学习笔记 --- LINUX LCD显示原理与驱动分析
在分析驱动之前，先来分析下显示原理，这里以S3C2440为例，看下这个芯片的LCD控制器时序图：
VSYNC ：帧数据脉冲，脉冲换屏，表示一屏数据开始
HSYNC ：行数据脉冲，脉冲换行，表示一行数据开始
LEND ：行结束脉冲，脉冲表示一行结束
VDEN ：数据使能，表示VD可以发数据
VCLK ：基准时钟，脉冲送往数据线送一次数据
VD ：数据
这些都是硬件管脚信号线，从图中可以看出一行中有效数据是HOZVAL+1个像素，(HSPW+1)+(HBPD+1)是屏幕左边黑框的像素，HFPD+1是屏幕右边黑框的像素，一般设置为左边等于右边，上边等于下边，iphone手机有很明显的黑框。那么上边就是(VSPW+1)+(VBPD+1)行，下边就是VFPD+1行，中间有效数据是LINEVAL+1行。假设LCD为240X320那么时序对应的显示图像就是(截图自韦东山老师)：
外面的大框表示LCD黑框，里面表示真正显示的有效数据240X320。接下来说下显示16bpp图像的原理：
16bpp图像意思就是一个像素要用16个位来表示，那么就有2的16次方种颜色，一个像素16位，占2个字节，一屏240X320像素，那么一屏数据占240X320X2个字节，所以显存至少要这么大的空间。一个像素由红绿蓝三原色构成，所以这两个字节包含了红绿蓝三种颜色的信息，他们的占用bit数的比率为5：6：5，也可以是5：5：5，先只说5：6：5格式的，5+6+5=16bit，高位到低位分别表示5位红色，6位绿色，5位蓝色组成了一个两字节数据放在显存区里面，然后LCD控制器将其搬到LCD上显示出来，他们在显存里面的存放有两种方式：
一般选择下面这种方式，先放低16位，再放高16位，S3C2440默认是小端存储，所以这样低位对应低地址，刚好可以对应起来；那么从显存传输到LCD时数据线[0-23]传输的格式如何？
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分析了原理，下面看驱动，LCD的驱动核心在内核fbmem.c里面，分析驱动从入口开始：
static int __init fbmem_init(void)
{
proc_create("fb", 0, NULL, &fb_proc_fops);
if (register_chrdev(FB_MAJOR,"fb",&fb_fops)) //注册为字符设备驱动，主设备号为FB_MAJOR
printk("unable to get major %d for fb devs\n", FB_MAJOR);
fb_class = class_create(THIS_MODULE, "graphics"); //创建类
if (IS_ERR(fb_class)) {
printk(KERN_WARNING "Unable to create fb class; errno = %ld\n", PTR_ERR(fb_class));
fb_class = NULL;
}
return 0;
}static const struct file_operations fb_fops = {
.owner = THIS_MODULE,
.read = fb_read,
.write = fb_write,
.unlocked_ioctl = fb_ioctl,
#ifdef CONFIG_COMPAT
.compat_ioctl = fb_compat_ioctl,
#endif
.mmap = fb_mmap,
.open = fb_open,
.release = fb_release,
#ifdef HAVE_ARCH_FB_UNMAPPED_AREA
.get_unmapped_area = get_fb_unmapped_area,
#endif
#ifdef CONFIG_FB_DEFERRED_IO
.fsync = fb_deferred_io_fsync,
#endif
};static int
fb_open(struct inode *inode, struct file *file)
__acquires(&info->lock)
__releases(&info->lock)
{
int fbidx = iminor(inode);
struct fb_info *info;
int res = 0;
if (fbidx >= FB_MAX)
return -ENODEV;
info = registered_fb[fbidx]; //这里从数组传入一个info
if (!info)
request_module("fb%d", fbidx);
info = registered_fb[fbidx];
if (!info)
return -ENODEV;
mutex_lock(&info->lock);
if (!try_module_get(info->fbops->owner)) {
res = -ENODEV;
goto out;
}
file->private_data = info;
if (info->fbops->fb_open) {
res = info->fbops->fb_open(info,1); //调用info的打开函数
if (res)
module_put(info->fbops->owner);
}
#ifdef CONFIG_FB_DEFERRED_IO
if (info->fbdefio)
fb_deferred_io_open(info, inode, file);
#endif
out:
mutex_unlock(&info->lock);
return res;
}static ssize_t
fb_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
unsigned long p = *ppos;
struct inode *inode = file->f_path.dentry->d_inode;
int fbidx = iminor(inode);
struct fb_info *info = registered_fb[fbidx];//熟悉吧，我们又看到这个数组了
u32 *buffer, *dst;
u32 __iomem *src;
int c, i, cnt = 0, err = 0;
unsigned long total_size;
if (!info || ! info->screen_base)//跟那个数组有关
return -ENODEV;
if (info->state != FBINFO_STATE_RUNNING)//跟那个数组有关
return -EPERM;
if (info->fbops->fb_read)//如果操作函数集里定义了read函数，就调用，否则就算了
return info->fbops->fb_read(info, buf, count, ppos);
total_size = info->screen_size;//跟那个数组有关
if (total_size == 0)
total_size = info->fix.smem_len;//跟那个数组有关
