驱动10/20——通过platform总线驱动实现
a.应用程序通过阻塞的io模型来读取number变量的值
b.number是内核驱动中的一个变量
c.number的值随着按键按下而改变（按键中断） 例如number=0 按下按键number=1 ,再次按下按键number=0
d.在按下按键的时候需要同时将led1的状态取反
e.驱动中需要编写字符设备驱动
f.驱动中需要自动创建设备节点
g.这个驱动需要的所有设备信息放在设备树的同一个节点中
test.c
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
//#include "myled.h"
#include
#include
#include
#include
#include
struct resource *res;//描述设备信息结构体
int irqno;
struct gpio_desc *desc;
struct gpio_desc *desc1;
wait_queue_head_t head;
unsigned int condition;
unsigned char number;
struct cdev *cdev;
struct class *cls;
struct device *dev;
dev_t dev1;
unsigned int major;
unsigned int minor;
//操作方法结构体
ssize_t mycdev_read(struct file *file, char __user *ubuf, size_t size, loff_t *loff)
{
int ret;
if (file->f_flags & O_NONBLOCK)
{
return -EINVAL;
}
else
{
ret = wait_event_interruptible(head, condition);
if (ret)
{
printk("接收阻塞，休眠\n");
return ret;
}
}
if (size > sizeof(char))
size = sizeof(char);
ret = copy_to_user(ubuf, &number, size);
if (ret)
{
printk("数据从内核向用户拷贝失败\n");
return -EIO;
}
condition = 0;
return size;
}
ssize_t mycdev_write(struct file *file, const char __user *ubuf, size_t size, loff_t *loff)
{
return 0;
}
int mycdev_open(struct inode *inode, struct file *file)
{
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
return 0;
}
struct file_operations fops =
{
.open = mycdev_open,
.read = mycdev_read,
.write = mycdev_write,
.release = mycdev_close,
};
//中断处理函数
irqreturn_t irq_handler(int irq, void *dev)
{
gpiod_set_value(desc, !gpiod_get_value(desc));
if (number == '0')
{
number = '1';
condition = 1;
wake_up_interruptible(&head);
}
else
{
number = '0';
condition = 1;
wake_up_interruptible(&head);
}
return IRQ_HANDLED;
}
// platfom总线设置
int pdrv_probe(struct platform_device *pdr)
{
int ret;
printk("%s:%d\n", __FILE__, __LINE__);
//获取设备信息
res = platform_get_resource(pdr, IORESOURCE_MEM, 0);
if (res == NULL)
{
printk("获取资源失败\n");
return -ENODATA;
}
//获取中断类型资源
irqno = platform_get_irq(pdr, 0);
if (irqno < 0)
{
printk("获取资源失败\n");
return irqno;
}
printk("%#x %d\n", res->start, irqno);
//获取gpio编号
desc = gpiod_get_from_of_node(pdr->dev.of_node, "led1", 0, GPIOD_OUT_LOW, NULL);
if (IS_ERR(desc))
{
printk("获取GPIO编号失败\n");
return PTR_ERR(desc);
}
//注册软中断号
ret = request_irq(irqno, irq_handler, IRQF_TRIGGER_FALLING, "key2——inte", NULL);
if (ret)
{
printk("注册中断号失败\n");
return ret;
}
printk("注册中断号成功\n");
condition = 0;
init_waitqueue_head(&head);
return 0;
}
int pdrv_remove(struct platform_device *pdrv)
{
free_irq(irqno, NULL);
//释放gpio编号
gpiod_set_value(desc, 0);
gpiod_put(desc);
printk("%s:%d\n", __FILE__, __LINE__);
return 0;
}
//定义compatible表
struct of_device_id oftable[] =
{
{.compatible = "hqyj,hello2"},
{},
};
MODULE_DEVICE_TABLE(of, oftable);
//定义并初始化对象
struct platform_driver pdrv = {
.probe = pdrv_probe,
.remove = pdrv_remove,
