ARM字符驱动实例

字符驱动实例本实验电路图4个LED指示灯的接口电路驱动程序#include<linux/kernel.h>#include<linux/module.h>#include<linux/init.h>#include<linux/fs.h>#include<linux/cdev.h>#include<linux/ioport.h>#include<asm-arm/io.h>#include<linux/ioctl.h>#include<linux/interrupt.h>#include<linux/delay.h>#include<linux/timer.h>#include<asm/irq.h>#include<linux/param.h>#include<linux/sched.h>#include<linux/errno.h>#include<asm/signal.h>定义request_mem_region所需的头文件定义I/O读写,I/O内存读写所需的头文件定义ioctl函数所需的头文件定义ioctl函数所需的头文件定义延迟与定时器函数所需的头文件定义中断函数所需的头文件#defineCDRIVER_NAME"LED_chrdev"#defineGPFCON(0X56000050)#defineGPFDAT(0X56000054)#defineGPFUP(0X56000058)staticvoid*gpfcon;staticvoid*gpfdat;staticvoid*gpfup;intCDRIVER_MAJOR=0;intCDRIVER_MINOR=0;intcount=1;定义物理地址定义映射后的虚拟地址指针loff_tLED_llseek(structfile*filp,loff_toff,intwhence);intLED_ioctl(structinode*inode,structfile*filp,unsignedintcmd,unsignedlongarg);intLED_open(structinode*inode,structfile*filp);intLED_release(structinode*inode,structfile*filp);externstructfile_operationsLED_fops;structcdev*LED_cdev;dev_tLED_dev;structfile_operationsLED_fops={.owner=THIS_MODULE,.llseek=LED_llseek,.open=LED_open,.release=LED_release,};staticint__initLED_init(void){……if(!request_mem_region(GPFCON,12,CDRIVER_NAME)){ printk(KERN_ERR"LED:io%Xisnotfree.\n",GPFCON); return-EBUSY; } gpfcon=ioremap_nocache(GPFCON,4); gpfdat=ioremap_nocache(GPFDAT,4); gpfup=ioremap_nocache(GPFUP,4); if(!gpfcon){ printk(KERN_ERR"LED:ioremapfailed\n");

iounmap(gpfcon); return-EINVAL; }申请I/O内存I/O内存映射若映射不成功,释放

if(!gpfdat){ printk(KERN_ERR"LED:ioremapfailed\n");

iounmap(gpfdat); return-EINVAL; } if(!gpfup){ printk(KERN_ERR"LED:ioremapfailed\n");

iounmap(gpfup); return-EINVAL; } return0;}若映射不成功,释放若映射不成功,释放intLED_open(structinode*inode,structfile*filp){ printk("LEDDeviceisopened\n"); writel((readl(gpfcon)&(1<<14)),gpfcon); writel((readl(gpfup)&(1<<7)),gpfup); writel((readl(gpfdat)&(0<<7)),gpfdat); ssleep(1);writel((readl(gpfdat)&(1<<7)),gpfdat); ssleep(1);writel((readl(gpfdat)&(0<<7)),gpfdat); try_module_get(THIS_MODULE); return0;}设为输出端口上拉禁止输出低电平,灯亮输出高电平,灯灭/*Release*/intLED_release(structinode*inode,structfile*filp){ printk("LEDDeciceisreleased!\n"); writel((readl(gpfcon)&(0<<14)),4); writel((readl(gpfup)&(1<<7)),4); writel((readl(gpfdat)&(0<<7)),4); module_put(THIS_MODULE); return0;}staticvoid__exitLED_exit(void) {printk("UnloadingLED_cdevnow...\n");

