#include <linux/mutex.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/i2c.h>
#include <linux/delay.h>
#include <linux/jiffies.h>
#include <linux/time.h>
#include <linux/cdev.h>
#include <asm/uaccess.h>
#include <linux/pm_runtime.h>
#include <linux/input/mt.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/platform_device.h>
#include <linux/async.h>
#include <linux/hrtimer.h>
#include <linux/init.h>
#include <linux/input.h>
#include <linux/ioport.h>
#include <linux/workqueue.h>
#include <linux/gpio.h>
#include <linux/irq.h>
#include <gsc3280/gpio.h>
#include <gsc3280/sysctl.h>
#include <asm/io.h>

#ifdef CONFIG_SSD1306_DEBUG
        #define dbg(msg...) printk(KERN_INFO msg)
#else
        #define dbg(msg...) do{}while(0)
#endif

struct gpio gsc3280_gpio[1] = {
        {GSC3280_GPA(31), GPIOF_OUT_INIT_HIGH, "OLED_RST"},
};

#define gsc3280_set_gpio_reg_bit(reg)   do{\
        unsigned int reg_val = 0; \
        reg_val = __raw_readl((volatile unsigned int *)(reg));\
        reg_val |= (0x1<<gsc3280_gpio[0].gpio);\
        __raw_writel(reg_val, (volatile unsigned int *)(reg));\
}while(0)

#define gsc3280_clr_gpio_reg_bit(reg) do{\
        unsigned int reg_val = 0; \
        reg_val = __raw_readl((volatile unsigned int *)(reg));\
        reg_val &= ~(0x1<<gsc3280_gpio[0].gpio);\
        __raw_writel(reg_val, (volatile unsigned int *)(reg));\
}while(0)

struct ssd1306_data{
        int temp;
};

struct ssd1306_data *ssd1306_dev;

#define SSD1306_CMD    0
#define SSD1306_DAT    1

#define SSD1306_WIDTH    128
#define SSD1306_HEIGHT  64

static uint8_t s_chDispalyBuffer[128][8];

