)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	u16 value = 0;
	u8 wdata;
	int ret;

	ret = kstrtou16(buf, 10, &value);
	if (ret < 0) {
		SENSOR_ERR("kstrtoul failed, ret=0x%x\n", ret);
		return ret;
	}

	SENSOR_INFO("thresh: %d\n",  value);

	data->ps_high_th = value;
	wdata = (u8)data->ps_high_th;
	gp2ap_i2c_write(0x8A, wdata, data->client);

	wdata = (u8)(data->ps_high_th>>8);
	gp2ap_i2c_write(0x8B, wdata, data->client);

	return size;
}

static ssize_t proximity_thresh_low_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);

	SENSOR_INFO("%d\n", data->ps_low_th);
	
	return scnprintf(buf, PAGE_SIZE, "%d\n", data->ps_low_th);
}

static ssize_t proximity_thresh_low_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t size)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	u16 value = 0;
	u8 wdata;
	int ret;

	ret = kstrtou16(buf, 10, &value);
	if (ret < 0) {
		SENSOR_ERR("kstrtoul failed, ret=0x%x\n", ret);
		return ret;
	}

	SENSOR_INFO("thresh: %d\n",  value);

	data->ps_low_th = value;
	wdata = (u8)data->ps_low_th;
	gp2ap_i2c_write(0x88, wdata, data->client);

	wdata = (u8)(data->ps_low_th>>8);
	gp2ap_i2c_write(0x89, wdata, data->client);

	return size;
}

static ssize_t proximity_avg_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	return snprintf(buf, PAGE_SIZE, "%d,%d,%d\n", data->avg[0],
		data->avg[1], data->avg[2]);
}

static ssize_t proximity_avg_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t size)
{
	struct gp2ap_data *data =  dev_get_drvdata(dev);
	bool new_value = false;

	if (sysfs_streq(buf, "1"))
		new_value = true;
	else if (sysfs_streq(buf, "0"))
		new_value = false;
	else {
		SENSOR_ERR("invalid value %d\n", *buf);
		return -EINVAL;
	}

	SENSOR_INFO("average enable = %d\n", new_value);

	if (new_value) {
		hrtimer_start(&data->prox_timer, data->prox_poll_delay,
			HRTIMER_MODE_REL);
	} else if (!new_value) {
		hrtimer_cancel(&data->prox_timer);
		cancel_work_sync(&data->work_prox);
	}

	return size;
}

static ssize_t modify_settings_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t size)
{
	struct gp2ap_data *data =  dev_get_drvdata(dev);

	if (data->ps_high_th == data->force_close_thd_high && data->ps_low_th == data->force_close_thd_low) {
		SENSOR_INFO("Skip changing proximity settings (%d, %d)\n",data->ps_high_th,data->ps_low_th);		
		return size;
	}

	if (sysfs_streq(buf, "1"))
		data->prox_settings = 1;
	else if (sysfs_streq(buf, "2"))
		data->prox_settings = 2;
	else {
		SENSOR_ERR("invalid value %d\n", *buf);
		return -EINVAL;
	}

	SENSOR_INFO("prox_settings = %d\n", data->prox_settings);

	gp2ap_write_settings(data);

	return size;
}

static ssize_t modify_settings_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);

	gp2ap_read_settings(data);

	return snprintf(buf, PAGE_SIZE, "%d\n", data->prox_settings);
}

static ssize_t settings_thd_high_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t size)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	u16 value = 0;
	int ret;

	ret = kstrtou16(buf, 10, &value);
	if (ret < 0) {
		SENSOR_ERR("kstrtoul failed, ret=0x%x\n", ret);
		return ret;
	}

	SENSOR_INFO("settings_thd_high: %d\n", value);

	data->settings_thd_high = value;

	return size;
}

static ssize_t settings_thd_high_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%d\n", data->settings_thd_high);
}

static ssize_t settings_thd_low_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t size)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	u16 value = 0;
	int ret;

	ret = kstrtou16(buf, 10, &value);
	if (ret < 0) {
		SENSOR_ERR("kstrtoul failed, ret=0x%x\n", ret);
		return ret;
	}

