添加power interface驱动模块框架

Makefile

@@ -3,7 +3,7 @@ CROSS_COMPILE=arm-poky-linux-gnueabi-
 #也可以同时编译多个模块  obj-m += export_symbol.o export_symbol1.o export_symbol2.o
 obj-m := coral.o
 
-coral-objs := main.o led.o light_ring.o ssegment.o ec_version.o buzzer.o fan.o writeprotect.o myname.o cash_drawers.o batteryled.o watchdog.o
+coral-objs := main.o led.o light_ring.o ssegment.o ec_version.o buzzer.o fan.o writeprotect.o myname.o cash_drawers.o batteryled.o watchdog.o power.o
 
 KERNELDIR := /lib/modules/$(shell uname -r)/build
 ccflags-y += -I./include

main.c

@@ -27,6 +27,7 @@
 #include "cash_drawers.h"
 #include "batteryled.h"
 #include "watchdog.h"
+#include "power.h"
 
 struct kobject *vfiec_kobj = NULL;
 
@@ -40,6 +41,7 @@ static int __init all_driver_init(void)
         ret = -ENOMEM;
     }
 
+    power_init();
     watchdog_init();
     batteryled_init();
     cashd_init();
@@ -58,6 +60,7 @@ static int __init all_driver_init(void)
 
 static void __exit all_driver_exit(void)
 {
+    power_exit();
     watchdog_exit();
     batteryled_exit();
     cashd_exit();