const uint8_t c_chFont1608[95][16] = {      
{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},/*" ",0*/
{0x00,0x00,0x00,0x00,0x00,0x00,0x1F,0xCC,0x00,0x0C,0x00,0x00,0x00,0x00,0x00,0x00},/*"!",1*/
{0x00,0x00,0x08,0x00,0x30,0x00,0x60,0x00,0x08,0x00,0x30,0x00,0x60,0x00,0x00,0x00},/*""",2*/
{0x02,0x20,0x03,0xFC,0x1E,0x20,0x02,0x20,0x03,0xFC,0x1E,0x20,0x02,0x20,0x00,0x00},/*"#",3*/
{0x00,0x00,0x0E,0x18,0x11,0x04,0x3F,0xFF,0x10,0x84,0x0C,0x78,0x00,0x00,0x00,0x00},/*"$",4*/
{0x0F,0x00,0x10,0x84,0x0F,0x38,0x00,0xC0,0x07,0x78,0x18,0x84,0x00,0x78,0x00,0x00},/*"%",5*/
{0x00,0x78,0x0F,0x84,0x10,0xC4,0x11,0x24,0x0E,0x98,0x00,0xE4,0x00,0x84,0x00,0x08},/*"&",6*/
{0x08,0x00,0x68,0x00,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},/*"'",7*/
{0x00,0x00,0x00,0x00,0x00,0x00,0x07,0xE0,0x18,0x18,0x20,0x04,0x40,0x02,0x00,0x00},/*"(",8*/
{0x00,0x00,0x40,0x02,0x20,0x04,0x18,0x18,0x07,0xE0,0x00,0x00,0x00,0x00,0x00,0x00},/*")",9*/
{0x02,0x40,0x02,0x40,0x01,0x80,0x0F,0xF0,0x01,0x80,0x02,0x40,0x02,0x40,0x00,0x00},/*"*",10*/
{0x00,0x80,0x00,0x80,0x00,0x80,0x0F,0xF8,0x00,0x80,0x00,0x80,0x00,0x80,0x00,0x00},/*"+",11*/
{0x00,0x01,0x00,0x0D,0x00,0x0E,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},/*",",12*/
{0x00,0x00,0x00,0x80,0x00,0x80,0x00,0x80,0x00,0x80,0x00,0x80,0x00,0x80,0x00,0x80},/*"-",13*/
{0x00,0x00,0x00,0x0C,0x00,0x0C,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},/*".",14*/
{0x00,0x00,0x00,0x06,0x00,0x18,0x00,0x60,0x01,0x80,0x06,0x00,0x18,0x00,0x20,0x00},/*"/",15*/
{0x00,0x00,0x07,0xF0,0x08,0x08,0x10,0x04,0x10,0x04,0x08,0x08,0x07,0xF0,0x00,0x00},/*"0",16*/
{0x00,0x00,0x08,0x04,0x08,0x04,0x1F,0xFC,0x00,0x04,0x00,0x04,0x00,0x00,0x00,0x00},/*"1",17*/
{0x00,0x00,0x0E,0x0C,0x10,0x14,0x10,0x24,0x10,0x44,0x11,0x84,0x0E,0x0C,0x00,0x00},/*"2",18*/
{0x00,0x00,0x0C,0x18,0x10,0x04,0x11,0x04,0x11,0x04,0x12,0x88,0x0C,0x70,0x00,0x00},/*"3",19*/
{0x00,0x00,0x00,0xE0,0x03,0x20,0x04,0x24,0x08,0x24,0x1F,0xFC,0x00,0x24,0x00,0x00},/*"4",20*/
{0x00,0x00,0x1F,0x98,0x10,0x84,0x11,0x04,0x11,0x04,0x10,0x88,0x10,0x70,0x00,0x00},/*"5",21*/
{0x00,0x00,0x07,0xF0,0x08,0x88,0x11,0x04,0x11,0x04,0x18,0x88,0x00,0x70,0x00,0x00},/*"6",22*/
{0x00,0x00,0x1C,0x00,0x10,0x00,0x10,0xFC,0x13,0x00,0x1C,0x00,0x10,0x00,0x00,0x00},/*"7",23*/