	SENSOR_INFO("settings_thd_low: %d\n", value);

	data->settings_thd_low = value;

	return size;
}

static ssize_t settings_thd_low_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%d\n", data->settings_thd_low);

}

static ssize_t pre_test_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);

	return snprintf(buf, PAGE_SIZE, "%d\n", data->pre_test);
}

static ssize_t pre_test_store(struct device *dev,
	struct device_attribute *attr, const char *buf, size_t size)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	u16 value = 0;
	int ret;

	ret = kstrtou16(buf, 10, &value);
	if (ret < 0) {
		SENSOR_ERR("kstrtoul failed, ret=0x%x\n", ret);
		return ret;
	}

	SENSOR_INFO("pre_test value = %d\n", value);

	data->pre_test = value;

	return size;
}


static void gp2ap_offset_work_func(struct work_struct *work)
{
	struct gp2ap_data *data = container_of((struct delayed_work *)work,
		struct gp2ap_data, offset_work);
		
	int   ps_data;
	u8    offset;

	if(!data->ps_enabled) return;
	
	ps_data = gp2ap_get_proximity_adc(data);
	SENSOR_INFO("offset=%d\n", ps_data);

	if (ps_data > 0)
		data->zero_detect = 0;
	else if (ps_data == 0 && data->zero_detect == 0) {
		SENSOR_INFO(" zero detection\n");
		data->zero_detect = 1;
		mutex_lock(&data->mutex_ps_onoff);
		disable_irq_wake(data->ps_irq);
		disable_irq(data->ps_irq);
		gp2ap_ps_onoff(0, data);
		gp2ap_ps_onoff(1, data);
		enable_irq_wake(data->ps_irq);
		enable_irq(data->ps_irq);
		mutex_unlock(&data->mutex_ps_onoff);

		gp2ap_i2c_read(REG_DYNAMIC_CAL_RESULT, &offset, sizeof(offset), data->client);

		if(!offset) {
			gp2ap_i2c_write(0x8D, 0, data->client);
			data->min_close_offset = MAX_OFFSET;
			data->high_offset = 0;
			SENSOR_INFO("offset = 0 , Restart sensor!");
			mutex_lock(&data->mutex_ps_onoff);
			gp2ap_ps_onoff(0, data);
			gp2ap_ps_onoff(1, data);
			mutex_unlock(&data->mutex_ps_onoff);
		}
	}
	gp2ap_update_min_close_offset(data);
	schedule_delayed_work(&data->offset_work, msecs_to_jiffies(OFFSET_TUNE_DELAY));
}

static ssize_t proximity_state_show(struct device *dev,
	struct device_attribute *attr, char *buf)
{   
	struct gp2ap_data *data = dev_get_drvdata(dev);
	int ps_data;

	ps_data = gp2ap_get_proximity_adc(data);

	return snprintf(buf, PAGE_SIZE, "%d\n", ps_data);
}

static ssize_t proximity_trim_show(struct device *dev,
	struct device_attribute *attr, char *buf)

{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	u8 value;

	gp2ap_i2c_read(REG_DYNAMIC_CAL_RESULT, &value, sizeof(value), data->client);

	return snprintf(buf, PAGE_SIZE, "%d\n", value);
}

static ssize_t dynamic_calib_enabled_show(struct device *dev,
					struct device_attribute *attr, char *buf)
{
	struct input_dev   *input_dev = to_input_dev(dev);
	struct gp2ap_data  *data = input_get_drvdata(input_dev);

	SENSOR_INFO("%s : %d\n", __func__, data->dynamic_calib_enabled);

	return sprintf(buf, "dynamic_calib_enabled:%d", data->dynamic_calib_enabled);
	
}

static ssize_t dynamic_calib_enabled_store(struct device *dev,
		struct device_attribute *attr, const char *buf, size_t count)
{
	struct gp2ap_data *data = dev_get_drvdata(dev);
	char               *endp;
	int                 enabled = simple_strtoul(buf, &endp, 10);

