s5pc110 lcd driver分析（1） (转）

s5pc110 lcd driver分析（1） (转）

2011-09-19 17:58

//设置寄存器0xF800_0130（Video Interrupt Control 0 Register） [16:15]位为01 = VSYNC，这两位可能的值为00 = BACK Porch，10 = ACTIVE int s3cfb_set_vsync_interrupt(struct s3cfb_global *ctrl, int enable) //设置寄存器0xF800_0130 enable或者disable第【12】位和第【0】位，分别表示 //INTFRMEN [12] Specifies the Video Frame Interrupt Enable Control Bit. //   0 = Disables Video Frame Interrupt //   1 = Enables Video Frame Interrupt //   Note: This bit is meaningful when INTEN is high //INTEN [0] Specifies the Video Interrupt Enable Control Bit. //   0 = Disables Video Interrupt //   1 = Enables Video Interrupt int s3cfb_set_global_interrupt(struct s3cfb_global *ctrl, int enable) static int s3cfb_init_global(void) {    fbdev->output = OUTPUT_RGB;    fbdev->rgb_mode = MODE_RGB_P;    fbdev->wq_count = 0;    init_waitqueue_head(&fbdev->wq);    mutex_init(&fbdev->lock);    s3cfb_set_output(fbdev);       //设置寄存器0xF800_0000 的第[28:26]位，这三位所代表的意义是 //Determines the output format of Video Controller. //   000 = RGB interface //   001 = Reserved //   010 = Indirect I80 interface for LDI0 //   011 = Indirect I80 interface for LDI1 //   100 = WB interface and RGB interface //   101 = Reserved //   110 = WB Interface and i80 interface for LDI0 //   111 = WB Interface and i80 interface for LDI1 //设置寄存器0xF800_0008 [15:14] [13:12]位，这些代表的意义 //   Reserved [15:14] Reserved. //   Note: This bit should be 1. //TVFORMATSEL [13:12] Specifies the output format of YUV data. //   00 = Reserved //   01 = YUV422 //   1x = YUV444 // 将这四位都设置为0    s3cfb_set_display_mode(fbdev); //设置寄存器0xF800_0000 的第[18][17]位，这两位所代表的意义是 //   RGSPSEL [18] Selects display mode (VIDOUT[1:0] == 2’b00). //   0 = RGB parallel format //   1 = RGB serial format //   Selects the display mode (VIDOUT[1:0] != 2’b00). //   0 = RGB parallel format //   PNRMODE [17] Controls inverting RGB_ORDER (@VIDCON3). //   0 = Normal: RGBORDER[2] @VIDCON3 //   1 = Invert: ~RGBORDER[2] @VIDCON3 //   Note: This bit is used for the previous version of FIMD. You do //   not have to use this bit if you use RGB_ORDER@VIDCON3 //   register. //这是设置这两位均为0             MODE_RGB_P = 0,                MODE_BGR_P = 1,                MODE_RGB_S = 2,                MODE_BGR_S = 3,    s3cfb_set_polarity(fbdev); //设置寄存器xF800_0004， 第[7]，[6],[5],[4] 位,这四位代表的意思是 //IVCLK [7] Controls the polarity of the VCLK active edge. //   0 = Video data is fetched at VCLK falling edge //   1 = Video data is fetched at VCLK rising edge //IHSYNC [6] Specifies the HSYNC pulse polarity. //   0 = Normal //   1 = Inverted //IVSYNC [5] Specifies the VSYNC pulse polarity. //   0 = Normal //   1 = Inverted //IVDEN [4] Specifies the VDEN signal polarity. //   0 = Normal //   1 = Inverted    s3cfb_set_timing(fbdev); //设置寄存器0xF800_0010 32位分别表示 //VBPDE [31:24] Vertical back porch specifies the number of inactive lines at the //   start of a frame after vertical synchronization period. (Only for even //   field of YVU interface //VBPD [23:16] Vertical back porch specifies the number of inactive lines at the //   start of a frame after vertical synchronization period. //VFPD [15:8] Vertical front porch specifies the number of inactive lines at the end //   of a frame before vertical synchronization period. //VSPW [7:0] Vertical sync pulse width determines the high-level width of VSYNC //   pulse by counting the number of inactive lines. //设置寄存器0xF800_0014， 32位分别表示 //VFPDE [31:24] Vertical front porch specifies the number of inactive lines at the end //   of a frame before vertical