Linux2.6.32.2內(nèi)核在mini2440上的移植

1、Linux-26322內(nèi)核在mini2440上的移植（六）添加LCD背光驅(qū)動(dòng)移植環(huán)境（紅色粗字體字為修改后內(nèi)容，藍(lán)色粗體字為特別注意內(nèi)容）1,主機(jī)環(huán)境：VMare下CentOS5.5,1G內(nèi)存。2，集成開(kāi)發(fā)環(huán)境：ElipseIDE編譯編譯環(huán)境：arm-linux-gccv4.4.3,arm-none-linux-gnueabi-gccv4.5.1。開(kāi)發(fā)板：mini2440,2Mnorflash,128Mnandflash。u-boot版本：u-boot-2009.08linux版本：linux-參考文章：嵌入式linux應(yīng)用開(kāi)發(fā)完全手冊(cè)，韋東山，編著。Mini2440之Linu

2、x移植開(kāi)發(fā)實(shí)戰(zhàn)指南到目前為止，我們一直都在命令行下移植，查看結(jié)果，LCD屏幕上似乎總是如伸手不見(jiàn)五指的黑夜，神秘而又無(wú)可奈何，從這里開(kāi)始，我們就要打開(kāi)這道神秘之門了?！?】LCD背光控制原理在mini2440/micro2440開(kāi)發(fā)板中，LCD背光是通過(guò)CPU的LCD_PWR引腳來(lái)控制的,從原理圖中可以看出，它對(duì)應(yīng)于GPG4，如圖LENDLIWULKL4VXIMEhll甘FRAhflEL7甘hflhI4USBENM3LCDVF1WLCDCTKLLENDGPCOVCLKGPC1VLINEiHSYNC/GPC2VFRAME:VSYNC.GPC3VM:VDEN，GPC斗L仁D_LPCOEGPC5LC

3、DLPCREV/GPC6LCD_PT/dev/backlight可以關(guān)閉LCD背光。在命令行種輸入：echo1/dev/backlight可以打開(kāi)LCD背光。為了實(shí)現(xiàn)這點(diǎn)，我們?cè)趌inux-/drivers/video/backlight目錄增加一個(gè)mini2440_backlight.c文件，內(nèi)容如下：#include#include#include#include#include#include#include#include#include#include#include#include#include#include#include#include#include#de

4、fineDEVICE_NAMEbacklight/設(shè)備名稱#defineDEVICE_MINOR5次設(shè)備號(hào)，這里我們將設(shè)備注冊(cè)為misc設(shè)備，這種設(shè)備的主設(shè)備號(hào)都為10externvoids3c2410_gpio_setpin(unsignedintpin,unsignedintto);externvoids3c2410_gpio_cfgpin(unsignedintpin,unsignedintfunction);staticintmini2440_backlight_ioctl(structinode*inode,structfile*file,unsignedintcmd,unsigne

5、dlongarg)switch(cmd)case0:當(dāng)接收的命令為0時(shí)，就將GPG4引腳設(shè)為低電平，關(guān)閉背光s3c2410_gpio_setpin(S3C2410_GPG(4),0);printk(DEVICE_NAMEturnoff!n);return0;case1:當(dāng)接收的命令為1時(shí)，就將GPG4引腳設(shè)為高電平，開(kāi)啟背光s3c2410_gpio_setpin(S3C2410_GPG(4),1);printk(DEVICE_NAMEturnon!n);return0;default:return-EINVAL;staticstructfile_operationsdev_fops=.owne

6、r=THIS_MODULE,.ioctl=mini2440_backlight_ioctl,/這里只使用控制IO口的方式來(lái)控制背光;staticstructmiscdevicemisc=.minor=DEVICE_MINOR,.name=DEVICE_NAME,.fops=&dev_fops,;staticint_initdev_init(void)intret;ret=misc_register(&misc);/注冊(cè)成misc設(shè)備if(retGraphicssupport-*Backlight&LCDdevicesupport-就可以找到該配置選項(xiàng)，如圖在這里，如果沒(méi)有被選中，按空格選中我們

7、剛剛加入的mini2440配置項(xiàng)，然后退出時(shí)保存內(nèi)核配置菜單，在命令行執(zhí)行：makeulmage將生成的arch/arm/boot/ulmage復(fù)制到/nfsboot目錄下，然后啟動(dòng)開(kāi)發(fā)板，可以在啟動(dòng)時(shí)看到LCD屏顯示的企鵝圖像，這說(shuō)明我們已經(jīng)點(diǎn)亮了背光?！?】編寫測(cè)試程序linux-test/codetest/backlight_test.c，代碼如下:#include#include#include#includeintmain(intargc,char*argv)intturn;intfd;/檢測(cè)命令后面帶的參數(shù)if(argc=1|argc2)printf(Usage:backlight

8、_teston|off!n);exit(1);/打開(kāi)背光設(shè)備fd=open(/dev/backlight,O_RDWR);if(fd0)printf(OpenBacklightDeviceFaild!n);exit(1);/判斷輸入的參數(shù)if(strcmp(argv1,on)=0)turn=1;elseif(strcmp(argv1,off)=0)turn=0;elseprintf(Usage:backlight_teston|off!n);exit(1);進(jìn)行IO控制ioctl(fd,turn);/關(guān)閉背光設(shè)備close(fd);return0;然后保存退出，之后在主機(jī)終端交叉編譯rootl

9、ocalhostcodetest#arm-linux-gcc-obacklight_testbacklight_test.c將其復(fù)制到nfsboot目錄下以便在開(kāi)發(fā)板掛載該目錄后能夠執(zhí)行rootlocalhostcodetest#cpbacklight_test/nfsboot/nfs【6】掛載nfs文件系統(tǒng)在目標(biāo)板的串口終端中執(zhí)行rootmini2440/mnt#mkdirnfsrootmini2440/mnt#lsdataetcjffs2nfstempyaffsrootmini2440/#mount-onolock-tnfs28:/nfsboot/nfs/mnt/nfs/注

10、意要加-onolock參數(shù)，否則掛載不上。rootmini2440/#cdmnt/nfsrootmini2440nfs#lsbacklight_test7】運(yùn)行測(cè)試程序rootmini2440nfs#./backlight_testrootmini2440nfs#./backlight_test-helpUsage:backlight_teston|off!rootmini2440nfs#rootmini2440nfs#./backlight_testoffbacklightturnoff!/觀察LCD屏，看到背光燈滅了rootmini2440nfs#./backlight_testonbacklightturnon!/觀察LCD屏，看到背光燈亮了rootmini24