基于MTK65xx平臺(tái)lcm和背光驅(qū)動(dòng)的編寫

1、基于MTK65xx平臺(tái)lcm和背光驅(qū)動(dòng)的編寫一、 與LCD驅(qū)動(dòng)相關(guān)的主要文件路徑mediatekplatformmt6573ubootmt6573_disp_drv.cmediatekplatformmt6573ubootmt6573_disp_drv_dpi.cmediatekplatformmt6573uboot mt6573_disp_drv_dbi.cmediatekplatformmt6573uboot mt6573_dpi_drv.cmediatekplatformmt6573uboot mt6573_dsi_drv.cmediatekplatformmt6573uboot mt6

2、573_lcd_drv.cmediateksourcekerneldriversvideomtkfb.cmediateksourcekerneldriversvideodisp_drv.cmediateksourcekerneldriversvideodisp_drv_dpi.cmediateksourcekerneldriversvideodisp_drv_dbi.cmediatekplatformmt6573kerneldriversvideolcd_drv.cmediatekplatformmt6573kerneldriversvideodpi_drv.cmediatekplatform

3、mt6573kerneldriversvideodsi_drv.cmediatekcustomcommonkernellcmLCM_NAMELCM_NAME.cmediatekplatformmt6573uboot mt6573_pwm.cmediatekplatformmt6573uboot mt65xx_leds.cmediateksourcekerneldriversledsleds.cmediatekcustomginwave73_gbkernelledsmt65xxcust_leds.c二、 怎樣新建一個(gè)LCD驅(qū)動(dòng)LCD模組主要包括LCD顯示屏和驅(qū)動(dòng)IC。比如LF040DNYB16a

4、模組的驅(qū)動(dòng)IC型號(hào)為NT35510。要在MTK6573平臺(tái)上新建這個(gè)lcd的驅(qū)動(dòng)，步驟如下：1、 在mediatekcustomcommonkernellcm目錄下新建文件夾nt35510,在此文件夾中新建nt35510.c。這就是LCM硬件層驅(qū)動(dòng)文件。2、 修改mediatekcustomcommonkernellcm mt65xx_lcm_list.c, 在 lcm_driver_list lcm_count 中增加nt35510_lcm_drv。3、 打開mediatekconfigginwave73_gbProjectConfig.mk，修改CUSTOM_UBOOT_LCM = nt3

5、5510, CUSTOM_KERNEL_LCM = nt35510；修改LCM_WIDTH、LCM_HEIGHT、BOOT_LOGO為正確的值。三、 驅(qū)動(dòng)文件（nt35510.c） 主要任務(wù)是實(shí)現(xiàn)LCM_DRIVER   nt35510_lcm_drv =     .name = "nt35510",.set_util_funcs = lcm_set_util_funcs,.get_params     = lcm_get_params,.init  &#

6、160;        = lcm_init,.suspend        = lcm_suspend,.resume         = lcm_resume,.compare_id     = lcm_compare_id, （1）lcm_get_params主要是設(shè)置LCM相關(guān)的參數(shù)，數(shù)據(jù)結(jié)構(gòu)如下：typedef str

7、uct    LCM_TYPE type;LCM_CTRL ctrl;               /! how to control LCM registers        unsigned int width;    unsigned int height;unsigned int io_select_mode; 

8、;    /DBI or DPI should select IO mode according to chip spec   /* particular parameters */    LCM_DBI_PARAMS dbi;    LCM_DPI_PARAMS dpi;    LCM_DSI_PARAMS dsi; LCM_PARAMS;LCM_TYPE 定義LCM與HOST間的接口，主要分為3種，DBI, DPI, DSI。其中DBI又分為

