linux 显示器驱动,基于S3C6410平台 - Linux中LCD设备驱动_Linux编程_Linux公社-Linux系统门户网站...

亦凉 2022-10-17 15:56 25阅读 0赞

上一篇说了framebuffer帧缓冲的有关知识，这一篇具体的说下LCD驱动的实现。

1、LCD设备驱动在linux内核中是作为平台设备存在，所以又要说那些已经说过很多遍的东西。

int \_\_devinit s3cfb\_init(void)

return platform\_driver\_register(&s3cfb\_driver);

static void \_\_exit s3cfb\_cleanup(void)

platform\_driver\_unregister(&s3cfb\_driver);

module\_init(s3cfb\_init);

module\_exit(s3cfb\_cleanup);

对应的platform\_driver结构体为：

static struct platform\_driver s3cfb\_driver = \{

.probe= s3cfb\_probe,

.remove= s3cfb\_remove,

.suspend= s3cfb\_suspend,

.resume= s3cfb\_resume,

.driver= \{

.name= "s3c-lcd",

.owner= THIS\_MODULE,

\},

\};

那么平台设备的资源呢？

/\* LCD Controller \*/

static u64 s3c\_device\_lcd\_dmamask = 0xffffffffUL;

struct platform\_device s3c\_device\_lcd = \{

.name = "s3c-lcd",

.id = -1,设备编号，-1表示只有这样一个设备

.num\_resources = ARRAY\_SIZE(s3c\_lcd\_resource),

.resource = s3c\_lcd\_resource,

.dev              = \{

.dma\_mask= &s3c\_device\_lcd\_dmamask,

.coherent\_dma\_mask= 0xffffffffUL

\};

static struct resource s3c\_lcd\_resource\[\] = \{

\[0\] = \{

.start = S3C64XX\_PA\_LCD,  //LCD的I/O内存的开始位置

.end   = S3C64XX\_PA\_LCD + SZ\_1M - 1,

.flags = IORESOURCE\_MEM,

\},

\[1\] = \{

.start = IRQ\_LCD\_VSYNC,    //LCD的开始中断号

.end   = IRQ\_LCD\_SYSTEM,  //LCD的结束中断号

.flags = IORESOURCE\_IRQ,

\};

2、分析其probe函数，源码如下：

/\*

\*  Probe

\*/

static int \_\_init s3cfb\_probe(struct platform\_device \*pdev)

struct resource \*res;

struct fb\_info \*fbinfo;

s3cfb\_info\_t \*info;

char driver\_name\[\] = "s3cfb";

int index = 0, ret, size;

fbinfo = framebuffer\_alloc(sizeof(s3cfb\_info\_t), &pdev->dev);申请一个s3cfb\_info\_t结构体的空间

if (!fbinfo)

return -ENOMEM;

platform\_set\_drvdata(pdev, fbinfo);

info = fbinfo->par;

info->dev = &pdev->dev;  填充info结构体变量的相应信息

res = platform\_get\_resource(pdev, IORESOURCE\_MEM, 0)；获取LCD平台设备所使用的I/O端口资源。

if (res == NULL) \{

dev\_err(&pdev->dev, "failed to get memory registers\\n");

ret = -ENXIO;

goto dealloc\_fb;

size = (res->end - res->start) + 1;

info->mem = request\_mem\_region(res->start, size, pdev->name);申请LCD设备所占的I/O空间

if (info->mem == NULL) \{

dev\_err(&pdev->dev, "failed to get memory region\\n");

ret = -ENOENT;

goto dealloc\_fb;

info->io = ioremap(res->start, size);将LCD的I/O端口所占用的这段I/O空间映射到内存的虚拟地址。

if (info->io == NULL) \{

dev\_err(&pdev->dev, "ioremap() of registers failed\\n");

ret = -ENXIO;

goto release\_mem;

s3cfb\_pre\_init();这个函数的源码在S3cfb\_fimd4x.c (linux2.6.28\\drivers\\video\\samsung)文件中，如下所示：

void s3cfb\_pre\_init(void)

