LCD笔记（3）写出LCD基本驱动框架

1. 分配fb_info

2. 设置fb_info

要设置哪些内容？根据APP的需求来。

3. 注册fb_info

主要是以上3步！

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/err.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/platform_device.h>
#include <linux/clk.h>
#include <linux/cpufreq.h>
#include <linux/io.h>

#include <asm/div64.h>

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

static struct fb_info *myfb_info;         //定义了一个fb_info结构体

static struct fb_ops myfb_ops = {
	.owner		= THIS_MODULE,            
	.fb_fillrect	= cfb_fillrect,       //画一个矩形，read write open由fbmem提供
	.fb_copyarea	= cfb_copyarea,       //将这块显存复制到另一个区域
	.fb_imageblit	= cfb_imageblit,      //画图 ，这些函数都由系统提供 不用自己写
};

/* 1. 入口 */
int __init lcd_drv_init(void)           //入口函数做分配、设置、注册fb_info结构体
{
	dma_addr_t phy_addr;          //定义一个变量存放物理地址
	
	/* 1.1 分配fb_info */
	myfb_info = framebuffer_alloc(0, NULL);        //分配一个fb_info

	/* 1.2 设置fb_info */                           //主要设置 var fix fbops
	/* a. var : LCD分辨率、颜色格式 */
	myfb_info->var.xres = 1024;                   
	myfb_info->var.yres = 600;
	myfb_info->var.bits_per_pixel = 16;  /* rgb565 */
	myfb_info->var.red.offset = 11;
	myfb_info->var.red.length = 5;

	myfb_info->var.green.offset = 5;
	myfb_info->var.green.length = 6;

	myfb_info->var.blue.offset = 0;
	myfb_info->var.blue.length = 5;
	

	/* b. fix */
	myfb_info->fix.smem_len = myfb_info->var.xres * myfb_info->var.yres * myfb_info->var.bits_per_pixel / 8;        //像素长度 
	if (myfb_info->var.bits_per_pixel == 24)
		myfb_info->fix.smem_len = myfb_info->var.xres * myfb_info->var.yres * 4;


	/* fb的虚拟地址 */
	myfb_info->screen_base = dma_alloc_wc(NULL, myfb_info->fix.smem_len, &phy_addr,
					 GFP_KERNEL);
	myfb_info->fix.smem_start = phy_addr;  /* fb的物理地址 */
	
	myfb_info->fix.type = FB_TYPE_PACKED_PIXELS;
	myfb_info->fix.visual = FB_VISUAL_TRUECOLOR;
	

	/* c. fbops */
	myfb_info->fbops = &myfb_ops;


	/* 1.3 注册fb_info */
	register_framebuffer(myfb_info);

	/* 1.4 硬件操作 */

	return 0;
}

/* 2. 出口 */
static void __exit lcd_drv_exit(void)            //和入口函数反过来操作
{
	/* 反过来操作 */
	/* 2.1 反注册fb_info */
	unregister_framebuffer(myfb_info);

	/* 2.2 释放fb_info */
	framebuffer_release(myfb_info);
}

module_init(lcd_drv_init);
module_exit(lcd_drv_exit);

MODULE_AUTHOR("www.100ask.net");
MODULE_DESCRIPTION("Framebuffer driver for the linux");
MODULE_LICENSE("GPL");