if (p >= total_size)
return 0;
if (count >= total_size)
count = total_size;
if (count + p > total_size)
count = total_size - p;
buffer = kmalloc((count > PAGE_SIZE) ? PAGE_SIZE : count,//开辟一个buffer
GFP_KERNEL);
if (!buffer)
return -ENOMEM;
src = (u32 __iomem *) (info->screen_base + p);//显存基地址也在里面
if (info->fbops->fb_sync)
info->fbops->fb_sync(info);
while (count) {
c = (count > PAGE_SIZE) ? PAGE_SIZE : count;
dst = buffer;//目的指针指向一个buffer（我们在上面开辟的）
for (i = c >> 2; i--; )
*dst++ = fb_readl(src++);//从基地址读取数据放进buffer中
if (c & 3) {
u8 *dst8 = (u8 *) dst;
u8 __iomem *src8 = (u8 __iomem *) src;
for (i = c & 3; i--;)
*dst8++ = fb_readb(src8++);
src = (u32 __iomem *) src8;
}
if (copy_to_user(buf, buffer, c))//将buffer中的数据拷贝到用户空间，这样在用户空间调用read函数时就把显存内容读出来了
{
err = -EFAULT;
break;
}
*ppos += c;
buf += c;
cnt += c;
count -= c;
}
kfree(buffer);
return (err) ? err : cnt;
}int
register_framebuffer(struct fb_info *fb_info)
{
int i;
struct fb_event event;
struct fb_videomode mode;
if (num_registered_fb == FB_MAX)
return -ENXIO;
if (fb_check_foreignness(fb_info))
return -ENOSYS;
/* check all firmware fbs and kick off if the base addr overlaps */
for (i = 0 ; i < FB_MAX; i++) {
if (!registered_fb[i])
continue;
if (registered_fb[i]->flags & FBINFO_MISC_FIRMWARE) {
if (fb_do_apertures_overlap(registered_fb[i], fb_info)) {
printk(KERN_ERR "fb: conflicting fb hw usage "
"%s vs %s - removing generic driver\n",
fb_info->fix.id,
registered_fb[i]->fix.id);
unregister_framebuffer(registered_fb[i]);
break;
}
}
}
num_registered_fb++;
for (i = 0 ; i < FB_MAX; i++)
if (!registered_fb[i])
break;
fb_info->node = i;
mutex_init(&fb_info->lock);
mutex_init(&fb_info->mm_lock);
fb_info->dev = device_create(fb_class, fb_info->device,
MKDEV(FB_MAJOR, i), NULL, "fb%d", i);
if (IS_ERR(fb_info->dev)) {
/* Not fatal */
printk(KERN_WARNING "Unable to create device for framebuffer %d; errno = %ld\n", i, PTR_ERR(fb_info->dev));
fb_info->dev = NULL;
} else
fb_init_device(fb_info);
if (fb_info->pixmap.addr == NULL) {
fb_info->pixmap.addr = kmalloc(FBPIXMAPSIZE, GFP_KERNEL);
if (fb_info->pixmap.addr) {
fb_info->pixmap.size = FBPIXMAPSIZE;
fb_info->pixmap.buf_align = 1;
fb_info->pixmap.scan_align = 1;
fb_info->pixmap.access_align = 32;
fb_info->pixmap.flags = FB_PIXMAP_DEFAULT;
}
}
fb_info->pixmap.offset = 0;
if (!fb_info->pixmap.blit_x)
fb_info->pixmap.blit_x = ~(u32)0;
if (!fb_info->pixmap.blit_y)
fb_info->pixmap.blit_y = ~(u32)0;
if (!fb_info->modelist.prev || !fb_info->modelist.next)
INIT_LIST_HEAD(&fb_info->modelist);
fb_var_to_videomode(&mode, &fb_info->var);
fb_add_videomode(&mode, &fb_info->modelist);
registered_fb[i] = fb_info; //这里放入info到registered_fb
event.info = fb_info;
if (!lock_fb_info(fb_info))
return -ENODEV;
fb_notifier_call_chain(FB_EVENT_FB_REGISTERED, &event);
unlock_fb_info(fb_info);
return 0;
}
static struct platform_driver s3c2410fb_driver = {
.probe = s3c2410fb_probe,
.remove = s3c2410fb_remove,
.suspend = s3c2410fb_suspend,
.resume = s3c2410fb_resume,
.driver = {
.name = "s3c2410-lcd",
.owner = THIS_MODULE,
},
};
int __init s3c2410fb_init(void)
{
int ret = platform_driver_register(&s3c2410fb_driver);