9、parallel DBI 和serial DBI。parallel DBI（B型DBI）的命令和數(shù)據(jù)都在數(shù)據(jù)總線D17:0上傳輸。CSX為低時(shí)數(shù)據(jù)有效。WRX線控制D17:0為寫時(shí)序，RDX控制D17:0為讀時(shí)序。D/CX指示D17:0上傳輸?shù)氖敲钸€是數(shù)據(jù)。注：MT6573使用LPA0線作為D/CX線，LPCE線作為CSX線，LWRB線作為WRX線，LRDB線作為RDX線。serial DBI（C型DBI）的命令和數(shù)據(jù)都在SPI接口上傳輸。CSX為低時(shí)SDA有效。SCL提供時(shí)鐘，DIN輸入，DOUT輸出。當(dāng)SDA_EN=1時(shí)，DIN線成為雙向的SDA線，即可輸入又可輸出，DOUT線不用。C型

10、DBI分為3線(沒(méi)有D/CX線)和4線（有D/CX線）兩種。3線的使用一個(gè)D/CX bit來(lái)區(qū)分命令/數(shù)據(jù)，4線的使用D/CX線來(lái)區(qū)分命令/數(shù)據(jù)。注：MT6573使用LSA0線作為D/CX線，LSCE線作為CSX線。LSCK線作為SCL線，LSDA線作為SDA線。DPI的命令在SPI上傳輸，Pixel data(RGB data)在D17:0上傳輸。其命令傳輸方式與serial DBI相同。對(duì)于Pixel data(RGB data)，需要自己的4條控制線：DPICK_PIN(RGB時(shí)鐘) 、DPIDE_PIN（RGB數(shù)據(jù)有效）、 DPIVSYNC(場(chǎng)同步)、 DPIHSYNC(行同步) 。t

11、ypedef enum    LCM_CTRL_NONE = 0,    LCM_CTRL_SERIAL_DBI,    LCM_CTRL_PARALLEL_DBI,    LCM_CTRL_GPIO LCM_CTRL定義LCM與HOST之間傳遞command的方式，有SERIAL_DBI、PARALLEL_DBI、GPIO幾種控制方式。如果是DPI接口，其LCM_CTRL可以選擇SERIAL_DBI或者GPIO。Width和height定義LCM的寬度和高度。io

12、_select_mode有這些選項(xiàng)：0（LCD_IO_SEL_16CPU_24RGB），1（LCD_IO_SEL_18CPU_18RGB），2（LCD_IO_SEL_24CPU_8RGB），3（LCD_IO_SEL_24CPU_ONLY）。根據(jù)driver IC 的定義填寫。LCM_×××_PARAMS根據(jù)不同的LCM_TYPE取值，這是針對(duì)DBI/DPI/DSI接口類型的詳細(xì)參數(shù)定義。比如LCM_DPI_PARAMS定義如下：typedef struct    unsigned int mipi_pll_clk_ref; 

13、  / 0.1    unsigned int mipi_pll_clk_div1;  / 0.63    unsigned int mipi_pll_clk_div2;  / 0.15    unsigned int dpi_clk_div;        / 2.32    unsigned int dpi_clk_duty;    

14、   / (dpi_clk_div - 1) . 31    /* polarity parameters */    LCM_POLARITY clk_pol;    LCM_POLARITY de_pol;    LCM_POLARITY vsync_pol;    LCM_POLARITY hsync_pol;    /* timing parameters */  &#

15、160; unsigned int hsync_pulse_width;    unsigned int hsync_back_porch;    unsigned int hsync_front_porch;    unsigned int vsync_pulse_width;    unsigned int vsync_back_porch;    unsigned int vsync_front_porch;  

16、0;     /* output format parameters */    LCM_DPI_FORMAT format;    LCM_COLOR_ORDER rgb_order;    unsigned int  is_serial_output;    /* intermediate buffers parameters */    unsigned int intermediat_bu

17、ffer_num; / 2.3    /* iopad parameters */    LCM_DRIVING_CURRENT io_driving_current;     LCM_DPI_PARAMS;其中，第一段前4項(xiàng)用于控制DPI時(shí)鐘，計(jì)算公式如下：Pixel Clock Frequency = 26MHz * mipi_pll_clk_div1 / (mipi_pll_clk_ref + 1)/ (2 * mipi_pll_clk_div2)/ dpi_clk_div第二段4個(gè)參數(shù)設(shè)

