s3c2440液晶屏驱动 （非内核自带） linux-4.1.24

对于，不想逐一检查内核自带驱动，想自己编写驱动。

1，make menuconfig 去掉 编译到内核，改为 M 编译为 模块（因为要用到里面的3个.ko 驱动）

Device Drivers --->
    Graphics support --->
        Support for frame buffer devices --->
            <M> S3C2410 LCD framebuffer support

2，make uImage && make modules 生成新内核  和 模块文件

烧写新内核或使用 nfs bootm 使用编译为 M 模块的内核启动。

复制 3个 ko 文件到 文件系统，这里用的是 NFS 网络文件系统。

cp drivers/video/fbdev/core/cfb*.ko /nfs_root/new_fs  (新的 4.1 内核是在这里，以前没有 这个 core 目录)

3, 使用原来的 2.6.22 的内核下的驱动程序，修改头文件后，编译为 .ko 文件放到 NFS 文件系统里，启动，如图所示

图忘拍了，有时是白屏，有时是竖的细彩线。

比较内核自带驱动 s3c2410fb.c 发现有个 usleep_range(1000, 1100);

而原来的 2.6.22 的驱动里面，是没有启用 clk 的。添加上这部分后，重新编译，试机成功。

最后是完整的驱动源码：

 #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>

 #include <asm/mach/map.h>
 #include <mach/regs-lcd.h>
 #include <mach/regs-gpio.h>
 #include <mach/fb.h>

 //参数定义
 #define LCD_WIDTH 480
 #define LCD_HEIGHT 272
 #define LCD_BIT 16

 #define LCD_CLKVAL 4
 #define LCD_TFT    3
 #define LCD_24BBP  0xd
 #define LCD_16BBP  0xc
 #define LCD_EN_OFF 0
 #define LCD_EN_ON  1
 #define LCD_VBPD   1
 #define LCD_LINEVAL  (LCD_HEIGHT - 1)
 #define LCD_VFPD   1
 #define LCD_VSPW   9
 #define LCD_HBPD   1
 #define LCD_HOZVAL (LCD_WIDTH - 1)
 #define LCD_HFPD   1
 #define LCD_HSPW   40
 #define LCD_INVVLINE 1
 #define LCD_INVVFRAME 1
 //调色板 u32 = unsigned int
 static u32 pseudo_palette[];

 /* from pxafb.c */
 static inline unsigned int chan_to_field(unsigned int chan, struct fb_bitfield *bf)
 {
     //只取16bit 数据
     chan &= 0xffff;
     //如 r = 16-5 = 11 : 右移去掉不要的位
     chan >>= ( - bf->length);
     //在移到高位去 就是右边补0
     return chan << bf->offset;
 }

 static int s3c_lcdfb_setcolreg(unsigned int regno, unsigned int red,
                  unsigned int green, unsigned int blue,
                  unsigned int transp, struct fb_info *info)
 {

     if( > regno)
     {
         unsigned int 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);
         pseudo_palette[regno] = val;
         return ;
     }
     return ;
 }

 static struct fb_ops s3c_ops = {
     .owner        = THIS_MODULE,
     .fb_setcolreg    = s3c_lcdfb_setcolreg,
     .fb_fillrect    = cfb_fillrect,
     .fb_copyarea    = cfb_copyarea,
     .fb_imageblit    = cfb_imageblit,
 };

 //定义GPIO
 static volatile unsigned long *gpb_con;
 static volatile unsigned long *gpc_con;
 static volatile unsigned long *gpd_con;
 static volatile unsigned long *gpg_con;

 static volatile unsigned long *gpb_dat;
 static volatile unsigned long *gpc_dat;
 static volatile unsigned long *gpd_dat;
 static volatile unsigned long *gpg_dat;

 struct lcd_regs {
     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[];
     unsigned long    dithmode;
     unsigned long    tpal;
     unsigned long    lcdintpnd;
     unsigned long    lcdsrcpnd;
     unsigned long    lcdintmsk;
     unsigned long    lpcsel;
 };

 static volatile struct lcd_regs * lcd_reg;