if (ret == 0)
ret = platform_driver_register(&s3c2412fb_driver);
return ret;
}
static void __exit s3c2410fb_cleanup(void)
{
platform_driver_unregister(&s3c2410fb_driver);
platform_driver_unregister(&s3c2412fb_driver);
}
module_init(s3c2410fb_init);
module_exit(s3c2410fb_cleanup);
MODULE_AUTHOR("Arnaud Patard , "
"Ben Dooks ");
MODULE_DESCRIPTION("Framebuffer driver for the s3c2410");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:s3c2410-lcd");
MODULE_ALIAS("platform:s3c2412-lcd");
所以可以知道最开始看的那个fbmem.c就是LCD驱动的driver端(叫做FrameBuffer驱动)，而这边跟平台有关的S3c2410fb.c等就是LCD驱动的divice端，这个跟之前分析的输入子系统很类似，也是分离的思想，把成熟的软件框架与硬件平台分开，软件框架(driver端)已经帮我们实现了，我们只需要编写divece端，最后把device注册到driver端就可以了。下面看看如何编写device端：
从S3c2410fb.c可以知道我们的LCD驱动就是按要求设置好这个info，然后注册到LCD驱动核心层。这里为了分析思路的清晰，先不考虑虚拟总线，我们自己写一个驱动照着填好这个info，然后设置好跟LCD有关的寄存器就差不多了，然后注册到LCD驱动核心。
1 先把框架写好：
#include
#include
#include
#include
#include
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#include
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static struct fb_info *s3c_lcd;
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 fix */
/* 2.2 设置可变的参数 var */
/* 2.3 设置操作函数 fbops*/
/* 2.4 其他的设置 */
/* 3. 硬件相关的操作 */
/* 3.1 配置GPIO用于LCD */
/* 3.2 根据LCD手册设置LCD控制器, 比如VCLK的频率等 */
/* 3.3 分配显存(framebuffer), 并把地址告诉LCD控制器 */
/* 4. 注册 */
register_framebuffer(s3c_lcd);
return 0;
}
static void lcd_exit(void)
{
}
module_init(lcd_init);
module_exit(lcd_exit);
MODULE_LICENSE("GPL");
struct fb_info {
int node;
int flags;
struct mutex lock; /* Lock for open/release/ioctl funcs */
struct mutex mm_lock; /* Lock for fb_mmap and smem_* fields */
struct fb_var_screeninfo var; /* Current var */
struct fb_fix_screeninfo fix; /* Current fix */
struct fb_monspecs monspecs; /* Current Monitor specs */
struct work_struct queue; /* Framebuffer event queue */
struct fb_pixmap pixmap; /* Image hardware mapper */
struct fb_pixmap sprite; /* Cursor hardware mapper */
struct fb_cmap cmap; /* Current cmap */
struct list_head modelist; /* mode list */
struct fb_videomode *mode; /* current mode */
#ifdef CONFIG_FB_BACKLIGHT
/* assigned backlight device */
/* set before framebuffer registration,
remove after unregister */
struct backlight_device *bl_dev;
/* Backlight level curve */
struct mutex bl_curve_mutex;
u8 bl_curve[FB_BACKLIGHT_LEVELS];
#endif
#ifdef CONFIG_FB_DEFERRED_IO
struct delayed_work deferred_work;
struct fb_deferred_io *fbdefio;
#endif
struct fb_ops *fbops;
struct device *device; /* This is the parent */
struct device *dev; /* This is this fb device */
int class_flag; /* private sysfs flags */
#ifdef CONFIG_FB_TILEBLITTING
struct fb_tile_ops *tileops; /* Tile Blitting */
#endif
char __iomem *screen_base; /* Virtual address */
unsigned long screen_size; /* Amount of ioremapped VRAM or 0 */
void *pseudo_palette; /* Fake palette of 16 colors */
#define FBINFO_STATE_RUNNING 0
#define FBINFO_STATE_SUSPENDED 1
u32 state; /* Hardware state i.e suspend */
void *fbcon_par; /* fbcon use-only private area */
/* From here on everything is device dependent */
void *par;
/* we need the PCI or similiar aperture base/size not
