VSYNC/VFRAME/STV：垂直同步信號(TFT)/幀同步信號(STN)/SEC TFT信號；
HSYNC/VLINE/CPV：水平同步信號(TFT)/行同步脈沖信號(STN)/SEC TFT信號；
VCLK/LCD_HCLK：象素時鐘信號(TFT/STN)/SEC TFT信號；
VD[23:0]：LCD像素數(shù)據(jù)輸出端口(TFT/STN/SEC TFT)；
VDEN/VM/TP：數(shù)據(jù)使能信號(TFT)/LCD驅(qū)動交流偏置信號(STN)/SEC TFT 信號；
LEND/STH：行結(jié)束信號(TFT)/SEC TFT信號；
LCD_LPCOE：SEC TFT OE信號；
LCD_LPCREV：SEC TFT REV信號；
LCD_LPCREVB：SEC TFT REVB信號。

A：顯示指針從矩形左上角的第一行第一個點開始，一個點一個點的在LCD上顯示，在上面的時序圖上用時間線表示就為VCLK，我們稱之為像素時鐘信號；
B：當(dāng)顯示指針一直顯示到矩形的右邊就結(jié)束這一行，那么這一行的動作在上面的時序圖中就稱之為1 Line；
C：接下來顯示指針又回到矩形的左邊從第二行開始顯示，注意，顯示指針在從第一行的右邊回到第二行的左邊是需要一定的時間的，我們稱之為行切換；
D：如此類推，顯示指針就這樣一行一行的顯示至矩形的右下角才把一副圖顯示完成。因此，這一行一行的顯示在時間線上看，就是時序圖上的HSYNC；
E：然而，LCD的顯示并不是對一副圖像快速的顯示一下，為了持續(xù)和穩(wěn)定的在LCD上顯示，就需要切換到另一幅圖上(另一幅圖可以和上一副圖一樣或者不一樣，目的只是為了將圖像持續(xù)的顯示在LCD上)。那么這一副一副的圖像就稱之為幀，在時序圖上就表示為1 Frame，因此從時序圖上可以看出1 Line只是1 Frame中的一行；
F：同樣的，在幀與幀切換之間也是需要一定的時間的，我們稱之為幀切換，那么LCD整個顯示的過程在時間線上看，就可表示為時序圖上的VSYNC。

VBPD(vertical back porch)：表示在一幀圖像開始時，垂直同步信號以后的無效的行數(shù)，對應(yīng)驅(qū)動中的upper_margin；
VFBD(vertical front porch)：表示在一幀圖像結(jié)束后，垂直同步信號以前的無效的行數(shù)，對應(yīng)驅(qū)動中的lower_margin；
VSPW(vertical sync pulse width)：表示垂直同步脈沖的寬度，用行數(shù)計算，對應(yīng)驅(qū)動中的vsync_len；
HBPD(horizontal back porch)：表示從水平同步信號開始到一行的有效數(shù)據(jù)開始之間的VCLK的個數(shù)，對應(yīng)驅(qū)動中的left_margin；
HFPD(horizontal front porth)：表示一行的有效數(shù)據(jù)結(jié)束到下一個水平同步信號開始之間的VCLK的個數(shù)，對應(yīng)驅(qū)動中的right_margin；
HSPW(horizontal sync pulse width)：表示水平同步信號的寬度，用VCLK計算，對應(yīng)驅(qū)動中的hsync_len；

LCDCON1：17?- 8位CLKVAL
??????????6?- 5位掃描模式(對于STN屏:4位單/雙掃、8位單掃)
??????????4?- 1位色位模式(1BPP、8BPP、16BPP等)

LCDCON2：31 - 24位VBPD
?????????23 - 14位LINEVAL
?????????13 - 6位VFPD
??????????5 - 0位VSPW

LCDCON3：25 - 19位HBPD
?????????18 - 8位HOZVAL
??????????7 - 0位HFPD

LCDCON4： 7 - 0位HSPW

LCDCON5：

struct fb_info {
????int node;
????int flags;
????struct fb_var_screeninfo var;/*LCD可變參數(shù)結(jié)構(gòu)體*/
????struct fb_fix_screeninfo fix;/*LCD固定參數(shù)結(jié)構(gòu)體*/
????struct fb_monspecs monspecs;?/*LCD顯示器標(biāo)準(zhǔn)*/
????struct work_struct queue;????/*幀緩沖事件隊列*/
????struct fb_pixmap pixmap;???? /*圖像硬件mapper*/
????struct fb_pixmap sprite;???? /*光標(biāo)硬件mapper*/
????struct fb_cmap cmap;???????? /*當(dāng)前的顏色表*/
????struct fb_videomode *mode;???/*當(dāng)前的顯示模式*/

#ifdef CONFIG_FB_BACKLIGHT
????struct backlight_device *bl_dev;/*對應(yīng)的背光設(shè)備*/
????struct mutex bl_curve_mutex;
????u8 bl_curve[FB_BACKLIGHT_LEVELS];/*背光調(diào)整*/
#endif
#ifdef CONFIG_FB_DEFERRED_IO
????struct delayed_work deferred_work;
????struct fb_deferred_io *fbdefio;
#endif

????struct fb_ops *fbops; /*對底層硬件操作的函數(shù)指針*/
????struct device *device;
????struct device *dev;???/*fb設(shè)備*/
????int class_flag;????
#ifdef CONFIG_FB_TILEBLITTING
????struct fb_tile_ops *tileops; /*圖塊Blitting*/
#endif
????char __iomem *screen_base;???/*虛擬基地址*/
????unsigned long screen_size;???/*LCD IO映射的虛擬內(nèi)存大小*/
????void *pseudo_palette;????????/*偽16色顏色表*/
#define FBINFO_STATE_RUNNING????0
#define FBINFO_STATE_SUSPENDED??1
????u32 state;??/*LCD的掛起或恢復(fù)狀態(tài)*/
????void *fbcon_par;
????void *par;????
};

struct fb_var_screeninfo {
????__u32 xres;????????????????/*可見屏幕一行有多少個像素點*/
????__u32 yres;????????????????/*可見屏幕一列有多少個像素點*/
????__u32 xres_virtual;????????/*虛擬屏幕一行有多少個像素點*/????????
????__u32 yres_virtual;????????/*虛擬屏幕一列有多少個像素點*/
????__u32 xoffset;?????????????/*虛擬到可見屏幕之間的行偏移*/
????__u32 yoffset;?????????????/*虛擬到可見屏幕之間的列偏移*/
????__u32 bits_per_pixel;??????/*每個像素的位數(shù)即BPP*/
????__u32 grayscale;???????????/*非0時，指的是灰度*/

????struct fb_bitfield red;????/*fb緩存的R位域*/
????struct fb_bitfield green;??/*fb緩存的G位域*/
????struct fb_bitfield blue;???/*fb緩存的B位域*/
????struct fb_bitfield transp;?/*透明度*/????

????__u32 nonstd;??????????????/* != 0 非標(biāo)準(zhǔn)像素格式*/
????__u32 activate;????????????????
????__u32 height;??????????????/*高度*/
????__u32 width;???????????????/*寬度*/
????__u32 accel_flags;????

