Linux-led device driver 1

Development Environment: Red Hat Enterprise 5, mini2440-2.6.29 version

Cross-compiler 4.3.2

I am running on a mini2440 board. It is suitable for students without a basic driver.

The source code is as follows:

#include <linux/module.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/init.h>#include <linux/delay.h>#include <asm/uaccess.h>#include <asm/irq.h>#include <asm/io.h>#include <mach/regs-gpio.h>#include <mach/hardware.h>#include <linux/gpio.h>//#include <mach/gpio-nrs.h>#define LED_MAJOR 234  #define DEVICE_NAME "leds"     static unsigned long led_table[]={      S3C2410_GPF3,      S3C2410_GPF4,      S3C2410_GPF5,      S3C2410_GPF6,     };    static unsigned long led_cfg_table[]={      S3C2410_GPF3_OUTP,      S3C2410_GPF4_OUTP,      S3C2410_GPF5_OUTP,      S3C2410_GPF6_OUTP,  };    int led_ioctl(struct inode *inode, struct file *file, unsigned int cmd , unsigned long arg){      switch(cmd){          case 0:              s3c2410_gpio_setpin(led_table[0],0);              s3c2410_gpio_setpin(led_table[1],1);              s3c2410_gpio_setpin(led_table[2],1);              s3c2410_gpio_setpin(led_table[3],1);          break;          case 1:              s3c2410_gpio_setpin(led_table[0],1);              s3c2410_gpio_setpin(led_table[1],0);              s3c2410_gpio_setpin(led_table[2],1);              s3c2410_gpio_setpin(led_table[3],1);              break;          case 2:              s3c2410_gpio_setpin(led_table[0],1);              s3c2410_gpio_setpin(led_table[1],1);              s3c2410_gpio_setpin(led_table[2],0);              s3c2410_gpio_setpin(led_table[3],1);              break;          case 3:              s3c2410_gpio_setpin(led_table[0],1);              s3c2410_gpio_setpin(led_table[1],1);              s3c2410_gpio_setpin(led_table[2],1);              s3c2410_gpio_setpin(led_table[3],0);              break;          default:              return -EINVAL;              break;      }     return 0;  }      struct file_operations led_ops = {     .owner = THIS_MODULE,      .ioctl = led_ioctl,  };    static int __init init_led(void)  {      int i, ret;      ret = register_chrdev(LED_MAJOR,DEVICE_NAME,&led_ops);      if(ret < 0){          printk(DEVICE_NAME, "can't register major number/n");      }      for(i = 0; i < 4; i++){          s3c2410_gpio_cfgpin(led_table[i],led_cfg_table[i]);          s3c2410_gpio_setpin(led_table[i],1);      }      printk(DEVICE_NAME "initialized/n");      return 0;  }    static void __exit exit_led(void)  {      unregister_chrdev(LED_MAJOR,DEVICE_NAME);  }    module_init(init_led);  module_exit(exit_led);  MODULE_LICENSE("GPL");  MODULE_AUTHOR("linwei");
Makefile is as follows:
ifneq ($(KERNELRELEASE),)obj-m := led2.oelseKDIR := /home/smb/kernel/linux-2.6.29all:make -C $(KDIR) M=$(PWD) modules ARCH=arm CROSS_COMPILE=arm-linux-clean:rm -f *.ko *.o *.mod.o *.mod.c *.symvers  modul*endif
The test procedure is as follows:
#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <sys/ioctl.h>int main(int argc, char **argv){int on;int led_no;int fd;if (argc != 3 || sscanf(argv[1], "%d", &led_no) != 1 || sscanf(argv[2],"%d", &on) != 1 ||    on < 0 || on > 1 || led_no < 0 || led_no > 3) {fprintf(stderr, "Usage: leds led_no 0|1\n");exit(1);}fd = open("/dev/leds", 0);if (fd < 0) {fd = open("/dev/leds", 0);}if (fd < 0) {perror("open device leds");exit(1);}ioctl(fd, on, led_no);close(fd);return 0;}
Virtual Machine running diagram:
Development Board running diagram
It took me one morning to make everyone laugh and record my drive life.