{0x00,0x00,0x0E,0x38,0x11,0x44,0x10,0x84,0x10,0x84,0x11,0x44,0x0E,0x38,0x00,0x00},/*"8",24*/
{0x00,0x00,0x07,0x00,0x08,0x8C,0x10,0x44,0x10,0x44,0x08,0x88,0x07,0xF0,0x00,0x00},/*"9",25*/
{0x00,0x00,0x00,0x00,0x00,0x00,0x03,0x0C,0x03,0x0C,0x00,0x00,0x00,0x00,0x00,0x00},/*":",26*/
{0x00,0x00,0x00,0x00,0x00,0x01,0x01,0x06,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},/*";",27*/
{0x00,0x00,0x00,0x80,0x01,0x40,0x02,0x20,0x04,0x10,0x08,0x08,0x10,0x04,0x00,0x00},/*"<",28*/
{0x02,0x20,0x02,0x20,0x02,0x20,0x02,0x20,0x02,0x20,0x02,0x20,0x02,0x20,0x00,0x00},/*"=",29*/
{0x00,0x00,0x10,0x04,0x08,0x08,0x04,0x10,0x02,0x20,0x01,0x40,0x00,0x80,0x00,0x00},/*">",30*/
{0x00,0x00,0x0E,0x00,0x12,0x00,0x10,0x0C,0x10,0x6C,0x10,0x80,0x0F,0x00,0x00,0x00},/*"?",31*/
{0x03,0xE0,0x0C,0x18,0x13,0xE4,0x14,0x24,0x17,0xC4,0x08,0x28,0x07,0xD0,0x00,0x00},/*"@",32*/
{0x00,0x04,0x00,0x3C,0x03,0xC4,0x1C,0x40,0x07,0x40,0x00,0xE4,0x00,0x1C,0x00,0x04},/*"A",33*/
{0x10,0x04,0x1F,0xFC,0x11,0x04,0x11,0x04,0x11,0x04,0x0E,0x88,0x00,0x70,0x00,0x00},/*"B",34*/
{0x03,0xE0,0x0C,0x18,0x10,0x04,0x10,0x04,0x10,0x04,0x10,0x08,0x1C,0x10,0x00,0x00},/*"C",35*/
{0x10,0x04,0x1F,0xFC,0x10,0x04,0x10,0x04,0x10,0x04,0x08,0x08,0x07,0xF0,0x00,0x00},/*"D",36*/
{0x10,0x04,0x1F,0xFC,0x11,0x04,0x11,0x04,0x17,0xC4,0x10,0x04,0x08,0x18,0x00,0x00},/*"E",37*/
{0x10,0x04,0x1F,0xFC,0x11,0x04,0x11,0x00,0x17,0xC0,0x10,0x00,0x08,0x00,0x00,0x00},/*"F",38*/
{0x03,0xE0,0x0C,0x18,0x10,0x04,0x10,0x04,0x10,0x44,0x1C,0x78,0x00,0x40,0x00,0x00},/*"G",39*/
{0x10,0x04,0x1F,0xFC,0x10,0x84,0x00,0x80,0x00,0x80,0x10,0x84,0x1F,0xFC,0x10,0x04},/*"H",40*/
{0x00,0x00,0x10,0x04,0x10,0x04,0x1F,0xFC,0x10,0x04,0x10,0x04,0x00,0x00,0x00,0x00},/*"I",41*/
{0x00,0x03,0x00,0x01,0x10,0x01,0x10,0x01,0x1F,0xFE,0x10,0x00,0x10,0x00,0x00,0x00},/*"J",42*/
{0x10,0x04,0x1F,0xFC,0x11,0x04,0x03,0x80,0x14,0x64,0x18,0x1C,0x10,0x04,0x00,0x00},/*"K",43*/
{0x10,0x04,0x1F,0xFC,0x10,0x04,0x00,0x04,0x00,0x04,0x00,0x04,0x00,0x0C,0x00,0x00},/*"L",44*/
{0x10,0x04,0x1F,0xFC,0x1F,0x00,0x00,0xFC,0x1F,0x00,0x1F,0xFC,0x10,0x04,0x00,0x00},/*"M",45*/
{0x10,0x04,0x1F,0xFC,0x0C,0x04,0x03,0x00,0x00,0xE0,0x10,0x18,0x1F,0xFC,0x10,0x00},/*"N",46*/
{0x07,0xF0,0x08,0x08,0x10,0x04,0x10,0x04,0x10,0x04,0x08,0x08,0x07,0xF0,0x00,0x00},/*"O",47*/