????/*定時：除了pixclock本身外，其他的都以像素時鐘為單位*/
????__u32 pixclock;????????????/*像素時鐘(皮秒)*/
????__u32 left_margin;?????????/*行切換，從同步到繪圖之間的延遲*/
????__u32 right_margin;????????/*行切換，從繪圖到同步之間的延遲*/
????__u32 upper_margin;????????/*幀切換，從同步到繪圖之間的延遲*/
????__u32 lower_margin;????????/*幀切換，從繪圖到同步之間的延遲*/
????__u32 hsync_len;???????????/*水平同步的長度*/
????__u32 vsync_len;???????????/*垂直同步的長度*/
????__u32 sync;
????__u32 vmode;
????__u32 rotate;
????__u32 reserved[5];?????????/*保留*/
};

struct fb_fix_screeninfo {
????char id[16];????????????????/*字符串形式的標(biāo)示符 */
????unsigned long smem_start;???/*fb緩存的開始位置 */
????__u32 smem_len;?????????????/*fb緩存的長度 */
????__u32 type;?????????????????/*看FB_TYPE_* */
????__u32 type_aux;?????????????/*分界*/
????__u32 visual;???????????????/*看FB_VISUAL_* */
????__u16 xpanstep;?????????????/*如果沒有硬件panning就賦值為0 */
????__u16 ypanstep;?????????????/*如果沒有硬件panning就賦值為0 */
????__u16 ywrapstep;????????????/*如果沒有硬件ywrap就賦值為0 */
????__u32 line_length;??????????/*一行的字節(jié)數(shù) */
????unsigned long mmio_start;???/*內(nèi)存映射IO的開始位置*/
????__u32 mmio_len;?????????????/*內(nèi)存映射IO的長度*/
????__u32 accel;
????__u16 reserved[3];??????????/*保留*/
};

struct fb_ops {

????struct module *owner;

????//檢查可變參數(shù)并進(jìn)行設(shè)置
????int (*fb_check_var)(struct fb_var_screeninfo *var, struct fb_info *info);

????//根據(jù)設(shè)置的值進(jìn)行更新，使之有效
????int (*fb_set_par)(struct fb_info *info);

????//設(shè)置顏色寄存器
????int (*fb_setcolreg)(unsigned regno, unsigned red, unsigned green,
?????????????unsigned blue, unsigned transp, struct fb_info *info);

????//顯示空白
????int (*fb_blank)(int blank, struct fb_info *info);

????//矩形填充
????void (*fb_fillrect) (struct fb_info *info, const struct fb_fillrect *rect);

????//復(fù)制數(shù)據(jù)
????void (*fb_copyarea) (struct fb_info *info, const struct fb_copyarea *region);

????//圖形填充
????void (*fb_imageblit) (struct fb_info *info, const struct fb_image *image);
};

/* LCD Controller */

//LCD控制器的資源信息
static struct resource s3c_lcd_resource[] = {
????[0] = {
????????.start = S3C24XX_PA_LCD, //控制器IO端口開始地址
????????.end = S3C24XX_PA_LCD + S3C24XX_SZ_LCD - 1,//控制器IO端口結(jié)束地址
????????.flags = IORESOURCE_MEM,//標(biāo)識為LCD控制器IO端口，在驅(qū)動中引用這個就表示引用IO端口
????},
????[1] = {
????????.start = IRQ_LCD,//LCD中斷
????????.end = IRQ_LCD,
????????.flags = IORESOURCE_IRQ,//標(biāo)識為LCD中斷
????}
};

static u64 s3c_device_lcd_dmamask = 0xffffffffUL;

struct platform_device s3c_device_lcd = {
????.name???????? = "s3c2410-lcd",//作為平臺設(shè)備的LCD設(shè)備名
????.id???????? = -1,
????.num_resources?= ARRAY_SIZE(s3c_lcd_resource),//資源數(shù)量
????.resource???? = s3c_lcd_resource,//引用上面定義的資源
????.dev = {
????????.dma_mask?= &s3c_device_lcd_dmamask,
????????.coherent_dma_mask?= 0xffffffffUL
????}
};

EXPORT_SYMBOL(s3c_device_lcd);//導(dǎo)出定義的LCD平臺設(shè)備，好在mach-smdk2440.c的smdk2440_devices[]中添加到平臺設(shè)備列表中

/* LCD driver info */

//LCD硬件的配置信息，注意這里我使用的LCD是NEC 3.5寸TFT屏，這些參數(shù)要根據(jù)具體的LCD屏進(jìn)行設(shè)置
static struct s3c2410fb_display smdk2440_lcd_cfg __initdata = {

??? //這個地方的設(shè)置是配置LCD寄存器5，這些宏定義在regs-lcd.h中，計算后二進(jìn)制為：111111111111，然后對照數(shù)據(jù)手冊上LCDCON5的各位來看，注意是從右邊開始
????.lcdcon5?= S3C2410_LCDCON5_FRM565 |
?????????????? S3C2410_LCDCON5_INVVLINE |
?????????????? S3C2410_LCDCON5_INVVFRAME |
?????????????? S3C2410_LCDCON5_PWREN |
?????????????? S3C2410_LCDCON5_HWSWP,

????.type????= S3C2410_LCDCON1_TFT,//TFT類型

????/* NEC 3.5'' */
????.width??????? = 240,//屏幕寬度
????.height?????? = 320,//屏幕高度

??? //以下一些參數(shù)在上面的時序圖分析中講到過,各參數(shù)的值請跟據(jù)具體的LCD屏數(shù)據(jù)手冊結(jié)合上面時序分析來設(shè)定
????.pixclock???? = 100000,//像素時鐘
????.xres???????? = 240,//水平可見的有效像素
????.yres???????? = 320,//垂直可見的有效像素
????.bpp????????? = 16,//色位模式
????.left_margin??= 19,//行切換，從同步到繪圖之間的延遲
????.right_margin?= 36,//行切換，從繪圖到同步之間的延遲
????.hsync_len????= 5,//水平同步的長度
????.upper_margin?= 1,//幀切換，從同步到繪圖之間的延遲
????.lower_margin?= 5,//幀切換，從繪圖到同步之間的延遲
????.vsync_len????= 1,//垂直同步的長度
};

static struct s3c2410fb_mach_info smdk2440_fb_info __initdata = {
????.displays??????? = &smdk2440_lcd_cfg,//應(yīng)用上面定義的配置信息
????.num_displays????= 1,
????.default_display = 0,

????.gpccon??????????= 0xaaaa555a,//將GPC0、GPC1配置成LEND和VCLK，將GPC8-15配置成VD0-7,其他配置成普通輸出IO口
????.gpccon_mask???? = 0xffffffff,
????.gpcup???????????= 0x0000ffff,//禁止GPIOC的上拉功能
????.gpcup_mask??????= 0xffffffff,
????.gpdcon??????????= 0xaaaaaaaa,//將GPD0-15配置成VD8-23
????.gpdcon_mask???? = 0xffffffff,
????.gpdup???????????= 0x0000ffff,//禁止GPIOD的上拉功能
????.gpdup_mask??????= 0xffffffff,

????.lpcsel????????? = 0x0,//這個是三星TFT屏的參數(shù)，這里不用
};

//S3C2440初始化函數(shù)
static void __init smdk2440_machine_init(void)
{

??? //調(diào)用該函數(shù)將上面定義的LCD硬件信息保存到平臺數(shù)據(jù)中
????s3c24xx_fb_set_platdata(&smdk2440_fb_info);
????
????s3c_i2c0_set_platdata(NULL);

????platform_add_devices(smdk2440_devices, ARRAY_SIZE(smdk2440_devices));
????smdk_machine_init();
}

void __init s3c24xx_fb_set_platdata(struct s3c2410fb_mach_info *pd)
{
????struct s3c2410fb_mach_info *npd;

????npd = kmalloc(sizeof(*npd), GFP_KERNEL);
????if (npd) {
????????memcpy(npd, pd, sizeof(*npd));

??????? //這里就是將內(nèi)核中定義的s3c2410fb_mach_info結(jié)構(gòu)體數(shù)據(jù)保存到LCD平臺數(shù)據(jù)中，所以在寫驅(qū)動的時候就可以直接在平臺數(shù)據(jù)中獲取s3c2410fb_mach_info結(jié)構(gòu)體的數(shù)據(jù)(即LCD各種參數(shù)信息)進(jìn)行操作
????????s3c_device_lcd.dev.platform_data = npd;
????} else {
????????printk(KERN_ERR "no memory for LCD platform data/n");
????}
}

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/dma-mapping.h>
#include <linux/fb.h>
#include <linux/clk.h>
#include <linux/interrupt.h>
#include <linux/mm.h>

#include <linux/slab.h>
#include <linux/delay.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/div64.h>
#include <mach/regs-lcd.h>
#include <mach/regs-gpio.h>
#include <mach/fb.h>
#include <linux/pm.h>

/*FrameBuffer設(shè)備名稱*/
static char?driver_name[] = "my2440_lcd";

/*定義一個結(jié)構(gòu)體用來維護(hù)驅(qū)動程序中各函數(shù)中用到的變量
??先別看結(jié)構(gòu)體要定義這些成員，到各函數(shù)使用的地方就明白了*/
struct my2440fb_var
{
????int lcd_irq_no;?????????? /*保存LCD中斷號*/
????struct clk *lcd_clock;????/*保存從平臺時鐘隊列中獲取的LCD時鐘*/
????struct resource *lcd_mem;?/*LCD的IO空間*/
????void __iomem *lcd_base;???/*LCD的IO空間映射到虛擬地址*/
????struct device *dev;

????struct s3c2410fb_hw?regs;?/*表示5個LCD配置寄存器，s3c2410fb_hw定義在mach-s3c2410/include/mach/fb.h中*/

????/*定義一個數(shù)組來充當(dāng)調(diào)色板。
????據(jù)數(shù)據(jù)手冊描述，TFT屏色位模式為8BPP時，調(diào)色板(顏色表)的長度為256，調(diào)色板起始地址為0x4D000400*/
????u32????palette_buffer[256];?

