驱动开发作业3——GPIO子系统
作业1：在内核模块中启用定时器，定时1s，让LED1以1s为周期实现流水灯
myled.c(驱动文件)
/*
* Copyright (c) 2023 by Huijie Xia, All Rights Reserved.
* @Author: Huijie Xia
* @Date: 2023-06-29 08:56:26
* @LastEditTime: 2023-07-11 15:36:16
* @FilePath: /B_Drive/day8/01_myled/myled.c
* @version:
* @Description: GPIO子系统
*/
#include
#include
#include
#include
#include
#include
struct device_node* dnode;
struct timer_list mytimer; /* 定义计时器对象 */
unsigned int gpiono;
void mytimer_func(struct timer_list* timer)
{
if (gpio_get_value(gpiono) == 0) {
/* 设置管脚输出高电平,点亮LED */
gpio_set_value(gpiono, 1);
} else {
/* 设置管脚输出低电平,熄灭LED */
gpio_set_value(gpiono, 0);
}
mod_timer(&mytimer, jiffies + HZ);
}
/**
* @description: 入口：在安装驱动的时候入口函数执行,做资源申请的工作
* demo_init:驱动入口的名字
* __init:它是给编译器使用的,告诉编译器将这个函数放在.init.text段中
* @return {*}
*/
static int __init demo_init(void)
{
int ret;
/* 1.1 通过路径获取节点 */
dnode = of_find_node_by_path("/myleds");
if (dnode == NULL) {
printk("get device node error! __%d__\n", __LINE__);
return -ENXIO;
}
printk("get device node successful! __%d__\n", __LINE__);
/* 1.2 根据设备树节点解析LED1的GPIO编号 */
gpiono = of_get_named_gpio(dnode, "led1-gpios", 0);
if (gpiono < 0) {
printk("analysis GPIO number error! __%d__\n", __LINE__);
return gpiono;
}
printk("analysis GPIO number successful! GPIO number = %d! __%d__\n", gpiono, __LINE__);
/* 1.3 申请gpio编号 */
ret = gpio_request(gpiono, NULL);
if (ret < 0) {
printk("request GPIO number error! __%d__\n", __LINE__);
return ret;
}
printk("request GPIO number successful! __%d__\n", __LINE__);
/* 1.4 设置LED1对应的GPIO管脚为输出模式 */
ret = gpio_direction_output(gpiono, 0);
if (ret < 0) {
printk("set GPIO output error! __%d__\n", __LINE__);
return ret;
}
printk("set GPIO output successful! __%d__\n", __LINE__);
/* 2.1 初始化定时器对象 */
mytimer.expires = jiffies + HZ; /* 设置1s定时 */
timer_setup(&mytimer, mytimer_func, 0);
/* 2.2 将定时器对象注册进入内核并启动 */
add_timer(&mytimer);
return 0;
}
/**
* @description: 出口：在卸载驱动的时候出口函数执行，做资源释放的工作
* demo_exit:驱动出口的名字
* __exit:它是给编译器使用的,告诉编译器将这个函数放在.exit.text段中
* @return {*}
*/
static void __exit demo_exit(void)
{
/* 1. 设置管脚输出低点平,熄灭LED */
gpio_set_value(gpiono, 0);
/* 2. 释放gpio编号 */
gpio_free(gpiono);
/* 3. 注销定时器 */
del_timer(&mytimer);
}
/* 告诉内核入口地址 */
module_init(demo_init);
/* 告诉内核出口地址 */
module_exit(demo_exit);
/* 许可证：遵从GPL协议 */
MODULE_LICENSE("GPL");
作业2：基于GPIO子系统完成LED灯驱动的注册，并利用应用程序测试
chrdevled.c(驱动文件)
/*
* Copyright (c) 2023 by Huijie Xia, All Rights Reserved.