/\* initialize the fimd specific \*/

s3cfb\_fimd.vidintcon0 &= ~S3C\_VIDINTCON0\_FRAMESEL0\_MASK;

s3cfb\_fimd.vidintcon0 |= S3C\_VIDINTCON0\_FRAMESEL0\_VSYNC;

s3cfb\_fimd.vidintcon0 |= S3C\_VIDINTCON0\_INTFRMEN\_ENABLE;

writel(s3cfb\_fimd.vidintcon0, S3C\_VIDINTCON0);

这个函数中涉及到一个结构体s3cfb\_fimd\_info\_t s3cfb\_fimd，和这个函数在同一个文件中定义，列出部分源码：

s3cfb\_fimd\_info\_t s3cfb\_fimd = \{

.vidcon0 = S3C\_VIDCON0\_INTERLACE\_F\_PROGRESSIVE | S3C\_VIDCON0\_VIDOUT\_RGB\_IF | S3C\_VIDCON0\_L1\_DATA16\_SUB\_16\_MODE | \\

S3C\_VIDCON0\_L0\_DATA16\_MAIN\_16\_MODE | S3C\_VIDCON0\_PNRMODE\_RGB\_P | \\

S3C\_VIDCON0\_CLKVALUP\_ALWAYS | S3C\_VIDCON0\_CLKDIR\_DIVIDED | S3C\_VIDCON0\_CLKSEL\_F\_HCLK | \\

S3C\_VIDCON0\_ENVID\_DISABLE | S3C\_VIDCON0\_ENVID\_F\_DISABLE,

.dithmode = (S3C\_DITHMODE\_RDITHPOS\_5BIT | S3C\_DITHMODE\_GDITHPOS\_6BIT | S3C\_DITHMODE\_BDITHPOS\_5BIT ) & S3C\_DITHMODE\_DITHERING\_DISABLE,

\#if defined (CONFIG\_FB\_S3C\_BPP\_8)

.wincon0 =  S3C\_WINCONx\_BYTSWP\_ENABLE | S3C\_WINCONx\_BURSTLEN\_4WORD | S3C\_WINCONx\_BPPMODE\_F\_8BPP\_PAL,

.wincon1 =  S3C\_WINCONx\_HAWSWP\_ENABLE | S3C\_WINCONx\_BURSTLEN\_4WORD | S3C\_WINCONx\_BPPMODE\_F\_16BPP\_565 | S3C\_WINCONx\_BLD\_PIX\_PLANE | S3C\_WINCONx\_ALPHA\_SEL\_1,

.bpp = S3CFB\_PIXEL\_BPP\_8,

.bytes\_per\_pixel = 1,

.wpalcon = S3C\_WPALCON\_W0PAL\_16BIT,

..........

.vidosd1c = S3C\_VIDOSDxC\_ALPHA1\_B(S3CFB\_MAX\_ALPHA\_LEVEL) | S3C\_VIDOSDxC\_ALPHA1\_G(S3CFB\_MAX\_ALPHA\_LEVEL) | S3C\_VIDOSDxC\_ALPHA1\_R(S3CFB\_MAX\_ALPHA\_LEVEL),

.vidosd2c = S3C\_VIDOSDxC\_ALPHA1\_B(S3CFB\_MAX\_ALPHA\_LEVEL) | S3C\_VIDOSDxC\_ALPHA1\_G(S3CFB\_MAX\_ALPHA\_LEVEL) | S3C\_VIDOSDxC\_ALPHA1\_R(S3CFB\_MAX\_ALPHA\_LEVEL),

.vidosd3c = S3C\_VIDOSDxC\_ALPHA1\_B(S3CFB\_MAX\_ALPHA\_LEVEL) | S3C\_VIDOSDxC\_ALPHA1\_G(S3CFB\_MAX\_ALPHA\_LEVEL) | S3C\_VIDOSDxC\_ALPHA1\_R(S3CFB\_MAX\_ALPHA\_LEVEL),

