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| #include <linux/init.h>
#include <linux/module.h>
#include <linux/gpio.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/delay.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/uaccess.h>
#define LED_GPIO 20
#define DEVICE_NAME "rk3588_led"
#define DEVICE_CLASS "led_class"
static int led_gpio = -1;
static int major_number;
static struct class *led_class = NULL;
static struct device *led_device = NULL;
static int led_open(struct inode *, struct file *);
static int led_release(struct inode *, struct file *);
static ssize_t led_write(struct file *, const char __user *, size_t, loff_t *);
static struct file_operations fops = {
.owner = THIS_MODULE,
.open = led_open,
.release = led_release,
.write = led_write,
};
static int led_open(struct inode *inodep, struct file *filep)
{
printk(KERN_INFO "LED device opened\n");
return 0;
}
static int led_release(struct inode *inodep, struct file *filep)
{
printk(KERN_INFO "LED device closed\n");
return 0;
}
static ssize_t led_write(struct file *filep, const char __user *buf, size_t len, loff_t *off)
{
char kbuf[2];
if (copy_from_user(kbuf, buf, len > 1 ? 1 : len) != 0) {
printk(KERN_ERR "Failed to copy data from user\n");
return -EFAULT;
}
if (kbuf[0] == '1') {
gpio_set_value(led_gpio, 1);
printk(KERN_INFO "LED turned ON\n");
} else if (kbuf[0] == '0') {
gpio_set_value(led_gpio, 0);
printk(KERN_INFO "LED turned OFF\n");
} else {
printk(KERN_WARNING "Invalid input. Use '1' to turn ON, '0' to turn OFF\n");
return -EINVAL;
}
return len;
}
static int __init led_init(void)
{
int ret;
ret = gpio_request(LED_GPIO, "led_gpio");
if (ret < 0) {
printk(KERN_ERR "Failed to request GPIO %d\n", LED_GPIO);
return ret;
}
ret = gpio_direction_output(LED_GPIO, 0);
if (ret < 0) {
printk(KERN_ERR "Failed to set GPIO direction\n");
gpio_free(LED_GPIO);
return ret;
}
led_gpio = LED_GPIO;
major_number = register_chrdev(0, DEVICE_NAME, &fops);
if (major_number < 0) {
printk(KERN_ERR "Failed to register character device\n");
gpio_free(led_gpio);
return major_number;
}
led_class = class_create(DEVICE_CLASS);
if (IS_ERR(led_class)) {
printk(KERN_ERR "Failed to create device class\n");
unregister_chrdev(major_number, DEVICE_NAME);
gpio_free(led_gpio);
return PTR_ERR(led_class);
}
led_device = device_create(led_class, NULL, MKDEV(major_number, 0), NULL, DEVICE_NAME);
if (IS_ERR(led_device)) {
printk(KERN_ERR "Failed to create device\n");
class_destroy(led_class);
unregister_chrdev(major_number, DEVICE_NAME);
gpio_free(led_gpio);
return PTR_ERR(led_device);
}
printk(KERN_INFO "LED driver initialized\n");
printk(KERN_INFO "Device created at /dev/%s\n", DEVICE_NAME);
return 0;
}
static void __exit led_exit(void)
{
if (led_gpio >= 0) {
gpio_set_value(led_gpio, 0);
gpio_free(led_gpio);
}
device_destroy(led_class, MKDEV(major_number, 0));
class_destroy(led_class);
unregister_chrdev(major_number, DEVICE_NAME);
printk(KERN_INFO "LED driver unloaded\n");
}
module_init(led_init);
module_exit(led_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Your Name");
MODULE_DESCRIPTION("RK3588 LED driver with character device interface");
|