For Apple Silicon use the temperature sensors from IOKIT

Classes/FanControl.h

@@ -25,6 +25,7 @@
 #import "NSFileManager+DirectoryLocations.h"
 #import "smc.h"
 #import "smcWrapper.h"
+#import "IOKitSensor.h"
 #import "MachineDefaults.h"
 
 #import "Power.h"

Classes/FanControl.m

@@ -150,7 +150,11 @@ NSUserDefaults *defaults;
 			@0, PREF_AC_SELECTION,
 			@0, PREF_CHARGING_SELECTION,
 			@0, PREF_MENU_DISPLAYMODE,
-			[MachineDefaults isAppleSilicon] ? @"Tp0D" : @"TC0D", PREF_TEMPERATURE_SENSOR,
+#if TARGET_CPU_ARM64
+            @"",PREF_TEMPERATURE_SENSOR,
+#else
+            @"TC0D",PREF_TEMPERATURE_SENSOR,
+#endif
             @0, PREF_NUMBEROF_LAUNCHES,
             @NO,PREF_DONATIONMESSAGE_DISPLAY,
 			[NSArchiver archivedDataWithRootObject:[NSColor blackColor]],PREF_MENU_TEXTCOLOR,
@@ -399,7 +403,11 @@ NSUserDefaults *defaults;
     
     if (bNeedTemp == true) {
         // Read current temperature and format text for the menubar.
+#if TARGET_CPU_ARM64
+        c_temp = [IOKitSensor getSOCTemperature];
+#else
         c_temp = [smcWrapper get_maintemp];
+#endif
         
         if ([[defaults objectForKey:PREF_TEMP_UNIT] intValue]==0) {
             temp = [NSString stringWithFormat:@"%@%CC",@(c_temp),(unsigned short)0xb0];
@@ -741,10 +749,10 @@ NSUserDefaults *defaults;
 #pragma mark **Power Watchdog-Methods**
 
 - (void)systemWillSleep:(id)sender{
-	if ([MachineDefaults isAppleSilicon]) {
+#if TARGET_CPU_ARM64
 	[FanControl setRights];
 	[self setFansToAuto:true];
-	}
+#endif
 }
 
 - (void)systemDidWakeFromSleep:(id)sender{

Classes/IOKitSensor.h

@@ -0,0 +1,57 @@
+/*
+ *    FanControl
+ *
+ *    Copyright (c) 2006-2012 Hendrik Holtmann
+ *
+ *    Sensor.h - MacBook(Pro) FanControl application
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#import <Foundation/Foundation.h>
+
+#import <IOKit/hidsystem/IOHIDEventSystemClient.h>
+#import <IOKit/hidsystem/IOHIDServiceClient.h>
+
+// https://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-1035.70.7/IOHIDFamily/AppleHIDUsageTables.h.auto.html
+#define kHIDPage_AppleVendor    0xff00
+#define kHIDUsage_AppleVendor_TemperatureSensor    0x0005
+
+// https://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-1035.70.7/IOHIDFamily/IOHIDEventTypes.h.auto.html
+#ifdef __LP64__
+typedef double IOHIDFloat;
+#else
+typedef float IOHIDFloat;
+#endif
+
+// https://opensource.apple.com/source/IOHIDFamily/IOHIDFamily-1035.70.7/IOHIDFamily/IOHIDEventTypes.h.auto.html
+#define IOHIDEventFieldBase(type) (type << 16)
+#define kIOHIDEventTypeTemperature  15
+
+
+typedef struct __IOHIDEvent *IOHIDEventRef;
+typedef struct __IOHIDServiceClient *IOHIDServiceClientRef;
+
+IOHIDEventSystemClientRef IOHIDEventSystemClientCreate(CFAllocatorRef);
+void IOHIDEventSystemClientSetMatching(IOHIDEventSystemClientRef, CFDictionaryRef);
+IOHIDEventRef IOHIDServiceClientCopyEvent(IOHIDServiceClientRef, int64_t, int32_t, int64_t);
+IOHIDFloat IOHIDEventGetFloatValue(IOHIDEventRef event, uint32_t field);
+
+@interface IOKitSensor : NSObject {
+}
+
++ (float) getSOCTemperature;
+
+@end