 //定义fb_info
 static struct fb_info * s3c_lcd;
 static int lcd_init(void)
 {
     //1,分配一个fb_info
     s3c_lcd = framebuffer_alloc(, NULL);

     struct clk *clk;
     clk = clk_get(NULL, "lcd");
     if (IS_ERR(clk)) {
         printk("failed to get lcd clock source\n");
     }

     clk_prepare_enable(clk);
     printk("got and enabled clock\n");

     usleep_range(, );

     //2,设置
     //2,1 设置固定的参数
     strcpy(s3c_lcd->fix.id, "mylcd");
     s3c_lcd->fix.smem_len  = LCD_WIDTH * LCD_HEIGHT * LCD_BIT / ;
     s3c_lcd->fix.type        = FB_TYPE_PACKED_PIXELS;
     s3c_lcd->fix.visual      = FB_VISUAL_TRUECOLOR;
     s3c_lcd->fix.line_length = LCD_WIDTH * LCD_BIT / ; //单位 bytes
     //物理地址由 dma_alloc_writecombine 函数分配
     //s3c_lcd->fix.smem_start  = LCD_FRAMEBUFFER;
     //s3c_lcd->fix.mmio_len    = LCD_WIDTH * LCD_HEIGHT * LCD_BIT / 8;

     //2,2 设置可变的参数
     s3c_lcd->var.width  = LCD_WIDTH;
     s3c_lcd->var.height = LCD_HEIGHT;
     s3c_lcd->var.xres         = LCD_WIDTH;
     s3c_lcd->var.yres         = LCD_HEIGHT;
     s3c_lcd->var.xres_virtual = LCD_WIDTH;
     s3c_lcd->var.yres_virtual = LCD_HEIGHT;
     s3c_lcd->var.bits_per_pixel = LCD_BIT;
     //RGB 5 6 5
     s3c_lcd->var.red.length   = ;
     s3c_lcd->var.red.offset   = ;
     s3c_lcd->var.green.length = ;
     s3c_lcd->var.green.offset = ;
     s3c_lcd->var.blue.length  = ;
     s3c_lcd->var.blue.offset  = ;
     s3c_lcd->var.activate     = FB_ACTIVATE_NOW;

     s3c_lcd->var.pixclock = ;

     //2,3 设置操作函数
     s3c_lcd->fbops = &s3c_ops;

     //2.4 其它的设置
     s3c_lcd->screen_size = LCD_WIDTH * LCD_HEIGHT * LCD_BIT / ;
     s3c_lcd->pseudo_palette = pseudo_palette;

     //3,硬件相关的操作
     //3,1 配置GPIO
     gpb_con = ioremap(0x56000010, );
     gpb_dat = gpb_con + ;

     gpc_con = ioremap(0x56000020, );
     gpc_dat = gpc_con + ;

     gpd_con = ioremap(0x56000030, );
     gpc_dat = gpd_con + ;

     gpg_con = ioremap(0x56000060, );
     gpg_dat = gpg_con + ;

     *gpc_con = 0xaaaaaaaa;   // GPIO管脚用于VD[7:0],LCDVF[2:0],VM,VFRAME,VLINE,VCLK,LEND
     *gpd_con = 0xaaaaaaaa;   // GPIO管脚用于VD[23:8]

     *gpb_con &= ~();        //配置背光引脚为输出
     *gpb_con |= ;
     *gpb_dat &= ;           //默认输出低电平

     *gpg_con &= ~(<<*);   //GPGCON 4 配置为 LCD_POWER
     *gpg_con |= (<<*);