18、置DPICK_PIN(RGB時(shí)鐘) 、DPIDE_PIN（RGB數(shù)據(jù)有效）、 DPIVSYNC(場(chǎng)同步)、 DPIHSYNC(行同步)線是上升沿還是下降沿有效。行同步脈沖開始前和開始后的幾個(gè)時(shí)鐘周期，是行信號(hào)消隱期；場(chǎng)同步開始前和開始后的幾個(gè)行周期，是場(chǎng)信號(hào)消隱期。消隱期不傳遞圖像信號(hào)。消隱期特性由第三段六個(gè)參數(shù)定義：hsync_pulse_width;    hsync_back_porch; hsync_front_porch;  vsync_pulse_width;  vsync_back_porch;  vsync_front

19、_porch;LCM_DPI_FORMAT指定每個(gè)像素中RGB各占幾個(gè)bit.LCM_COLOR_ORDER指定RGB的順序。上述參數(shù)的值，均依照LCM spec及驅(qū)動(dòng)IC datasheet中的定義。這里要說(shuō)說(shuō)一個(gè)特別之處。NT35510使用DPI接口，SERIAL_DBI ctrl 方式時(shí)，沒(méi)有D/CX線，datasheet上定義的傳輸方式是9 bits，即在數(shù)據(jù)byte前加個(gè)D/CX bit。但使用了NT35510的LCMLF040DNYB16a，其spec中卻另外定義了其串口使用16 bits 模式傳輸。Byte1 是標(biāo)志byte, 前3位分別為 R/W bit, D/CX bit,

20、High/Low bit；Byte2 則是命令或數(shù)據(jù)。NT35510的每個(gè)command長(zhǎng)度為2byte，還可能帶有若干bytes的參數(shù)，比如命令F001,參數(shù)AA，應(yīng)該這樣傳輸：0x20 0xF0 0x00 0x01 0x40 0xAA。（2）lcm_init主要實(shí)現(xiàn)LCM的初始化，包括如下步驟：config_gpio配置GPIO。發(fā)送reset信號(hào)。RESET pin low和RESET pin high需要持續(xù)的時(shí)間一般為若干ms, 以datasheet 為準(zhǔn)。init_lcm_registers初始化LCM的寄存器。具體可以廠家提供的初始代碼為參考。一般在此函數(shù)末尾，都會(huì)使用喚醒命令組

21、（見(jiàn)后文），使LCM進(jìn)入工作狀態(tài)。（3）lcm_suspend 使LCM休眠，使用特定的命令，并遵守datasheet定義的時(shí)間特性。常用命令組如下：0X2800 (or  0X28) set display off 0X1000 (or  0X10) enter sleep mode對(duì)nt35510而言，還有一種更深睡眠的狀態(tài)deep standby mode，使用如下命令進(jìn)入：0X4F00  0X01（4）lcm_resume使LCM蘇醒，使用特定的命令，并遵守datasheet定義的時(shí)間特性。喚醒命令組：0X1100 (or 0X11) exit

22、sleep mode0X2900 (or 0X29) set display on對(duì)nt35510而言，如果在lcm_suspend中使LCM enter deep standby mode，則不能使用喚醒命令組，需要使用reset信號(hào)并要重新init_lcm_registers。四、 驅(qū)動(dòng) nt35510_lcm_drv怎樣被上層使用Mtkfb.c中實(shí)現(xiàn)了LCM的platform driver：static struct platform_driver   mtkfb_driver =     .driver =  

23、60;      .name    = “mtk-fb”,        .bus     = &platform_bus_type,        .probe   = mtkfb_probe,        .remove  =

24、 mtkfb_remove,            .suspend = mtkfb_suspend,        .resume  = mtkfb_resume,    ,    mtkfb_probe會(huì)調(diào)用函數(shù)mtkfb_find_lcm_driver來(lái)發(fā)現(xiàn)LCM的硬件層驅(qū)動(dòng)。mtkfb_find_lcm_driverDISP_Se

25、lectDevicedisp_drv_get_lcm_driver，檢查lcm_driver_list, 得到當(dāng)前使用的LCM及其驅(qū)動(dòng)名稱。Mt6573_devs.c中，定義了framebuffer型的platform device，這個(gè)設(shè)備在mt6573_board_init()調(diào)用時(shí)被注冊(cè)。它所對(duì)應(yīng)的驅(qū)動(dòng)就是上文提到的mtkfb_driverstatic struct platform_device   mt6573_device_fb =     .name = "mtkfb",    .