????u32?pseudo_pal[16];???
????unsigned int palette_ready;?/*標(biāo)識調(diào)色板是否準(zhǔn)備好了*/
};

/*用做清空調(diào)色板(顏色表)*/
#define PALETTE_BUFF_CLEAR (0x80000000)????

/*LCD平臺驅(qū)動結(jié)構(gòu)體，平臺驅(qū)動結(jié)構(gòu)體定義在platform_device.h中，該結(jié)構(gòu)體成員接口函數(shù)在第②步中實現(xiàn)*/
static struct platform_driver lcd_fb_driver =
{
????.probe?????= lcd_fb_probe,?????????????? /*FrameBuffer設(shè)備探測*/
????.remove????= __devexit_p(lcd_fb_remove),?/*FrameBuffer設(shè)備移除*/
????.suspend???= lcd_fb_suspend,???????????? /*FrameBuffer設(shè)備掛起*/
????.resume????= lcd_fb_resume,??????????????/*FrameBuffer設(shè)備恢復(fù)*/
????.driver????=
????{
????????/*注意這里的名稱一定要和系統(tǒng)中定義平臺設(shè)備的地方一致，這樣才能把平臺設(shè)備與該平臺設(shè)備的驅(qū)動關(guān)聯(lián)起來*/
????????.name?= "s3c2410-lcd",
????????.owner?= THIS_MODULE,
????},
};

static int __init lcd_init(void)
{
????/*在Linux中，幀緩沖設(shè)備被看做是平臺設(shè)備，所以這里注冊平臺設(shè)備*/
????return platform_driver_register(&lcd_fb_driver);
}

static void __exit lcd_exit(void)
{
????/*注銷平臺設(shè)備*/
????platform_driver_unregister(&lcd_fb_driver);
}

module_init(lcd_init);
module_exit(lcd_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Huang Gang");
MODULE_DESCRIPTION("My2440 LCD FrameBuffer Driver");

/*LCD FrameBuffer設(shè)備探測的實現(xiàn)，注意這里使用一個__devinit宏，到lcd_fb_remove接口函數(shù)實現(xiàn)的地方講解*/
static int __devinit lcd_fb_probe(struct platform_device *pdev)
{
????int i;
????int ret;
????struct resource?*res;??/*用來保存從LCD平臺設(shè)備中獲取的LCD資源*/
????struct fb_info??*fbinfo;?/*FrameBuffer驅(qū)動所對應(yīng)的fb_info結(jié)構(gòu)體*/
????struct s3c2410fb_mach_info?*mach_info;?/*保存從內(nèi)核中獲取的平臺設(shè)備數(shù)據(jù)*/
????struct my2440fb_var?*fbvar;?/*上面定義的驅(qū)動程序全局變量結(jié)構(gòu)體*/
????struct s3c2410fb_display?*display;?/*LCD屏的配置信息結(jié)構(gòu)體，該結(jié)構(gòu)體定義在mach-s3c2410/include/mach/fb.h中*/

????/*獲取LCD硬件相關(guān)信息數(shù)據(jù)，在前面講過內(nèi)核使用s3c24xx_fb_set_platdata函數(shù)將LCD的硬件相關(guān)信息保存到
???? 了LCD平臺數(shù)據(jù)中，所以這里我們就從平臺數(shù)據(jù)中取出來在驅(qū)動中使用*/
????mach_info = pdev->dev.platform_data;
????if(mach_info == NULL)
????{
????????/*判斷獲取數(shù)據(jù)是否成功*/
????????dev_err(&pdev->dev, "no platform data for lcd/n");
????????return -EINVAL;
????}

????/*獲得在內(nèi)核中定義的FrameBuffer平臺設(shè)備的LCD配置信息結(jié)構(gòu)體數(shù)據(jù)*/
????display = mach_info->displays + mach_info->default_display;

??? /*給fb_info分配空間，大小為my2440fb_var結(jié)構(gòu)的內(nèi)存，framebuffer_alloc定義在fb.h中在fbsysfs.c中實現(xiàn)*/
????fbinfo = framebuffer_alloc(sizeof(struct my2440fb_var), &pdev->dev);
????if(!fbinfo)
????{
????????dev_err(&pdev->dev, "framebuffer alloc of registers failed/n");
????????ret = -ENOMEM;
????????goto err_noirq;
????}
????platform_set_drvdata(pdev, fbinfo);/*重新將LCD平臺設(shè)備數(shù)據(jù)設(shè)置為fbinfo，好在后面的一些函數(shù)中來使用*/

????/*這里的用途其實就是將fb_info的成員par(注意是一個void類型的指針)指向這里的私有變量結(jié)構(gòu)體fbvar，
???? 目的是到其他接口函數(shù)中再取出fb_info的成員par，從而能繼續(xù)使用這里的私有變量*/
????fbvar = fbinfo->par;
????fbvar->dev = &pdev->dev;

????/*在系統(tǒng)定義的LCD平臺設(shè)備資源中獲取LCD中斷號,platform_get_irq定義在platform_device.h中*/
????fbvar->lcd_irq_no = platform_get_irq(pdev, 0);
????if(fbvar->lcd_irq_no < 0)
????{
????????/*判斷獲取中斷號是否成功*/
????????dev_err(&pdev->dev, "no lcd irq for platform/n");
????????return -ENOENT;
????}

????/*獲取LCD平臺設(shè)備所使用的IO端口資源，注意這個IORESOURCE_MEM標(biāo)志和LCD平臺設(shè)備定義中的一致*/
????res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
????if(res == NULL)
????{
????????/*判斷獲取資源是否成功*/
????????dev_err(&pdev->dev, "failed to get memory region resource/n");
????????return -ENOENT;
????}

????/*申請LCD IO端口所占用的IO空間(注意理解IO空間和內(nèi)存空間的區(qū)別),request_mem_region定義在ioport.h中*/
????fbvar->lcd_mem = request_mem_region(res->start, res->end - res->start + 1, pdev->name);
????if(fbvar->lcd_mem == NULL)
????{
????????/*判斷申請IO空間是否成功*/
????????dev_err(&pdev->dev, "failed to reserve memory region/n");
????????return -ENOENT;
????}

????/*將LCD的IO端口占用的這段IO空間映射到內(nèi)存的虛擬地址，ioremap定義在io.h中
???? 注意：IO空間要映射后才能使用，以后對虛擬地址的操作就是對IO空間的操作*/
????fbvar->lcd_base = ioremap(res->start, res->end - res->start + 1);
????if(fbvar->lcd_base == NULL)
????{
????????/*判斷映射虛擬地址是否成功*/
????????dev_err(&pdev->dev, "ioremap() of registers failed/n");
????????ret = -EINVAL;
????????goto err_nomem;
????}