{0x10,0x04,0x1F,0xFC,0x10,0x84,0x10,0x80,0x10,0x80,0x10,0x80,0x0F,0x00,0x00,0x00},/*"P",48*/
{0x07,0xF0,0x08,0x18,0x10,0x24,0x10,0x24,0x10,0x1C,0x08,0x0A,0x07,0xF2,0x00,0x00},/*"Q",49*/
{0x10,0x04,0x1F,0xFC,0x11,0x04,0x11,0x00,0x11,0xC0,0x11,0x30,0x0E,0x0C,0x00,0x04},/*"R",50*/
{0x00,0x00,0x0E,0x1C,0x11,0x04,0x10,0x84,0x10,0x84,0x10,0x44,0x1C,0x38,0x00,0x00},/*"S",51*/
{0x18,0x00,0x10,0x00,0x10,0x04,0x1F,0xFC,0x10,0x04,0x10,0x00,0x18,0x00,0x00,0x00},/*"T",52*/
{0x10,0x00,0x1F,0xF8,0x10,0x04,0x00,0x04,0x00,0x04,0x10,0x04,0x1F,0xF8,0x10,0x00},/*"U",53*/
{0x10,0x00,0x1E,0x00,0x11,0xE0,0x00,0x1C,0x00,0x70,0x13,0x80,0x1C,0x00,0x10,0x00},/*"V",54*/
{0x1F,0xC0,0x10,0x3C,0x00,0xE0,0x1F,0x00,0x00,0xE0,0x10,0x3C,0x1F,0xC0,0x00,0x00},/*"W",55*/
{0x10,0x04,0x18,0x0C,0x16,0x34,0x01,0xC0,0x01,0xC0,0x16,0x34,0x18,0x0C,0x10,0x04},/*"X",56*/
{0x10,0x00,0x1C,0x00,0x13,0x04,0x00,0xFC,0x13,0x04,0x1C,0x00,0x10,0x00,0x00,0x00},/*"Y",57*/
{0x08,0x04,0x10,0x1C,0x10,0x64,0x10,0x84,0x13,0x04,0x1C,0x04,0x10,0x18,0x00,0x00},/*"Z",58*/
{0x00,0x00,0x00,0x00,0x00,0x00,0x7F,0xFE,0x40,0x02,0x40,0x02,0x40,0x02,0x00,0x00},/*"[",59*/
{0x00,0x00,0x30,0x00,0x0C,0x00,0x03,0x80,0x00,0x60,0x00,0x1C,0x00,0x03,0x00,0x00},/*"\",60*/
{0x00,0x00,0x40,0x02,0x40,0x02,0x40,0x02,0x7F,0xFE,0x00,0x00,0x00,0x00,0x00,0x00},/*"]",61*/
{0x00,0x00,0x00,0x00,0x20,0x00,0x40,0x00,0x40,0x00,0x40,0x00,0x20,0x00,0x00,0x00},/*"^",62*/
{0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01,0x00,0x01},/*"_",63*/
{0x00,0x00,0x40,0x00,0x40,0x00,0x20,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00},/*"`",64*/
{0x00,0x00,0x00,0x98,0x01,0x24,0x01,0x44,0x01,0x44,0x01,0x44,0x00,0xFC,0x00,0x04},/*"a",65*/
{0x10,0x00,0x1F,0xFC,0x00,0x88,0x01,0x04,0x01,0x04,0x00,0x88,0x00,0x70,0x00,0x00},/*"b",66*/
{0x00,0x00,0x00,0x70,0x00,0x88,0x01,0x04,0x01,0x04,0x01,0x04,0x00,0x88,0x00,0x00},/*"c",67*/
{0x00,0x00,0x00,0x70,0x00,0x88,0x01,0x04,0x01,0x04,0x11,0x08,0x1F,0xFC,0x00,0x04},/*"d",68*/
{0x00,0x00,0x00,0xF8,0x01,0x44,0x01,0x44,0x01,0x44,0x01,0x44,0x00,0xC8,0x00,0x00},/*"e",69*/
{0x00,0x00,0x01,0x04,0x01,0x04,0x0F,0xFC,0x11,0x04,0x11,0x04,0x11,0x00,0x18,0x00},/*"f",70*/
