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 if (entry.empty()) { 18 return path + "/"s + type + id; 19 } 20 21 return path + "/"s + type + id + "_"s + entry; 22 } 23 24 /** @brief Return the path to the phandle file matching value in io-channels. 25 * 26 * This function will take two passed in paths. 27 * One path is used to find the io-channels file. 28 * The other path is used to find the phandle file. 29 * The 4 byte phandle value is read from the phandle file(s). 30 * The 4 byte phandle value and 4 byte index value is read from io-channels. 31 * When a match is found, the path to the matching phandle file is returned. 32 * 33 * @param[in] iochanneldir - Path to file for getting phandle from io-channels 34 * @param[in] phandledir - Path to use for reading from phandle file 35 * 36 * @return Path to phandle file with value matching that in io-channels 37 */ 38 std::string findPhandleMatch( 39 const std::string& iochanneldir, 40 const std::string& phandledir); 41 42 /** @brief Find hwmon instances from an open-firmware device tree path 43 * 44 * Look for a matching hwmon instance given an 45 * open firmware device path. 46 * 47 * @param[in] ofNode- The open firmware device path. 48 * 49 * @returns[in] - The hwmon instance path or an empty 50 * string if no match is found. 51 */ 52 std::string findHwmonFromOFPath(const std::string& ofNode); 53 54 /** @brief Return the path to use for a call out. 55 * 56 * Return an empty string if a callout path cannot be 57 * found. 58 * 59 * @param[in] instancePath - /sys/class/hwmon/hwmon<N> path. 60 * 61 * @return Path to use for call out 62 */ 63 std::string findCalloutPath(const std::string& instancePath); 64 65 namespace hwmonio 66 { 67 static constexpr auto retries = 10; 68 static constexpr auto delay = std::chrono::milliseconds{100}; 69 70 /** @class HwmonIO 71 * @brief Convenience wrappers for HWMON sysfs attribute IO. 72 * 73 * Unburden the rest of the application from having to check 74 * ENOENT after every hwmon attribute io operation. Hwmon 75 * device drivers can be unbound at any time; the program 76 * cannot always be terminated externally before we try to 77 * do an io. 78 */ 79 class HwmonIO 80 { 81 public: 82 HwmonIO() = delete; 83 HwmonIO(const HwmonIO&) = default; 84 HwmonIO(HwmonIO&&) = default; 85 HwmonIO& operator=(const HwmonIO&) = default; 86 HwmonIO& operator=(HwmonIO&&) = default; 87 ~HwmonIO() = default; 88 89 /** @brief Constructor 90 * 91 * @param[in] path - hwmon instance root - eg: 92 * /sys/class/hwmon/hwmon<N> 93 */ 94 explicit HwmonIO(const std::string& path); 95 96 /** @brief Perform formatted hwmon sysfs read. 97 * 98 * Propagates any exceptions other than ENOENT. 99 * ENOENT will result in a call to exit(0) in case 100 * the underlying hwmon driver is unbound and 101 * the program is inadvertently left running. 102 * 103 * For possibly transient errors will retry up to 104 * the specified number of times. 105 * 106 * @param[in] type - The hwmon type (ex. temp). 107 * @param[in] id - The hwmon id (ex. 1). 108 * @param[in] sensor - The hwmon sensor (ex. input). 109 * @param[in] retries - The number of times to retry. 110 * @param[in] delay - The time to sleep between retry attempts. 111 * 112 * @return val - The read value. 113 */ 114 int64_t read( 115 const std::string& type, 116 const std::string& id, 117 const std::string& sensor, 118 size_t retries, 119 std::chrono::milliseconds delay) const; 120 121 /** @brief Perform formatted hwmon sysfs write. 122 * 123 * Propagates any exceptions other than ENOENT. 124 * ENOENT will result in a call to exit(0) in case 125 * the underlying hwmon driver is unbound and 126 * the program is inadvertently left running. 127 * 128 * For possibly transient errors will retry up to 129 * the specified number of times. 130 * 131 * @param[in] val - The value to be written. 132 * @param[in] type - The hwmon type (ex. fan). 133 * @param[in] id - The hwmon id (ex. 1). 134 * @param[in] retries - The number of times to retry. 135 * @param[in] delay - The time to sleep between retry attempts. 136 */ 137 void write( 138 uint32_t val, 139 const std::string& type, 140 const std::string& id, 141 const std::string& sensor, 142 size_t retries, 143 std::chrono::milliseconds delay) const; 144 145 146 /** @brief Hwmon instance path access. 147 * 148 * @return path - The hwmon instance path. 149 */ 150 std::string path() const; 151 152 private: 153 std::string p; 154 }; 155 } // namespace hwmonio 156 } 157 158 // vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4 159