????/*從平臺時鐘隊列中獲取LCD的時鐘，這里為什么要取得這個時鐘，從LCD屏的時序圖上看，各種控制信號的延遲
???? 都跟LCD的時鐘有關(guān)。系統(tǒng)的一些時鐘定義在arch/arm/plat-s3c24xx/s3c2410-clock.c中*/
????fbvar->lcd_clock = clk_get(NULL, "lcd");
????if(!fbvar->lcd_clock)
????{
????????/*判斷獲取時鐘是否成功*/
????????dev_err(&pdev->dev, "failed to find lcd clock source/n");
????????ret = -ENOENT;
????????goto err_nomap;
????}
????/*時鐘獲取后要使能后才可以使用，clk_enable定義在arch/arm/plat-s3c/clock.c中*/
????clk_enable(fbvar->lcd_clock);

????/*申請LCD中斷服務(wù)，上面獲取的中斷號lcd_fb_irq，使用快速中斷方式:IRQF_DISABLED
???? 中斷服務(wù)程序為:lcd_fb_irq，將LCD平臺設(shè)備pdev做參數(shù)傳遞過去了*/
????ret = request_irq(fbvar->lcd_irq_no, lcd_fb_irq, IRQF_DISABLED, pdev->name, fbvar);
????if(ret)
????{
????????/*判斷申請中斷服務(wù)是否成功*/
????????dev_err(&pdev->dev, "IRQ%d error %d/n", fbvar->lcd_irq_no, ret);
????????ret = -EBUSY;
????????goto err_noclk;
????}
????/*好了，以上是對要使用的資源進(jìn)行了獲取和設(shè)置。下面就開始初始化填充fb_info結(jié)構(gòu)體*/

????/*首先初始化fb_info中代表LCD固定參數(shù)的結(jié)構(gòu)體fb_fix_screeninfo*/
????/*像素值與顯示內(nèi)存的映射關(guān)系有5種，定義在fb.h中?，F(xiàn)在采用FB_TYPE_PACKED_PIXELS方式，在該方式下，
????像素值與內(nèi)存直接對應(yīng)，比如在顯示內(nèi)存某單元寫入一個"1"時，該單元對應(yīng)的像素值也將是"1"，這使得應(yīng)用層
????把顯示內(nèi)存映射到用戶空間變得非常方便。Linux中當(dāng)LCD為TFT屏?xí)r，顯示驅(qū)動管理顯示內(nèi)存就是基于這種方式*/
????strcpy(fbinfo->fix.id, driver_name);/*字符串形式的標(biāo)識符*/
????fbinfo->fix.type = FB_TYPE_PACKED_PIXELS;
????fbinfo->fix.type_aux = 0;/*以下這些根據(jù)fb_fix_screeninfo定義中的描述，當(dāng)沒有硬件是都設(shè)為0*/
????fbinfo->fix.xpanstep = 0;
????fbinfo->fix.ypanstep = 0;
????fbinfo->fix.ywrapstep= 0;
????fbinfo->fix.accel = FB_ACCEL_NONE;

??? /*接著，再初始化fb_info中代表LCD可變參數(shù)的結(jié)構(gòu)體fb_var_screeninfo*/
????fbinfo->var.nonstd??????????= 0;
????fbinfo->var.activate????????= FB_ACTIVATE_NOW;
????fbinfo->var.accel_flags?????= 0;
????fbinfo->var.vmode???????????= FB_VMODE_NONINTERLACED;
????fbinfo->var.xres????????????= display->xres;
????fbinfo->var.yres????????????= display->yres;
????fbinfo->var.bits_per_pixel??= display->bpp;

??? /*指定對底層硬件操作的函數(shù)指針, 因內(nèi)容較多故其定義在第③步中再講*/
????fbinfo->fbops???????????????= &my2440fb_ops;

??? /*初始化色調(diào)色板(顏色表)為空*/
????for(i = 0; i < 256; i++)
????{
????????fbvar->palette_buffer[i] = PALETTE_BUFF_CLEAR;
????}

????for (i = 0; i < mach_info->num_displays; i++) /*fb緩存的長度*/
????{
????????/*計算FrameBuffer緩存的最大大小，這里右移3位(即除以8)是因為色位模式BPP是以位為單位*/
????????unsigned long smem_len = (mach_info->displays[i].xres * mach_info->displays[i].yres * mach_info->displays[i].bpp) >> 3;

????????if(fbinfo->fix.smem_len < smem_len)
????????{
????????????fbinfo->fix.smem_len = smem_len;
????????}
????}

????/*初始化LCD控制器之前要延遲一段時間*/
????msleep(1);

????/*初始化完fb_info后，開始對LCD各寄存器進(jìn)行初始化，其定義在后面講到*/
????my2440fb_init_registers(fbinfo);

????/*初始化完寄存器后，開始檢查fb_info中的可變參數(shù)，其定義在后面講到*/
????my2440fb_check_var(fbinfo);
????
????/*申請幀緩沖設(shè)備fb_info的顯示緩沖區(qū)空間，其定義在后面講到*/
????ret = my2440fb_map_video_memory(fbinfo);
????if (ret)
????{
????????dev_err(&pdev->dev, "failed to allocate video RAM: %d/n", ret);
????????ret = -ENOMEM;
????????goto err_nofb;
????}

????/*最后，注冊這個幀緩沖設(shè)備fb_info到系統(tǒng)中, register_framebuffer定義在fb.h中在fbmem.c中實現(xiàn)*/
????ret = register_framebuffer(fbinfo);
????if (ret < 0)
????{
????????dev_err(&pdev->dev, "failed to register framebuffer device: %d/n", ret);
????????goto err_video_nomem;
????}

????/*對設(shè)備文件系統(tǒng)的支持(對設(shè)備文件系統(tǒng)的理解請參閱：嵌入式Linux之我行——設(shè)備文件系統(tǒng)剖析與使用)
???? 創(chuàng)建frambuffer設(shè)備文件，device_create_file定義在linux/device.h中*/
????ret = device_create_file(&pdev->dev, &dev_attr_debug);
????if (ret)
????{
????????dev_err(&pdev->dev, "failed to add debug attribute/n");
????}

????return 0;

/*以下是上面錯誤處理的跳轉(zhuǎn)點*/
err_nomem:
????release_resource(fbvar->lcd_mem);
????kfree(fbvar->lcd_mem);

err_nomap:
????iounmap(fbvar->lcd_base);

err_noclk:
????clk_disable(fbvar->lcd_clock);
????clk_put(fbvar->lcd_clock);

err_noirq:
????free_irq(fbvar->lcd_irq_no, fbvar);

err_nofb:
????platform_set_drvdata(pdev, NULL);
????framebuffer_release(fbinfo);

err_video_nomem:
????my2440fb_unmap_video_memory(fbinfo);

????return ret;
}

/*LCD中斷服務(wù)程序*/
static irqreturn_t lcd_fb_irq(int irq, void *dev_id)
{
????struct my2440fb_var????*fbvar = dev_id;
????void __iomem *lcd_irq_base;
????unsigned long lcdirq;

????/*LCD中斷掛起寄存器基地址*/
????lcd_irq_base = fbvar->lcd_base + S3C2410_LCDINTBASE;

????/*讀取LCD中斷掛起寄存器的值*/
????lcdirq = readl(lcd_irq_base + S3C24XX_LCDINTPND);

????/*判斷是否為中斷掛起狀態(tài)*/
????if(lcdirq & S3C2410_LCDINT_FRSYNC)
????{
????????/*填充調(diào)色板*/
????????if (fbvar->palette_ready)
????????{
????????????my2440fb_write_palette(fbvar);
????????}

????????/*設(shè)置幀已插入中斷請求*/
????????writel(S3C2410_LCDINT_FRSYNC, lcd_irq_base + S3C24XX_LCDINTPND);
????????writel(S3C2410_LCDINT_FRSYNC, lcd_irq_base + S3C24XX_LCDSRCPND);
????}

????return IRQ_HANDLED;
}

/*填充調(diào)色板*/
static void my2440fb_write_palette(struct my2440fb_var *fbvar)
{
????unsigned int i;
????void __iomem *regs = fbvar->lcd_base;

????fbvar->palette_ready = 0;

????for (i = 0; i < 256; i++)
????{
????????unsigned long ent = fbvar->palette_buffer[i];