{0x00,0x00,0x00,0xD6,0x01,0x29,0x01,0x29,0x01,0x29,0x01,0xC9,0x01,0x06,0x00,0x00},/*"g",71*/
{0x10,0x04,0x1F,0xFC,0x00,0x84,0x01,0x00,0x01,0x00,0x01,0x04,0x00,0xFC,0x00,0x04},/*"h",72*/
{0x00,0x00,0x01,0x04,0x19,0x04,0x19,0xFC,0x00,0x04,0x00,0x04,0x00,0x00,0x00,0x00},/*"i",73*/
{0x00,0x00,0x00,0x03,0x00,0x01,0x01,0x01,0x19,0x01,0x19,0xFE,0x00,0x00,0x00,0x00},/*"j",74*/
{0x10,0x04,0x1F,0xFC,0x00,0x24,0x00,0x40,0x01,0xB4,0x01,0x0C,0x01,0x04,0x00,0x00},/*"k",75*/
{0x00,0x00,0x10,0x04,0x10,0x04,0x1F,0xFC,0x00,0x04,0x00,0x04,0x00,0x00,0x00,0x00},/*"l",76*/
{0x01,0x04,0x01,0xFC,0x01,0x04,0x01,0x00,0x01,0xFC,0x01,0x04,0x01,0x00,0x00,0xFC},/*"m",77*/
{0x01,0x04,0x01,0xFC,0x00,0x84,0x01,0x00,0x01,0x00,0x01,0x04,0x00,0xFC,0x00,0x04},/*"n",78*/
{0x00,0x00,0x00,0xF8,0x01,0x04,0x01,0x04,0x01,0x04,0x01,0x04,0x00,0xF8,0x00,0x00},/*"o",79*/
{0x01,0x01,0x01,0xFF,0x00,0x85,0x01,0x04,0x01,0x04,0x00,0x88,0x00,0x70,0x00,0x00},/*"p",80*/
{0x00,0x00,0x00,0x70,0x00,0x88,0x01,0x04,0x01,0x04,0x01,0x05,0x01,0xFF,0x00,0x01},/*"q",81*/
{0x01,0x04,0x01,0x04,0x01,0xFC,0x00,0x84,0x01,0x04,0x01,0x00,0x01,0x80,0x00,0x00},/*"r",82*/
{0x00,0x00,0x00,0xCC,0x01,0x24,0x01,0x24,0x01,0x24,0x01,0x24,0x01,0x98,0x00,0x00},/*"s",83*/
{0x00,0x00,0x01,0x00,0x01,0x00,0x07,0xF8,0x01,0x04,0x01,0x04,0x00,0x00,0x00,0x00},/*"t",84*/
{0x01,0x00,0x01,0xF8,0x00,0x04,0x00,0x04,0x00,0x04,0x01,0x08,0x01,0xFC,0x00,0x04},/*"u",85*/
{0x01,0x00,0x01,0x80,0x01,0x70,0x00,0x0C,0x00,0x10,0x01,0x60,0x01,0x80,0x01,0x00},/*"v",86*/
{0x01,0xF0,0x01,0x0C,0x00,0x30,0x01,0xC0,0x00,0x30,0x01,0x0C,0x01,0xF0,0x01,0x00},/*"w",87*/
{0x00,0x00,0x01,0x04,0x01,0x8C,0x00,0x74,0x01,0x70,0x01,0x8C,0x01,0x04,0x00,0x00},/*"x",88*/
{0x01,0x01,0x01,0x81,0x01,0x71,0x00,0x0E,0x00,0x18,0x01,0x60,0x01,0x80,0x01,0x00},/*"y",89*/
{0x00,0x00,0x01,0x84,0x01,0x0C,0x01,0x34,0x01,0x44,0x01,0x84,0x01,0x0C,0x00,0x00},/*"z",90*/
{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x01,0x00,0x3E,0xFC,0x40,0x02,0x40,0x02},/*"{",91*/
{0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00,0xFF,0xFF,0x00,0x00,0x00,0x00,0x00,0x00},/*"|",92*/
{0x00,0x00,0x40,0x02,0x40,0x02,0x3E,0xFC,0x01,0x00,0x00,0x00,0x00,0x00,0x00,0x00},/*"}",93*/
{0x00,0x00,0x60,0x00,0x80,0x00,0x80,0x00,0x40,0x00,0x40,0x00,0x20,0x00,0x20,0x00},/*"~",94*/
};