.driver = {
.name = "test1",
.of_match_table = oftable,
},
};
static int __init mycdev_init(void)
{
int ret, i;
//注册设备驱动
// 1,分配设备驱动对象
cdev = cdev_alloc();
if (NULL == cdev)
{
printk("申请驱动对象空间失败\n");
ret = -ENOMEM;
goto ERR1;
// return -ENOMEM;
}
// 2，初始化对象
cdev_init(cdev, &fops);
// 3，设备号的申请
ret = alloc_chrdev_region(&dev1, 0, 3, "LED");
if (ret != 0)
{
printk("申请设备号失败\n");
goto ERR2;
}
major = MAJOR(dev1);
minor = MINOR(dev1);
printk("动态设备号申请成功\n");
// 4，注册字符设备驱动
ret = cdev_add(cdev, dev1, 3);
if (ret != 0)
{
printk("注册设备驱动失败\n");
goto ERR3;
}
printk("注册字符设备驱动成功：%d\n", dev1);
// 5，自动创建设备节点
//创建目录
cls = class_create(THIS_MODULE, "LED");
if (IS_ERR(cls))
{
printk("向上提交目录失败\n");
goto ERR4;
}
printk("向上提交目录成功\n");
//创建设备节点 3次
for (i = 0; i < 3; i++)
{
dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
if (IS_ERR(dev))
{
printk("向上提交节点失败\n");
ret = PTR_ERR(dev);
goto ERR5;
}
}
printk("向上提交节点成功\n");
platform_driver_register(&pdrv);
return 0;
ERR5:
for (--i; i >= 0; i--)
{
device_destroy(cls, MKDEV(major, i));
}
class_destroy(cls);
ERR4:
cdev_del(cdev);
ERR3:
unregister_chrdev_region(dev1, 3);
ERR2:
kfree(cdev);
ERR1:
return ret;
}
static void __exit mycdev_exit(void)
{
int i;
platform_driver_unregister(&pdrv);
for (i = 0; i < 3; i++)
{
device_destroy(cls, MKDEV(major, i));
}
//销毁目录
class_destroy(cls);
// 2，注销字符设备驱动
cdev_del(cdev);
// 3,释放设备号
unregister_chrdev_region(dev1, 3);
// 4，释放动态申请的空间
kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL"); drv.c
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
//#include "myled.h"
#include
#include
#include
#include
#include
struct resource *res;//描述设备信息结构体
int irqno;
struct gpio_desc *desc;
struct gpio_desc *desc1;
wait_queue_head_t head;
unsigned int condition;
unsigned char number;
struct cdev *cdev;
struct class *cls;
struct device *dev;
dev_t dev1;
unsigned int major;
unsigned int minor;
//操作方法结构体
ssize_t mycdev_read(struct file *file, char __user *ubuf, size_t size, loff_t *loff)
{
int ret;
if (file->f_flags & O_NONBLOCK)
{
return -EINVAL;
}
else
{
ret = wait_event_interruptible(head, condition);
if (ret)
{
printk("接收阻塞，休眠\n");
return ret;
}
}
if (size > sizeof(char))
size = sizeof(char);
ret = copy_to_user(ubuf, &number, size);
if (ret)
{
printk("数据从内核向用户拷贝失败\n");
return -EIO;
}
condition = 0;
return size;
}
ssize_t mycdev_write(struct file *file, const char __user *ubuf, size_t size, loff_t *loff)
{
return 0;
}
int mycdev_open(struct inode *inode, struct file *file)
{
return 0;
}
int mycdev_close(struct inode *inode, struct file *file)
{
return 0;
}
struct file_operations fops =
{
.open = mycdev_open,
.read = mycdev_read,
.write = mycdev_write,
.release = mycdev_close,
};
//中断处理函数
irqreturn_t irq_handler(int irq, void *dev)
{
gpiod_set_value(desc, !gpiod_get_value(desc));
if (number == '0')