????????if (ent == PALETTE_BUFF_CLEAR)
????????{
????????????continue;
????????}

????????writel(ent, regs + S3C2410_TFTPAL(i));

????????if (readw(regs + S3C2410_TFTPAL(i)) == ent)
????????{
????????????fbvar->palette_buffer[i] = PALETTE_BUFF_CLEAR;
????????}
????????else
????????{
????????????fbvar->palette_ready = 1;
????????}
????}
}

/*LCD各寄存器進(jìn)行初始化*/
static int my2440fb_init_registers(struct fb_info *fbinfo)
{
????unsigned long flags;
????void __iomem *tpal;
????void __iomem *lpcsel;

????/*從lcd_fb_probe探測函數(shù)設(shè)置的私有變量結(jié)構(gòu)體中再獲得LCD相關(guān)信息的數(shù)據(jù)*/
????struct my2440fb_var????*fbvar = fbinfo->par;
????struct s3c2410fb_mach_info *mach_info = fbvar->dev->platform_data;

????/*獲得臨時調(diào)色板寄存器基地址，S3C2410_TPAL宏定義在mach-s3c2410/include/mach/regs-lcd.h中。
????注意對于lpcsel這是一個針對三星TFT屏的一個專用寄存器，如果用的不是三星的TFT屏應(yīng)該不用管它。*/
????tpal = fbvar->lcd_base + S3C2410_TPAL;
????lpcsel = fbvar->lcd_base + S3C2410_LPCSEL;

????/*在修改下面寄存器值之前先屏蔽中斷，將中斷狀態(tài)保存到flags中*/
????local_irq_save(flags);

????/*這里就是在上一篇章中講到的把IO端口C和D配置成LCD模式*/
????modify_gpio(S3C2410_GPCUP, mach_info->gpcup, mach_info->gpcup_mask);
????modify_gpio(S3C2410_GPCCON, mach_info->gpccon, mach_info->gpccon_mask);
????modify_gpio(S3C2410_GPDUP, mach_info->gpdup, mach_info->gpdup_mask);
????modify_gpio(S3C2410_GPDCON, mach_info->gpdcon, mach_info->gpdcon_mask);

????/*恢復(fù)被屏蔽的中斷*/
????local_irq_restore(flags);

????writel(0x00, tpal);/*臨時調(diào)色板寄存器使能禁止*/
????writel(mach_info->lpcsel, lpcsel);/*在上一篇中講到過，它是三星TFT屏的一個寄存器，這里可以不管*/

????return 0;
}

/*該函數(shù)實現(xiàn)修改GPIO端口的值，注意第三個參數(shù)mask的作用是將要設(shè)置的寄存器值先清零*/
static inline void modify_gpio(void __iomem *reg, unsigned long set, unsigned long mask)
{
????unsigned long tmp;

????tmp = readl(reg) & ~mask;
????writel(tmp | set, reg);
}

/*檢查fb_info中的可變參數(shù)*/
static int my2440fb_check_var(struct fb_info *fbinfo)
{
????unsigned i;

????/*從lcd_fb_probe探測函數(shù)設(shè)置的平臺數(shù)據(jù)中再獲得LCD相關(guān)信息的數(shù)據(jù)*/
????struct fb_var_screeninfo *var = &fbinfo->var;/*fb_info中的可變參數(shù)*/
????struct my2440fb_var????*fbvar = fbinfo->par;/*在lcd_fb_probe探測函數(shù)中設(shè)置的私有結(jié)構(gòu)體數(shù)據(jù)*/
????struct s3c2410fb_mach_info *mach_info = fbvar->dev->platform_data;/*LCD的配置結(jié)構(gòu)體數(shù)據(jù)，這個配置結(jié)構(gòu)體的賦值在上一篇章的"3. 幀緩沖設(shè)備作為平臺設(shè)備"中*/

????struct s3c2410fb_display *display = NULL;
????struct s3c2410fb_display *default_display = mach_info->displays + mach_info->default_display;
????int type = default_display->type;/*LCD的類型，看上一篇章的"3. 幀緩沖設(shè)備作為平臺設(shè)備"中的type賦值是TFT類型*/

????/*驗證X/Y解析度*/
????if (var->yres == default_display->yres &&
????????var->xres == default_display->xres &&
????????var->bits_per_pixel == default_display->bpp)
????{
????????display = default_display;
????}
????else
????{
????????for (i = 0; i < mach_info->num_displays; i++)
????????{
????????????if (type == mach_info->displays[i].type &&
???????????? var->yres == mach_info->displays[i].yres &&
???????????? var->xres == mach_info->displays[i].xres &&
???????????? var->bits_per_pixel == mach_info->displays[i].bpp)
????????????{
????????????????display = mach_info->displays + i;
????????????????break;
????????????}
????????}
????}

????if (!display)
????{
????????return -EINVAL;
????}

????/*配置LCD配置寄存器1中的5-6位(配置成TFT類型)和配置LCD配置寄存器5*/
????fbvar->regs.lcdcon1 = display->type;
????fbvar->regs.lcdcon5 = display->lcdcon5;

????/* 設(shè)置屏幕的虛擬解析像素和高度寬度 */
????var->xres_virtual = display->xres;
????var->yres_virtual = display->yres;
????var->height = display->height;
????var->width = display->width;

????/* 設(shè)置時鐘像素，行、幀切換值，水平同步、垂直同步長度值 */
????var->pixclock = display->pixclock;
????var->left_margin = display->left_margin;
????var->right_margin = display->right_margin;
????var->upper_margin = display->upper_margin;
????var->lower_margin = display->lower_margin;
????var->vsync_len = display->vsync_len;
????var->hsync_len = display->hsync_len;

????/*設(shè)置透明度*/
????var->transp.offset = 0;
????var->transp.length = 0;

????/*根據(jù)色位模式(BPP)來設(shè)置可變參數(shù)中R、G、B的顏色位域。對于這些參數(shù)值的設(shè)置請參考CPU數(shù)據(jù)
????手冊中"顯示緩沖區(qū)與顯示點對應(yīng)關(guān)系圖"，例如在上一篇章中我就畫出了8BPP和16BPP時的對應(yīng)關(guān)系圖*/
????switch (var->bits_per_pixel)
????{
????????case 1:
????????case 2:
????????case 4:
????????????var->red.offset??= 0;
????????????var->red.length??= var->bits_per_pixel;
????????????var->green?????? = var->red;
????????????var->blue??????? = var->red;
????????????break;
????????case 8:/* 8 bpp 332 */
????????????if (display->type != S3C2410_LCDCON1_TFT)
????????????{
????????????????var->red.length?????= 3;
????????????????var->red.offset?????= 5;
????????????????var->green.length???= 3;
????????????????var->green.offset???= 2;
????????????????var->blue.length????= 2;
????????????????var->blue.offset????= 0;
????????????}else{
????????????????var->red.offset?????= 0;
????????????????var->red.length?????= 8;
????????????????var->green????????? = var->red;
????????????????var->blue?????????? = var->red;
????????????}
????????????break;
????????case 12:/* 12 bpp 444 */
????????????var->red.length???????? = 4;
????????????var->red.offset???????? = 8;
????????????var->green.length?????? = 4;
????????????var->green.offset?????? = 4;
????????????var->blue.length??????? = 4;
????????????var->blue.offset??????? = 0;
????????????break;
????????case 16:/* 16 bpp */
????????????if (display->lcdcon5 & S3C2410_LCDCON5_FRM565)
????????????{
????????????????/* 565 format */
????????????????var->red.offset??????= 11;
????????????????var->green.offset????= 5;
????????????????var->blue.offset???? = 0;
????????????????var->red.length??????= 5;
????????????????var->green.length????= 6;
????????????????var->blue.length???? = 5;
????????????} else {
????????????????/* 5551 format */
????????????????var->red.offset??????= 11;
????????????????var->green.offset????= 6;
????????????????var->blue.offset???? = 1;
????????????????var->red.length??????= 5;
????????????????var->green.length????= 5;
????????????????var->blue.length???? = 5;
????????????}
????????????break;
????????case 32:/* 24 bpp 888 and 8 dummy */
????????????var->red.length????????= 8;
????????????var->red.offset????????= 16;
????????????var->green.length????? = 8;
????????????var->green.offset????? = 8;
????????????var->blue.length?????? = 8;
????????????var->blue.offset?????? = 0;
????????????break;
????}