	SENSOR_INFO("dynamic_calib_enabled = %s\n", buf);

	if (!(endp != buf &&
			(endp == (buf + strlen(buf))
				|| (endp == (buf + strlen(buf) - 1) && *endp == '\n')))) {
		SENSOR_INFO("invalid num : %s", buf);
		return count;
	}

	data->dynamic_calib_enabled = enabled;

	if (data->dynamic_calib_enabled) {
		data->ps_low_th  = data->calib_target + 205;
		data->ps_high_th = data->calib_target + 305;
	} else {
		data->ps_low_th  = 205;
		data->ps_high_th = 305;
	}

	return count;
}

static DEVICE_ATTR(name, 0444, name_read, NULL);
static DEVICE_ATTR(vendor, 0444, vendor_read, NULL);
static DEVICE_ATTR(raw_data, 0444, proximity_state_show, NULL);
static DEVICE_ATTR(prox_register, 0644, proximity_register_read_show, proximity_register_write_store);
static DEVICE_ATTR(prox_trim, 0444, proximity_trim_show, NULL);
static DEVICE_ATTR(prox_cal, 0664, proximity_cal_show, proximity_cal_store);
static DEVICE_ATTR(thresh_high, S_IRUGO | S_IWUSR | S_IWGRP,
	proximity_thresh_high_show, proximity_thresh_high_store);
static DEVICE_ATTR(thresh_low, S_IRUGO | S_IWUSR | S_IWGRP,
	proximity_thresh_low_show, proximity_thresh_low_store);
static DEVICE_ATTR(dynamic_calib_enabled, 0664,
		dynamic_calib_enabled_show, dynamic_calib_enabled_store);
static DEVICE_ATTR(prox_avg, 0644,
		proximity_avg_show, proximity_avg_store);
static DEVICE_ATTR(modify_settings, 0664, modify_settings_show, modify_settings_store);
static DEVICE_ATTR(settings_thd_high, 0664, settings_thd_high_show, settings_thd_high_store);
static DEVICE_ATTR(settings_thd_low, 0664, settings_thd_low_show, settings_thd_low_store);
static DEVICE_ATTR(pre_test, 0664, pre_test_show, pre_test_store);

static struct device_attribute *proximity_attrs[] = {
	&dev_attr_name,
	&dev_attr_vendor,
	&dev_attr_raw_data,
	&dev_attr_thresh_low,
	&dev_attr_thresh_high,
	&dev_attr_prox_cal,
	&dev_attr_prox_register,
	&dev_attr_prox_trim,
	&dev_attr_dynamic_calib_enabled,
	&dev_attr_prox_avg,
	&dev_attr_modify_settings,
	&dev_attr_settings_thd_high,
	&dev_attr_settings_thd_low,
	&dev_attr_pre_test,
	NULL,
};

static enum hrtimer_restart gp2ap_prox_timer_func(struct hrtimer *timer)
{
	struct gp2ap_data *data = container_of(timer,
		struct gp2ap_data, prox_timer);
	queue_work(data->prox_wq, &data->work_prox);
	hrtimer_forward_now(&data->prox_timer, data->prox_poll_delay);
	return HRTIMER_RESTART;
}

static void proximity_get_avg_val(struct gp2ap_data *data)
{
	int min = 0, max = 0, avg = 0;
	int i;
	int ps_data;

	for (i = 0; i < PROX_READ_NUM; i++) {
		msleep(40);
		ps_data = gp2ap_get_proximity_adc(data);
		if(ps_data < 0) continue;
		avg += ps_data;
		if (!i)
			min = ps_data;
		else if (ps_data < min)
			min = ps_data;
		if (ps_data > max)
			max = ps_data;
	}

	avg /= PROX_READ_NUM;
	data->avg[0] = min;
	data->avg[1] = avg;
	data->avg[2] = max;
}

static void gp2ap_work_func_prox(struct work_struct *work)
{
	struct gp2ap_data *data = container_of(work,
		struct gp2ap_data, work_prox);

