#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/fb.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
#include <linux/interrupt.h>
#include <linux/workqueue.h>
#include <linux/wait.h>
#include <linux/platform_device.h>
#include <linux/clk.h> 
#include <asm/io.h>
#include <asm/uaccess.h>
#include <asm/div64.h> 
#include <asm/mach/map.h>
#include <asm/arch/regs-lcd.h>
#include <asm/arch/regs-gpio.h>
#include <asm/arch/fb.h>

/*LCD :  480*272     */
#define   LCD_xres     480        //LCD 行分辨率
#define   LCD_yres     272          //LCD列分辨率
 

/* GPIO prot   */
static unsigned long  *GPBcon;
static unsigned long  *GPCcon;
static unsigned long  *GPDcon;
static unsigned long  *GPGcon;  //GPG4:控制LCD信号 
static unsigned long  *GPBdat;   //GPB0: 控制背光


/* LCD control */ 
 struct  lcd_reg{  
              unsigned long    lcdcon1; 
              unsigned long       lcdcon2;  
              unsigned long       lcdcon3; 
              unsigned long       lcdcon4; 
              unsigned long       lcdcon5; 
              unsigned long       lcdsaddr1;     
              unsigned long       lcdsaddr2;     
              unsigned long       lcdsaddr3 ;
              unsigned long       redlut;   
              unsigned long       greenlut;
              unsigned long       bluelut;
              unsigned long       reserved[9];  
              unsigned long       dithmode;     
              unsigned long       tpal ;            
              unsigned long       lcdintpnd;
              unsigned long       lcdsrcpnd;
              unsigned long       lcdintmsk;
              unsigned long       tconsel;  
};

static struct lcd_reg  *lcd_reg;
 
static struct fb_info *my_lcd;    //定义一个全局变量
static u32 pseudo_palette[16];   //调色板数组,被fb_info->pseudo_palette调用

static inline unsigned int chan_to_field(unsigned int chan, struct fb_bitfield *bf)
{
/*内核中的单色都是16位,默认从左到右排列,比如G颜色[0x1f],那么chan就等于0XF800*/
       chan       &= 0xffff;
       chan       >>= 16 - bf->length;    //右移,将数据靠到位0上
       return chan << bf->offset;    //左移一定偏移值,放入16色数据中对应的位置
}

static int my_lcdfb_setcolreg(unsigned int regno, unsigned int red,unsigned int green, unsigned int blue,unsigned int transp, struct fb_info *info)      //设置调色板函数,供内核调用
{
       unsigned int val;      
       if (regno >=16)                //调色板数组不能大于15
              return 1;

       /* 用red,green,blue三个颜色值构造出16色数据val */
       val  = chan_to_field(red,      &info->var.red);
       val |= chan_to_field(green, &info->var.green);
       val |= chan_to_field(blue,      &info->var.blue);
      
       ((u32 *)(info->pseudo_palette))[regno] = val;     //放到调色板数组中
       return 0;
}


static struct fb_ops my_lcdfb_ops = {
      .owner           = THIS_MODULE,
      .fb_setcolreg  = my_lcdfb_setcolreg,//调用my_lcdfb_setcolreg()函数,来设置调色板fb_info-> pseudo_palette
      .fb_fillrect       = cfb_fillrect,     //填充矩形
      .fb_copyarea   = cfb_copyarea,     //复制数据
      .fb_imageblit  = cfb_imageblit,    //绘画图形,
};

static int lcd_init(void)
{
  /*1.申请一个fb_info结构体*/
  my_lcd= framebuffer_alloc(0,0); 

  /*2.设置fb_info*/
 
  /* 2.1设置固定的参数fb_info-> fix */
  /*my_lcd->fix.smem_start    物理地址后面注册MDA缓存区设置*/ 
  strcpy(my_lcd->fix.id, "mylcd");                       //名字
  my_lcd->fix.smem_len =LCD_xres*LCD_yres*2;             //地址长
  my_lcd->fix.type        =FB_TYPE_PACKED_PIXELS;
  my_lcd->fix.visual            =FB_VISUAL_TRUECOLOR;            //真彩色
  my_lcd->fix.line_length      =LCD_xres*2;               //LCD 一行的字节

  /* 2.2 设置可变的参数fb_info-> var  */
  my_lcd->var.xres        =LCD_xres;                          //可见屏X 分辨率
  my_lcd->var.yres        =LCD_yres;                          //可见屏y 分辨率
  my_lcd->var.xres_virtual     =LCD_xres;                   //虚拟屏x分辨率
  my_lcd->var.yres_virtual     =LCD_yres;                   //虚拟屏y分辨率
  my_lcd->var.xoffset           = 0;                     //虚拟到可见屏幕之间的行偏移
  my_lcd->var.yoffset           =0;                      //虚拟到可见屏幕之间的行偏移

  my_lcd->var.bits_per_pixel=16;                //像素为16BPP
  my_lcd->var.grayscale       =   0;            //灰色比例
 
  my_lcd->var.red.offset      =     11;
  my_lcd->var.red.length      =     5;
  my_lcd->var.green.offset  =       5;
  my_lcd->var.green.length  =       6;
  my_lcd->var.blue.offset     =     0;
  my_lcd->var.blue.length     =     5;