{
number = '1';
condition = 1;
wake_up_interruptible(&head);
}
else
{
number = '0';
condition = 1;
wake_up_interruptible(&head);
}
return IRQ_HANDLED;
}
// platfom总线设置
int pdrv_probe(struct platform_device *pdr)
{
int ret;
printk("%s:%d\n", __FILE__, __LINE__);
//获取设备信息
res = platform_get_resource(pdr, IORESOURCE_MEM, 0);
if (res == NULL)
{
printk("获取资源失败\n");
return -ENODATA;
}
//获取中断类型资源
irqno = platform_get_irq(pdr, 0);
if (irqno < 0)
{
printk("获取资源失败\n");
return irqno;
}
printk("%#x %d\n", res->start, irqno);
//获取gpio编号
desc = gpiod_get_from_of_node(pdr->dev.of_node, "led1", 0, GPIOD_OUT_LOW, NULL);
if (IS_ERR(desc))
{
printk("获取GPIO编号失败\n");
return PTR_ERR(desc);
}
//注册软中断号
ret = request_irq(irqno, irq_handler, IRQF_TRIGGER_FALLING, "key2——inte", NULL);
if (ret)
{
printk("注册中断号失败\n");
return ret;
}
printk("注册中断号成功\n");
condition = 0;
init_waitqueue_head(&head);
return 0;
}
int pdrv_remove(struct platform_device *pdrv)
{
free_irq(irqno, NULL);
//释放gpio编号
gpiod_set_value(desc, 0);
gpiod_put(desc);
printk("%s:%d\n", __FILE__, __LINE__);
return 0;
}
//定义compatible表
struct of_device_id oftable[] =
{
{.compatible = "hqyj,hello2"},
{},
};
MODULE_DEVICE_TABLE(of, oftable);
//定义并初始化对象
struct platform_driver pdrv = {
.probe = pdrv_probe,
.remove = pdrv_remove,
.driver = {
.name = "test1",
.of_match_table = oftable,
},
};
static int __init mycdev_init(void)
{
int ret, i;
//注册设备驱动
// 1,分配设备驱动对象
cdev = cdev_alloc();
if (NULL == cdev)
{
printk("申请驱动对象空间失败\n");
ret = -ENOMEM;
goto ERR1;
// return -ENOMEM;
}
// 2，初始化对象
cdev_init(cdev, &fops);
// 3，设备号的申请
ret = alloc_chrdev_region(&dev1, 0, 3, "LED");
if (ret != 0)
{
printk("申请设备号失败\n");
goto ERR2;
}
major = MAJOR(dev1);
minor = MINOR(dev1);
printk("动态设备号申请成功\n");
// 4，注册字符设备驱动
ret = cdev_add(cdev, dev1, 3);
if (ret != 0)
{
printk("注册设备驱动失败\n");
goto ERR3;
}
printk("注册字符设备驱动成功：%d\n", dev1);
// 5，自动创建设备节点
//创建目录
cls = class_create(THIS_MODULE, "LED");
if (IS_ERR(cls))
{
printk("向上提交目录失败\n");
goto ERR4;
}
printk("向上提交目录成功\n");
//创建设备节点 3次
for (i = 0; i < 3; i++)
{
dev = device_create(cls, NULL, MKDEV(major, i), NULL, "myled%d", i);
if (IS_ERR(dev))
{
printk("向上提交节点失败\n");
ret = PTR_ERR(dev);
goto ERR5;
}
}
printk("向上提交节点成功\n");
platform_driver_register(&pdrv);
return 0;
ERR5:
for (--i; i >= 0; i--)
{
device_destroy(cls, MKDEV(major, i));
}
class_destroy(cls);
ERR4:
cdev_del(cdev);
ERR3:
unregister_chrdev_region(dev1, 3);
ERR2:
kfree(cdev);
ERR1:
return ret;
}
static void __exit mycdev_exit(void)
{
int i;
platform_driver_unregister(&pdrv);
for (i = 0; i < 3; i++)
{
device_destroy(cls, MKDEV(major, i));
}
//销毁目录
class_destroy(cls);
// 2，注销字符设备驱动
cdev_del(cdev);
// 3,释放设备号
unregister_chrdev_region(dev1, 3);
// 4，释放动态申请的空间
kfree(cdev);
}
module_init(mycdev_init);
module_exit(mycdev_exit);
MODULE_LICENSE("GPL");