iounmap(gpfcon); iounmap(gpfdat); iounmap(gpfup); cdev_del(LED_cdev); unregister_chrdev_region(LED_dev,count); }释放内存makefileifneq($(KERNELRELEASE),)obj-m:=LED_chrdev.oelsePWD:=$(shellpwd)default:$(MAKE)-C$(KERNELDIR)M=$(PWD)endif最终生成LED_chrdev.ko的可执行文件件应用程序#include<stdio.h>#include<stdlib.h>#include<fcntl.h>#include<errno.h>#include<unistd.h>#include<linux/delay.h>#include<sys/ioctl.h>#defineDEVICE_GPIOTEST"/dev/LED_chrdev"intmain(intargc,char*argv[]){intfd;fd=open(DEVICE_GPIOTEST,O_RDONLY);提供对文件控控制的函数open等提供对I/O控制的函数数提供错误号errno的的定义，用于于错误处理linux/unix的的系统调用，，包含了许多多系统服务的的函数原型,例如read,write等函函数。if(fd<0){perror("cannotopendevice");exit(1);}close(fd);return0;}makefileTEST_LED:TEST_LED.o$(LD)-rTEST_LED.o-oTEST_LEDTEST_LED.o:TEST_LED.c$(CC)-O2-Wall-I$(INCLUDE)-L$(LIB)-cTEST_LED.c-oTEST_LED.o最终生成TEST_LED的可执行行文件将驱动程序编编译进内核在超级终端下下将驱动程序序LED_chrdev.ko和应用程序TEST_LED下载到到/tmp路径下执行Chmod755LED_chrdev.koChmod755TEST_LEDInsmodLED_chrdev.ko./TEST_LED观察灯的情况况!将驱动程序编编译进内核一.将驱动程程序LED_chrdev.c放在相应的目目录下,比如如对于字符设设备,就放置置在fs2410/drivers/char/;二.修改drivers/…/Makefile文件三.修改drivers/…/Kconfig配置文件四.重新编译译内核,下载载将驱动程序放放在相应的目目录下修改drivers/char/Makefile修改drivers/char/Makefile修改drivers/char/Kconfig这些将出现在在内核的编译译配置中简化我们的设设计对I/O端口口定义的简化化,加入头文文件#include<asm/arch/regs-gpio.h>对I/O端口口操作的简化化,加入头文文件#include<asm/arch/hardware.h>#include<asm/arch/regs-gpio.h>#include<asm/arch/regs-gpio.h>I/O端口不不同功能的定定义对特殊功能寄寄存器的定义义#include<asm/arch/hardware.h>在<asm/arch/hardware.h>中包含了了对I/O端口口操作的函数数externvoids3c2410_gpio_cfgpin(unsignedintpin,unsignedintfunction);externvoids3c2410_gpio_pullup(unsignedintpin,unsignedintto);externvoids3c2410_gpio_setpin(unsignedintpin,unsignedintto);externunsignedints3c2410_gpio_getpin(unsignedintpin);函数在arch/arm/mach-s3c2410/gpio.c中定义/*s3c2410_gpio_cfgpin:设定定特定端口的的功能*eg:*s3c2410_gpio_cfgpin(S3C2410_GPA0,S3C2410_GPA0_ADDR0);*s3c2410_gpio_cfgpin(S3C2410_GPF7,S3C2410_GPF7_OUTP);*/将GPF7设设置成输出端端口s3c2410_gpio_cfgpinvoids3c2410_gpio_cfgpin(unsignedintpin,unsignedintfunction){staticvoid*base;unsignedlongmask;unsignedlongcon;unsignedlongflags;base=ioremap_nocache(S3C2410_GPIO_PA_BASE(pin),0x0000004);if(pin<S3C2410_GPIO_BANKB){mask=1<<S3C2410_GPIO_OFFSET(pin);}else{mask=3<<S3C2410_GPIO_OFFSET(pin)*2;}local_irq_save(flags);con=__raw_readl(base+0x00);con&=~mask;con|=function;__raw_writel(con,base+0x00);local_irq_restore(flags);}将端口对应的的GPnCON寄存器进进行I/O内内存映射根据相应的功功能对GPnCON寄存存器的对应位位写入相应的的值externvoids3c2410_gpio_pullup(unsignedintpin,unsignedintto);/*s3c2410_gpio_pullup**设置特定定端口的上拉拉**to=1=>disablethepull-up*0=>enablethepull-up**例子:**s3c2410_gpio_pullup(S3C2410_GPB0,0);*s3c2410_gpio_pullup(S3C2410_GPF7,1);*/s3c2410_gpio_getpinunsignedints3c2410_gpio_getpin(unsignedintpin);**设置特定输入入端口的值**返返回非0=>高电平平*0=>低电平平**例子:**s3c2410_gpio_getpin(S3C2410_GPB0);*s3c2410_gpio_getpin(S3C2410_GPE8);*/s3c2410_gpio_getpinunsignedints3c2410_gpio_getpin(unsignedintpin){staticvoid*data;unsignedlongoffs=S3C2410_GPIO_OFFSET(pin);data=ioremap_nocache(S3C2410_GPIO_PA_BASE(pin)+0x04,0x0000004);return__raw_readl(data)&(1<<offs);}将端口对应的的GPnDAT寄存器进进行I/O内内存映射读入GPnDAT寄存器器中对应位的的值s3c2410_gpio_setpinexternvoids3c2410_gpio_setpin(unsignedintpin,unsignedintto);/**设置特定定输出端口的的高/低电平平**to=1=>高电平平*0=>低电平平**例子:**s3c2410_gpio_setpin(S3C2410_GPB0,0);*s3c2410_gpio_setpin(S3C2410_GPF7,0);*/对驱动程序的的修改……#include<asm/arch/regs-gpio.h>#include<asm/arch/hardware.h>对I/O端口口定义的头文文件对I/O端口口操作的头文文件staticint__initLED_init(void){……s3c2410_gpio_cfgpin(S3C2410_GPF7,S3C2410_GPF7_OUTP);s3c2410_gpio_pullup(S3C2410_GPF7,1);s3c2410_gpio_setpin(S3C2410_GPF7,0);return-EINVAL;}intLED_open(structinode*inode,structfile*filp){printk("LEDDeviceisopened\n");s3c2410_gpio_setpin(S3C2410_GPF7,0);ssleep(1);s3c2410_gpio_setpin(S3C2410_GPF7,1);ssleep(1);s3c2410_gpio_setpin(S3C2410_GPF7,0);try_module_get(THIS_MODULE);return0;}/*Release*/intLED_release(structinode*inode,structfile*filp){printk("LEDDeciceisreleased!\n");s3c2410_gpio_cfgpin(S3C2410_GPF7,S3C2410_GPF7_INP);s3c2410_gpio_pullup(S3C2410_GPF7,0);s3c2410_gpio_setpin(S3C2410_GPF7,1);module_put(THIS_MODULE);return0;}中断驱动程程序的简化化……#include<asm/arch/irq.h>#include<asm/arch/regs-irq.h>对各个中断断号的定义义对中断寄存存器定义的的头文件asm-arm/arch-s3c2410/irq.hIrq：表示所要要申请的中中断号；中断号在include/asm-arm/arch-s3c2410/irq.h中定义义asm-arm/arch-s3c2410/irq.h#include<asm/arch/regs-irq.h><arch/arm/math-s3c2410/irq.c>在<arch/arm/math-s3c2410/irq.c>中定义义有中断操操作的相关关函数,可可以通过extern语句句加入这些些函数在<arch/arm/math-s3c2410/irq.c>中定义义有中断操操作的相关关函数s3c_irq_mask(unsignedintirqno)//中断断屏蔽s3c_irq_unmask(unsignedintirqno)//中断断使能s3c_irq_ack(unsignedintirqno)//清中中断挂起void__inits3c2410_init_irq(void)//中中断初初始化s3c_irqext_mask(unsignedintirqno)//外部中断断屏蔽s3c_irqext_ack(unsignedintirqno)//清清外部中断断挂起s3c_irqext_unmask(unsignedintirqno)//外部部中断使能能<arch/arm/math-s3c2410/irq.c>函数：s3c_irq_mask(unsignedintirqno)参数：irqno表示中断断号作用:屏屏蔽特定定中断例子：s3c_irq_mask（（IRQ_EINT0）s3c_irq_mask(unsignedintirqno){unsignedlongma