.vidosd4c = S3C\_VIDOSDxC\_ALPHA1\_B(S3CFB\_MAX\_ALPHA\_LEVEL) | S3C\_VIDOSDxC\_ALPHA1\_G(S3CFB\_MAX\_ALPHA\_LEVEL) | S3C\_VIDOSDxC\_ALPHA1\_R(S3CFB\_MAX\_ALPHA\_LEVEL),

.vidintcon0 = S3C\_VIDINTCON0\_FRAMESEL0\_VSYNC | S3C\_VIDINTCON0\_FRAMESEL1\_NONE | S3C\_VIDINTCON0\_INTFRMEN\_DISABLE | \\

S3C\_VIDINTCON0\_FIFOSEL\_WIN0 | S3C\_VIDINTCON0\_FIFOLEVEL\_25 | S3C\_VIDINTCON0\_INTFIFOEN\_DISABLE | S3C\_VIDINTCON0\_INTEN\_ENABLE,

.vidintcon1 = 0,

.xoffset = 0,

.yoffset = 0,

.w1keycon0 = S3C\_WxKEYCON0\_KEYBLEN\_DISABLE | S3C\_WxKEYCON0\_KEYEN\_F\_DISABLE | S3C\_WxKEYCON0\_DIRCON\_MATCH\_FG\_IMAGE | S3C\_WxKEYCON0\_COMPKEY(0x0),

.............

.w4keycon1 = S3C\_WxKEYCON1\_COLVAL(0xffffff),

.sync = 0,

.cmap\_static = 1,

.vs\_offset = S3CFB\_DEFAULT\_DISPLAY\_OFFSET,

.brightness = S3CFB\_DEFAULT\_BRIGHTNESS,

.backlight\_level = S3CFB\_DEFAULT\_BACKLIGHT\_LEVEL,

.backlight\_power = 1,

.lcd\_power = 1,

\};

那么对应的结构体原型在哪呢？

在S3cfb.h (linux2.6.28\\drivers\\video\\samsung)文件中，如下所示：

看那些对应的注释，也应该大致明白这个结构体的作用，存储与显示控制器有关的信息，还有显示屏幕的信息。不知道大家对s3cfb\_fimd\_info\_t这个结构体的命名有何看法？名字往往代表了这个结构体的作用。其实这个结构体的名字给我们的信息是：

fimd—   ——    ——

FIMD:Fully Interactive Mobile Display (完全交互式移动显示设备)

这是第一个概念，另一个概念是OSD，我查了下资料，有这样的含义：

OSD是on-screen display的简称，即屏幕菜单式调节方式。一般是按Menu键后屏幕弹出的显示器各项调节项目信息的矩形菜单，可通过该菜单对显示器各项工作指标包括色彩、模式、几何形状等进行调整，从而达到最佳的使用状态。

现在对这个结构体的认识是不是深刻多了？

typedef struct \{

/\* Screen size \*/

int width;

int height;

/\* Screen info \*/

int xres;

int yres;

/\* Virtual Screen info \*/

int xres\_virtual;

int yres\_virtual;

int xoffset;

int yoffset;

/\* OSD Screen size \*/

int osd\_width;

int osd\_height;

/\* OSD Screen info \*/

int osd\_xres;

int osd\_yres;

/\* OSD Screen info \*/

int osd\_xres\_virtual;

int osd\_yres\_virtual;

int bpp;

int bytes\_per\_pixel;

unsigned long pixclock;

int hsync\_len;

int left\_margin;

int right\_margin;

int vsync\_len;

int upper\_margin;

int lower\_margin;

int sync;

int cmap\_grayscale:1;

int cmap\_inverse:1;

int cmap\_static:1;

int unused:29;

/\* backlight info \*/

int backlight\_min;

int backlight\_max;

int backlight\_default;

int vs\_offset;

int brightness;

int palette\_win;

int backlight\_level;

int backlight\_power;

int lcd\_power;

s3cfb\_vsync\_info\_t vsync\_info;

s3cfb\_vs\_info\_t vs\_info;

/\* lcd configuration registers \*/

unsigned long lcdcon1;

unsigned long lcdcon2;

unsigned long lcdcon3;

unsigned long lcdcon4;

unsigned long lcdcon5;

