Update call out algorithm for iio hwmon instance
When readSysfsWithCallout() or writeSysfsWithCallout() get run, use the
instancePath to search for a call out path. For instances with an hwmon
driver, the passed in path should be used. For instances with an iio
driver, search for a phandle file that has a value matching to that in
the io-channels file for this phosphor-hwmon instance. If an error occurs
on the read or write, use that matching phandle path to create a call
out path.
Resolves openbmc/openbmc#1265
Change-Id: I6390d0dfb3d67ce8a55d171ca9a3cb8f3057a8c9
Signed-off-by: Brandon Wyman <v2cib530@us.ibm.com>
diff --git a/sysfs.cpp b/sysfs.cpp
index ad99bf7..3ca2ec4 100644
--- a/sysfs.cpp
+++ b/sysfs.cpp
@@ -25,30 +25,37 @@
#include <fstream>
using namespace phosphor::logging;
+namespace fs = std::experimental::filesystem;
-std::string findHwmon(const std::string& ofNode)
+static constexpr auto ofRoot = "/sys/firmware/devicetree/base";
+
+/**
+ * @brief Return the path to the phandle file matching value in io-channels.
+ *
+ * This function will take two passed in paths.
+ * One path is used to find the io-channels file.
+ * The other path is used to find the phandle file.
+ * The 4 byte phandle value is read from the phandle file(s).
+ * The 4 byte phandle value and 4 byte index value is read from io-channels.
+ * When a match is found, the path to the matching phandle file is returned.
+ *
+ * @param[in] iochanneldir - Path to file for getting phandle from io-channels
+ * @param[in] phandledir - Path to use for reading from phandle file
+ *
+ * @return Path to phandle file with value matching that in io-channels
+ */
+std::string findPhandleMatch(const std::string& iochanneldir,
+ const std::string& phandledir)
{
- namespace fs = std::experimental::filesystem;
- static constexpr auto hwmonRoot = "/sys/class/hwmon";
- static constexpr auto ofRoot = "/sys/firmware/devicetree/base";
-
- fs::path fullOfPath{ofRoot};
- fullOfPath /= ofNode;
- fs::path fullOfPathPhandle{fullOfPath};
- fullOfPathPhandle /= "phandle";
-
- for (const auto& hwmonInst : fs::directory_iterator(hwmonRoot))
+ for (const auto& ofInst : fs::recursive_directory_iterator(phandledir))
{
- auto path = hwmonInst.path();
- path /= "of_node";
-
- if (fs::canonical(path) != fullOfPath)
+ auto path = ofInst.path();
+ if ("phandle" == ofInst.path().filename())
{
- // Try to find HWMON instance via phandle values.
- // Used for IIO device drivers.
- path /= "io-channels";
- if (fs::exists(path) && fs::exists(fullOfPathPhandle))
+ auto ioChannelsPath = iochanneldir + "/io-channels";
+ if (fs::exists(ioChannelsPath))
{
+ auto fullOfPathPhandle = ofInst.path();
std::ifstream ioChannelsFile(path);
std::ifstream pHandleFile(fullOfPathPhandle);
@@ -64,17 +71,74 @@
if (ioChannelsValue == pHandleValue)
{
- return hwmonInst.path();
+ return ofInst.path();
}
}
catch (const std::exception& e)
{
log<level::INFO>(e.what());
+ continue;
}
-
}
- continue;
+ }
+ }
+
+ return std::string();
+}
+
+/**
+ * @brief Return the path to use for a call out.
+ *
+ * If the path does not contain iio-hwmon, assume passed in path is the call
+ * out path.
+ *
+ * @param[in] ofPath - Open firmware path to search for matching phandle value
+ *
+ * @return Path to use for call out
+ */
+std::string findCalloutPath(const std::string& ofPath)
+{
+ static constexpr auto iioHwmonStr = "iio-hwmon";
+
+ if (ofPath.find(iioHwmonStr) != std::string::npos)
+ {
+ auto matchpath = findPhandleMatch(ofPath, ofRoot);
+ auto n = matchpath.rfind('/');
+ if (n != std::string::npos)
+ {
+ return matchpath.substr(0, n);
+ }
+ }
+
+ return ofPath;
+}
+
+std::string findHwmon(const std::string& ofNode)
+{
+ static constexpr auto hwmonRoot = "/sys/class/hwmon";
+
+ fs::path fullOfPath{ofRoot};
+ fullOfPath /= ofNode;
+
+ for (const auto& hwmonInst : fs::directory_iterator(hwmonRoot))
+ {
+ auto path = hwmonInst.path();
+ path /= "of_node";
+ if (fs::canonical(path) != fullOfPath)
+ {
+ // Try to find HWMON instance via phandle values.
+ // Used for IIO device drivers.
+ auto ofpath = fullOfPath.string();
+ auto matchpath = findPhandleMatch(path, ofpath);
+ if (!std::string(matchpath).empty())
+ {
+ return hwmonInst.path();
+ }
+ else
+ {
+ continue;
+ }
}
return hwmonInst.path();
@@ -98,6 +162,8 @@
std::string fullPath = make_sysfs_path(instancePath,
type, id, sensor);
+ auto callOutPath = findCalloutPath(fs::canonical(instancePath));
+
ifs.exceptions(std::ifstream::failbit
| std::ifstream::badbit
| std::ifstream::eofbit);
@@ -121,7 +187,7 @@
ReadFailure::CALLOUT_ERRNO(rc),
xyz::openbmc_project::Sensor::Device::
ReadFailure::CALLOUT_DEVICE_PATH(
- fs::canonical(instancePath).c_str()));
+ fs::canonical(callOutPath).c_str()));
exit(EXIT_FAILURE);
}
@@ -145,6 +211,8 @@
std::string fullPath = make_sysfs_path(instancePath,
type, id, sensor);
+ auto callOutPath = findCalloutPath(fs::canonical(instancePath));
+
ofs.exceptions(std::ofstream::failbit
| std::ofstream::badbit
| std::ofstream::eofbit);
@@ -165,7 +233,7 @@
WriteFailure::CALLOUT_ERRNO(rc),
xyz::openbmc_project::Control::Device::
WriteFailure::CALLOUT_DEVICE_PATH(
- fs::canonical(instancePath).c_str()));
+ fs::canonical(callOutPath).c_str()));
exit(EXIT_FAILURE);
}