平台总线probe函数的编写-16
作者：互联网
平台总线probe函数的编写
编写probe函数的思路:
从device.c里面获得硬件资源
- 方式一:直接获得，不推荐
- 方法二:只用函数获得
#include <linux/platform_device.h>
extern struct resource *platform_get_resource(struct platform_device *,unsigned int, unsigned int);
参数
- 第一个platform_device 指针
- 第二个是类型 resource 结构体中的 flags，
- 第三个相同的flags的第几个 resource 可以是一个数组，但是这个不是和该数组的位置对应，只和 flag 是第几个有关
- 返回值 struct resource * 不为NULL成功
注册杂项/字符设备，完善file_operation结构体，并生成设备节点注册之前要先登记:
#include <linux/ioport.h>
struct resource * request_mem_region(start,n,name)
参数
- 第一个 resource 结构体中的start 对应的内存地址
- 第二个 resource 结构体总的start 到ent 一共有几个地址
- 第三个 name 这个随便起一个
- 返回值 struct resource * 不为NULL成功
卸载登记
#include <linux/ioport.h>
release_mem_region(start,n)
参数
- 第一个 resource 结构体中的start 对应的内存地址
- 第二个 resource 结构体总的start 到ent 一共有几个地址
代码 一下是以rk3399的板子为例做的，如果是其他更换寄存器地址
- beep_driver.c
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/errno.h>
#include <linux/ioport.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/uaccess.h>
#include <linux/io.h>
unsigned int *vir_gpio5_dr;
struct resource *beep_mem;
struct resource *beep_mem_tmp;
int misc_open(struct inode * inode, struct file * file){
printk("hello misc_open \n");
return 0;
}
int misc_release(struct inode * inode, struct file * file){
printk("hello misc_release bye bye \n");
return 0;
}
int misc_read(struct file* file, char __user * ubuf, size_t size, loff_t * loff_t){
char kbuf[64] = "heheh_read";
printk("hello misc_read \n");
if(copy_to_user(ubuf, kbuf, strlen(kbuf)) != 0 ){
printk("copy_to_user error \n");
return -1;
}
return 0;
}
int misc_write(struct file * file, const char __user * ubuf, size_t size, loff_t * loff_t){
printk("hello misc_write \n");
char kbuf[64] = {0};
if (copy_from_user(kbuf, ubuf, size) != 0)
{
printk("copy_from_to_user error \n");
return -1;
}
printk("kbuf is %s \n", kbuf);
if (kbuf[0] == 1){
*vir_gpio5_dr = 0x4a400000;
}else if (kbuf[0] == 0)
{
*vir_gpio5_dr = 0x4a000000;
}
return 0;
}
struct file_operations misc_fops =
{
.owner = THIS_MODULE,
.open = misc_open,
.release = misc_release,
.read = misc_read,
.write = misc_write
};
struct miscdevice misc_dev =
{
.minor = MISC_DYNAMIC_MINOR,
.name = "hello_misc",
.fops = &misc_fops
};
int beep_probe(struct platform_device *pdev){
int ret = 0;
printk("beep_probe 匹配成功了 \n");
//不安全
printk("beep_res不安全 %s \n", pdev->resource[0].name);
//第三个参数为同一类型下的第几个
beep_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (beep_mem == NULL)
{
printk("platform_get_resource is error \n");
return -1;
}
printk("platform_get_resource is ok");
printk("beep_res start is 0x%x \n", beep_mem ->start);
printk("beep_res end is 0x%x \n",beep_mem ->end);
vir_gpio5_dr = ioremap(beep_mem->start,1);
if (vir_gpio5_dr == NULL)
{
printk("GPIO5_DR ioremap error \n");
return -1;
}
printk("GPIO5_DR ioremap ok \n");
ret = misc_register(&misc_dev);
if (ret <0)
{
printk("misc_registe is error \n");
}
printk("misc registe is succeed \n");
#if 0
beep_mem_tmp = request_mem_region(beep_mem->start,beep_mem->end - beep_mem->start + 1, "beep");
if (beep_mem_tmp == NULL)
{
printk("request_mem_region is error \n");
goto err_region;
}
return 0;
err_region:
release_mem_region(beep_mem->start,beep_mem->end - beep_mem->start + 1);
return -1;
#endif
return 0;
}
int beep_remove(struct platform_device *pdev){
printk("beep_remove \n");
}
const struct platform_device_id beep_idtable = {
.name = "beep_test"
};
struct platform_driver beep_device =
{
.probe = beep_probe,
.remove = beep_remove,
.driver = {
.name = "123",
.owner = THIS_MODULE
},
.id_table = &beep_idtable
};
static int beep_driver_init(void){
printk(KERN_EMERG "hello world enter \n");
int ret = 0;
ret = platform_driver_register(&beep_device);
if (ret < 0)
{
printk("platform_driver_register 失败\n");
}
printk("platform_driver_register ok\n");
return 0;
}
static void beep_driver_exit(void){
printk(KERN_EMERG "hello world exit! \n");
platform_driver_unregister(&beep_device);
misc_deregister(&misc_dev);
iounmap(vir_gpio5_dr);
}
module_init(beep_driver_init);
module_exit(beep_driver_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("LIYU");
- beep_device.c
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
struct resource beep_res[] =
{
[0] = {
.start = 0xff790000,
.end = 0xff790004,
.flags = IORESOURCE_MEM,
.name = "GPIO5_DR"
}
};
void beep_release(struct device *dev){
printk("beep_release \n");
}
struct platform_device beep_device =
{
.name = "beep_test",
.id = -1,
.resource = beep_res,
.num_resources = ARRAY_SIZE(beep_res),
.dev = {
.release = beep_release
}
};
static int deivce_init(void){
printk(KERN_EMERG "hello world enter \n");
int ret;
ret = platform_device_register(&beep_device);
return ret;
}
static void device_exit(void){
printk(KERN_EMERG "hello world exit! \n");
platform_device_unregister(&beep_device);
}
module_init(deivce_init);
module_exit(device_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("LIYU");
- app.c
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
int main(int argc, char const *argv[]){
int fd;
char buf[64] = {0};
char buf_write[64] = "write aaaaaaaaa";
fd = open("/dev/hello_misc",O_RDWR);
if (fd < 0)
{
printf("open error \n");
return fd;
}
printf("open success \n");
//字符串转化为整型
buf[0] = atoi(argv[1]);
printf("buf[0] %d \n", buf[0]);
write(fd,buf,sizeof(buf));
close(fd);
return 0;
}
标签：resource,struct,16,misc,probe,总线,beep,printk,include 来源： https://blog.csdn.net/yangbinbingA/article/details/117771136