26、id   = 0,    .num_resources = ARRAY_SIZE(resource_fb),    .resource      = resource_fb,    .dev =         .dma_mask = &mtkfb_dmamask,        .cohe

27、rent_dma_mask = 0xffffffff,    ,;在linux 內(nèi)核中l(wèi)cd 設(shè)備驅(qū)動(dòng)所使用的是framebuffer設(shè)備類型，framebuffer設(shè)備驅(qū)動(dòng)程序的核心數(shù)據(jù)結(jié)構(gòu)是fb_ops；用戶空間就是通過(guò)此結(jié)構(gòu)體，調(diào)用其中的函數(shù)來(lái)對(duì)LCD實(shí)現(xiàn)控制。Mtkfb.c中定義并實(shí)現(xiàn)了fb_ops類型的mtkfb_ops。一個(gè)使用mtkfb_ops的例子見(jiàn)mediateksourcekerneldriversgpupvrservices43rdpartymtklfb mtklfb_displayclass.c。static struct  fb

28、_ops  mtkfb_ops =     .owner          = THIS_MODULE,    .fb_open        = mtkfb_open,    .fb_release     = mtkfb_release,    .fb_setcol

29、reg   = mtkfb_setcolreg, /批量配置顏色參數(shù)    .fb_pan_display = mtkfb_pan_display_proxy, /虛擬屏幕內(nèi)容顯示    .fb_fillrect    = cfb_fillrect, /填充區(qū)域顯示    .fb_copyarea    = cfb_copyarea, /復(fù)制區(qū)域顯示    .fb_imageblit &

30、#160; = cfb_imageblit, /顯示圖象    .fb_cursor      = mtkfb_soft_cursor, /光標(biāo)顯示    .fb_check_var   = mtkfb_check_var, /檢查并配置fb_var_screeninfo參數(shù)    .fb_set_par     = mtkfb_set_par, /change display mode and

31、set parameter    .fb_ioctl       = mtkfb_ioctl, /特定ioctl配置LCD屏幕特性;五、 Frame Buffer 設(shè)備驅(qū)動(dòng)mtkfb_driver中的各個(gè)函數(shù)會(huì)調(diào)用到DISP_xxx函數(shù)（DISP_drv.c）,而DISP_xxx會(huì)調(diào)用到LCD_xxx函數(shù)（lcd_drv.c）以及LCM硬件層驅(qū)動(dòng)。mtkfb_probe的主要工作如下：* find lcm driver* Register interrupt handler (call back func

32、tion), Init screen update wait queue, create screen update kThread* Allocate and initialize frame buffer device (fb_info , mtkfb_device), select panel type according to machine type*  Initialize Display Driver PDD Layer (DISP_init)*  Initialize fb_info struct (mtkfb_fbinfo_init)*  Reg

33、ister mtkfb_device fs  to system (mtkfb_register_sysfs)*  Register fb_info to system (register_framebuffer)fb_info結(jié)構(gòu)定義如下：struct fb_info int node;int flags;struct mutex lock; /* Lock for open/release/ioctl funcs */struct mutex mm_lock; /* Lock for fb_mmap and smem_* fields */struct  fb

34、_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

35、 hardware mapper */struct fb_cmap cmap; /* Current cmap */struct list_head modelist;      /* mode list */struct fb_videomode *mode; /* current mode */#ifdef CONFIG_FB_BACKLIGHT struct backlight_device *bl_dev;struct mutex bl_curve_mutex; u8 bl_curveFB_BACKLIGHT_LEV

