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1
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#include <fcntl.h>
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2
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#include <linux/gpio.h>
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3
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#include <sys/ioctl.h>
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4
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5
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#include <cerrno>
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6
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#include <chrono>
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7
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#include <cstring>
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8
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#include <iostream>
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9
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#include <thread>
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10
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11
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static constexpr auto s_which_gpio_chip = "/dev/gpiochip2";
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12
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static constexpr auto s_which_gpio_line = 10;
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13
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14
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int main()
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15
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{
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16
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int chip_fd = open(s_which_gpio_chip, O_RDWR);
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17
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if (chip_fd < 0)
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18
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{
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19
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std::cout << "failed to open gpio chip: " << strerror(errno) << std::endl;
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20
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return -1;
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21
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}
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22
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23
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gpio_v2_line_request request{};
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24
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request.num_lines = 1;
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25
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request.offsets[0] = s_which_gpio_line;
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26
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request.event_buffer_size = 16;
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27
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request.config.num_attrs = 0;
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28
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request.config.flags = GPIO_V2_LINE_FLAG_OUTPUT;
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29
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30
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if (ioctl(chip_fd, GPIO_V2_GET_LINE_IOCTL, &request) != 0)
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31
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{
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32
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std::cout << "GPIO_V2_GET_LINE_IOCTL failed: " << strerror(errno) << std::endl;
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33
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return -2;
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34
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}
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35
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36
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int line_fd = request.fd;
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37
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if (line_fd < 0)
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38
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{
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39
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std::cout << "GPIO_V2_GET_LINE_IOCTL returned unexpected fd: " << line_fd << std::endl;
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40
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return -3;
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41
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}
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42
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43
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for (;;)
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44
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{
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45
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// set pin active
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46
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std::cout << "setting pin to ACTIVE!" << std::endl;
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47
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gpio_v2_line_values values_1{.bits = 1u, .mask = 1u};
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48
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if (ioctl(line_fd, GPIO_V2_LINE_SET_VALUES_IOCTL, &values_1) != 0)
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49
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{
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50
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std::cout << "GPIO_V2_LINE_SET_VALUES_IOCTL failed: " << strerror(errno) << std::endl;
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51
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return -4;
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52
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}
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53
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54
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// read pin state
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55
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gpio_v2_line_values confirm_values_1{.bits = 0u, .mask = 1u};
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56
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if (ioctl(line_fd, GPIO_V2_LINE_GET_VALUES_IOCTL, &confirm_values_1) != 0)
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57
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{
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58
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std::cout << "GPIO_V2_LINE_GET_VALUES_IOCTL failed: " << strerror(errno) << std::endl;
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59
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return -5;
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60
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}
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61
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std::cout << "confirming pin state as " << ((confirm_values_1.bits & 1u) ? "ACTIVE" : "INACTIVE") << "!"
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62
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<< std::endl;
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63
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64
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std::this_thread::sleep_for(std::chrono::seconds(5));
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65
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66
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// set pin inactive
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67
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std::cout << "setting pin to INACTIVE!" << std::endl;
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68
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gpio_v2_line_values values_2{.bits = 0u, .mask = 1u};
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69
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if (ioctl(line_fd, GPIO_V2_LINE_SET_VALUES_IOCTL, &values_2) != 0)
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70
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{
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71
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std::cout << "GPIO_V2_LINE_SET_VALUES_IOCTL failed: " << strerror(errno) << std::endl;
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72
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return -4;
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73
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}
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74
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75
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// read pin state
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76
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gpio_v2_line_values confirm_values_2{.bits = 0u, .mask = 1u};
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77
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if (ioctl(line_fd, GPIO_V2_LINE_GET_VALUES_IOCTL, &confirm_values_2) != 0)
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78
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{
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79
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std::cout << "GPIO_V2_LINE_GET_VALUES_IOCTL failed: " << strerror(errno) << std::endl;
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80
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return -5;
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81
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}
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82
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std::cout << "confirming pin state as " << ((confirm_values_2.bits & 1u) ? "ACTIVE" : "INACTIVE") << "!"
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83
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<< std::endl;
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84
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85
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std::this_thread::sleep_for(std::chrono::seconds(5));
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86
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}
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87
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}
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88
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