1 #pragma once 2 3 #include <chrono> 4 #include <exception> 5 #include <fstream> 6 #include <string> 7 8 namespace sysfs { 9 10 inline std::string make_sysfs_path(const std::string& path, 11 const std::string& type, 12 const std::string& id, 13 const std::string& entry) 14 { 15 using namespace std::literals; 16 17 return path + "/"s + type + id + "_"s + entry; 18 } 19 20 /** @brief Return the path to the phandle file matching value in io-channels. 21 * 22 * This function will take two passed in paths. 23 * One path is used to find the io-channels file. 24 * The other path is used to find the phandle file. 25 * The 4 byte phandle value is read from the phandle file(s). 26 * The 4 byte phandle value and 4 byte index value is read from io-channels. 27 * When a match is found, the path to the matching phandle file is returned. 28 * 29 * @param[in] iochanneldir - Path to file for getting phandle from io-channels 30 * @param[in] phandledir - Path to use for reading from phandle file 31 * 32 * @return Path to phandle file with value matching that in io-channels 33 */ 34 std::string findPhandleMatch( 35 const std::string& iochanneldir, 36 const std::string& phandledir); 37 38 /** @brief Find hwmon instances 39 * 40 * Look for a matching hwmon instance given an 41 * open firmware device path. 42 * 43 * @param[in] ofNode- The open firmware device path. 44 * 45 * @returns[in] - The hwmon instance path or an empty 46 * string if no match is found. 47 */ 48 std::string findHwmon(const std::string& ofNode); 49 50 /** @brief Return the path to use for a call out. 51 * 52 * Return an empty string if a callout path cannot be 53 * found. 54 * 55 * @param[in] instancePath - /sys/class/hwmon/hwmon<N> path. 56 * 57 * @return Path to use for call out 58 */ 59 std::string findCalloutPath(const std::string& instancePath); 60 61 namespace hwmonio 62 { 63 static constexpr auto retries = 10; 64 static constexpr auto delay = std::chrono::milliseconds{100}; 65 66 /** @class HwmonIO 67 * @brief Convenience wrappers for HWMON sysfs attribute IO. 68 * 69 * Unburden the rest of the application from having to check 70 * ENOENT after every hwmon attribute io operation. Hwmon 71 * device drivers can be unbound at any time; the program 72 * cannot always be terminated externally before we try to 73 * do an io. 74 */ 75 class HwmonIO 76 { 77 public: 78 HwmonIO() = delete; 79 HwmonIO(const HwmonIO&) = default; 80 HwmonIO(HwmonIO&&) = default; 81 HwmonIO& operator=(const HwmonIO&) = default; 82 HwmonIO& operator=(HwmonIO&&) = default; 83 ~HwmonIO() = default; 84 85 /** @brief Constructor 86 * 87 * @param[in] path - hwmon instance root - eg: 88 * /sys/class/hwmon/hwmon<N> 89 */ 90 explicit HwmonIO(const std::string& path); 91 92 /** @brief Perform formatted hwmon sysfs read. 93 * 94 * Propogates any exceptions other than ENOENT. 95 * ENOENT will result in a call to exit(0) in case 96 * the underlying hwmon driver is unbound and 97 * the program is inadvertently left running. 98 * 99 * For possibly transient errors will retry up to 100 * the specified number of times. 101 * 102 * @param[in] type - The hwmon type (ex. temp). 103 * @param[in] id - The hwmon id (ex. 1). 104 * @param[in] sensor - The hwmon sensor (ex. input). 105 * @param[in] retries - The number of times to retry. 106 * @param[in] delay - The time to sleep between retry attempts. 107 * 108 * @return val - The read value. 109 */ 110 uint32_t read( 111 const std::string& type, 112 const std::string& id, 113 const std::string& sensor, 114 size_t retries, 115 std::chrono::milliseconds delay) const; 116 117 /** @brief Perform formatted hwmon sysfs write. 118 * 119 * Propogates any exceptions other than ENOENT. 120 * ENOENT will result in a call to exit(0) in case 121 * the underlying hwmon driver is unbound and 122 * the program is inadvertently left running. 123 * 124 * For possibly transient errors will retry up to 125 * the specified number of times. 126 * 127 * @param[in] val - The value to be written. 128 * @param[in] type - The hwmon type (ex. fan). 129 * @param[in] id - The hwmon id (ex. 1). 130 * @param[in] retries - The number of times to retry. 131 * @param[in] delay - The time to sleep between retry attempts. 132 */ 133 void write( 134 uint32_t val, 135 const std::string& type, 136 const std::string& id, 137 const std::string& sensor, 138 size_t retries, 139 std::chrono::milliseconds delay) const; 140 141 142 /** @brief Hwmon instance path access. 143 * 144 * @return path - The hwmon instance path. 145 */ 146 std::string path() const; 147 148 private: 149 std::string p; 150 }; 151 } // namespace hwmonio 152 } 153 154 // vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4 155