synchronization period. (Only for the even //   field of YVU interface). //HBPD [23:16] Horizontal back porch specifies the number of VCLK periods //   between the falling edge of HSYNC and start of active data. //HFPD [15:8] Horizontal front porch specifies the number of VCLK periods //   between the end of active data and rising edge of HSYNC. //HSPW [7:0] Horizontal sync pulse width determines the high-level width of //   HSYNC pulse by counting the number of VCLK.    s3cfb_set_lcd_size(fbdev); //设置寄存器0xF800_0018， 22位有效位分别表示 //LINEVAL [21:11] Determines the vertical size of display. In the Interlace mode, //   (LINEVAL + 1) should be even. //HOZVAL [10:0] Determines the horizontal size of display. //NOTE: HOZVAL = (Horizontal display size) -1 and LINEVAL = (Vertical display size) –1.    return 0; } 我们继续看probe函数 /////////////////////////////////////////    LCDDEBUG("%s, s3cfb init global\n", __func__);    s3cfb_init_global();    LCDDEBUG("%s, s3cfb init global done\n", __func__);    #if !defined(CONFIG_FB_S3C_DUMMYLCD)    s3cfb_display_on(fbdev); //设置寄存器0xF800_0000 的第[1][0]为，这两位分别表示 //ENVID [1] Enables/ disables video output and logic immediately. //   0 = Disables the video output and display control signal. //   1 = Enables the video output and display control signal //ENVID_F [0] Enables/ disables video output and logic at current frame end. //   0 = Disables the video output and display control signal. //   1 = Enables the video output and display control signal. //   * If this bit is set to “on” and “off”, then “H” is read and video //   controller is enabled until the end of current frame. //这里设置这两位为1 #endif    /* panel control */ #if defined(CONFIG_FB_S3C_TL2796)    if (pdata->backlight_on)        pdata->backlight_on(pdev); #elif defined(CONFIG_FB_S3C_LTE480WV)    LCDDEBUG("%s, pdata->backlight_onoff:%p\n", __func__, pdata->backlight_onoff); //如果满足条件， 调用lte480wv_backlight_onoff，打开背光    if (pdata->backlight_onoff)        pdata->backlight_onoff(pdev, 1); #endif #if !defined(CONFIG_FB_S3C_DUMMYLCD)    LCDDEBUG("%s, pdata->reset_lcd:%p\n", __func__, pdata->reset_lcd); //如果满足条件，调用lte480wv_reset_lcd函数， GPH0_6脚是LCD的 reset引脚 //我们可以看到在函数lte480wv_reset_lcd中首先调用gpio_request，第一个参数传递宏S5PC11X_GPH0(6)，用这个参数直接索引一个静态数组 //static struct gpio_desc gpio_desc[ARCH_NR_GPIOS] 在数组中找到相应gpio_desc元素的struct gpio_chip成员地址，判断是否函数指针 //chip->request是否为空，如果存在则调用此函数，在我们的平台中，这个函数并不存在，第二个参数是label的值，如果内核选项CONFIG_DEBUG_FS //为真，那么结构体struct gpio_desc包含成员Label,需要将参数二赋值给它，反之为空 // //调用gpio_direction_output(unsigned gpio, int value)，此函数同样，利用参数一S5PC11X_GPH0(6)，找到相应的struct gpio_chip，判断成员 //direction_output函数指针是否为空，不为空则调用此函数status = chip->direction_output(chip, gpio, value);实际调用函数 //gpio_direction_output(S5PC11X_GPH0(6), 1)， 配置引脚S5PC11X_GPH0(6) （E020_0C00）为output,输出dat为1 //mdelay(10);延时10ms //调用函数gpio_set_value(S5PC11X_GPH0(6), 0)        #define gpio_set_value   __gpio_set_value        __gpio_set_value(unsigned gpio, int value) // driver/gpio/gpiolib.c            通过第一个参数S5PC11X_GPH0(6)找到相应的结构体struct gpio_chip            调用结构体的成员，函数指针void   (*set)(struct gpio_chip *chip,                        unsigned offset, int value);            set指向函数s3c_gpiolib_set 这个函数位于/arch/arm/plat-s3c/pgio.c        这个函数写GPH0(6)的数据寄存器为0 //由此可知这里向GPH0(6)发一个低电平 //mdelay(10) //调用函数gpio_set_value(S5PC11X_GPH0(6), 1)在发一个高电平 //mdelay(10) //gpio_free(S5PC11X_GPH0(6)); 释放该引脚           if (pdata->reset_lcd)        pdata->reset_lcd(pdev); #endif    LCDDEBUG("%s, fbdev lcd init ldi:%p\n", __func__, fbdev->lcd->init_ldi);    if (fbdev->lcd->init_ldi)        