#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
static int ab_system_status_value = 0;
static int ab_sync_status_value = 0;
static int ota_status_value = 0;
// ab_system_status节点读写
static ssize_t ab_system_status_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
char buffer[32];
int len = snprintf(buffer, sizeof(buffer), “%d\n”, ab_system_status_value);
return simple_read_from_buffer(buf, count, ppos, buffer, len);
}
static ssize_t ab_system_status_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
char input[32];
int value;
if (count > sizeof(input) - 1) return -EINVAL; if (copy_from_user(input, buf, count)) return -EFAULT; input[count] = '\0'; if (sscanf(input, "%d", &value) == 1) { ab_system_status_value = value; return count; } return -EINVAL;
}
// ab_sync_status节点读写
static ssize_t ab_sync_status_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
char buffer[32];
int len = snprintf(buffer, sizeof(buffer), “%d\n”, ab_sync_status_value);
return simple_read_from_buffer(buf, count, ppos, buffer, len);
}
static ssize_t ab_sync_status_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
char input[32];
int value;
if (count > sizeof(input) - 1) return -EINVAL; if (copy_from_user(input, buf, count)) return -EFAULT; input[count] = '\0'; if (sscanf(input, "%d", &value) == 1) { ab_sync_status_value = value; return count; } return -EINVAL;
}
// ota_status节点读写
static ssize_t ota_status_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
char buffer[32];
int len = snprintf(buffer, sizeof(buffer), “%d\n”, ota_status_value);
return simple_read_from_buffer(buf, count, ppos, buffer, len);
}
static ssize_t ota_status_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
{
char input[32];
int value;
if (count > sizeof(input) - 1) return -EINVAL; if (copy_from_user(input, buf, count)) return -EFAULT; input[count] = '\0'; if (sscanf(input, "%d", &value) == 1) { ota_status_value = value; return count; } return -EINVAL;
}
// proc节点操作结构体
static const struct proc_ops ab_system_status_ops = {
.proc_read = ab_system_status_read,
.proc_write = ab_system_status_write,
};
static const struct proc_ops ab_sync_status_ops = {
.proc_read = ab_sync_status_read,
.proc_write = ab_sync_status_write,
};
static const struct proc_ops ota_status_ops = {
.proc_read = ota_status_read,
.proc_write = ota_status_write,
};
// 设备树匹配表
static const struct of_device_id fibo_ab_ota_of_match[] = {
{ .compatible = “fibocom,fibo_ab_ota”, },
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, fibo_ab_ota_of_match);
// probe函数
static int fibo_ab_ota_probe(struct platform_device *pdev)
{
int ret;
pr_info("fibo_ab_ota_probe called\n"); if (!proc_create("ab_system_status", 0664, NULL, &ab_system_status_ops)) { pr_err("Failed to create ab_system_status proc entry\n"); return -ENOMEM; } if (!proc_create("ab_sync_status", 0664, NULL, &ab_sync_status_ops)) { pr_err("Failed to create ab_sync_status proc entry\n"); remove_proc_entry("ab_system_status", NULL); return -ENOMEM; } if (!proc_create("ota_status", 0664, NULL, &ota_status_ops)) { pr_err("Failed to create ota_status proc entry\n"); remove_proc_entry("ab_system_status", NULL); remove_proc_entry("ab_sync_status", NULL); return -ENOMEM; } return 0;
}
// remove函数
static int fibo_ab_ota_remove(struct platform_device *pdev)
{
pr_info(“fibo_ab_ota_remove called\n”);
remove_proc_entry(“ab_system_status”, NULL);
remove_proc_entry(“ab_sync_status”, NULL);
remove_proc_entry(“ota_status”, NULL);
return 0;
}
// 平台驱动结构体
static struct platform_driver fibo_ab_ota_driver = {
.probe = fibo_ab_ota_probe,
.remove = fibo_ab_ota_remove,
.driver = {
.name = “fibo_ab_ota”,
.owner = THIS_MODULE,
.of_match_table = fibo_ab_ota_of_match,
},
};
static int __init fibo_ab_ota_init(void)
{
return platform_driver_register(&fibo_ab_ota_driver);
}
static void __exit fibo_ab_ota_exit(void)
{
platform_driver_unregister(&fibo_ab_ota_driver);
}
module_init(fibo_ab_ota_init);
module_exit(fibo_ab_ota_exit);
MODULE_DESCRIPTION(“fibo ab ota Module”);
MODULE_AUTHOR(“qujunyang”);
MODULE_LICENSE(“GPL”);
检查驱动代码是否存在问题，不要gpio功能
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这篇博客介绍了内核编程中，除了使用copy_to_user和copy_from_user之外，如何利用simple_read_from_buffer和simple_write_to_buffer进行简单读写操作。文章以GPIO读取为例，阐述了这两个函数在内核与用户空间交互过程中的应用。
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