xref: /openbmc/phosphor-hwmon/sysfs.hpp (revision 043d3230)
1 #pragma once
2 
3 #include <chrono>
4 #include <exception>
5 #include <fstream>
6 #include <string>
7 
8 namespace sysfs
9 {
10 
11 inline std::string make_sysfs_path(const std::string& path,
12                                    const std::string& type,
13                                    const std::string& id,
14                                    const std::string& entry)
15 {
16     using namespace std::literals;
17 
18     if (entry.empty())
19     {
20         return path + "/"s + type + id;
21     }
22 
23     return path + "/"s + type + id + "_"s + entry;
24 }
25 
26 /** @brief Return the path to the phandle file matching value in io-channels.
27  *
28  *  This function will take two passed in paths.
29  *  One path is used to find the io-channels file.
30  *  The other path is used to find the phandle file.
31  *  The 4 byte phandle value is read from the phandle file(s).
32  *  The 4 byte phandle value and 4 byte index value is read from io-channels.
33  *  When a match is found, the path to the matching phandle file is returned.
34  *
35  *  @param[in] iochanneldir - Path to file for getting phandle from io-channels
36  *  @param[in] phandledir - Path to use for reading from phandle file
37  *
38  *  @return Path to phandle file with value matching that in io-channels
39  */
40 std::string findPhandleMatch(const std::string& iochanneldir,
41                              const std::string& phandledir);
42 
43 /** @brief Find hwmon instances from an open-firmware device tree path
44  *
45  *  Look for a matching hwmon instance given an
46  *  open firmware device path.
47  *
48  *  @param[in] ofNode- The open firmware device path.
49  *
50  *  @returns[in] - The hwmon instance path or an empty
51  *                 string if no match is found.
52  */
53 std::string findHwmonFromOFPath(const std::string& ofNode);
54 
55 /** @brief Find hwmon instances from a device path
56  *
57  *  Look for a matching hwmon instance given a device path that
58  *  starts with /devices.  This path is the DEVPATH udev attribute
59  *  for the device except it has the '/hwmon/hwmonN' stripped off.
60  *
61  *  @param[in] devPath - The device path.
62  *
63  *  @return - The hwmon instance path or an empty
64  *            string if no match is found.
65  */
66 std::string findHwmonFromDevPath(const std::string& devPath);
67 
68 /** @brief Return the path to use for a call out.
69  *
70  *  Return an empty string if a callout path cannot be
71  *  found.
72  *
73  *  @param[in] instancePath - /sys/class/hwmon/hwmon<N> path.
74  *
75  *  @return Path to use for call out
76  */
77 std::string findCalloutPath(const std::string& instancePath);
78 
79 } // namespace sysfs
80 
81 // vim: tabstop=8 expandtab shiftwidth=4 softtabstop=4
82