驱动程序
1 #include <linux/module.h>
2 #include <linux/kernel.h>
3 #include <linux/fs.h>
4 #include <linux/init.h>
5 #include <linux/delay.h>
6 #include <linux/irq.h>
7 #include <asm/uaccess.h>
8 #include <asm/irq.h>
9 #include <asm/io.h>
10 #include <asm/arch/regs-gpio.h>
11 #include <asm/hardware.h>
12 #include <linux/poll.h>
13
14 #define DEVICE_NAME "key_dev3" /* 加载模式后，执行”cat /proc/devices”命令看到的设备名称 */
15
16 static struct class *key_class;
17 static struct class_device *key_class_dev;
18
19 volatile unsigned long *gpfcon;
20 volatile unsigned long *gpfdat;
21
22 volatile unsigned long *gpgcon;
23 volatile unsigned long *gpgdat;
24
25 /* 创建以个等待队列头 */
26 static DECLARE_WAIT_QUEUE_HEAD(key_waitq);
27
28 /* 中断事件标志, 中断服务程序将它置1，third_drv_read将它清0 */
29 static volatile int ev_press = 0;
30
31 struct pin_desc{
32 unsigned int pin;
33 unsigned int key_val;
34 };
35 /* 键值: 按下时, 0x01, 0x02, 0x03, 0x04 */
36 /* 键值: 松开时, 0x81, 0x82, 0x83, 0x84 */
37 static unsigned char key_val;
38
39 struct pin_desc pins_desc[4] = {
40 {S3C2410_GPF0, 0x01},
41 {S3C2410_GPF2, 0x02},
42 {S3C2410_GPG3, 0x03},
43 {S3C2410_GPG11, 0x04},
44 };
45
46 /*
47 * 确定按键值
48 */
49 static irqreturn_t keys_irq(int irq, void *dev_id)
50 {
51 struct pin_desc * pindesc = (struct pin_desc *)dev_id;
52 unsigned int pinval;
53
54 pinval = s3c2410_gpio_getpin(pindesc->pin);
55
56 if (pinval)
57 {
58 /* 松开 */
59 key_val = 0x80 | pindesc->key_val;
60 }
61 else
62 {
63 /* 按下 */
64 key_val = pindesc->key_val;
65 }
66
67 ev_press = 1; /* 表示中断发生了 */
68 wake_up_interruptible(&key_waitq); /* 唤醒休眠的进程 */
69 return IRQ_RETVAL(IRQ_HANDLED);
70 }
71
72 static int key_dev3_open(struct inode *inode, struct file *file)
73 {
74 /* 配置GPF0,2为输入引脚 */
75 /* 配置GPG3,11为输入引脚 */
76 request_irq(IRQ_EINT0, keys_irq, IRQT_BOTHEDGE, "S2", &pins_desc[0]);
77 request_irq(IRQ_EINT2, keys_irq, IRQT_BOTHEDGE, "S3", &pins_desc[1]);
78 request_irq(IRQ_EINT11, keys_irq, IRQT_BOTHEDGE, "S4", &pins_desc[2]);
79 request_irq(IRQ_EINT19, keys_irq, IRQT_BOTHEDGE, "S5", &pins_desc[3]);
80
81 return 0;
82 }
83
84 ssize_t key_dev3_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
85 {
86 if (size != 1)
87 return -EINVAL;
88
89 /* 如果没有按键动作, 休眠 */
90 wait_event_interruptible(key_waitq, ev_press);
91
92 /* 如果有按键动作, 返回键值 */
93 copy_to_user(buf, &key_val, 1);
94 ev_press = 0;
95 return 1;
96 }
97
98 int key_dev3_close(struct inode *inode, struct file *file)
99 {
100 free_irq(IRQ_EINT0, &pins_desc[0]);
101 free_irq(IRQ_EINT2, &pins_desc[1]);
102 free_irq(IRQ_EINT11, &pins_desc[2]);
103 free_irq(IRQ_EINT19, &pins_desc[3]);
104 return 0;
105 }
106
107 static unsigned key_dev3_poll(struct file *file, poll_table *wait)
108 {
109 unsigned int mask = 0;
110 poll_wait(file,&key_waitq,wait);
111 if (ev_press)
112 mask |= POLLIN | POLLRDNORM;
113
114 return mask;
115 }
116
117 static struct file_operations sencod_drv_fops = {
118 .owner = THIS_MODULE, /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */
119 .open = key_dev3_open,
120 .read = key_dev3_read,
121 .release = key_dev3_close,
122 .poll = key_dev3_poll,
123
124 };
125
126 int major;
127 static int key_drv_init(void)
128 {
129 major = register_chrdev(0, DEVICE_NAME, &sencod_drv_fops);
130
131 key_class = class_create(THIS_MODULE, DEVICE_NAME);
132
133 key_class_dev = class_device_create(key_class, NULL, MKDEV(major, 0), NULL, DEVICE_NAME); /* /dev/keys */
134
135 gpfcon = (volatile unsigned long *)ioremap(0x56000050, 16);
136 gpfdat = gpfcon + 1;
137
138 gpgcon = (volatile unsigned long *)ioremap(0x56000060, 16);
139 gpgdat = gpgcon + 1;
140
141 return 0;
142 }
143
144 static void key_drv_exit(void)
145 {
146 unregister_chrdev(major, DEVICE_NAME);
147 class_device_unregister(key_class_dev);
148 class_destroy(key_class);
149 iounmap(gpfcon);
150 iounmap(gpgcon);
151 return 0;
152 }
153
154 module_init(key_drv_init);
155
156 module_exit(key_drv_exit);
157
158 MODULE_LICENSE("GPL");
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测试程序
1 #include <sys/types.h>
2 #include <sys/stat.h>
3 #include <fcntl.h>
4 #include <stdio.h>
5 #include <poll.h>
6
7 /* thirddrvtest
8 */
9 int main(int argc, char **argv)
10 {
11 int fd;
12 unsigned char key_val;
13 int ret;
14
15 struct pollfd fds[1];
16
17 fd = open("/dev/key_dev3", O_RDWR);
18 if (fd < 0)
19 {
20 printf("can't open!\n");
21 }
22
23 fds[0].fd = fd;
24 fds[0].events = POLLIN;
25 while (1)
26 {
27 ret = poll(fds, 1, 5000);
28 if (ret == 0)
29 {
30 printf("time out\n");
31 }
32 else
33 {
34 read(fd, &key_val, 1);
35 printf("key_val = 0x%x\n", key_val);
36 }
37 }
38
39 return 0;
40 }
View Code