/\* GPIOs \*/

unsigned long gpcup;

unsigned long gpcup\_mask;

unsigned long gpccon;

unsigned long gpccon\_mask;

unsigned long gpdup;

unsigned long gpdup\_mask;

unsigned long gpdcon;

unsigned long gpdcon\_mask;

/\* lpc3600 control register \*/

unsigned long lpcsel;

unsigned long lcdtcon1;

unsigned long lcdtcon2;

unsigned long lcdtcon3;

unsigned long lcdosd1;

unsigned long lcdosd2;

unsigned long lcdosd3;

unsigned long lcdsaddrb1;

unsigned long lcdsaddrb2;

unsigned long lcdsaddrf1;

unsigned long lcdsaddrf2;

unsigned long lcdeaddrb1;

unsigned long lcdeaddrb2;

unsigned long lcdeaddrf1;

unsigned long lcdeaddrf2;

unsigned long lcdvscrb1;

unsigned long lcdvscrb2;

unsigned long lcdvscrf1;

unsigned long lcdvscrf2;

unsigned long lcdintcon;

unsigned long lcdkeycon;

unsigned long lcdkeyval;

unsigned long lcdbgcon;

unsigned long lcdfgcon;

unsigned long lcddithcon;

unsigned long vidcon0;

unsigned long vidcon1;

unsigned long vidtcon0;

unsigned long vidtcon1;

unsigned long vidtcon2;

unsigned long vidtcon3;

unsigned long wincon0;

unsigned long wincon2;

unsigned long wincon1;

unsigned long wincon3;

unsigned long wincon4;

unsigned long vidosd0a;

unsigned long vidosd0b;

unsigned long vidosd0c;

unsigned long vidosd1a;

unsigned long vidosd1b;

unsigned long vidosd1c;

unsigned long vidosd1d;

unsigned long vidosd2a;

unsigned long vidosd2b;

unsigned long vidosd2c;

unsigned long vidosd2d;

unsigned long vidosd3a;

unsigned long vidosd3b;

unsigned long vidosd3c;

unsigned long vidosd4a;

unsigned long vidosd4b;

unsigned long vidosd4c;

unsigned long vidw00add0b0;

unsigned long vidw00add0b1;

unsigned long vidw01add0;

unsigned long vidw01add0b0;

unsigned long vidw01add0b1;

unsigned long vidw00add1b0;

unsigned long vidw00add1b1;

unsigned long vidw01add1;

unsigned long vidw01add1b0;

unsigned long vidw01add1b1;

unsigned long vidw00add2b0;

unsigned long vidw00add2b1;

unsigned long vidw02add0;

unsigned long vidw03add0;

unsigned long vidw04add0;

unsigned long vidw02add1;

unsigned long vidw03add1;

unsigned long vidw04add1;

unsigned long vidw00add2;

unsigned long vidw01add2;

unsigned long vidw02add2;

unsigned long vidw03add2;

unsigned long vidw04add2;

unsigned long vidintcon;

unsigned long vidintcon0;

unsigned long vidintcon1;

unsigned long w1keycon0;

unsigned long w1keycon1;

unsigned long w2keycon0;

unsigned long w2keycon1;

unsigned long w3keycon0;

unsigned long w3keycon1;

unsigned long w4keycon0;

unsigned long w4keycon1;

unsigned long win0map;

unsigned long win1map;

unsigned long win2map;

unsigned long win3map;

unsigned long win4map;

unsigned long wpalcon;

unsigned long dithmode;

unsigned long intclr0;

unsigned long intclr1;

unsigned long intclr2;

unsigned long win0pal;

unsigned long win1pal;

/\* utility functions \*/

void (\*set\_backlight\_power)(int);

void (\*set\_lcd\_power)(int);

void (\*set\_brightness)(int);

int (\*map\_video\_memory)(s3cfb\_info\_t \*);

int (\*unmap\_video\_memory)(s3cfb\_info\_t \*);

