commit ee73f5bdd1996ee9d4f65ddbc69804ea0b1b59e9
author James Feist <james.feist@linux.intel.com> Wed Aug 01 16:31:42 2018 -0700
committer James Feist <james.feist@linux.intel.com> Mon Oct 22 09:18:28 2018 -0700
tree 6563db6a97d9d3354aaffee8a0bcee6e9882e723
parent 0fe4cb34b5292a559693407ebc0b38645c6c19d6

Make hwmon work with double or int64 interface

Deduce type based on interface using decltype
and if it is double apply scale to the value.

Tested-by: Noticed that on dbus using busctl and debug
server that doubles were produced and scaled.

Also verifed that hwmon still produced int64_t values when
building with current phosphor-dbus-interfaces.

Change-Id: I00e21d5ef0ea6cee0eb30baa0b39cde95e7f4a86
Signed-off-by: James Feist <james.feist@linux.intel.com>

sensor.cpp

diff --git a/sensor.cpp b/sensor.cpp
index 0a0971f..5c97e0c 100644
--- a/sensor.cpp
+++ b/sensor.cpp
@@ -8,6 +8,7 @@
 #include "sensorset.hpp"
 #include "sysfs.hpp"
 
+#include <cmath>
 #include <cstring>
 #include <experimental/filesystem>
 #include <phosphor-logging/elog-errors.hpp>
@@ -21,6 +22,19 @@
 using namespace phosphor::logging;
 using namespace sdbusplus::xyz::openbmc_project::Common::Error;
 
+// todo: this can be deleted once we move to double
+// helper class to set the scale on the value iface only when it's available
+template <typename T>
+void setScale(T& iface, int64_t value, double)
+{
+}
+template <typename T>
+void setScale(T& iface, int64_t value, int64_t)
+{
+    iface->scale(value);
+}
+
+// todo: this can be simplified once we move to the double interface
 Sensor::Sensor(const SensorSet::key_type& sensor,
                const hwmonio::HwmonIO& ioAccess, const std::string& devPath) :
     sensor(sensor),
@@ -84,7 +98,7 @@
     }
 }
 
-int64_t Sensor::adjustValue(int64_t value)
+SensorValueType Sensor::adjustValue(SensorValueType value)
 {
 // Because read doesn't have an out pointer to store errors.
 // let's assume negative values are errors if they have this
@@ -100,6 +114,11 @@
     value = static_cast<decltype(value)>(
         static_cast<double>(value) * sensorAdjusts.gain + sensorAdjusts.offset);
 
+    if constexpr (std::is_same<SensorValueType, double>::value)
+    {
+        value *= std::pow(10, scale);
+    }
+
     return value;
 }
 
@@ -113,7 +132,7 @@
     auto& obj = std::get<Object>(info);
     auto& objPath = std::get<std::string>(info);
 
-    int64_t val = 0;
+    SensorValueType val = 0;
     std::shared_ptr<StatusObject> statusIface = nullptr;
     auto it = obj.find(InterfaceType::STATUS);
     if (it != obj.end())
@@ -145,7 +164,10 @@
     if (hwmon::getAttributes(sensor.first, attrs))
     {
         iface->unit(hwmon::getUnit(attrs));
-        iface->scale(hwmon::getScale(attrs));
+
+        setScale(iface, hwmon::getScale(attrs), val);
+
+        scale = hwmon::getScale(attrs);
     }
 
     auto maxValue = env::getEnv("MAXVALUE", sensor);