smem_start/size as smem_start may just be an object
allocated inside the aperture so may not actually overlap */
resource_size_t aperture_base;
resource_size_t aperture_size;
};
#include
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//对显存的一些操作函数：
static struct fb_ops s3c_lcdfb_ops = {
.owner = THIS_MODULE,
// .fb_setcolreg = atmel_lcdfb_setcolreg,
.fb_fillrect = cfb_fillrect, //这三个照着写,以后再分析
.fb_copyarea = cfb_copyarea,
.fb_imageblit = cfb_imageblit,
};
static struct fb_info *s3c_lcd;
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"); //名称
s3c_lcd->fix.smem_len = 240*320*16/8; //显存大小，16bpp所以16位表示一个像素点，240x320的屏幕有240x320个点，再x16就是总位数，再/8就是总字节数
s3c_lcd->fix.type = FB_TYPE_PACKED_PIXELS;
s3c_lcd->fix.visual = FB_VISUAL_TRUECOLOR; /* TFT 真彩色*/
s3c_lcd->fix.line_length = 240*2; //一行的长度，一行240个点，每个点两个字节(16bit)，所以*2
/* 2.2 设置可变的参数 */
s3c_lcd->var.xres = 240; //行
s3c_lcd->var.yres = 320; //列
s3c_lcd->var.xres_virtual = 240; //这里设置虚拟屏，我们设置虚拟屏为一样大小
s3c_lcd->var.yres_virtual = 320;
s3c_lcd->var.bits_per_pixel = 16; //每个像素16位
/* RGB:565 */
s3c_lcd->var.red.offset = 11; //16位表示一个像素点的格式是R:G:B分别占5:6:5位
s3c_lcd->var.red.length = 5;
s3c_lcd->var.green.offset = 5;
s3c_lcd->var.green.length = 6;
s3c_lcd->var.blue.offset = 0;
s3c_lcd->var.blue.length = 5;
s3c_lcd->var.activate = FB_ACTIVATE_NOW;
/* 2.3 设置操作函数 */
s3c_lcd->fbops = &s3c_lcdfb_ops; //对显存的操作函数，透明处理等操作
/* 2.4 其他的设置 */
//s3c_lcd->pseudo_palette =; //
//s3c_lcd->screen_base = ; /* 显存的虚拟地址 */
s3c_lcd->screen_size = 240*324*16/8; //和显存大小一样设置
/* 3. 硬件相关的操作 */
/* 3.1 配置GPIO用于LCD */
/* 3.2 根据LCD手册设置LCD控制器, 比如VCLK的频率等 */
/* 3.3 分配显存(framebuffer), 并把地址告诉LCD控制器 */
//s3c_lcd->fix.smem_start = xxx; /* 显存的物理地址 */
/* 4. 注册 */
register_framebuffer(s3c_lcd);
return 0;
}
static void lcd_exit(void)
{
}
module_init(lcd_init);
module_exit(lcd_exit);
MODULE_LICENSE("GPL");
#include
#include
#include
#include
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#include
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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;
};
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;
s3c_lcd->fix.type = FB_TYPE_PACKED_PIXELS;
s3c_lcd->fix.visual = FB_VISUAL_TRUECOLOR; /* TFT */
s3c_lcd->fix.line_length = 240*2;
/* 2.2 设置可变的参数 */
s3c_lcd->var.xres = 240;
s3c_lcd->var.yres = 320;
s3c_lcd->var.xres_virtual = 240;
s3c_lcd->var.yres_virtual = 320;
s3c_lcd->var.bits_per_pixel = 16;
/* RGB:565 */
s3c_lcd->var.red.offset = 11;
s3c_lcd->var.red.length = 5;
s3c_lcd->var.green.offset = 5;
s3c_lcd->var.green.length = 6;
s3c_lcd->var.blue.offset = 0;
s3c_lcd->var.blue.length = 5;
s3c_lcd->var.activate = FB_ACTIVATE_NOW;
/* 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;
//s3c_lcd->screen_base = ; /* 显存的虚拟地址 */
s3c_lcd->screen_size = 240*324*16/8;
/* 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));
/* 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);
lcd_regs->lcdsaddr2 = ((s3c_lcd->fix.smem_start + s3c_lcd->fix.smem_len) >> 1) & 0x1fffff;
lcd_regs->lcdsaddr3 = (240*16/16); /* 一行的长度(单位: 2字节) */
//s3c_lcd->fix.smem_start = xxx; /* 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");