36、ELS;#endif#ifdef CONFIG_FB_DEFERRED_IOstruct delayed_work deferred_work;struct fb_deferred_io *fbdefio;#endifstruct fb_ops *fbops;struct device *device; /* This is the parent */struct device *dev; /* This is this fb device */int class_flag;          

37、          /* private sysfs flags */#ifdef CONFIG_FB_TILEBLITTINGstruct fb_tile_ops *tileops;    /* Tile Blitting */#endifchar _iomem *screen_base; /* Virtual address */unsigned long screen_size; /* Amount of ioremapped VRAM or 0 */ voi

38、d *pseudo_palette; /* Fake palette of 16 colors */ #define FBINFO_STATE_RUNNING 0#define FBINFO_STATE_SUSPENDED 1u32  state; /* Hardware state i.e suspend */void *fbcon_par;                /* fbcon use-only private

39、area */* From here on everything is device dependent */void *par; struct apertures_struct unsigned int count;struct aperture resource_size_t base;resource_size_t size; ranges0; *apertures;1）fb_var_screeninfo 這個(gè)結(jié)構(gòu)描述了顯示卡的特性： NOTE:  _u32 是表示 unsigned 不帶符號(hào)的 32 bits 的數(shù)據(jù)類型，其余類推。這是 Linu

40、x 內(nèi)核中所用到的數(shù)據(jù)類型，如果是開發(fā)用戶空間（user-space）的程序，可以根據(jù)具體計(jì)算機(jī)平臺(tái)的情況，用 unsigned long 等等來(lái)代替 struct fb_var_screeninfo  _u32 xres; /* visible resolution */ /可視區(qū)域 _u32 yres; _u32 xres_virtual; /* virtual resolution */ /可視區(qū)域 _u32 yres_virtual; _u32 xoffset; /* offset from virtual to v

41、isible resolution */ /可視區(qū)域的偏移 _u32 yoffset; _u32 bits_per_pixel; /* guess what */ /每一象素的bit數(shù) _u32 grayscale; /* != 0 Gray levels instead of colors */等于零就成黑白 struct fb_bitfield red; /* bitfield in fb mem if true color, */真彩的bit機(jī)構(gòu) struct fb_bitfield green; /* else only length

42、is significant */ struct fb_bitfield blue; struct fb_bitfield transp; /* transparency */ 透明 _u32 nonstd; /* != 0 Non standard pixel format */ 不是標(biāo)準(zhǔn)格式 _u32 activate; /* see FB_ACTIVATE_* */ _u32 height; /* height of picture in mm */ 內(nèi)存中的圖像高度 _u32 width; /* width of pictur

43、e in mm */ 內(nèi)存中的圖像寬度 _u32 accel_flags; /* acceleration flags (hints) */ 加速標(biāo)志 /* Timing: All values in pixclocks, except pixclock (of course) */ 時(shí)序-_-這些部分就是顯示器的顯示方法了，可以找相關(guān)的資料看看 _u32 pixclock; /* pixel clock in ps (pico seconds) */ _u32 left_margin; /* time from sync to picture

44、 */ _u32 right_margin; /* time from picture to sync */ _u32 upper_margin; /* time from sync to picture */ _u32 lower_margin; _u32 hsync_len; /* length of horizontal sync */ 水平可視區(qū)域 _u32 vsync_len; /* length of vertical sync */ 垂直可視區(qū)域 _u32 sync; /* see FB_SYNC_* */ _

45、u32 vmode; /* see FB_VMODE_* */ _u32 reserved6; /* Reserved for future compatibility */ 備用以后開發(fā)  2) fb_fix_screeninfon 這個(gè)結(jié)構(gòu)在顯卡被設(shè)定模式后創(chuàng)建，它描述顯示卡的屬性，并且系統(tǒng)運(yùn)行時(shí)不能被修改；比如FrameBuffer內(nèi)存的起始地址。它依賴于被設(shè)定的模式，當(dāng)一個(gè)模式被設(shè)定后，內(nèi)存信息由顯示卡硬件給出，內(nèi)存的位置等信息就不可以修改。 struct fb_fix_screeninfo  char id16; /* id