power.c

@@ -0,0 +1,289 @@
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/cdev.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/device.h>
+#include <linux/stat.h>
+#include <linux/poll.h>
+
+#include <linux/sched.h>
+#include <linux/timer.h>
+#include <linux/workqueue.h>
+
+#include <linux/io.h>
+#include "gpioregs.h"
+
+#define DEVICE_NAME "power"
+#define CLASS_NAME "power_class"
+#define BUFFER_SIZE 1024
+
+// 可以通过模块参数指定主设备号和次设备号
+static int power_major = 56; // 默认主设备号
+static int power_minor = 70;   // 默认次设备号
+module_param(power_major, int, S_IRUGO);
+module_param(power_minor, int, S_IRUGO);
+MODULE_PARM_DESC(power_major, "Major device number");
+MODULE_PARM_DESC(power_minor, "Minor device number");
+
+static struct class *char_class = NULL;
+static struct device *char_device = NULL;
+static struct cdev my_cdev;
+static dev_t dev_num;
+
+// 设备结构体
+struct power_dev
+{
+    char *buffer;
+    size_t size;
+    struct mutex lock;
+    struct cdev cdev;
+    wait_queue_head_t read_wait;
+    struct delayed_work delay_work1;
+};
+
+static struct power_dev *dev = NULL;
+
+static void delay_work_func(struct work_struct *work)
+{    
+    printk(KERN_INFO "delay_work_func\n");
+}
+
+// 文件打开操作
+static int power_open(struct inode *inode, struct file *filp)
+{
+    struct power_dev *dev;
+
+    dev = container_of(inode->i_cdev, struct power_dev, cdev);
+    filp->private_data = dev;
+
+    printk(KERN_INFO "power: Device opened (major=%d, minor=%d)\n",
+           imajor(inode), iminor(inode));
+    return 0;
+}
+
+// 文件释放操作
+static int power_release(struct inode *inode, struct file *filp)
+{
+    // release_region(PORT_80, 1);
+    printk(KERN_INFO "power: Device closed\n");
+    return 0;
+}
+
+// 读操作 - 支持cat命令
+static ssize_t power_read(struct file *filp, char __user *buf,
+                             size_t count, loff_t *f_pos)
+{
+    struct power_dev *dev = filp->private_data;
+    ssize_t retval = 0;
+    size_t available;
+    int read_count = 0;
+    int ret = 0;
+
+    if (mutex_lock_interruptible(&dev->lock))
+        return -ERESTARTSYS;
+
+    // 这里read_count没有固定为4个字节，是为了便于后续扩展
+    if (count > dev->size)
+    {
+        read_count = dev->size;
+    }
+    else
+    {
+        read_count = count;
+    }
+    ret = copy_to_user(buf, dev->buffer, read_count);
+    if (ret != 0)
+    {
+        printk(KERN_INFO "power: copy_to_user failed\n");
+        goto out;
+    }
+
+    printk(KERN_INFO "power: Read %zu bytes\n", count);
+
+out:
+    mutex_unlock(&dev->lock);
+    return ret;
+}
+
+// 写操作
+static ssize_t power_write(struct file *filp, const char __user *buf,
+                              size_t count, loff_t *f_pos)
+{
+    struct power_dev *dev = filp->private_data;
+    ssize_t retval = 0;
+    size_t available;
+    int ret = 0;
+
+    // 加锁
+    if (mutex_lock_interruptible(&dev->lock))
+    {
+        return -ERESTARTSYS;
+    }
+
+    // 计算可写数据量
+    if (count > BUFFER_SIZE)
+    {
+        count = BUFFER_SIZE;
+    }
+
+    // 拷贝数据
+    ret = copy_from_user(dev->buffer, buf, count);
+    if (ret != 0)
+    {
+        printk(KERN_INFO "power: copy_from_user failed\n");
+        goto out;
+    }
+
+    dev->size = count;
+
+    printk(KERN_INFO "power: Written %zu bytes\n", count);
+
+out:
+    mutex_unlock(&dev->lock);
+
+    // 调度延迟工作
+    if (ret == 0)
+    {
+        schedule_delayed_work(&dev->delay_work1, msecs_to_jiffies(10));
+    }
+    return count;
+}
+
+static unsigned int power_poll(struct file *filp, poll_table *wait)
+{
+    // poll_wait(filp, &dev->read_wait, wait);
+    return 0;
+}
+
+// 文件操作结构体
+static struct file_operations fops = {
+    .owner = THIS_MODULE,
+    .open = power_open,
+    .release = power_release,
+    .read = power_read,
+    .write = power_write,
+    .poll = power_poll,
+};
+
+// 模块初始化
+int power_init(void)
+{
+    int result;
+
+    printk(KERN_INFO "power: Initializing driver with major=%d, minor=%d\n",
+           power_major, power_minor);
+
+    // 检查主设备号是否有效
+    if (power_major <= 0)
+    {
+        printk(KERN_ALERT "power: Invalid major number %d\n", power_major);
+        return -EINVAL;
+    }
+
+    // 构建设备号
+    dev_num = MKDEV(power_major, power_minor);
+
+    // 注册设备号 - 使用指定的主设备号
+    result = register_chrdev_region(dev_num, 1, DEVICE_NAME);
+    if (result < 0)
+    {
+        printk(KERN_ALERT "power: Failed to register major number %d\n", power_major);
+        printk(KERN_ALERT "power: Try using a different major number\n");
+        return result;
+    }
+
+    printk(KERN_INFO "power: Registered with major=%d, minor=%d\n",
+           MAJOR(dev_num), MINOR(dev_num));
+
+    // 分配设备结构体
+    dev = kmalloc(sizeof(struct power_dev), GFP_KERNEL);
+    if (!dev)
+    {
+        result = -ENOMEM;
+        goto fail_malloc;
+    }
+    memset(dev, 0, sizeof(struct power_dev));
+    init_waitqueue_head(&dev->read_wait);
+
+    // 分配缓冲区
+    dev->buffer = kmalloc(BUFFER_SIZE, GFP_KERNEL);
+    if (!dev->buffer)
+    {
+        result = -ENOMEM;
+        goto fail_buffer;
+    }
+
+    // 初始化互斥锁
+    mutex_init(&dev->lock);
+
+    INIT_DELAYED_WORK(&dev->delay_work1, delay_work_func);
+
+    // 初始化字符设备
+    cdev_init(&dev->cdev, &fops);
+    dev->cdev.owner = THIS_MODULE;
+
+    // 添加字符设备到系统
+    result = cdev_add(&dev->cdev, dev_num, 1);
+    if (result)
+    {
+        printk(KERN_ALERT "power: Failed to add cdev\n");
+        goto fail_cdev;
+    }
+
+    // 创建设备类
+    char_class = class_create(THIS_MODULE, CLASS_NAME);
+    if (IS_ERR(char_class))
+    {
+        result = PTR_ERR(char_class);
+        printk(KERN_ALERT "power: Failed to create class\n");
+        goto fail_class;
+    }
+
+    // 创建设备
+    char_device = device_create(char_class, NULL, dev_num, NULL, DEVICE_NAME);
+    if (IS_ERR(char_device))
+    {
+        result = PTR_ERR(char_device);
+        printk(KERN_ALERT "power: Failed to create device\n");
+        goto fail_device;
+    }
+
+    printk(KERN_INFO "power: Driver initialized successfully\n");
+    printk(KERN_INFO "power: Device node: /dev/%s (major=%d, minor=%d)\n",
+           DEVICE_NAME, power_major, power_minor);
+    return 0;
+
+fail_device:
+    class_destroy(char_class);
+fail_class:
+    cdev_del(&dev->cdev);
+fail_cdev:
+    kfree(dev->buffer);
+fail_buffer:
+    kfree(dev);
+fail_malloc:
+    unregister_chrdev_region(dev_num, 1);
+    return result;
+}
+
+// 模块退出
+void power_exit(void)
+{
+    cancel_delayed_work_sync(&dev->delay_work1);
+    device_destroy(char_class, dev_num);
+    class_destroy(char_class);
+
+    if (dev)
+    {
+        cdev_del(&dev->cdev);
+        if (dev->buffer)
+            kfree(dev->buffer);
+        kfree(dev);
+    }
+
+    unregister_chrdev_region(dev_num, 1);
+    printk(KERN_INFO "power: Driver removed (major=%d, minor=%d)\n",
+           power_major, power_minor);
+}

power.h

@@ -0,0 +1,7 @@
+#ifndef __POWER_INTERFACE_H__
+#define __POWER_INTERFACE_H__
+
+int power_init(void);
+int power_exit(void);
+
+#endif