/* 2.3 设置操作函数fb_info-> fbops  */
  my_lcd->fbops                 = &my_lcdfb_ops;


  /* 2.4 设置fb_info 其它的成员  */ 
 /*my_lcd->screen_base    虚拟地址在后面注册MDA缓存区设置*/
  my_lcd->pseudo_palette   =pseudo_palette;            //保存调色板数组
  my_lcd->screen_size          =LCD_xres * LCD_yres *2;     //虚拟地址长

  /*3   设置硬件相关的操作*/
  /*3.1 配置LCD引脚*/
  GPBcon                     = ioremap(0x56000010, 8);
  GPBdat                     = GPBcon+1;
  GPCcon                     = ioremap(0x56000020, 4);
  GPDcon              　　　　= ioremap(0x56000030, 4);
  GPGcon            　　　　  = ioremap(0x56000060, 4);

  *GPBcon            &=~(0x03<<(0*2));
  *GPBcon            |= (0x01<<(0*2));     //PGB0背光
  *GPBdat            &=~(0X1<<0);           //关背光
  *GPCcon            =0xaaaaaaaa;
  *GPDcon            =0xaaaaaaaa;
  *GPGcon            |=(0x03<<(4*2));    //GPG4:LCD信号

  /*3.2 根据LCD手册设置LCD控制器,参考之前的裸机驱动*/
  lcd_reg=ioremap(0X4D000000, sizeof( lcd_reg) );
   /*HCLK:100Mhz */
   lcd_reg->lcdcon1     = (4<<8) | (0X3<<5) |  (0x0C<<1) ;
   lcd_reg->lcdcon2     = ((3)<<24) | (271<<14) |  ((1)<<6) |((0)<<0);
   lcd_reg->lcdcon3     = ((16)<<19) | (479<<8) | ((10));
   lcd_reg->lcdcon4     = (4);
   lcd_reg->lcdcon5     = (1<<11) | (1<<9) | (1<<8) |(1<<0);     

   lcd_reg->lcdcon1     &=~(1<<0);              // 关闭PWREN信号输出
   lcd_reg->lcdcon5     &=~(1<<3);              //禁止PWREN信号

 /* 3.3  分配显存(framebuffer),把地址告诉LCD控制器和fb_info*/
   my_lcd->screen_base=dma_alloc_writecombine(0,my_lcd->fix.smem_len,  &my_lcd->fix.smem_start, GFP_KERNEL);

   /*lcd控制器的地址必须是物理地址*/
   lcd_reg->lcdsaddr1 =(my_lcd->fix.smem_start>>1)&0X3FFFFFFF;  //保存缓冲起始地址A[30:1]  
   lcd_reg->lcdsaddr2 =((my_lcd->fix.smem_start+my_lcd->screen_size)>>1)&0X1FFFFF; //保存存缓冲结束地址A[21:1]
   lcd_reg->lcdsaddr3 =LCD_xres& 0x3ff;　　　　　　　　//OFFSIZE[21:11]:保存LCD上一行结尾和下一行开头的地址之间的差
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　  //PAGEWIDTH [10:0]:保存LCD一行占的宽度(半字数为单位)

   /*4开启LCD,并注册fb_info: register_framebuffer()*/
   /*4.1 直接在init函数中开启LCD(后面讲到电源管理,再来优化)*/
  lcd_reg->lcdcon1      |=1<<0;         //输出PWREN信号
  lcd_reg->lcdcon5      |=1<<3;        //允许PWREN信号
  *GPBdat                   |=(0X1<<0);           //开背光

   /*4.2 注册fb_info*/
   register_framebuffer(my_lcd);
   return 0;
}

static int lcd_exit(void)
{
   /* 1卸载内核中的fb_info*/
     unregister_framebuffer(my_lcd);

  /*2 控制LCDCON1关闭PWREN信号,关背光,iounmap注销地址*/
   lcd_reg->lcdcon1 &=~(1<<0);              // 关闭PWREN信号输出
   lcd_reg->lcdcon5 &=~(1<<3);            //禁止PWREN信号
   *GPBdat            &=~(0X1<<4);           //关背光
   iounmap(GPBcon);
   iounmap(GPCcon);
   iounmap(GPDcon);
   iounmap(GPGcon);

  /*3.释放DMA缓存地址dma_free_writecombine()*/
  dma_free_writecombine(0,my_lcd->screen_size,my_lcd->screen_base,my_lcd->fix.smem_start);

   /*4.释放注册的fb_info*/
   framebuffer_release(my_lcd);

   return 0;
}

module_init(lcd_init);
module_exit(lcd_exit);
MODULE_LICENSE("GPL");