module_init()函数在include/linux/init.h中定义。
内核与buffer驱动发生关系的第一次地点是在s3c2410fb_init函数，该函数就只有一条语句:
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return platform_driver_register (&s3c2410fb_driver)；
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在driver/video/s3c2410fb.c中，s3c2410fb_driver的定义如下:
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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,
},
};
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为了向内核添加一个platform设备，程序员应该填写两个数据结构platform_device 和platform_driver，
这两个数据结构的定义都可以在include/linux/platform_device.h文件中找到:
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struct platform_device {
const char * name;
int id;
struct device dev;
u32 num_resources;
struct resource * resource;
};
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struct platform_driver {
int (*probe)(struct platform_device *);
int (*remove)(struct platform_device *);
void (*shutdown)(struct platform_device *);
int (*suspend)(struct platform_device *, pm_message_t state);
int (*suspend_late)(struct platform_device *, pm_message_t state);
int (*resume_early)(struct platform_device *);
int (*resume)(struct platform_device *);
struct device_driver driver;
};
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arch/arm/plat-s3c24xx/devs.c可以找到填写platform_device的代码:
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struct platform_device s3c_device_lcd = {
.name = "s3c2410-lcd",
.id = -1,
.num_resources = ARRAY_SIZE(s3c_lcd_resource),
.resource = s3c_lcd_resource,
.dev = {
.dma_mask = &s3c_device_lcd_dmamask,
.coherent_dma_mask = 0xffffffffUL
}
};
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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));
s3c_device_lcd.dev.platform_data = npd;
} else {
printk(KERN_ERR "no memory for LCD platform data\n");
}
}
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然后在arch/arm/mach-s3c2410/mach-smdk2410.c的smdk2410_map_io函数中调用s3c24xx_fb_set_platdata( )，具体为：
s3c24xx_fb_set_platdata(&smdk2410_lcd_platdata);
在调用platform_driver_register (&s3c2410fb_driver)；函数时，传给s3c2410fb_probe()函数的参数为s3c_device_lcd数据结构的地址，platform_device和platform_driver数据结构之间的联系通过name字段来联系。
上面主要是讲了platform_device和platform_driver之间的关系和实现的过程，下面讲lcd控制器的硬件和软件参数设置。
相关的数据结构定义于include/asm-arm/arch-s3c2410/fb.h中，列出如下:
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struct s3c2410fb_hw {
unsigned long lcdcon1;
unsigned long lcdcon2;
unsigned long lcdcon3;
unsigned long lcdcon4;
unsigned long lcdcon5;
};
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/* LCD description */
struct s3c2410fb_display {
/* LCD type */
unsigned type;
/* Screen size */
unsigned short width;
unsigned short height;
/* Screen info */
unsigned short xres;
unsigned short yres;
unsigned short bpp;
unsigned pixclock; /* pixclock in picoseconds */
unsigned short left_margin; /* value in pixels (TFT) or HCLKs (STN) */
unsigned short right_margin; /* value in pixels (TFT) or HCLKs (STN) */
unsigned short hsync_len; /* value in pixels (TFT) or HCLKs (STN) */
unsigned short upper_margin; /* value in lines (TFT) or 0 (STN) */
unsigned short lower_margin; /* value in lines (TFT) or 0 (STN) */
unsigned short vsync_len; /* value in lines (TFT) or 0 (STN) */
/* lcd configuration registers */
unsigned long lcdcon5;
};
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struct s3c2410fb_mach_info {
struct s3c2410fb_display *displays; /* attached diplays info */
unsigned num_displays; /* number of defined displays */
unsigned default_display;
/* GPIOs */
unsigned long gpcup;
unsigned long gpcup_mask;
unsigned long gpccon;
unsigned long gpccon_mask;
unsigned long gpdup;
unsigned long gpdup_mask;
unsigned long gpdcon;
unsigned long gpdcon_mask;
/* lpc3600 control register */
unsigned long lpcsel;
};
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下面的结构定义于include/linux/fb.h
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struct fb_info {
int node;
int flags;
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;
};
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