* @Author: Huijie Xia
* @Date: 2023-06-29 08:56:26
* @LastEditTime: 2023-07-11 17:02:51
* @FilePath: /B_Drive/day8/02_chrdevled/chrdevled.c
* @version:
* @Description: GPIO子系统
*/
#include
#include
#include
#include
#include
#include
#include
struct cdev* cdev;
struct class* cls;
struct device* dev;
struct device_node* dnode;
unsigned int gpiono[3];
/* !!!注意:静态指定时，主设备号major必须小于等于511!!! */
unsigned int major = 0;
unsigned int minor = 0;
const int count = 3;
#define CNAME "chrdevled"
#define LED_ON _IO('l', 1)
#define LED_OFF _IO('l', 0)
char* propname[3] = { "led1-gpios", "led2-gpios", "led3-gpios" };
int mycdev_open(struct inode* inode, struct file* file)
{
/* 获取打开文件的次设备号 */
unsigned int led_minor = MINOR(inode->i_rdev);
/* 将获取的次设备号放入file结构体中private_data成员 */
file->private_data = (void*)led_minor;
// printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
ssize_t mycdev_read(struct file* file, char __user* ubuf, size_t size, loff_t* offs)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
ssize_t mycdev_write(struct file* file, const char __user* ubuf, size_t size, loff_t* offs)
{
printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
int mycdev_close(struct inode* inode, struct file* file)
{
// printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
return 0;
}
long mycdev_ioctl(struct file* file, unsigned int cmd, unsigned long arg)
{
unsigned int led_minor = (int)file->private_data;
// printk("%s:%s:%d\n", __FILE__, __func__, __LINE__);
switch (led_minor) {
case 0: /* 控制LED1 */
switch (cmd) {
case LED_ON:
/* 设置管脚输出高点平,点亮LED */
gpio_set_value(gpiono[0], 1);
break;
case LED_OFF:
/* 设置管脚输出低点平,熄灭LED */
gpio_set_value(gpiono[0], 0);
break;
default:
break;
}
break;
case 1: /* 控制LED2 */
switch (cmd) {
case LED_ON:
/* 设置管脚输出高点平,点亮LED */
gpio_set_value(gpiono[1], 1);
break;
case LED_OFF:
/* 设置管脚输出低点平,熄灭LED */
gpio_set_value(gpiono[1], 0);
break;
default:
break;
}
break;
case 2: /* 控制LED3 */
switch (cmd) {
case LED_ON:
/* 设置管脚输出高点平,点亮LED */
gpio_set_value(gpiono[2], 1);
break;
case LED_OFF:
/* 设置管脚输出低点平,熄灭LED */
gpio_set_value(gpiono[2], 0);
default:
break;
}
break;
default:
break;
}
return 0;
}
struct file_operations fops = {
.open = mycdev_open,
.read = mycdev_read,
.write = mycdev_write,
.unlocked_ioctl = mycdev_ioctl,
.release = mycdev_close,
};
/**
* @description: 入口：在安装驱动的时候入口函数执行,做资源申请的工作
* demo_init:驱动入口的名字
* __init:它是给编译器使用的,告诉编译器将这个函数放在.init.text段中
* @return {*}
*/
static int __init mychrdev_init(void)
{
int ret, i;
dev_t devno;
/* 1.1 分配字符设备驱动对象空间 cdev_alloc */
cdev = cdev_alloc();
if (cdev == NULL) {
printk("cdev alloc memory error line : %d\n", __LINE__);
ret = -ENOMEM;
goto ERR1;
}
printk("cdev alloc memory successful line : %d\n", __LINE__);
/* 1.2 字符设备驱动对象部分初始化 cdev_init */
cdev_init(cdev, &fops);
/* 1.3 申请设备号 */
if (major > 0) {
/* 静态申请设备号 register_chrdev_region */
ret = register_chrdev_region(MKDEV(major, minor), count, CNAME);
if (ret) {
printk("static:request device number error line : %d\n", __LINE__);
goto ERR2;
}
printk("static:request device number successful line : %d\n", __LINE__);
} else {
/* 动态申请设备号 alloc_chrdev_region */
ret = alloc_chrdev_region(&devno, 0, count, CNAME);
if (ret) {
printk("dynamic:request device number error line : %d\n", __LINE__);
goto ERR2;
}
printk("dynamic:request device number successful line : %d\n", __LINE__);
major = MAJOR(devno);
minor = MINOR(devno);
}
/* 1.4 注册字符设备驱动对象 cdev_add */
ret = cdev_add(cdev, MKDEV(major, minor), count);
if (ret) {
printk("register char device driver error line : %d\n", __LINE__);
goto ERR3;
}
printk("register char device driver successful line : %d\n", __LINE__);
/* 2.1 向上提交目录信息 class_create */
cls = class_create(THIS_MODULE, CNAME);
if (IS_ERR(cls)) {
printk("submit directory error line : %d\n", __LINE__);
goto ERR4;
}
printk("submit directory successful line : %d\n", __LINE__);
/* 2.2 向上提交设备节点信息 */
for (i = 0; i < count; i++) {
dev = device_create(cls, NULL, MKDEV(major, minor + i), NULL, "chrdevled%d", i);