\}s3cfb\_fimd\_info\_t;

下一篇接着从这里分析：

s3cfb\_set\_backlight\_power(1);

s3cfb\_set\_lcd\_power(1);

s3cfb\_set\_backlight\_level(S3CFB\_DEFAULT\_BACKLIGHT\_LEVEL);

info->clk = clk\_get(NULL, "lcd");

if (!info->clk || IS\_ERR(info->clk)) \{

printk(KERN\_INFO "failed to get lcd clock source\\n");

ret =  -ENOENT;

goto release\_io;

clk\_enable(info->clk);

printk("S3C\_LCD clock got enabled :: %ld.%03ld Mhz\\n", PRINT\_MHZ(clk\_get\_rate(info->clk)));

s3cfb\_fimd.vsync\_info.count = 0;

init\_waitqueue\_head(&s3cfb\_fimd.vsync\_info.wait\_queue);

res = platform\_get\_resource(pdev, IORESOURCE\_IRQ, 0);

if (res == NULL) \{

dev\_err(&pdev->dev, "failed to get irq\\n");

ret = -ENXIO;

goto release\_clock;

ret = request\_irq(res->start, s3cfb\_irq, 0, "s3c-lcd", pdev);

if (ret != 0) \{

printk("Failed to install irq (%d)\\n", ret);

goto release\_clock;

msleep(5);

for (index = 0; index < S3CFB\_NUM; index++) \{

s3cfb\_info\[index\].mem = info->mem;

s3cfb\_info\[index\].io = info->io;

s3cfb\_info\[index\].clk = info->clk;

s3cfb\_init\_fbinfo(&s3cfb\_info\[index\], driver\_name, index);

/\* Initialize video memory \*/

ret = s3cfb\_map\_video\_memory(&s3cfb\_info\[index\]);

if (ret) \{

printk("Failed to allocate video RAM: %d\\n", ret);

ret = -ENOMEM;

goto release\_irq;

ret = s3cfb\_init\_registers(&s3cfb\_info\[index\]);

ret = s3cfb\_check\_var(&s3cfb\_info\[index\].fb.var, &s3cfb\_info\[index\].fb);

if (index < 2)\{

if (fb\_alloc\_cmap(&s3cfb\_info\[index\].fb.cmap, 256, 0) < 0)

goto dealloc\_fb;

\} else \{

if (fb\_alloc\_cmap(&s3cfb\_info\[index\].fb.cmap, 16, 0) < 0)

goto dealloc\_fb;

ret = register\_framebuffer(&s3cfb\_info\[index\].fb);

if (ret < 0) \{

printk(KERN\_ERR "Failed to register framebuffer device: %d\\n", ret);

goto free\_video\_memory;

printk(KERN\_INFO "fb%d: %s frame buffer device\\n", s3cfb\_info\[index\].fb.node, s3cfb\_info\[index\].fb.fix.id);

/\* create device files \*/

ret = device\_create\_file(&(pdev->dev), &dev\_attr\_backlight\_power);

if (ret < 0)

printk(KERN\_WARNING "s3cfb: failed to add entries\\n");

ret = device\_create\_file(&(pdev->dev), &dev\_attr\_backlight\_level);

if (ret < 0)

printk(KERN\_WARNING "s3cfb: failed to add entries\\n");

ret = device\_create\_file(&(pdev->dev), &dev\_attr\_lcd\_power);

if (ret < 0)

printk(KERN\_WARNING "s3cfb: failed to add entries\\n");

return 0;

free\_video\_memory:

s3cfb\_unmap\_video\_memory(&s3cfb\_info\[index\]);

release\_irq:

free\_irq(res->start, &info);

release\_clock:

clk\_disable(info->clk);

clk\_put(info->clk);

release\_io:

iounmap(info->io);

release\_mem:

release\_resource(info->mem);

kfree(info->mem);

dealloc\_fb:

framebuffer\_release(fbinfo);

return ret;

linux 显示器驱动,基于S3C6410平台 - Linux中LCD设备驱动_Linux编程_Linux公社-Linux系统门户网站...

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