嵌入式学习——硬件（Linux内核驱动编程platform、内核定时器、DS18B20）——day61

1. platform驱动框架

1.1 设备device

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>void led_release(struct device *dev)
{printk("leds has been released\n");
}static struct resource led_resources[] = 
{[0] = {.start = 0x56000010,.end = 0x56000010 + 8,.name = "led1~4",.flags = IORESOURCE_IO}
};struct platform_device led_device = 
{.name = "Mini2440_leds",.id = -1,.dev = {.release = led_release},.resource = led_resources,.num_resources = ARRAY_SIZE(led_resources)
};static int __init led_device_init(void)
{return platform_device_register(&led_device);
}static void __exit led_device_exit(void)
{platform_device_unregister(&led_device);
}module_init(led_device_init);
module_exit(led_device_exit);MODULE_LICENSE("GPL");

1.2 驱动driver

#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/miscdevice.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/device.h>
#include <asm/uaccess.h>
#include <asm/io.h>unsigned int *regGPBCON;
unsigned int *regGPBDAT;
int led_driver_open(struct inode *p_node, struct file *fp)
{printk("open\n");return 0;
}ssize_t led_driver_read(struct file *fp, char __user *user_buffer, size_t n, loff_t * offset)
{printk("read\n");return 0;
}void ledOn(unsigned int n)
{*regGPBDAT |= (0x0F << 5);if(n < 1 || n > 4){return;}*regGPBDAT &= ~(1 << (n + 4));
}ssize_t led_driver_write(struct file *fp, const char __user *user_buffer, size_t n, loff_t *offset)
{char s[10];copy_from_user(s, user_buffer, n);ledOn(s[0]);printk("write\n");return n;
}int led_driver_close(struct inode *p_node, struct file *fp)
{printk("close\n");return 0;
}struct file_operations fops =
{.owner = THIS_MODULE,.release = led_driver_close,.open = led_driver_open,.read = led_driver_read,.write = led_driver_write,
};static struct miscdevice led_dev = 
{.minor = MISC_DYNAMIC_MINOR,.fops = &fops,.name = "led"
};static  int led_probe(struct platform_device *dev)
{int ret ;unsigned int GPBCON;printk("led_probe\n");ret = misc_register(&led_dev);if(ret){return ret;}GPBCON = dev->resource[0].start;regGPBCON = ioremap(GPBCON, 8);regGPBDAT = regGPBCON + 1;*regGPBCON &= ~((3 << 10) | (3 << 12) | (3 << 14) | (3 << 16));*regGPBCON |= (1 << 10) | (1 << 12) | (1 << 14) | (1 << 16);*regGPBDAT |= (0x0F << 5);return 0;
}int led_remove(struct platform_device *dev)
{printk("led_remove\n");misc_deregister(&led_dev);return 0;
}static struct platform_driver led_driver = 
{.driver = {.name = "Mini2440_leds",.owner = THIS_MODULE},.probe = led_probe,.remove = led_remove};static int __init led_driver_init(void)
{return platform_driver_register(&led_driver);
}static void __exit led_driver_exit(void)
{platform_driver_unregister(&led_driver);
}module_init(led_driver_init);
module_exit(led_driver_exit);MODULE_LICENSE("GPL");

2. 内核定时器驱动——（3秒延时）

#include <linux/init.h>
#include <linux/module.h>
#include <linux/timer.h>static struct timer_list tl;void timeout(unsigned long n)
{printk("timeout : %lu\n", jiffies);tl.data = jiffies;mod_timer(&tl, jiffies + 3 * HZ);
}static int __init timer_driver_init(void)
{init_timer(&tl);	tl.function = timeout;tl.data = jiffies;tl.expires = jiffies + 3 * HZ;add_timer(&tl);return 0;
}static void __exit timer_driver_exit(void)
{del_timer(&tl);
}module_init(timer_driver_init);
module_exit(timer_driver_exit);MODULE_LICENSE("GPL");