struct i2c_client *ssd1306_client;

static void ssd1306_write_byte(uint8_t chData, uint8_t chCmd) 
{
    uint8_t cmd = 0x00;
    uint8_t tmp[2];    

    memset(tmp,0,2);

    if (chCmd) {
        cmd = 0x40;
    } else {
        cmd = 0x00;
    }

    tmp[0] = cmd;
    tmp[1] = chData;

    i2c_master_send(ssd1306_client, tmp , 2);
}

#if 0
int ssd1306_read_bytes(uint8_t *data, uint16_t len)
{
        return i2c_master_recv(ssd1306_client, data, len);
}
#endif


void ssd1306_display_on(void)
{
	printk(KERN_INFO "ssd1306_display_on\n");
    ssd1306_write_byte(0x8D, SSD1306_CMD);  
    ssd1306_write_byte(0x14, SSD1306_CMD);  
    ssd1306_write_byte(0xAF, SSD1306_CMD);  
}
  
/**
  * @brief  OLED turns off
  *        
  * @param  None
  *        
  * @retval  None
**/
void ssd1306_display_off(void)
{
    ssd1306_write_byte(0x8D, SSD1306_CMD);  
    ssd1306_write_byte(0x10, SSD1306_CMD); 
    ssd1306_write_byte(0xAE, SSD1306_CMD);  
}

void ssd1306_refresh_gram(void)
{
    uint8_t i, j;
    
    for (i = 0; i < 8; i ++) {  
        ssd1306_write_byte(0xB0 + i, SSD1306_CMD);    
        ssd1306_write_byte(0x02, SSD1306_CMD); 
        ssd1306_write_byte(0x10, SSD1306_CMD);    
        for (j = 0; j < 128; j ++) {
            ssd1306_write_byte(s_chDispalyBuffer[j][i], SSD1306_DAT); 
        }
    }  
}


void ssd1306_clear_screen(uint8_t chFill)  
{ 
    memset(s_chDispalyBuffer,chFill, sizeof(s_chDispalyBuffer));
    ssd1306_refresh_gram();
}

/**
  * @brief  Draws a piont on the screen
  *        
  * @param  chXpos: Specifies the X position
  * @param  chYpos: Specifies the Y position
  * @param  chPoint: 0: the point turns off    1: the piont turns on 
  *        
  * @retval None
**/

void ssd1306_draw_point(uint8_t chXpos, uint8_t chYpos, uint8_t chPoint)
{
    uint8_t chPos, chBx, chTemp = 0;
    
    if (chXpos > 127 || chYpos > 63) {
        return;
    }
    chPos = 7 - chYpos / 8; // 
    chBx = chYpos % 8;
    chTemp = 1 << (7 - chBx);
    
    if (chPoint) {
        s_chDispalyBuffer[chXpos][chPos] |= chTemp;
        
    } else {
        s_chDispalyBuffer[chXpos][chPos] &= ~chTemp;
    }
}
      
/**
  * @brief  Fills a rectangle
  *        
  * @param  chXpos1: Specifies the X position 1 (X top left position)
  * @param  chYpos1: Specifies the Y position 1 (Y top left position)
  * @param  chXpos2: Specifies the X position 2 (X bottom right position)
  * @param  chYpos3: Specifies the Y position 2 (Y bottom right position)
  *        
  * @retval 
**/

void ssd1306_fill_screen(uint8_t chXpos1, uint8_t chYpos1, uint8_t chXpos2, uint8_t chYpos2, uint8_t chDot)  
{  
    uint8_t chXpos, chYpos; 
    
    for (chXpos = chXpos1; chXpos <= chXpos2; chXpos ++) {
        for (chYpos = chYpos1; chYpos <= chYpos2; chYpos ++) {
            ssd1306_draw_point(chXpos, chYpos, chDot);
        }
    }    
    
    ssd1306_refresh_gram();
}


/**
  * @brief Displays one character at the specified position    
  *        
  * @param  chXpos: Specifies the X position
  * @param  chYpos: Specifies the Y position
  * @param  chSize: 
  * @param  chMode
  * @retval 
**/
void ssd1306_display_char(uint8_t chXpos, uint8_t chYpos, uint8_t chChr, uint8_t chSize, uint8_t chMode)
{          
    uint8_t i, j;
    uint8_t chTemp, chYpos0 = chYpos;
    
    chChr = chChr - ' ';                  
    for (i = 0; i < chSize; i ++) {  
        if (chMode) {
            chTemp = c_chFont1608[chChr][i];
        } else {
            chTemp = ~c_chFont1608[chChr][i];
        }
        
        for (j = 0; j < 8; j ++) {
            if (chTemp & 0x80) {
                ssd1306_draw_point(chXpos, chYpos, 1);
            } else {
                ssd1306_draw_point(chXpos, chYpos, 0);
            }
            chTemp <<= 1;
            chYpos ++;
            
            if ((chYpos - chYpos0) == chSize) {
                chYpos = chYpos0;
                chXpos ++;
                break;
            }
        }      
    } 
}   