????return 0;
}

/*申請幀緩沖設(shè)備fb_info的顯示緩沖區(qū)空間*/
static int __init my2440fb_map_video_memory(struct fb_info *fbinfo)
{
????dma_addr_t map_dma;/*用于保存DMA緩沖區(qū)總線地址*/
????struct my2440fb_var????*fbvar = fbinfo->par;/*獲得在lcd_fb_probe探測函數(shù)中設(shè)置的私有結(jié)構(gòu)體數(shù)據(jù)*/
????unsigned map_size = PAGE_ALIGN(fbinfo->fix.smem_len);/*獲得FrameBuffer緩存的大小, PAGE_ALIGN定義在mm.h中*/

????/*將分配的一個寫合并DMA緩存區(qū)設(shè)置為LCD屏幕的虛擬地址(對于DMA請參考DMA相關(guān)知識)
????dma_alloc_writecombine定義在arch/arm/mm/dma-mapping.c中*/
????fbinfo->screen_base = dma_alloc_writecombine(fbvar->dev, map_size, &map_dma, GFP_KERNEL);

????if (fbinfo->screen_base)
????{
????????/*設(shè)置這片DMA緩存區(qū)的內(nèi)容為空*/
????????memset(fbinfo->screen_base, 0x00, map_size);

????????/*將DMA緩沖區(qū)總線地址設(shè)成fb_info不可變參數(shù)中framebuffer緩存的開始位置*/
????????fbinfo->fix.smem_start = map_dma;
????}

????return fbinfo->screen_base ? 0 : -ENOMEM;
}

/*釋放幀緩沖設(shè)備fb_info的顯示緩沖區(qū)空間*/
static inline void my2440fb_unmap_video_memory(struct fb_info *fbinfo)
{
????struct my2440fb_var????*fbvar = fbinfo->par;
????unsigned map_size = PAGE_ALIGN(fbinfo->fix.smem_len);

????/*跟申請DMA的地方想對應(yīng)*/
????dma_free_writecombine(fbvar->dev, map_size, fbinfo->screen_base, fbinfo->fix.smem_start);
}


/*LCD FrameBuffer設(shè)備移除的實現(xiàn)，注意這里使用一個__devexit宏，和lcd_fb_probe接口函數(shù)相對應(yīng)。
??在Linux內(nèi)核中，使用了大量不同的宏來標(biāo)記具有不同作用的函數(shù)和數(shù)據(jù)結(jié)構(gòu)，這些宏在include/linux/init.h
??頭文件中定義，編譯器通過這些宏可以把代碼優(yōu)化放到合適的內(nèi)存位置，以減少內(nèi)存占用和提高內(nèi)核效率。
??__devinit、__devexit就是這些宏之一，在probe()和remove()函數(shù)中應(yīng)該使用__devinit和__devexit宏。
??又當(dāng)remove()函數(shù)使用了__devexit宏時，則在驅(qū)動結(jié)構(gòu)體中一定要使用__devexit_p宏來引用remove()，
??所以在第①步中就用__devexit_p來引用lcd_fb_remove接口函數(shù)。*/
static int __devexit lcd_fb_remove(struct platform_device *pdev)
{
????struct fb_info *fbinfo = platform_get_drvdata(pdev);
????struct my2440fb_var????*fbvar = fbinfo->par;

????/*從系統(tǒng)中注銷幀緩沖設(shè)備*/
????unregister_framebuffer(fbinfo);

????/*停止LCD控制器的工作*/
????my2440fb_lcd_enable(fbvar, 0);

????/*延遲一段時間，因為停止LCD控制器需要一點時間 */
????msleep(1);

????/*釋放幀緩沖設(shè)備fb_info的顯示緩沖區(qū)空間*/
????my2440fb_unmap_video_memory(fbinfo);

????/*將LCD平臺數(shù)據(jù)清空和釋放fb_info空間資源*/
????platform_set_drvdata(pdev, NULL);
????framebuffer_release(fbinfo);

????/*釋放中斷資源*/
????free_irq(fbvar->lcd_irq_no, fbvar);

????/*釋放時鐘資源*/
????if (fbvar->lcd_clock)
????{
????????clk_disable(fbvar->lcd_clock);
????????clk_put(fbvar->lcd_clock);
????????fbvar->lcd_clock = NULL;
????}

????/*釋放LCD IO空間映射的虛擬內(nèi)存空間*/
????iounmap(fbvar->lcd_base);

????/*釋放申請的LCD IO端口所占用的IO空間*/
????release_resource(fbvar->lcd_mem);
????kfree(fbvar->lcd_mem);

????return 0;
}

/*停止LCD控制器的工作*/
static void my2440fb_lcd_enable(struct my2440fb_var *fbvar, int enable)
{
????unsigned long flags;

????/*在修改下面寄存器值之前先屏蔽中斷，將中斷狀態(tài)保存到flags中*/
????local_irq_save(flags);

????if (enable)
????{
????????fbvar->regs.lcdcon1 |= S3C2410_LCDCON1_ENVID;
????}
????else
????{
????????fbvar->regs.lcdcon1 &= ~S3C2410_LCDCON1_ENVID;
????}

????writel(fbvar->regs.lcdcon1, fbvar->lcd_base + S3C2410_LCDCON1);

????/*恢復(fù)被屏蔽的中斷*/
????local_irq_restore(flags);
}

/*對LCD FrameBuffer平臺設(shè)備驅(qū)動電源管理的支持,CONFIG_PM這個宏定義在內(nèi)核中*/
#ifdef CONFIG_PM
/*當(dāng)配置內(nèi)核時選上電源管理，則平臺設(shè)備的驅(qū)動就支持掛起和恢復(fù)功能*/
static int lcd_fb_suspend(struct platform_device *pdev, pm_message_t state)
{
????/*掛起LCD設(shè)備，注意這里掛起LCD時并沒有保存LCD控制器的各種狀態(tài)，所以在恢復(fù)后LCD不會繼續(xù)顯示掛起前的內(nèi)容
???? 若要繼續(xù)顯示掛起前的內(nèi)容，則要在這里保存LCD控制器的各種狀態(tài)，這里就不講這個了，以后講到電源管理再講*/
????struct fb_info *fbinfo = platform_get_drvdata(pdev);
????struct my2440fb_var????*fbvar = fbinfo->par;

????/*停止LCD控制器的工作*/
????my2440fb_lcd_enable(fbvar, 0);

????msleep(1);

????/*停止時鐘*/
????clk_disable(fbvar->lcd_clock);

????return 0;
}

static?int lcd_fb_resume(struct platform_device *pdev)
{
????/*恢復(fù)掛起的LCD設(shè)備*/
????struct fb_info *fbinfo = platform_get_drvdata(pdev);
????struct my2440fb_var????*fbvar = fbinfo->par;

????/*開啟時鐘*/
????clk_enable(fbvar->lcd_clock);

????/*初始化LCD控制器之前要延遲一段時間*/
????msleep(1);

????/*恢復(fù)時重新初始化LCD各寄存器*/
????my2440fb_init_registers(fbinfo);

????/*重新激活fb_info中所有的參數(shù)配置，該函數(shù)定義在第③步中再講*/
????my2440fb_activate_var(fbinfo);

????/*正與掛起時講到的那樣，因為沒保存掛起時LCD控制器的各種狀態(tài)，
????所以恢復(fù)后就讓LCD顯示空白，該函數(shù)定義也在第③步中再講*/
????my2440fb_blank(FB_BLANK_UNBLANK, fbinfo);

????return 0;
}
#else
/*如果配置內(nèi)核時沒選上電源管理,則平臺設(shè)備的驅(qū)動就不支持掛起和恢復(fù)功能,這兩個函數(shù)也就無需實現(xiàn)了*/
#define lcd_fb_suspend????NULL
#define lcd_fb_resume????NULL
#endif

??? fbinfo->flags?????????????? = FBINFO_FLAG_DEFAULT;

??? fbinfo->pseudo_palette????? = &fbvar->pseudo_pal;

?