Classes/IOKitSensor.m

@@ -0,0 +1,72 @@
+/*
+ *    FanControl
+ *
+ *    Copyright (c) 2006-2012 Hendrik Holtmann
+ *
+ *    Sensor.m - MacBook(Pro) FanControl application
+ *
+ *    This program is free software; you can redistribute it and/or modify
+ *    it under the terms of the GNU General Public License as published by
+ *    the Free Software Foundation; either version 2 of the License, or
+ *    (at your option) any later version.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU General Public License for more details.
+ *
+ *    You should have received a copy of the GNU General Public License
+ *    along with this program; if not, write to the Free Software
+ *    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#import "IOKitSensor.h"
+
+@implementation IOKitSensor
+
+static BOOL isSOCSensor(CFStringRef sensorName) {
+    return CFStringHasPrefix(sensorName, CFSTR("PMU")) &&
+    !CFStringHasSuffix(sensorName, CFSTR("tcal")); // Ignore "PMU tcal" as it seems static
+}
+
+static float toOneDecimalPlace(float value) {
+    return roundf(10.0f * value) / 10.0f;
+}
+
++ (float) getSOCTemperature {
+    
+    IOHIDEventSystemClientRef eventSystemClient = IOHIDEventSystemClientCreate(kCFAllocatorDefault);
+    CFArrayRef services = IOHIDEventSystemClientCopyServices(eventSystemClient);
+    if (services) {
+        
+        float socSensorSum = 0.0f;
+        int socSensorCount = 0;
+        
+        for (int i = 0; i < CFArrayGetCount(services); i++) {
+            IOHIDServiceClientRef serviceClientRef = (IOHIDServiceClientRef)CFArrayGetValueAtIndex(services, i);
+            CFStringRef sensorName = IOHIDServiceClientCopyProperty(serviceClientRef, CFSTR("Product"));
+            if (sensorName) {
+                if (isSOCSensor(sensorName)) {
+                    IOHIDEventRef event = IOHIDServiceClientCopyEvent(serviceClientRef, kIOHIDEventTypeTemperature, 0, 0);
+                    if (event) {
+                        IOHIDFloat sensorTemperature = IOHIDEventGetFloatValue(event, IOHIDEventFieldBase(kIOHIDEventTypeTemperature));
+                        CFRelease(event);
+                        socSensorSum += sensorTemperature;
+                        socSensorCount++;
+                    }
+                }
+                CFRelease(sensorName);
+            }
+        }
+        
+        CFRelease(services);
+        CFRelease(eventSystemClient);
+        
+        float avgSOCTemp = socSensorCount > 0 ? socSensorSum / socSensorCount: 0.0f;
+        return toOneDecimalPlace(avgSOCTemp);
+    }
+    
+    return 0.0f;
+}
+
+@end

Classes/MachineDefaults.h

@@ -30,7 +30,6 @@
 	int machine_num;
 }
 
-+ (BOOL)isAppleSilicon;
 + (NSString *)computerModel;
 - (instancetype)init:(NSString*)p_machine ;
 

Classes/MachineDefaults.m

@@ -22,9 +22,6 @@
 
 #import "MachineDefaults.h"
 #import "NSFileManager+DirectoryLocations.h"
-#include <sys/types.h>
-#include <sys/sysctl.h>
-#include <mach/machine.h>
 
 @interface MachineDefaults ()
 {
@@ -126,14 +123,6 @@
 	return defaultsDict;
 }
 
-+ (BOOL)isAppleSilicon
-{
-    cpu_type_t cpu_type;
-    size_t size = sizeof(cpu_type);
-    sysctlbyname("hw.cputype", &cpu_type, &size, NULL, 0);
-    return cpu_type == CPU_TYPE_ARM64;
-}
-
 + (NSString *)computerModel
 {
     static NSString *computerModel = nil;