/**
  * @brief  Displays a string on the screen
  *        
  * @param  chXpos: Specifies the X position
  * @param  chYpos: Specifies the Y position
  * @param  pchString: Pointer to a string to display on the screen 
  *        
  * @retval  None
**/
void ssd1306_display_string(uint8_t chXpos, uint8_t chYpos, const uint8_t *pchString, uint8_t chSize, uint8_t chMode)
{
    while (*pchString != '\0') {      
        if (chXpos > (SSD1306_WIDTH - chSize / 2)) {
            chXpos = 0;
            chYpos += chSize;
            if (chYpos > (SSD1306_HEIGHT - chSize)) {
                chYpos = chXpos = 0;
                ssd1306_clear_screen(0x00);
            }
        }
        
        ssd1306_display_char(chXpos, chYpos, *pchString, chSize, chMode);
        chXpos += chSize / 2;
        pchString ++;
    }
}


void ssd1306_init(void)
{

	printk(KERN_INFO "ssd1306_init\n");
    ssd1306_write_byte(0xAE, SSD1306_CMD);//--turn off oled panel
    ssd1306_write_byte(0x00, SSD1306_CMD);//---set low column address
    ssd1306_write_byte(0x10, SSD1306_CMD);//---set high column address
    ssd1306_write_byte(0x40, SSD1306_CMD);//--set start line address  Set Mapping RAM Display Start Line (0x00~0x3F)
    ssd1306_write_byte(0x81, SSD1306_CMD);//--set contrast control register
    ssd1306_write_byte(0xCF, SSD1306_CMD);// Set SEG Output Current Brightness
    ssd1306_write_byte(0xA1, SSD1306_CMD);//--Set SEG/Column Mapping    
    ssd1306_write_byte(0xC0, SSD1306_CMD);//Set COM/Row Scan Direction  
    ssd1306_write_byte(0xA6, SSD1306_CMD);//--set normal display
    ssd1306_write_byte(0xA8, SSD1306_CMD);//--set multiplex ratio(1 to 64)
    ssd1306_write_byte(0x3f, SSD1306_CMD);//--1/64 duty
    ssd1306_write_byte(0xD3, SSD1306_CMD);//-set display offset    Shift Mapping RAM Counter (0x00~0x3F)
    ssd1306_write_byte(0x00, SSD1306_CMD);//-not offset
    ssd1306_write_byte(0xd5, SSD1306_CMD);//--set display clock divide ratio/oscillator frequency
    ssd1306_write_byte(0x80, SSD1306_CMD);//--set divide ratio, Set Clock as 100 Frames/Sec
    ssd1306_write_byte(0xD9, SSD1306_CMD);//--set pre-charge period
    ssd1306_write_byte(0xF1, SSD1306_CMD);//Set Pre-Charge as 15 Clocks & Discharge as 1 Clock
    ssd1306_write_byte(0xDA, SSD1306_CMD);//--set com pins hardware configuration
    ssd1306_write_byte(0x12, SSD1306_CMD);
    ssd1306_write_byte(0xDB, SSD1306_CMD);//--set vcomh
    ssd1306_write_byte(0x40, SSD1306_CMD);//Set VCOM Deselect Level
    ssd1306_write_byte(0x20, SSD1306_CMD);//-Set Page Addressing Mode (0x00/0x01/0x02)
    ssd1306_write_byte(0x02, SSD1306_CMD);//
    ssd1306_write_byte(0x8D, SSD1306_CMD);//--set Charge Pump enable/disable
    ssd1306_write_byte(0x14, SSD1306_CMD);//--set(0x10) disable
    ssd1306_write_byte(0xA4, SSD1306_CMD);// Disable Entire Display On (0xa4/0xa5)
    ssd1306_write_byte(0xA6, SSD1306_CMD);// Disable Inverse Display On (0xa6/a7) 
    ssd1306_write_byte(0xAF, SSD1306_CMD);//--turn on oled panel
    ssd1306_display_on();
    ssd1306_clear_screen(0xff);
    
