LCD程序步骤：1. 分配一个fb_info 2. 设置 3. 硬件相关的操作4. 注册 register_framebuffer 5.入口函数 6.出口函数
#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>static int s3c_lcdfb_setcolreg(unsigned int regno, unsigned int red,
unsigned int green, unsigned int blue, unsigned int transp, struct fb_info *info); 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[9]; unsigned long dithmode; unsigned long tpal; unsigned long lcdintpnd; unsigned long lcdsrcpnd; unsigned long lcdintmsk; unsigned long lpcsel;};//LCD控制器的寄存器，寄存器是4字节，所以要添加unsigned long reserved[9];static struct fb_ops s3c_lcdfb_ops = {
.owner = THIS_MODULE, .fb_setcolreg = s3c_lcdfb_setcolreg, .fb_fillrect = cfb_fillrect, .fb_copyarea = cfb_copyarea, .fb_imageblit = cfb_imageblit,}; static struct fb_info *s3c_lcd;static volatile unsigned long *gpbcon;static volatile unsigned long *gpbdat;static volatile unsigned long *gpccon;static volatile unsigned long *gpdcon;static volatile unsigned long *gpgcon;static volatile struct lcd_regs* lcd_regs;static u32 pseudo_palette[16]; /* from pxafb.c */static inline unsigned int chan_to_field(unsigned int chan, struct fb_bitfield *bf){ chan &= 0xffff; chan >>= 16 - bf->length; 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){ unsigned int val; if (regno > 16) return 1;/* 用red,green,blue三原色构造出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; pseudo_palette[regno] = val; return 0;}static int lcd_init(void)
{ /* 1. 分配一个fb_info */ s3c_lcd = framebuffer_alloc(0, NULL);/* 2. 设置 */
/* 2.1 设置固定的参数 */ strcpy(s3c_lcd->fix.id, "mylcd"); s3c_lcd->fix.smem_len = 240*320*16/8; //显存的长度=分辨率*每象素字节数 s3c_lcd->fix.type = FB_TYPE_PACKED_PIXELS; /* Packed Pixels */ s3c_lcd->fix.visual = FB_VISUAL_TRUECOLOR; /* TFT */ s3c_lcd->fix.line_length = 240*2; //每行的长度，以字节为单位/* 2.2 设置可变的参数 */ s3c_lcd->var.xres = 240; //x方向分辨率 s3c_lcd->var.yres = 320; //Y方向分辨率 s3c_lcd->var.xres_virtual = 240; //x方向虚拟分辨率 s3c_lcd->var.yres_virtual = 320; //Y方向虚拟分辨率 s3c_lcd->var.bits_per_pixel = 16; //每个象素使用多少位/* RGB:565 */
s3c_lcd->var.red.offset = 11; //红色偏移值为11 s3c_lcd->var.red.length = 5;//红色位长为5 s3c_lcd->var.green.offset = 5;//绿色偏移值为5 s3c_lcd->var.green.length = 6;//绿色位长为6s3c_lcd->var.blue.offset = 0;//绿色偏移值为0
s3c_lcd->var.blue.length = 5;//蓝色位长为5s3c_lcd->var.activate = FB_ACTIVATE_NOW; //使设置的值立即生效
/* 2.3 设置操作函数 */ s3c_lcd->fbops = &s3c_lcdfb_ops;/* 2.4 其他的设置 */ s3c_lcd->pseudo_palette = pseudo_palette; //存放调色板所调颜色的数组 //s3c_lcd->screen_base = ; /* 显存的虚拟地址 */ s3c_lcd->screen_size = 240*324*16/8;//显存的大小/* 3. 硬件相关的操作 */
/* 3.1 配置GPIO用于LCD */ gpbcon = ioremap(0x56000010, 8); gpbdat = gpbcon+1; gpccon = ioremap(0x56000020, 4); gpdcon = ioremap(0x56000030, 4); gpgcon = ioremap(0x56000060, 4);*gpccon = 0xaaaaaaaa; /* GPIO管脚用于VD[7:0],LCDVF[2:0],VM,VFRAME,VLINE,VCLK,LEND */