	proximity_get_avg_val(data);
}

static int gp2ap110s_parse_dt(struct device *dev, struct gp2ap_data *data)
{
	struct device_node *np = dev->of_node;
	enum of_gpio_flags flags;
	int ret;

	data->p_out =  of_get_named_gpio_flags(np, "gp2ap110s,gpio_int", 0, &flags);
	if (data->p_out < 0) {
		SENSOR_ERR("Cannot set p_out through DTSI, ret=%d\n", data->p_out);
		return -EINVAL;
	}

	ret = of_property_read_u32(np, "gp2ap110s,led_reg_val_1",
		&data->led_reg_val_1);
	if (ret < 0) {
		SENSOR_ERR("Cannot set led_reg_val_1 through DTSI, ret=%d\n", ret);
		data->led_reg_val_1 = LED_REG_VAL_1;
	}

	data->led_reg_val = data->led_reg_val_1;

	ret = of_property_read_u32(np, "gp2ap110s,ps_high_th_1",
		&data->ps_high_th_1);
	if (ret < 0) {
		SENSOR_ERR("Cannot set ps_high_th_1 through DTSI, ret=%d\n", ret);
		data->ps_high_th_1 = HIGH_THD_1;
	}

	data->ps_high_th = data->ps_high_th_1;

	ret = of_property_read_u32(np, "gp2ap110s,ps_low_th_1",
		&data->ps_low_th_1);
	if (ret < 0) {
		SENSOR_ERR("Cannot set ps_low_th_1 through DTSI, ret=%d\n", ret);
		data->ps_low_th_1 = LOW_THD_1;
	}

	data->ps_low_th = data->ps_low_th_1;

	ret = of_property_read_u32(np, "gp2ap110s,ps_high_th_2",
		&data->ps_high_th_2);
	if (ret < 0) {
		SENSOR_ERR("Cannot set ps_high_th_2 through DTSI, ret=%d\n", ret);
		data->ps_high_th_2 = HIGH_THD_2;
	}

	ret = of_property_read_u32(np, "gp2ap110s,ps_low_th_2",
		&data->ps_low_th_2);
	if (ret < 0) {
		SENSOR_ERR("Cannot set ps_low_th_2 through DTSI, ret=%d\n", ret);
		data->ps_low_th_2 = LOW_THD_2;
	}

	ret = of_property_read_u32(np, "gp2ap110s,led_reg_val_2",
		&data->led_reg_val_2);
	if (ret < 0) {
		SENSOR_ERR("Cannot set led_reg_val_2 through DTSI, ret=%d\n", ret);
		data->led_reg_val_2 = LED_REG_VAL_2;
	}

	ret = of_property_read_u32(np, "gp2ap110s,settings_thd_low",
		&data->settings_thd_low);
	if (ret < 0) {
		SENSOR_ERR("Cannot set settings_thd_low through DTSI, ret=%d\n", ret);
		return -EINVAL;
	}

	ret = of_property_read_u32(np, "gp2ap110s,settings_thd_high",
		&data->settings_thd_high);
	if (ret < 0) {
		SENSOR_ERR("Cannot set settings_thd_high through DTSI, ret=%d\n", ret);
		return -EINVAL;
	}

	ret = of_property_read_u32(np, "gp2ap110s,force_close_thd_low",
		&data->force_close_thd_low);
	if (ret < 0) {
		data->force_close_thd_low = FORCE_CLOSE_LOW_THD;
		SENSOR_ERR("Cannot set through DTSI, use default force_close_thd_low = %d\n", data->force_close_thd_low);
	}

	ret = of_property_read_u32(np, "gp2ap110s,force_close_thd_high",
		&data->force_close_thd_high);
	if (ret < 0) {
		data->force_close_thd_high = FORCE_CLOSE_HIGH_THD;
		SENSOR_ERR("Cannot set through DTSI, use default force_close_thd_high = %d\n", data->force_close_thd_high);
	}

	return 0;
}

static int gp2ap_i2c_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
{
	struct gp2ap_data *gp2ap;
	u8 value = 0;
	int err = 0;

