Linux驱动之内核自带的S3C2440的LCD驱动分析

    memcpy(&info->regs, &mach_info->regs, sizeof(info->regs));

    /* Stop the video and unset ENVID if set */

    info->regs.lcdcon1 &= ~S3C2410_LCDCON1_ENVID;

    lcdcon1 = readl(S3C2410_LCDCON1);

    writel(lcdcon1 & ~S3C2410_LCDCON1_ENVID, S3C2410_LCDCON1);

    // add by thisway.diy@163.com, for eBlocks

    s3c2410_gpio_setpin(S3C2410_GPB0, 0);    // back light control

    info->mach_info            = pdev->dev.platform_data;

    fbinfo->fix.type        = FB_TYPE_PACKED_PIXELS;

    fbinfo->fix.type_aux        = 0;

    fbinfo->fix.xpanstep        = 0;

    fbinfo->fix.ypanstep        = 0;

    fbinfo->fix.ywrapstep        = 0;

    fbinfo->fix.accel        = FB_ACCEL_NONE;

    fbinfo->var.nonstd        = 0;

    fbinfo->var.activate        = FB_ACTIVATE_NOW;

    fbinfo->var.height        = mach_info->height;

    fbinfo->var.width        = mach_info->width;

    fbinfo->var.accel_flags     = 0;

    fbinfo->var.vmode        = FB_VMODE_NONINTERLACED;

    fbinfo->fbops            = &s3c2410fb_ops;

    fbinfo->flags            = FBINFO_FLAG_DEFAULT;

    fbinfo->pseudo_palette      = &info->pseudo_pal;

    fbinfo->var.xres        = mach_info->xres.defval;

    fbinfo->var.xres_virtual    = mach_info->xres.defval;

    fbinfo->var.yres        = mach_info->yres.defval;

    fbinfo->var.yres_virtual    = mach_info->yres.defval;

    fbinfo->var.bits_per_pixel  = mach_info->bpp.defval;

    fbinfo->var.upper_margin    = S3C2410_LCDCON2_GET_VBPD(mregs->lcdcon2) + 1;

    fbinfo->var.lower_margin    = S3C2410_LCDCON2_GET_VFPD(mregs->lcdcon2) + 1;

    fbinfo->var.vsync_len        = S3C2410_LCDCON2_GET_VSPW(mregs->lcdcon2) + 1;

    fbinfo->var.left_margin        = S3C2410_LCDCON3_GET_HFPD(mregs->lcdcon3) + 1;

    fbinfo->var.right_margin    = S3C2410_LCDCON3_GET_HBPD(mregs->lcdcon3) + 1;

    fbinfo->var.hsync_len        = S3C2410_LCDCON4_GET_HSPW(mregs->lcdcon4) + 1;

    fbinfo->var.red.offset      = 11;

    fbinfo->var.green.offset    = 5;

    fbinfo->var.blue.offset     = 0;

    fbinfo->var.transp.offset   = 0;

    fbinfo->var.red.length      = 5;

    fbinfo->var.green.length    = 6;

    fbinfo->var.blue.length     = 5;

    fbinfo->var.transp.length   = 0;

    fbinfo->fix.smem_len        =    mach_info->xres.max *

                    mach_info->yres.max *

                    mach_info->bpp.max / 8;//

    for (i = 0; i < 256; i++)

        info->palette_buffer[i] = PALETTE_BUFF_CLEAR;

    if (!request_mem_region((unsigned long)S3C24XX_VA_LCD, SZ_1M, 's3c2410-lcd')) {

        ret = -EBUSY;

        goto dealloc_fb;

    }

    dprintk('got LCD regionn');

    ret = request_irq(irq, s3c2410fb_irq, IRQF_DISABLED, pdev->name, info);

    if (ret) {

        dev_err(&pdev->dev, 'cannot get irq %d - err %dn', irq, ret);

        ret = -EBUSY;

        goto release_mem;

    }

    info->clk = clk_get(NULL, 'lcd');

    if (!info->clk || IS_ERR(info->clk)) {

        printk(KERN_ERR 'failed to get lcd clock sourcen');

        ret = -ENOENT;

        goto release_irq;

    }

    clk_enable(info->clk);//使能LCD时钟

    dprintk('got and enabled clockn');

    msleep(1);

    /* Initialize video memory */

    ret = s3c2410fb_map_video_memory(info);//分配显存

    if (ret) {

        printk( KERN_ERR 'Failed to allocate video RAM: %dn', ret);

        ret = -ENOMEM;

        goto release_clock;

    }

    dprintk('got video memoryn');

    ret = s3c2410fb_init_registers(info);/*3、硬件相关的设备，配置LCD寄存器*/

    ret = s3c2410fb_check_var(&fbinfo->var, fbinfo);

    ret = register_framebuffer(fbinfo);/*4、注册fbinfo结构到registered_fb数组*/

    if (ret < 0) {

        printk(KERN_ERR 'Failed to register framebuffer device: %dn', ret);

        goto free_video_memory;

    }

    /* create device files */

    device_create_file(&pdev->dev, &dev_attr_debug);

    printk(KERN_INFO 'fb%d: %s frame buffer devicen',

        fbinfo->node, fbinfo->fix.id);

    return 0;

free_video_memory:

    s3c2410fb_unmap_video_memory(info);

release_clock:

    clk_disable(info->clk);

    clk_put(info->clk);

release_irq:

    free_irq(irq,info);

release_mem:

     release_mem_region((unsigned long)S3C24XX_VA_LCD, S3C24XX_SZ_LCD);

dealloc_fb:

    framebuffer_release(fbinfo);

    return ret;

}

可以看到这个函数最终是注册了fbinfo结构体到帧缓存驱动的registered_fb数组。

大概总结一下这个函数的功能：

1、分配一个fb_info结构

2、设置fb_info结构

3、硬件相关的操作，配置LCD时钟、配置IO端口、配置LCD寄存器。

4、最终注册fbinfo结构到registered_fb数组

 s3c2410fb_remove函数的过程与s3c2410fb_probe函数相反