     //3,2 配置lcdcon1 ~ lcdcon5
     lcd_reg          = ioremap(0x4d000000, sizeof(struct lcd_regs));
     lcd_reg->lcdcon1 = LCD_CLKVAL<< | LCD_TFT<< | LCD_16BBP<< | LCD_EN_OFF;
     lcd_reg->lcdcon2 = LCD_VBPD<< | LCD_LINEVAL<< | LCD_VFPD<< | LCD_VSPW;
     lcd_reg->lcdcon3 = LCD_HBPD<< | LCD_HOZVAL<< | LCD_HFPD;
     lcd_reg->lcdcon4 = LCD_HSPW;
     lcd_reg->lcdcon5 = << | LCD_INVVLINE<< | LCD_INVVFRAME<< | ;
     //屏幕宽度 * 16bit 颜色值 / words : 1 words = 2 byte
     lcd_reg->lcdsaddr3 = LCD_WIDTH *  / ;

     //3,3 设置显存 bramebuffer, 并把地址告诉lcd 控制器
     s3c_lcd->screen_base = dma_alloc_writecombine(NULL, s3c_lcd->fix.smem_len, &s3c_lcd->fix.smem_start, GFP_KERNEL);

     lcd_reg->lcdsaddr1 = (s3c_lcd->fix.smem_start>>)<< | ((s3c_lcd->fix.smem_start>>) & 0x1fffff);
     lcd_reg->lcdsaddr2 = ((s3c_lcd->fix.smem_start + s3c_lcd->fix.smem_len)>>) & 0x1fffff;

     unsigned long saddr1,saddr2,saddr3;
     saddr1  = s3c_lcd->fix.smem_start >> ;
     saddr2  = s3c_lcd->fix.smem_start;
     saddr2 += s3c_lcd->fix.line_length * s3c_lcd->var.yres;
     saddr2 >>= ;
     saddr3 = S3C2410_OFFSIZE() |
      S3C2410_PAGEWIDTH((s3c_lcd->fix.line_length / ) & 0x3ff);

     lcd_reg->lcdsaddr1 = saddr1;
     lcd_reg->lcdsaddr2 = saddr2;
     lcd_reg->lcdsaddr3 = saddr3;

     printk("fb %x \n", LCD_CLKVAL<< | LCD_TFT<< | LCD_16BBP<< | LCD_EN_OFF);
     printk("fb %x \n", LCD_VBPD<< | LCD_LINEVAL<< | LCD_VFPD<< | LCD_VSPW);
     printk("fb %x \n", LCD_HBPD<< | LCD_HOZVAL<< | LCD_HFPD);
     printk("fb %x \n", LCD_HSPW);
     printk("fb %x \n", << | LCD_INVVLINE<< | LCD_INVVFRAME<< | );

     printk("fb %x \n", saddr1);
     printk("fb %x \n", saddr2);
     printk("fb %x \n", saddr3);

     //打开 LCD_POWER 背光
     lcd_reg->lcdcon1 |= LCD_EN_ON;
     *gpb_dat |= ;
     lcd_reg->lcdcon5 &= ~(<<);
     lcd_reg->lcdcon5 |=  (<<);

     //4,注册
     register_framebuffer(s3c_lcd);
     return ;
 }

 static void lcd_exit(void)
 {
     //关背光
     *gpb_dat &= ;
     lcd_reg->lcdcon5 &= ~(<<);
     lcd_reg->lcdcon1 &= LCD_EN_OFF;

     //注销显存
     dma_free_writecombine(NULL,s3c_lcd->fix.smem_len,s3c_lcd->screen_base,s3c_lcd->fix.smem_start);

     //注销
     framebuffer_release(s3c_lcd);

     //注销framebuf
     unregister_framebuffer(s3c_lcd);

     //取消map
     iounmap(gpb_con);
     iounmap(gpc_con);
     iounmap(gpd_con);
     iounmap(gpg_con);
     iounmap(lcd_reg);
 }

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

试验的时候要先加载那3个 .ko

insmod cfbcopyarea.ko
insmod cfbfillrect.ko
insmod cfbimgblt.ko
insmod lcd.ko  编译出来的 lcd 驱动