1 /*
2 * Copyright (c) 2011-2023, Shanghai Real-Thread Electronic Technology Co.,Ltd
3 *
4 * Change Logs:
5 * Date Author Notes
6 * 2020-12-03 quanzhao the first version
7 */
8
9 #include <time.h>
10 #include <string.h>
11 #include <rtthread.h>
12
13 static struct rt_device zero_dev;
14
zero_read(rt_device_t dev,rt_off_t pos,void * buffer,rt_size_t size)15 static rt_ssize_t zero_read (rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size)
16 {
17 rt_memset(buffer, 0, size);
18 return size;
19 }
20
zero_write(rt_device_t dev,rt_off_t pos,const void * buffer,rt_size_t size)21 static rt_ssize_t zero_write (rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size)
22 {
23 return size;
24 }
25
zero_control(rt_device_t dev,int cmd,void * args)26 static rt_err_t zero_control (rt_device_t dev, int cmd, void *args)
27 {
28 return RT_EOK;
29 }
30
31 #ifdef RT_USING_DEVICE_OPS
32 const static struct rt_device_ops zero_ops =
33 {
34 RT_NULL,
35 RT_NULL,
36 RT_NULL,
37 zero_read,
38 zero_write,
39 zero_control
40 };
41 #endif
42
zero_device_init(void)43 int zero_device_init(void)
44 {
45 static rt_bool_t init_ok = RT_FALSE;
46
47 if (init_ok)
48 {
49 return 0;
50 }
51 RT_ASSERT(!rt_device_find("zero"));
52 zero_dev.type = RT_Device_Class_Miscellaneous;
53
54 #ifdef RT_USING_DEVICE_OPS
55 zero_dev.ops = &zero_ops;
56 #else
57 zero_dev.init = RT_NULL;
58 zero_dev.open = RT_NULL;
59 zero_dev.close = RT_NULL;
60 zero_dev.read = zero_read;
61 zero_dev.write = zero_write;
62 zero_dev.control = zero_control;
63 #endif
64
65 /* no private */
66 zero_dev.user_data = RT_NULL;
67
68 rt_device_register(&zero_dev, "zero", RT_DEVICE_FLAG_RDWR);
69
70 init_ok = RT_TRUE;
71
72 return 0;
73 }
74 INIT_DEVICE_EXPORT(zero_device_init);
75
76