fbdev->lcd->init_ldi(); /////////////////////////////////// 我们继续返回主程序看probe函数 ///////////////////////////////    /* prepare memory */    LCDDEBUG(" %s, s3cfb_alloc_framebuffer \n",__func__);    if (s3cfb_alloc_framebuffer())        goto err_alloc; ************************************* static int s3cfb_alloc_framebuffer(void) 分析    struct s3c_platform_fb *pdata = to_fb_plat(fbdev->dev);    int ret, i;    /* alloc for framebuffers */    fbdev->fb = (struct fb_info **) kmalloc(pdata->nr_wins * \            sizeof(struct fb_info *), GFP_KERNEL);    //按照平台数据设置的window数分配全局结构体struct s3cfb_global fbdev的成员fb的空间，fb的类型是struct fb_info**    //这里分配的是二级指针的空间    if (!fbdev->fb){   //错误处理        err("not enough memory\n");        ret = -ENOMEM;        goto err_alloc;    }        /* alloc for each framebuffer */    //外循环用pdata->nr_wins的值控制，这里等于5    for (i = 0; i < pdata->nr_wins; i++) {        fbdev->fb[i] = framebuffer_alloc(sizeof(struct s3cfb_window), \                fbdev->dev);        //fbdev->fb[i]的类型为struct fb_info*，调用函数framebuffer_alloc得到分配的struct fb_info空间的起始地址        // framebuffer_alloc 函数分析            * framebuffer_alloc - creates a new frame buffer info structure             *             * @size: size of driver private data, can be zero             * @dev: pointer to the device for this fb, this can be NULL             *             * Creates a new frame buffer info structure. Also reserves @size bytes            * for driver private data (info->par). info->par (if any) will be             * aligned to sizeof(long).             *            * Returns the new structure, or NULL if an error occured.            这里sizeof(struct s3cfb_window)=136 sizeof(struct fb_info)=596            一共分配了136+596 bytes内存空间，info->par指向驱动私有数据struct s3cfb_window        if (!fbdev->fb[i]) { //如果空间分配失败            err("not enough memory\n");            ret = -ENOMEM;            goto err_alloc_fb;        }        ret = s3cfb_init_fbinfo(i);//初始化相应的struct fb_info        if (ret) {            err("failed to allocate memory for fb%d\n", i);            ret = -ENOMEM;            goto err_alloc_fb;        }        if (i == pdata->default_win) {            if (s3cfb_map_video_memory(fbdev->fb[i])) {                err("failed to map video memory " \                    "for default window (%d)\n", i);                ret = -ENOMEM;                goto err_alloc_fb;            }//这里默认的win是0,所以需要把第一个win的Memory空间映射到内核虚拟地址空间        }    } *************************************    LCDDEBUG(" %s, s3cfb_alloc_framebuffer done\n",__func__);    if (s3cfb_register_framebuffer())        goto err_alloc; **************************************** 下面我们看s3cfb_register_framebuffer函数，这个函数主要是通过调用register_framebuffer实现5个window的注册 宏定义CONFIG_FRAMEBUFFER_CONSOLE 为真， 该配置项在内核的kconfig文件中为 config FRAMEBUFFER_CONSOLE    tristate "Framebuffer Console support"    depends on FB    select CRC32    help       Low-level framebuffer-based console driver. 这个konfig文件位于/drivers/video/console/kconfig int s3cfb_register_framebuffer(void) {    struct s3c_platform_fb *pdata = to_fb_plat(fbdev->dev);    int ret, i;    for (i = 0; i < pdata->nr_wins; i++) {        ret = register_framebuffer(fbdev->fb[i]);        if (ret) {            err("failed to register framebuffer device\n");            return -EINVAL;        } #ifndef CONFIG_FRAMEBUFFER_CONSOLE        if (i == pdata->default_win) {            s3cfb_check_var(&fbdev->fb[i]->var, fbdev->fb[i]);            s3cfb_set_par(fbdev->fb[i]);            s3cfb_draw_logo(fbdev->fb[i]);        } #endif    }    return 0; }