/*Framebuffer底層硬件操作各接口函數(shù)*/
static struct fb_ops my2440fb_ops =
{
????.owner??????????= THIS_MODULE,
????.fb_check_var???= my2440fb_check_var,/*第②步中已實現(xiàn)*/
????.fb_set_par?????= my2440fb_set_par,/*設(shè)置fb_info中的參數(shù)，主要是LCD的顯示模式*/
????.fb_blank???????= my2440fb_blank,/*顯示空白(即：LCD開關(guān)控制)*/
????.fb_setcolreg???= my2440fb_setcolreg,/*設(shè)置顏色表*/
????/*以下三個函數(shù)是可選的，主要是提供fb_console的支持，在內(nèi)核中已經(jīng)實現(xiàn)，這里直接調(diào)用即可*/
????.fb_fillrect????= cfb_fillrect,/*定義在drivers/video/cfbfillrect.c中*/
????.fb_copyarea????= cfb_copyarea,/*定義在drivers/video/cfbcopyarea.c中*/
????.fb_imageblit???= cfb_imageblit,/*定義在drivers/video/cfbimgblt.c中*/
};

/*設(shè)置fb_info中的參數(shù)，這里根據(jù)用戶設(shè)置的可變參數(shù)var調(diào)整固定參數(shù)fix*/
static int my2440fb_set_par(struct fb_info *fbinfo)
{
????/*獲得fb_info中的可變參數(shù)*/
????struct fb_var_screeninfo *var = &fbinfo->var;

????/*判斷可變參數(shù)中的色位模式，根據(jù)色位模式來設(shè)置色彩模式*/
????switch (var->bits_per_pixel)
????{
????????case 32:
????????case 16:
????????case 12:/*12BPP時，設(shè)置為真彩色(分成紅、綠、藍(lán)三基色)*/
????????????fbinfo->fix.visual = FB_VISUAL_TRUECOLOR;
????????????break;
????????case 1:/*1BPP時，設(shè)置為黑白色(分黑、白兩種色，FB_VISUAL_MONO01代表黑，FB_VISUAL_MONO10代表白)*/
????????????fbinfo->fix.visual = FB_VISUAL_MONO01;
????????????break;
????????default:/*默認(rèn)設(shè)置為偽彩色，采用索引顏色顯示*/
????????????fbinfo->fix.visual = FB_VISUAL_PSEUDOCOLOR;
????????????break;
????}

????/*設(shè)置fb_info中固定參數(shù)中一行的字節(jié)數(shù)，公式：1行字節(jié)數(shù)=(1行像素個數(shù)*每像素位數(shù)BPP)/8 */
????fbinfo->fix.line_length = (var->xres_virtual * var->bits_per_pixel) / 8;

????/*修改以上參數(shù)后，重新激活fb_info中的參數(shù)配置(即：使修改后的參數(shù)在硬件上生效)*/
????my2440fb_activate_var(fbinfo);

????return 0;
}

/*重新激活fb_info中的參數(shù)配置*/
static void my2440fb_activate_var(struct fb_info *fbinfo)
{
????/*獲得結(jié)構(gòu)體變量*/
????struct my2440fb_var?*fbvar = fbinfo->par;
????void __iomem *regs = fbvar->lcd_base;

????/*獲得fb_info可變參數(shù)*/
????struct fb_var_screeninfo *var = &fbinfo->var;

????/*計算LCD控制寄存器1中的CLKVAL值, 根據(jù)數(shù)據(jù)手冊中該寄存器的描述，計算公式如下：
????* STN屏：VCLK = HCLK / (CLKVAL * 2), CLKVAL要求>= 2
????* TFT屏：VCLK = HCLK / [(CLKVAL + 1) * 2], CLKVAL要求>= 0*/
????int clkdiv = my2440fb_calc_pixclk(fbvar, var->pixclock) / 2;

????/*獲得屏幕的類型*/
????int type = fbvar->regs.lcdcon1 & S3C2410_LCDCON1_TFT;

????if (type == S3C2410_LCDCON1_TFT)
????{
????????/*根據(jù)數(shù)據(jù)手冊按照TFT屏的要求配置LCD控制寄存器1-5*/
????????my2440fb_config_tft_lcd_regs(fbinfo, &fbvar->regs);

????????--clkdiv;

????????if (clkdiv < 0)
????????{
????????????clkdiv = 0;
????????}
????}
????else
????{
????????/*根據(jù)數(shù)據(jù)手冊按照STN屏的要求配置LCD控制寄存器1-5*/
????????my2440fb_config_stn_lcd_regs(fbinfo, &fbvar->regs);

????????if (clkdiv < 2)
????????{
????????????clkdiv = 2;
????????}
????}

????/*設(shè)置計算的LCD控制寄存器1中的CLKVAL值*/
????fbvar->regs.lcdcon1 |= S3C2410_LCDCON1_CLKVAL(clkdiv);

????/*將各參數(shù)值寫入LCD控制寄存器1-5中*/
????writel(fbvar->regs.lcdcon1 & ~S3C2410_LCDCON1_ENVID, regs + S3C2410_LCDCON1);
????writel(fbvar->regs.lcdcon2, regs + S3C2410_LCDCON2);
????writel(fbvar->regs.lcdcon3, regs + S3C2410_LCDCON3);
????writel(fbvar->regs.lcdcon4, regs + S3C2410_LCDCON4);
????writel(fbvar->regs.lcdcon5, regs + S3C2410_LCDCON5);

????/*配置幀緩沖起始地址寄存器1-3*/
????my2440fb_set_lcdaddr(fbinfo);

????fbvar->regs.lcdcon1 |= S3C2410_LCDCON1_ENVID,
????writel(fbvar->regs.lcdcon1, regs + S3C2410_LCDCON1);
}

/*計算LCD控制寄存器1中的CLKVAL值*/
static unsigned int my2440fb_calc_pixclk(struct my2440fb_var *fbvar, unsigned long pixclk)
{
????/*獲得LCD的時鐘*/
????unsigned long clk = clk_get_rate(fbvar->lcd_clock);

????/* 像素時鐘單位是皮秒，而時鐘的單位是赫茲，所以計算公式為：
???? * Hz -> picoseconds is / 10^-12
???? */
????unsigned long long div = (unsigned long long)clk * pixclk;

????div >>= 12;????????????/* div / 2^12 */
????do_div(div, 625 * 625UL * 625); /* div / 5^12, do_div宏定義在asm/div64.h中*/

????return div;
}

/*根據(jù)數(shù)據(jù)手冊按照TFT屏的要求配置LCD控制寄存器1-5*/
static void my2440fb_config_tft_lcd_regs(const struct fb_info *fbinfo, struct s3c2410fb_hw *regs)
{
????const struct my2440fb_var?*fbvar = fbinfo->par;
????const struct fb_var_screeninfo *var = &fbinfo->var;

????/*根據(jù)色位模式設(shè)置LCD控制寄存器1和5，參考數(shù)據(jù)手冊*/
????switch (var->bits_per_pixel)
????{
????????case 1:/*1BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_TFT1BPP;
????????????break;
????????case 2:/*2BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_TFT2BPP;
????????????break;
????????case 4:/*4BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_TFT4BPP;
????????????break;
????????case 8:/*8BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_TFT8BPP;
????????????regs->lcdcon5 |= S3C2410_LCDCON5_BSWP | S3C2410_LCDCON5_FRM565;
????????????regs->lcdcon5 &= ~S3C2410_LCDCON5_HWSWP;
????????????break;
????????case 16:/*16BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_TFT16BPP;
????????????regs->lcdcon5 &= ~S3C2410_LCDCON5_BSWP;
????????????regs->lcdcon5 |= S3C2410_LCDCON5_HWSWP;
????????????break;
????????case 32:/*32BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_TFT24BPP;
????????????regs->lcdcon5 &= ~(S3C2410_LCDCON5_BSWP | S3C2410_LCDCON5_HWSWP | S3C2410_LCDCON5_BPP24BL);
????????????break;
????????default:/*無效的BPP*/
????????????dev_err(fbvar->dev, "invalid bpp %d/n", var->bits_per_pixel);
????}