	SENSOR_INFO("gp2ap_probe start !! \n");

	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
		SENSOR_ERR("i2c functionality failed\n");
		return -ENOMEM;
	}

	/* Allocate memory for driver data */
	gp2ap = kzalloc(sizeof(struct gp2ap_data), GFP_KERNEL);
	if (!gp2ap) {
		SENSOR_ERR("failed memory alloc\n");
		err = -ENOMEM;
		goto err_mem_alloc;
	}

	gp2ap->client = client;
	i2c_set_clientdata(client, gp2ap);

	/* Check if the device is there or not. (Shutdown operation) */
	value = 0x00;
	err = gp2ap_i2c_write(REG_COM1, value, gp2ap->client);
	if (err < 0) {
		SENSOR_ERR("gp2ap is not connected.(%d)\n", err);
		goto err_no_device;
	}

	err = gp2ap110s_parse_dt(&client->dev, gp2ap);
	if (err) {
		SENSOR_ERR("error in device tree");
		goto err_device_tree;
	}

	mutex_init(&gp2ap->mutex_ps_onoff);
	mutex_init(&gp2ap->mutex_enable);
	mutex_init(&gp2ap->mutex_interrupt);

	gp2ap->ps_enabled   = 0;
	gp2ap->ps_distance  = 1;
	gp2ap->calib_target = 63;
	gp2ap->dynamic_calib_enabled = 1;
	gp2ap->prox_settings = 0; // keep settings value 0 at boot time
	gp2ap->bytes = 14; // 4 bytes each for led_reg_val, thresholds & 1 byte each for ","
	gp2ap->pre_test = 0;
	gp2ap->zero_detect = 0;
	gp2ap->high_offset = 0;
	gp2ap->min_close_offset = MAX_OFFSET;

	value = 0x00;
	gp2ap_i2c_write(0x8D, value, gp2ap->client);

	if (gp2ap->dynamic_calib_enabled) {
		gp2ap_InitDataDynamicCalibration(gp2ap);
	} else {
		gp2ap_InitData(gp2ap);
		gp2ap->ps_low_th = 205;
		gp2ap->ps_high_th = 305;
	}

	gp2ap->tune_adc_count = 0;

	err = ps_input_init(gp2ap);

	if (err < 0) {
		SENSOR_ERR("failed to get input dev\n");
		goto err_ps_input_device;
	}

	err = sensors_register(&gp2ap->dev, gp2ap, proximity_attrs, MODULE_NAME);
	if (err < 0) {
		SENSOR_INFO("could not sensors_register\n");
		goto err_sensors_register;
	}

	/* For factory test mode, we use timer to get average proximity data. */
	/* prox_timer settings. we poll for light values using a timer. */
	hrtimer_init(&gp2ap->prox_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	gp2ap->prox_poll_delay = ns_to_ktime(2000 * NSEC_PER_MSEC);/*2 sec*/
	gp2ap->prox_timer.function = gp2ap_prox_timer_func;
	/* the timer just fires off a work queue request.  we need a thread
	to read the i2c (can be slow and blocking). */
	gp2ap->prox_wq = create_singlethread_workqueue("gp2a_prox_wq");
	if (!gp2ap->prox_wq) {
		err = -ENOMEM;
		SENSOR_ERR("could not create prox workqueue\n");
		goto err_create_prox_workqueue;
	}

	INIT_WORK(&gp2ap->work_prox, gp2ap_work_func_prox);
	INIT_WORK(&gp2ap->ps_int_work, gp2ap_ps_work_int_func);
	INIT_DELAYED_WORK(&gp2ap->offset_work, gp2ap_offset_work_func);

	err = gp2ap_setup_irq(gp2ap);

	if (err) {
		SENSOR_ERR("could not setup irq\n");
		goto err_setup_irq;
	}

	SENSOR_INFO("success\n");