46、entification string eg "TT Builtin" */ID unsigned long smem_start; /* Start of frame buffer mem */ 內(nèi)存起始 /* (physical address) */ 物理地址 _u32 smem_len; /* Length of frame buffer mem */ 內(nèi)存大小 _u32 type; /* see FB_TYPE_* */ _u32 type_aux; /* Interleave for interleaved Pl

47、anes */插入?yún)^(qū)域？ _u32 visual; /* see FB_VISUAL_* */ _u16 xpanstep; /* zero if no hardware panning */沒(méi)有硬件設(shè)備就為零 _u16 ypanstep; /* zero if no hardware panning */ _u16 ywrapstep; /* zero if no hardware ywrap */ _u32 line_length; /* length of a line in bytes */ 一行的字節(jié)表示 unsigned

48、long mmio_start; /* Start of Memory Mapped I/O */內(nèi)存映射的I/O起始 /* (physical address) */ _u32 mmio_len; /* Length of Memory Mapped I/O */ I/O的大小 _u32 accel; /* Type of acceleration available */ 可用的加速類型 _u16 reserved3; /* Reserved for future compatibility */  Mtkfb_device結(jié)構(gòu)定

49、義如下：struct mtkfb_device     int             state;    void           *fb_va_base;             /* MPU

50、 virtual address */    dma_addr_t      fb_pa_base;             /* Bus physical address */    unsigned long   fb_size_in_byte;    unsigned long   layer

51、_enable;    MTK_FB_FORMAT   layer_formatHW_OVERLAY_COUNT;    unsigned int    layer_config_dirty;    int             xscale, yscale, mirror;    /* transform

52、ations. rotate is stored in fb_info->var */    u32             pseudo_palette17;    struct fb_info  *fb_info;                /*

53、 Linux fbdev framework data */    struct device   *dev;六、 uBoot階段Mt6573_board.c中，board_init函數(shù)執(zhí)行硬件先期初始化工作，它調(diào)用mt65xx_disp_init函數(shù)(Mt6573_disp_drv.c)。board_initmt65xx_disp_initDISP_Initdisp_drv_init_contextDISP_DetectDevicedisp_drv_get_lcm_driverlcm_driver_list disp_drv_init_con

54、textDISP_GetDriverDPI / DISP_GetDriverDBI / DISP_GetDriverDSIDISP_GetDriverDPI (mt6573_disp_drv_dpi.c)DPI_DISP_DRV. dpi_initinit_dpiDPI_Init （Mt6573_dpi_drv.c）DISP_GetDriverDBI  (mt6573_disp_drv_dbi.c)DBI_DISP_DRV. dbi_initinit_lcdLCD_xxx（Mt6573_lcd_drv.c）DISP_GetDriverDSI  (mt6573_disp_dr

55、v_dsi.c)DSI_DISP_DRV. dsi_initinit_lcd，init_dsiDSI_Init（Mt6573_dsi_drv.c）DISP_InitLCD_Init  (Mt6573_lcd_drv.c) DISP_UpdateScreenLCD_StartTransfer  (Mt6573_lcd_drv.c)七、 背光控制Cust_leds.c中定義了cust_mt65xx_led類型的數(shù)組cust_led_list，列出了平臺(tái)的所有l(wèi)ed設(shè)備，包括不同顏色的led燈，軌跡球、鍵盤、按鍵、LCD等的背光燈。不同led設(shè)備可以有各自不同的背光控制

56、方式，比如PWM（脈沖寬度調(diào)制）方式，GPIO方式，PMIC方式，用戶自定義方式等。如下所示：static struct  cust_mt65xx_led   cust_led_listMT65XX_LED_TYPE_TOTAL = "red",               MT65XX_LED_MODE_PWM, PWM3,"green",             MT65XX_LED_MODE_PWM, PWM2,"blue",              MT65XX_LED_MODE_PWM, PWM1,"jogball-backlight&