}

#if 0
static int ssd1306_detect(struct i2c_adapter *adapter, int address, int kind)
{    
    printk(KERN_INFO "ssd1306_detect\n");

    ssd1306_client = kzalloc(sizeof(struct i2c_client), GFP_KERNEL);
    ssd1306_client->addr    = address;
    ssd1306_client->adapter = adapter;
    ssd1306_client->driver  = &ssd1306_driver;
    strcpy(ssd1306_client->name, "ssd1306");
    
    i2c_attach_client(ssd1306_client);
    
    ssd1306_init();

    ssd1306_clear_screen(0x00);
    ssd1306_display_off();

    ssd1306_display_string(18, 0, "hello, Linux!", 16, 1);
    ssd1306_display_string(0, 16, "this is an i2c driver demo!", 16, 1);
    ssd1306_refresh_gram();
    ssd1306_display_on();
    
    return 0;
}

static int ssd1306_probe(struct i2c_adapter *adapter)
{
    return i2c_probe(adapter, &addr_data, ssd1306_detect);
}
#endif

static int ssd1306_probe(struct i2c_client *client, const struct i2c_device_id *id)
{
	int err;

	printk(KERN_INFO "________________________ssd1306_probe\n");
	
	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
                err = -ENODEV;
                return err;
        }

	ssd1306_client = client;
        ssd1306_client->addr = client->addr;

	ssd1306_dev = kzalloc(sizeof(*ssd1306_dev),GFP_KERNEL);
        if(!ssd1306_dev)
        {
                err = -ENOMEM;
                return -1;
        }

        i2c_set_clientdata(ssd1306_client, ssd1306_dev);	

	ssd1306_init();

	ssd1306_clear_screen(0x00);
	ssd1306_display_off();

	ssd1306_display_string(18, 0, "hello, Linux!", 16, 1);
	ssd1306_display_string(0, 16, "this is an i2c driver demo!", 16, 1);
	ssd1306_refresh_gram();
	ssd1306_display_on();

	printk(KERN_INFO "ssd1306_work_ok\n");

	return 0;
}


static int __devexit  ssd1306_remove(struct i2c_client *client)
{
    printk(KERN_INFO "ssd1306_detach\n");

    ssd1306_display_off();
    ssd1306_clear_screen(0x00);

    return 0;
}

static const struct i2c_device_id ssd1306_id[]={
        {"ssd1306", 0},
        { },
};

static struct i2c_driver ssd1306_driver = {
    .driver = {
            .name    = "ssd1306",
            .owner   = THIS_MODULE,
        },
    .probe   = ssd1306_probe,
    .remove  = __devexit_p(ssd1306_remove),
    .id_table =  ssd1306_id,

};


static int __init ssd1306_module_init(void)
{
    int ret = -1;

    printk(KERN_INFO "ssd1306 driver init...\n");
    ret = i2c_add_driver(&ssd1306_driver);
    if(ret < 0)
	printk(KERN_INFO "add ssd1306 driver fail......\n");
    return ret;
}

static void __exit ssd1306_module_exit(void)
{
    printk(KERN_INFO "ssd1306 driver exit...\n");
    i2c_del_driver(&ssd1306_driver);
}

module_init(ssd1306_module_init);
module_exit(ssd1306_module_exit);

MODULE_AUTHOR("songxingjia@china-cpu.com");
MODULE_DESCRIPTION("OLED SSD1306 DRIVER");
MODULE_LICENSE("GPL");