Android为Tiny4412设备驱动在proc目录下添加一个可读版本信息的文件

//定义proc文件系统节点struct proc_dir_entry *dev_dir , *dev_version;//创建一个目录dev_dir = proc_mkdir("Tiny4412_leds", NULL); //创建一个文件dev_version = create_proc_entry("version", S_IRUGO, dev_dir); //调用读版本的函数dev_version->read_proc = proc_read_version ;

#define VERSION_LEN 20char Tiny4412_LED_version[VERSION_LEN] = "20170908/n";int proc_read_version(char *page, char **start, off_t off, int count, int *eof,         void *data){ int len ;  len = sprintf(page,Tiny4412_LED_version); //将字符串写入page,相当于copy到用户层 return len ;}

#include <linux/kernel.h>#include <linux/module.h>#include <linux/miscdevice.h>#include <linux/fs.h>#include <linux/types.h>#include <linux/moduleparam.h>#include <linux/slab.h>#include <linux/ioctl.h>#include <linux/cdev.h>#include <linux/delay.h>#include <linux/gpio.h>#include <mach/gpio.h>#include <plat/gpio-cfg.h>//添加必要的头文件#include <linux/proc_fs.h>#include <linux/uaccess.h>#define DEVICE_NAME "leds"static int led_gpios[] = { EXYNOS4212_GPM4(0), EXYNOS4212_GPM4(1), EXYNOS4212_GPM4(2), EXYNOS4212_GPM4(3),};#define LED_NUM ARRAY_SIZE(led_gpios)static long tiny4412_leds_ioctl(struct file *filp, unsigned int cmd, unsigned long arg){ switch(cmd) { case 0: case 1:  if (arg > LED_NUM) {  return -EINVAL;  }  gpio_set_value(led_gpios[arg], !cmd);  //printk(DEVICE_NAME": %d %d/n", arg, cmd);  break; default:  return -EINVAL; } return 0;}static struct file_operations tiny4412_led_dev_fops = { .owner  = THIS_MODULE, .unlocked_ioctl = tiny4412_leds_ioctl,};static struct miscdevice tiny4412_led_dev = { .minor  = MISC_DYNAMIC_MINOR, .name  = DEVICE_NAME, .fops  = &tiny4412_led_dev_fops,};#define VERSION_LEN 20char Tiny4412_LED_version[VERSION_LEN] = "20170908/n";int proc_read_version(char *page, char **start, off_t off, int count, int *eof, void *data){ int len ;  len = sprintf(page,Tiny4412_LED_version); return len ;}static int __init tiny4412_led_dev_init(void) { int ret; int i; for (i = 0; i < LED_NUM; i++) { ret = gpio_request(led_gpios[i], "LED"); if (ret) {  printk("%s: request GPIO %d for LED failed, ret = %d/n", DEVICE_NAME,   led_gpios[i], ret);  return ret; } s3c_gpio_cfgpin(led_gpios[i], S3C_GPIO_OUTPUT); gpio_set_value(led_gpios[i], 1); } //杂类设备 ret = misc_register(&tiny4412_led_dev); //定义proc文件系统节点 struct proc_dir_entry *dev_dir , *dev_version; //创建一个目录 dev_dir = proc_mkdir("Tiny4412_leds", NULL);  //创建一个文件 dev_version = create_proc_entry("version", S_IRUGO, dev_dir);  //调用读版本的函数 dev_version->read_proc = proc_read_version ; printk(DEVICE_NAME"/tinitialized/n"); return ret;}static void __exit tiny4412_led_dev_exit(void) { int i; for (i = 0; i < LED_NUM; i++) { gpio_free(led_gpios[i]); } misc_deregister(&tiny4412_led_dev);}module_init(tiny4412_led_dev_init);module_exit(tiny4412_led_dev_exit);MODULE_LICENSE("GPL");MODULE_AUTHOR("FriendlyARM Inc & Y.X.YANG modify");