LCD驱动分析(三)： framebuffer驱动的注册

这里最好牵涉到几个文件S3cfb.c、S3cfb_fimd6x.c setuo-fb.c fb_mem.c

在这里之前最好知道pci，和memio一些术语的意思

S3cfb.c中的s3cfb_probe设备探测，是驱动注册的主要函数

 

/*定义一个结构体用来维护驱动程序中各函数中用到的变量
  先别看结构体要定义这些成员，到各函数使用的地方就明白了*/
static int __devinit s3cfb_probe(struct platform_device *pdev)
{
    struct s3c_platform_fb *pdata;/*LCD屏配置信息结构体*/
    struct s3cfb_global *fbdev;/*驱动程序全局变量结构体*/
    struct resource *res; /*用来保存从LCD平台设备中获取的LCD资源*/
    int i, j, ret = 0;

    printk("%s\n",__func__);
    fbdev = kzalloc(sizeof(struct s3cfb_global), GFP_KERNEL);
    if (!fbdev) {
        dev_err(&pdev->dev, "failed to allocate for "
            "global fb structure\n");
        ret = -ENOMEM;
        goto err_global;
    }
    fbdev->dev = &pdev->dev;

    fbdev->regulator = regulator_get(&pdev->dev, "pd");
    if (!fbdev->regulator) {
        dev_err(fbdev->dev, "failed to get regulator\n");
        ret = -EINVAL;
        goto err_regulator;
    }
    ret = regulator_enable(fbdev->regulator);
    if (ret < 0) {
        dev_err(fbdev->dev, "failed to enable regulator\n");
        ret = -EINVAL;
        goto err_regulator;
    }

    /*获取LCD参数信息*/
    pdata = to_fb_plat(&pdev->dev);
    if (!pdata) {
        dev_err(fbdev->dev, "failed to get platform data\n");
        ret = -EINVAL;
        goto err_pdata;
    }

    fbdev->lcd = (struct s3cfb_lcd *)pdata->lcd;

    /*配置GPIO端口*/
    if (pdata->cfg_gpio)
        pdata->cfg_gpio(pdev);

    /*设置时钟参数*/
    if (pdata->clk_on)
        pdata->clk_on(pdev, &fbdev->clock);

    /*获取LCD平台设备所使用的IO端口资源，注意这个IORESOURCE_MEM标志和LCD平台设备定义中的一致*/
    res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
    if (!res) {
        dev_err(fbdev->dev, "failed to get io memory region\n");
        ret = -EINVAL;
        goto err_io;
    }

    /*申请LCD IO端口所占用的IO空间(注意理解IO空间和内存空间的区别),request_mem_region定义在ioport.h中*/
    res = request_mem_region(res->start,
                 res->end - res->start + 1, pdev->name);
    if (!res) {
        dev_err(fbdev->dev, "failed to request io memory region\n");
        ret = -EINVAL;
        goto err_io;
    }

    /*将LCD的IO端口占用的这段IO空间映射到内存的虚拟地址，ioremap定义在io.h中
         注意：IO空间要映射后才能使用，以后对虚拟地址的操作就是对IO空间的操作*/
    fbdev->regs = ioremap(res->start, res->end - res->start + 1);
    if (!fbdev->regs) {
        dev_err(fbdev->dev, "failed to remap io region\n");
        ret = -EINVAL;
        goto err_mem;
    }
#ifdef CONFIG_FB_S3C_LTE480WV
    /*设置寄存器初始状态*/
    s3cfb_pre_init_para(fbdev);
#endif

    /*设置gamma 值*/
    s3cfb_set_gamma(fbdev);
    /*设置VSYNC中断*/
    s3cfb_set_vsync_interrupt(fbdev, 1);
    /*设置全局中断*/
    s3cfb_set_global_interrupt(fbdev, 1);
    /*fb设备参数信息初始化*/
    s3cfb_init_global(fbdev);

    /*为framebuffer分配空间，进行内存映射，填充fb_info*/
    if (s3cfb_alloc_framebuffer(fbdev)) {
        ret = -ENOMEM;
        goto err_alloc;
    }

    /*注册fb设备到系统中*/
    if (s3cfb_register_framebuffer(fbdev)) {
        ret = -EINVAL;
        goto err_register;
    }

    s3cfb_set_clock(fbdev);
    s3cfb_set_window(fbdev, pdata->default_win, 1);

    s3cfb_display_on(fbdev);

    fbdev->irq = platform_get_irq(pdev, 0);
    if (request_irq(fbdev->irq, s3cfb_irq_frame, IRQF_SHARED,
            pdev->name, fbdev)) {
        dev_err(fbdev->dev, "request_irq failed\n");
        ret = -EINVAL;
        goto err_irq;
    }

#ifdef CONFIG_FB_S3C_LCD_INIT
    if (pdata->backlight_on)
        pdata->backlight_on(pdev);

    if (!bootloaderfb && pdata->reset_lcd)
        pdata->reset_lcd(pdev);

    if (pdata->lcd_on)
        pdata->lcd_on(pdev);
#endif

#ifdef CONFIG_HAS_EARLYSUSPEND
    fbdev->early_suspend.suspend = s3cfb_early_suspend;
    fbdev->early_suspend.resume = s3cfb_late_resume;
    fbdev->early_suspend.level = EARLY_SUSPEND_LEVEL_DISABLE_FB;
    register_early_suspend(&fbdev->early_suspend);
#endif

    /*对设备文件系统的支持，创建fb设备文件*/
    ret = device_create_file(&(pdev->dev), &dev_attr_win_power);
    if (ret < 0)
        dev_err(fbdev->dev, "failed to add sysfs entries\n");

    dev_info(fbdev->dev, "registered successfully\n");

    /*显示开机logo*/
#if !defined(CONFIG_FRAMEBUFFER_CONSOLE) && defined(CONFIG_LOGO)
    if (fb_prepare_logo( fbdev->fb[pdata->default_win], FB_ROTATE_UR)) {
        printk("Start display and show logo\n");
        /* Start display and show logo on boot */
        fb_set_cmap(&fbdev->fb[pdata->default_win]->cmap, fbdev->fb[pdata->default_win]);
        fb_show_logo(fbdev->fb[pdata->default_win], FB_ROTATE_UR);
    }
#endif

    return 0;
}