121 lines
2.7 KiB
C
121 lines
2.7 KiB
C
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/fs.h>
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#include <linux/delay.h>
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#include <linux/poll.h>
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#include <linux/mutex.h>
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#include <linux/wait.h>
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#include <linux/uaccess.h>
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#include <asm/io.h>
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#include <linux/device.h>
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static int major;
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static struct class *led_class;
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/* registers */
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// RCC_PLL4CR地址：0x50000000 + 0x894
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static volatile unsigned int *RCC_PLL4CR;
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// RCC_MP_AHB4ENSETR 地址：0x50000000 + 0xA28
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static volatile unsigned int *RCC_MP_AHB4ENSETR;
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// GPIOA_MODER 地址：0x50002000 + 0x00
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static volatile unsigned int *GPIOA_MODER;
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// GPIOA_BSRR 地址： 0x50002000 + 0x18
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static volatile unsigned int *GPIOA_BSRR;
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static ssize_t led_write(struct file *filp, const char __user *buf,
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size_t count, loff_t *ppos)
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{
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char val;
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/* copy_from_user : get data from app */
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copy_from_user(&val, buf, 1);
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/* to set gpio register: out 1/0 */
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if (val)
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{
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/* set gpa10 to let led on */
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*GPIOA_BSRR = (1<<26);
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}
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else
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{
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/* set gpa10 to let led off */
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*GPIOA_BSRR = (1<<10);
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}
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return 1;
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}
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static int led_open(struct inode *inode, struct file *filp)
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{
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/* enalbe PLL4, it is clock source for all gpio */
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*RCC_PLL4CR |= (1<<0);
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while ((*RCC_PLL4CR & (1<<1)) == 0);
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/* enable gpioA */
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*RCC_MP_AHB4ENSETR |= (1<<0);
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/*
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* configure gpa10 as gpio
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* configure gpio as output
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*/
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*GPIOA_MODER &= ~(3<<20);
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*GPIOA_MODER |= (1<<20);
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return 0;
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}
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static struct file_operations led_fops = {
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.owner = THIS_MODULE,
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.write = led_write,
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.open = led_open,
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};
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/* 入口函数 */
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static int __init led_init(void)
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{
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printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
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major = register_chrdev(0, "100ask_led", &led_fops);
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/* ioremap(base_phy, size); */
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// RCC_PLL4CR地址：0x50000000 + 0x894
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RCC_PLL4CR = ioremap(0x50000000 + 0x894, 4);
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// RCC_MP_AHB4ENSETR 地址：0x50000000 + 0xA28
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RCC_MP_AHB4ENSETR = ioremap(0x50000000 + 0xA28, 4);
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// GPIOA_MODER 地址：0x50002000 + 0x00
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GPIOA_MODER = ioremap(0x50002000 + 0x00, 4);
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// GPIOA_BSRR 地址： 0x50002000 + 0x18
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GPIOA_BSRR = ioremap(0x50002000 + 0x18, 4);
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led_class = class_create(THIS_MODULE, "myled");
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device_create(led_class, NULL, MKDEV(major, 0), NULL, "myled"); /* /dev/myled */
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return 0;
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}
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static void __exit led_exit(void)
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{
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iounmap(RCC_PLL4CR);
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iounmap(RCC_MP_AHB4ENSETR);
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iounmap(GPIOA_MODER);
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iounmap(GPIOA_BSRR);
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device_destroy(led_class, MKDEV(major, 0));
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class_destroy(led_class);
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unregister_chrdev(major, "100ask_led");
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}
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module_init(led_init);
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module_exit(led_exit);
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MODULE_LICENSE("GPL");
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