Enable PowerStatsHAL to read NFC power state stats

This change adds support to PowerStatsHAL on sunfish devices for reading
NFC power state stats for inclusion with other subsystem power state stats.
The data is already present in sysfs; this CL (in combination with the
associated selinux change) simply adds reading of that data.

Bug: 217388683
Test: lshal debug android.hardware.power.stats@1.0::IPowerStats/default
Test: cat /sys/class/misc/st21nfc/device/power_stats
Change-Id: Ie0dc14880ba57722c2c43c8cf40783bcd3ff14b9

powerstats/service.cpp

@@ -128,6 +128,30 @@ int main(int /* argc */, char ** /* argv */) {
         std::vector<std::string>{"Off", "LP", "1080x2340@60"});
     service->addStateResidencyDataProvider(displaySdp);
 
+    // Add NFC power entity
+    StateResidencyConfig nfcStateConfig = {
+        .entryCountSupported = true,
+        .entryCountPrefix = "Cumulative count:",
+        .totalTimeSupported = true,
+        .totalTimePrefix = "Cumulative duration msec:",
+        .lastEntrySupported = true,
+        .lastEntryPrefix = "Last entry timestamp msec:"
+    };
+    std::vector<std::pair<std::string, std::string>> nfcStateHeaders = {
+        std::make_pair("Idle", "Idle mode:"),
+        std::make_pair("Active", "Active mode:"),
+        std::make_pair("Active-RW", "Active Reader/Writer mode:"),
+    };
+
+    sp<GenericStateResidencyDataProvider> nfcSdp =
+            new GenericStateResidencyDataProvider("/sys/class/misc/st21nfc/device/power_stats");
+
+    uint32_t nfcId = service->addPowerEntity("NFC", PowerEntityType::SUBSYSTEM);
+    nfcSdp->addEntity(nfcId,
+        PowerEntityConfig(generateGenericStateResidencyConfigs(nfcStateConfig, nfcStateHeaders)));
+
+    service->addStateResidencyDataProvider(nfcSdp);
+
     // Add Power Entities that require the Aidl data provider
     auto aidlSdp = sp<AidlStateResidencyDataProvider>::make();
     uint32_t citadelId = service->addPowerEntity("Citadel", PowerEntityType::SUBSYSTEM);