*gpdcon = 0xaaaaaaaa; /* GPIO管脚用于VD[23:8] */ *gpbcon &= ~(3); /* GPB0设置为输出引脚 */ *gpbcon |= 1; *gpbdat &= ~1; /* 输出低电平 */*gpgcon |= (3<<8); /* GPG4用作LCD_PWREN */
/* 3.2 根据LCD手册设置LCD控制器, 比如VCLK的频率等 */ lcd_regs = ioremap(0x4D000000, sizeof(struct lcd_regs)); //映射各lcd控制寄存器，/* bit[17:8]: VCLK = HCLK / [(CLKVAL+1) x 2], LCD手册P14
* 10MHz(100ns) = 100MHz / [(CLKVAL+1) x 2] * CLKVAL = 4 * bit[6:5]: 0b11, TFT LCD * bit[4:1]: 0b1100, 16 bpp for TFT * bit[0] : 0 = Disable the video output and the LCD control signal. */ lcd_regs->lcdcon1 = (4<<8) | (3<<5) | (0x0c<<1);/* 垂直方向的时间参数
* bit[31:24]: VBPD, VSYNC之后再过多长时间才能发出第1行数据 * LCD手册 T0-T2-T1=4 * VBPD=3 * bit[23:14]: 多少行, 320, 所以LINEVAL=320-1=319 * bit[13:6] : VFPD, 发出最后一行数据之后，再过多长时间才发出VSYNC * LCD手册T2-T5=322-320=2, 所以VFPD=2-1=1 * bit[5:0] : VSPW, VSYNC信号的脉冲宽度, LCD手册T1=1, 所以VSPW=1-1=0 */ lcd_regs->lcdcon2 = (3<<24) | (319<<14) | (1<<6) | (0<<0);/* 水平方向的时间参数
* bit[25:19]: HBPD, VSYNC之后再过多长时间才能发出第1行数据 * LCD手册 T6-T7-T8=17 * HBPD=16 * bit[18:8]: 多少列, 240, 所以HOZVAL=240-1=239 * bit[7:0] : HFPD, 发出最后一行里最后一个象素数据之后，再过多长时间才发出HSYNC * LCD手册T8-T11=251-240=11, 所以HFPD=11-1=10 */ lcd_regs->lcdcon3 = (16<<19) | (239<<8) | (10<<0);/* 水平方向的同步信号
* bit[7:0] : HSPW, HSYNC信号的脉冲宽度, LCD手册T7=5, 所以HSPW=5-1=4 */ lcd_regs->lcdcon4 = 4;
/* 信号的极性
* bit[11]: 1=565 format * bit[10]: 0 = The video data is fetched at VCLK falling edge * bit[9] : 1 = HSYNC信号要反转,即低电平有效 * bit[8] : 1 = VSYNC信号要反转,即低电平有效 * bit[6] : 0 = VDEN不用反转 * bit[3] : 0 = PWREN输出0 * bit[1] : 0 = BSWP * bit[0] : 1 = HWSWP 2440手册P413 */ lcd_regs->lcdcon5 = (1<<11) | (0<<10) | (1<<9) | (1<<8) | (1<<0);/* 3.3 分配显存(framebuffer), 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_regs->lcdsaddr1 = (s3c_lcd->fix.smem_start >> 1) & ~(3<<30);//存放起始地址 lcd_regs->lcdsaddr2 = ((s3c_lcd->fix.smem_start + s3c_lcd->fix.smem_len) >> 1) & 0x1fffff;//存放结束地址 lcd_regs->lcdsaddr3 = (240*16/16); /* 一行的长度(单位: 2字节) */ //s3c_lcd->fix.smem_start /* 显存的物理地址 *//* 启动LCD */ lcd_regs->lcdcon1 |= (1<<0); /* 使能LCD控制器 */ lcd_regs->lcdcon5 |= (1<<3); /* 使能LCD本身 */ *gpbdat |= 1; /* 输出高电平, 使能背光 *//* 4. 注册 */
register_framebuffer(s3c_lcd); return 0;}static void lcd_exit(void)
{ unregister_framebuffer(s3c_lcd); lcd_regs->lcdcon1 &= ~(1<<0); /* 关闭LCD本身 */ *gpbdat &= ~1; /* 关闭背光 */ dma_free_writecombine(NULL, s3c_lcd->fix.smem_len, s3c_lcd->screen_base, s3c_lcd->fix.smem_start); iounmap(lcd_regs); iounmap(gpbcon); iounmap(gpccon); iounmap(gpdcon); iounmap(gpgcon); framebuffer_release(s3c_lcd);}module_init(lcd_init);
module_exit(lcd_exit);MODULE_LICENSE("GPL");