1 #pragma once 2 3 #include "file_descriptor.hpp" 4 5 #include <linux/gpio.h> 6 7 #include <string> 8 #include <type_traits> 9 10 namespace phosphor 11 { 12 namespace gpio 13 { 14 15 typedef std::remove_reference<decltype( 16 gpiohandle_request::lineoffsets[0])>::type gpioNum_t; 17 18 typedef std::remove_reference<decltype(gpiohandle_data::values[0])>::type 19 gpioValue_t; 20 21 /** 22 * If the GPIO is an input or output 23 */ 24 enum class Direction 25 { 26 input, 27 output 28 }; 29 30 /** 31 * The possible values - low or high 32 */ 33 enum class Value 34 { 35 low, 36 high 37 }; 38 39 /** 40 * Represents a GPIO. 41 * 42 * Currently supports reading a GPIO. 43 * 44 * Write support may be added in the future. 45 */ 46 class GPIO 47 { 48 public: 49 GPIO() = delete; 50 GPIO(const GPIO&) = delete; 51 GPIO(GPIO&&) = default; 52 GPIO& operator=(const GPIO&) = delete; 53 GPIO& operator=(GPIO&&) = default; 54 ~GPIO() = default; 55 56 /** 57 * Constructor 58 * 59 * @param[in] device - the GPIO device file 60 * @param[in] gpio - the GPIO number 61 * @param[in] direction - the GPIO direction 62 */ 63 GPIO(const std::string& device, gpioNum_t gpio, Direction direction) : 64 device(device), gpio(gpio), direction(direction) 65 { 66 } 67 68 /** 69 * Reads the GPIO value 70 * 71 * Requests the GPIO line if it hasn't been done already. 72 * 73 * @return Value - the GPIO value 74 */ 75 Value read(); 76 77 /** 78 * Sets the GPIO value to low or high 79 * 80 * Requests the GPIO line if it hasn't been done already. 81 * 82 * @param[in] Value - the value to set 83 */ 84 void set(Value value); 85 86 private: 87 /** 88 * Requests a GPIO line from the GPIO device 89 * 90 * @param[in] defaultValue - The default value, required for 91 * output GPIOs only. 92 */ 93 void requestLine(Value defaultValue = Value::high); 94 95 /** 96 * The GPIO device name, like /dev/gpiochip0 97 */ 98 const std::string device; 99 100 /** 101 * The GPIO number 102 */ 103 const gpioNum_t gpio; 104 105 /** 106 * The GPIO direction 107 */ 108 const Direction direction; 109 110 /** 111 * File descriptor for the GPIO line 112 */ 113 power::util::FileDescriptor lineFD; 114 }; 115 116 } // namespace gpio 117 } // namespace phosphor 118