	return 0;
err_setup_irq:
	destroy_workqueue(gp2ap->prox_wq);
err_create_prox_workqueue:
	sensors_unregister(gp2ap->dev, proximity_attrs);
err_sensors_register:
	sensors_remove_symlink(&gp2ap->ps_input_dev->dev.kobj,
			gp2ap->ps_input_dev->name);
	sysfs_remove_group(&gp2ap->ps_input_dev->dev.kobj,
				&ps_attribute_group);	
	input_unregister_device(gp2ap->ps_input_dev);
err_ps_input_device:    
	mutex_destroy(&gp2ap->mutex_interrupt);
	mutex_destroy(&gp2ap->mutex_enable);
	mutex_destroy(&gp2ap->mutex_ps_onoff);
err_device_tree:
err_no_device:
	kfree(gp2ap);
err_mem_alloc:
	SENSOR_ERR("failed\n");
	return err;
}

static int gp2ap_remove(struct i2c_client *client)
{
	struct gp2ap_data *data = i2c_get_clientdata(client);
	u8 val;

	SENSOR_INFO("gp2ap_remove\n");

	if (data != NULL) {
		val = 0x00;
		gp2ap_i2c_write(REG_COM1, val, data->client);

		if (data->ps_enabled)
			disable_irq(data->ps_irq);

		free_irq(data->ps_irq, data);
		destroy_workqueue(data->prox_wq);
		sensors_unregister(data->dev, proximity_attrs);
		sensors_remove_symlink(&data->ps_input_dev->dev.kobj,
			data->ps_input_dev->name);
		sysfs_remove_group(&data->ps_input_dev->dev.kobj, &ps_attribute_group);
		input_unregister_device(data->ps_input_dev);	  	
		mutex_destroy(&data->mutex_ps_onoff);
		mutex_destroy(&data->mutex_enable);
		mutex_destroy(&data->mutex_interrupt);
		kfree(data);
	}

	return 0;
}

static void gp2ap_shutdown(struct i2c_client *client)
{
	struct gp2ap_data *data = i2c_get_clientdata(client);
	u8 val;

	SENSOR_INFO("gp2ap_shutdown\n");

	if (data != NULL) {
		val = 0x00;
		gp2ap_i2c_write(REG_COM1, val, data->client);

		if (data->ps_enabled)
			disable_irq(data->ps_irq);
		}
}

static int gp2ap_suspend(struct device *pdev)
{
	struct gp2ap_data *data = dev_get_drvdata(pdev);

	SENSOR_INFO("is called.\n");

	if (data->ps_enabled) {
		disable_irq(data->ps_irq);
		cancel_delayed_work_sync(&data->offset_work);
	}

	return 0;
}

static int gp2ap_resume(struct device *pdev)
{
	struct gp2ap_data *data = dev_get_drvdata(pdev);

	SENSOR_INFO("is called.\n");

	if (data->ps_enabled) {
		enable_irq(data->ps_irq);
		schedule_delayed_work(&data->offset_work, msecs_to_jiffies(OFFSET_TUNE_DELAY));
	}

	return 0;
}

static const struct dev_pm_ops gp2ap_pm_ops = {
	.suspend    = gp2ap_suspend,
	.resume     = gp2ap_resume
};

static const struct i2c_device_id gp2ap_device_id[] =
{
	{ "gp2a", 0 },
	{ }
};

static struct of_device_id gp2ap_i2c_match_table[] = {
  { .compatible = "sharp,gp2ap110s",},
  { },
};

static struct i2c_driver gp2ap_i2c_driver = {
	.driver = {
		.name = "gp2a",
		.owner = THIS_MODULE,
		.of_match_table = gp2ap_i2c_match_table,
		.pm = &gp2ap_pm_ops
	},
	.probe		= gp2ap_i2c_probe,
	.shutdown 	= gp2ap_shutdown,
	.remove 	= gp2ap_remove,
	.id_table	= gp2ap_device_id,
};

module_i2c_driver(gp2ap_i2c_driver);

MODULE_AUTHOR("Samsung Electronics");
MODULE_DESCRIPTION("Proximity Sensor driver for gp2ap110s00f");
MODULE_LICENSE("GPL");