????/*設(shè)置LCD配置寄存器2、3、4*/
????regs->lcdcon2 = S3C2410_LCDCON2_LINEVAL(var->yres - 1) |
????????????S3C2410_LCDCON2_VBPD(var->upper_margin - 1) |
????????????S3C2410_LCDCON2_VFPD(var->lower_margin - 1) |
????????????S3C2410_LCDCON2_VSPW(var->vsync_len - 1);

????regs->lcdcon3 = S3C2410_LCDCON3_HBPD(var->right_margin - 1) |
????????????S3C2410_LCDCON3_HFPD(var->left_margin - 1) |
????????????S3C2410_LCDCON3_HOZVAL(var->xres - 1);

????regs->lcdcon4 = S3C2410_LCDCON4_HSPW(var->hsync_len - 1);
}

/*根據(jù)數(shù)據(jù)手冊按照STN屏的要求配置LCD控制寄存器1-5*/
static void my2440fb_config_stn_lcd_regs(const struct fb_info *fbinfo, struct s3c2410fb_hw *regs)
{
????const struct my2440fb_var????*fbvar = fbinfo->par;
????const struct fb_var_screeninfo *var = &fbinfo->var;

????int type = regs->lcdcon1 & ~S3C2410_LCDCON1_TFT;
????int hs = var->xres >> 2;
????unsigned wdly = (var->left_margin >> 4) - 1;
????unsigned wlh = (var->hsync_len >> 4) - 1;

????if (type != S3C2410_LCDCON1_STN4)
????{
????????hs >>= 1;
????}

????/*根據(jù)色位模式設(shè)置LCD控制寄存器1，參考數(shù)據(jù)手冊*/
????switch (var->bits_per_pixel)
????{
????????case 1:/*1BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_STN1BPP;
????????????break;
????????case 2:/*2BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_STN2GREY;
????????????break;
????????case 4:/*4BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_STN4GREY;
????????????break;
????????case 8:/*8BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_STN8BPP;
????????????hs *= 3;
????????????break;
????????case 12:/*12BPP*/
????????????regs->lcdcon1 |= S3C2410_LCDCON1_STN12BPP;
????????????hs *= 3;
????????????break;
????????default:/*無效的BPP*/
????????????dev_err(fbvar->dev, "invalid bpp %d/n", var->bits_per_pixel);
????}
????
????/*設(shè)置LCD配置寄存器2、3、4, 參考數(shù)據(jù)手冊*/
????if (wdly > 3) wdly = 3;
????if (wlh > 3) wlh = 3;
????regs->lcdcon2 = S3C2410_LCDCON2_LINEVAL(var->yres - 1);

????regs->lcdcon3 =?S3C2410_LCDCON3_WDLY(wdly) |
????????????S3C2410_LCDCON3_LINEBLANK(var->right_margin / 8) |
????????????S3C2410_LCDCON3_HOZVAL(hs - 1);

????regs->lcdcon4 = S3C2410_LCDCON4_WLH(wlh);
}

/*配置幀緩沖起始地址寄存器1-3，參考數(shù)據(jù)手冊*/
static void my2440fb_set_lcdaddr(struct fb_info *fbinfo)
{
????unsigned long saddr1, saddr2, saddr3;
????struct my2440fb_var?*fbvar = fbinfo->par;
????void __iomem *regs = fbvar->lcd_base;

????saddr1 = fbinfo->fix.smem_start >> 1;
????saddr2 = fbinfo->fix.smem_start;
????saddr2 += fbinfo->fix.line_length * fbinfo->var.yres;
????saddr2 >>= 1;
????saddr3 = S3C2410_OFFSIZE(0) | S3C2410_PAGEWIDTH((fbinfo->fix.line_length / 2) & 0x3ff);

????writel(saddr1, regs + S3C2410_LCDSADDR1);
????writel(saddr2, regs + S3C2410_LCDSADDR2);
????writel(saddr3, regs + S3C2410_LCDSADDR3);
}

/*顯示空白，blank mode有5種模式，定義在fb.h中，是一個枚舉*/
static int my2440fb_blank(int blank_mode, struct fb_info *fbinfo)
{
????struct my2440fb_var?*fbvar = fbinfo->par;
????void __iomem *regs = fbvar->lcd_base;

????/*根據(jù)顯示空白的模式來設(shè)置LCD是開啟還是停止*/
????if (blank_mode == FB_BLANK_POWERDOWN)
????{
????????my2440fb_lcd_enable(fbvar, 0);/*在第②步中定義*/
????}
????else
????{
????????my2440fb_lcd_enable(fbvar, 1);/*在第②步中定義*/
????}

????/*根據(jù)顯示空白的模式來控制臨時調(diào)色板寄存器*/
????if (blank_mode == FB_BLANK_UNBLANK)
????{
????????/*臨時調(diào)色板寄存器無效*/
????????writel(0x0, regs + S3C2410_TPAL);
????}
????else
????{
????????/*臨時調(diào)色板寄存器有效*/
????????writel(S3C2410_TPAL_EN, regs + S3C2410_TPAL);
????}

????return 0;
}

/*設(shè)置顏色表*/
static int my2440fb_setcolreg(unsigned regno,unsigned red,unsigned green,unsigned blue,unsigned transp,struct fb_info *fbinfo)
{
????unsigned int val;
????struct my2440fb_var?*fbvar = fbinfo->par;
????void __iomem *regs = fbvar->lcd_base;

????switch (fbinfo->fix.visual)
????{
????????case FB_VISUAL_TRUECOLOR:
????????????/*真彩色*/
????????????if (regno < 16)
????????????{
????????????????u32 *pal = fbinfo->pseudo_palette;

????????????????val = chan_to_field(red, &fbinfo->var.red);
????????????????val |= chan_to_field(green, &fbinfo->var.green);
????????????????val |= chan_to_field(blue, &fbinfo->var.blue);

????????????????pal[regno] = val;
????????????}
????????????break;
????????case FB_VISUAL_PSEUDOCOLOR:
????????????/*偽彩色*/
????????????if (regno < 256)
????????????{
????????????????val = (red >> 0) & 0xf800;
????????????????val |= (green >> 5) & 0x07e0;
????????????????val |= (blue >> 11) & 0x001f;

????????????????writel(val, regs + S3C2410_TFTPAL(regno));

????????????????/*修改調(diào)色板*/
????????????????schedule_palette_update(fbvar, regno, val);
????????????}
????????????break;
????????default:
????????????return 1;
????}

????return 0;
}

static inline unsigned int chan_to_field(unsigned int chan, struct fb_bitfield *bf)
{
????chan &= 0xffff;
????chan >>= 16 - bf->length;
????return chan << bf->offset;
}

/*修改調(diào)色板*/
static void schedule_palette_update(struct my2440fb_var????*fbvar, unsigned int regno, unsigned int val)
{
????unsigned long flags;
????unsigned long irqen;

????/*LCD中斷掛起寄存器基地址*/
????void __iomem *lcd_irq_base = fbvar->lcd_base + S3C2410_LCDINTBASE;

????/*在修改中斷寄存器值之前先屏蔽中斷，將中斷狀態(tài)保存到flags中*/
????local_irq_save(flags);

????fbvar->palette_buffer[regno] = val;

????/*判斷調(diào)色板是否準(zhǔn)備就像*/
????if (!fbvar->palette_ready)
????{
????????fbvar->palette_ready = 1;

????????/*使能中斷屏蔽寄存器*/
????????irqen = readl(lcd_irq_base + S3C24XX_LCDINTMSK);
????????irqen &= ~S3C2410_LCDINT_FRSYNC;
????????writel(irqen, lcd_irq_base + S3C24XX_LCDINTMSK);
????}

????/*恢復(fù)被屏蔽的中斷*/
????local_irq_restore(flags);
}