if (IS_ERR(dev)) {
printk("submit device node infomation error line : %d\n", __LINE__);
goto ERR5;
}
}
/* 3.1 通过路径获取节点 */
dnode = of_find_node_by_path("/myleds");
if (dnode == NULL) {
printk("get device node error! __%d__\n", __LINE__);
return -ENXIO;
}
printk("get device node successful! __%d__\n", __LINE__);
for (i = 0; i < ARRAY_SIZE(propname); i++) {
/* 3.2 根据设备树节点解析LED的GPIO编号 */
gpiono[i] = of_get_named_gpio(dnode, propname[i], 0);
if (gpiono[i] < 0) {
printk("analysis %s GPIO number error! __%d__\n", propname[i], __LINE__);
return gpiono[i];
}
printk("analysis %s GPIO number successful! GPIO number = %d! __%d__\n", propname[i], gpiono[i], __LINE__);
/* 3.3 申请gpio编号 */
ret = gpio_request(gpiono[i], NULL);
if (ret < 0) {
printk("request %s GPIO number error! __%d__\n", propname[i], __LINE__);
return ret;
}
printk("request %s GPIO number successful! __%d__\n", propname[i], __LINE__);
/* 3.4 设置LED对应的GPIO管脚为输出模式 */
ret = gpio_direction_output(gpiono[i], 0);
if (ret < 0) {
printk("set %s GPIO output error! __%d__\n", propname[i], __LINE__);
return ret;
}
printk("set %s GPIO output successful! __%d__\n", propname[i], __LINE__);
}
return 0;
ERR5:
for (--i; i >= 0; i++) {
device_destroy(cls, MKDEV(major, minor + i));
}
class_destroy(cls); /* 销毁目录 */
ERR4:
cdev_del(cdev); /* 注销字符设备驱动对象 */
ERR3:
unregister_chrdev_region(MKDEV(major, minor), count); /* 销毁设备号 */
ERR2:
kfree(cdev); /* 释放对象空间 */
ERR1:
return ret;
}
/**
* @description: 出口：在卸载驱动的时候出口函数执行，做资源释放的工作
* demo_exit:驱动出口的名字
* __exit:它是给编译器使用的,告诉编译器将这个函数放在.exit.text段中
* @return {*}
*/
static void __exit mychrdev_exit(void)
{
int i;
/* 1. 销毁提交设备节点信息 */
for (i = 0; i < 3; i++) {
device_destroy(cls, MKDEV(major, minor + i));
}
/* 2. 销毁目录 */
class_destroy(cls);
/* 3. 注册字符设备驱动对象 */
cdev_del(cdev);
/* 4. 销毁设备号 */
unregister_chrdev_region(MKDEV(major, minor), count);
/* 5. 释放对象空间 */
kfree(cdev);
/* 6. 设置管脚输出低点平,熄灭LED */
for (i = 0; i < ARRAY_SIZE(propname); i++) {
gpio_set_value(gpiono[i], 0);
}
/* 7. 释放gpio编号 */
for (i = 0; i < ARRAY_SIZE(propname); i++) {
gpio_free(gpiono[i]);
}
}
/* 告诉内核入口地址 */
module_init(mychrdev_init);
/* 告诉内核出口地址 */
module_exit(mychrdev_exit);
/* 许可证：遵从GPL协议 */
MODULE_LICENSE("GPL"); test.c(测试文件)
/*
* Copyright (c) 2023 by Huijie Xia, All Rights Reserved.
* @Author: Huijie Xia
* @Date: 2023-07-03 14:44:33
* @LastEditTime: 2023-07-11 16:50:01
* @FilePath: /B_Drive/day8/02_chrdevled/test.c
* @version:
* @Description: 驱动控制硬件的测试文件
*/
#include
#include
#include
#include
#include
#include
#include
#define LED_ON _IO('l', 1)
#define LED_OFF _IO('l', 0)
#define ERR_MSG(msg) \
do { \
fprintf(stderr, "line : %d\n", __LINE__); \
perror(msg); \
} while (0)
char buf[128] = { 0 };
int main(int argc, const char* argv[])
{
int ledfd; /* 文件描述符 */
int hardware_which; /* 硬件设备选择 */
int choice; /* 设备选择 */
int whichled; /* LED选择 */
while (1) {
printf("请选择要控制的LED\n");
printf("1(LED1) 2(LED2) 3(LED3) > ");
scanf("%d", &whichled);
switch (whichled) {
case 1:
if ((ledfd = open("/dev/chrdevled0", O_RDWR)) == -1)
ERR_MSG("chrdevled0 open error");
while (1) {
printf("请选择要实现的功能\n");
printf("0(关灯) 1(开灯) 2(退出) > ");
scanf("%d", &choice);
if (choice == 0) {
ioctl(ledfd, LED_OFF);
} else if (choice == 1) {
ioctl(ledfd, LED_ON);
} else {
break;
}
}
close(ledfd);
break;
case 2:
if ((ledfd = open("/dev/chrdevled1", O_RDWR)) == -1)
ERR_MSG("chrdevled1 open error");
while (1) {
printf("请选择要实现的功能\n");
printf("0(关灯) 1(开灯) 2(退出) > ");
scanf("%d", &choice);
if (choice == 0) {
ioctl(ledfd, LED_OFF);
} else if (choice == 1) {
ioctl(ledfd, LED_ON);
} else {
break;
}
}
close(ledfd);
break;
case 3:
if ((ledfd = open("/dev/chrdevled2", O_RDWR)) == -1)
ERR_MSG("chrdevled2 open error");
while (1) {
printf("请选择要实现的功能\n");
printf("0(关灯) 1(开灯) 2(退出) > ");
scanf("%d", &choice);
if (choice == 0) {
ioctl(ledfd, LED_OFF);
} else if (choice == 1) {
ioctl(ledfd, LED_ON);
} else {
break;
}
}
close(ledfd);
break;
default:
break;
}
}
return 0;
}