Classes/smcWrapper.m

@@ -70,11 +70,7 @@ NSArray *allSensors;
     NSString *sensor = [[NSUserDefaults standardUserDefaults] objectForKey:PREF_TEMPERATURE_SENSOR];
     SMCReadKey2((char*)[sensor UTF8String], &val,conn);
     retValue = [self convertToNumber:val];
-    if ([MachineDefaults isAppleSilicon]) {
-        allSensors = [NSArray arrayWithObjects:@"Tp0D",@"Tp0P",nil];
-    } else {
     allSensors = [NSArray arrayWithObjects:@"TC0D",@"TC0P",@"TCAD",@"TC0H",@"TC0F",@"TCAH",@"TCBH",nil];
-    }
     if (retValue<=0 || floor(retValue) == 129 ) { //workaround for some iMac Models
         for (NSString *sensor in allSensors) {
             SMCReadKey2((char*)[sensor UTF8String], &val,conn);

smcFanControl.xcodeproj/project.pbxproj

@@ -32,6 +32,7 @@
 		8D11072B0486CEB800E47090 /* InfoPlist.strings in Resources */ = {isa = PBXBuildFile; fileRef = 089C165CFE840E0CC02AAC07 /* InfoPlist.strings */; };
 		8D11072D0486CEB800E47090 /* main.m in Sources */ = {isa = PBXBuildFile; fileRef = 29B97316FDCFA39411CA2CEA /* main.m */; settings = {ATTRIBUTES = (); }; };
 		8D11072F0486CEB800E47090 /* Cocoa.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 1058C7A1FEA54F0111CA2CBB /* Cocoa.framework */; };
+		B5A4D43B293A62F90084C50B /* IOKitSensor.m in Sources */ = {isa = PBXBuildFile; fileRef = B5A4D43A293A62F90084C50B /* IOKitSensor.m */; };
 		B5F20EE127FBCC78002EFD11 /* Sparkle.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 895BDA390B8F8F42003CD894 /* Sparkle.framework */; };
 		B5F20EE227FBCC78002EFD11 /* Sparkle.framework in CopyFiles */ = {isa = PBXBuildFile; fileRef = 895BDA390B8F8F42003CD894 /* Sparkle.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, ); }; };
 /* End PBXBuildFile section */
@@ -121,6 +122,8 @@
 		89FE24280B7F4CE900D2713C /* German */ = {isa = PBXFileReference; lastKnownFileType = wrapper.nib; name = German; path = German.lproj/MainMenu.nib; sourceTree = "<group>"; };
 		8D1107310486CEB800E47090 /* Info.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		8D1107320486CEB800E47090 /* smcFanControl.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = smcFanControl.app; sourceTree = BUILT_PRODUCTS_DIR; };
+		B5A4D43A293A62F90084C50B /* IOKitSensor.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = IOKitSensor.m; sourceTree = "<group>"; };
+		B5E84C88293A65840067AEC2 /* IOKitSensor.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = IOKitSensor.h; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -165,6 +168,8 @@
 				892A7F440B10B7700041B493 /* MachineDefaults.m */,
 				8932CF2213D0850F008BC447 /* SystemVersion.h */,
 				8932CF2313D08551008BC447 /* SystemVersion.m */,
+				B5E84C88293A65840067AEC2 /* IOKitSensor.h */,
+				B5A4D43A293A62F90084C50B /* IOKitSensor.m */,
 			);
 			path = Classes;
 			sourceTree = "<group>";
@@ -383,6 +388,7 @@
 				892A7F450B10B7700041B493 /* MachineDefaults.m in Sources */,
 				8932CF2413D08551008BC447 /* SystemVersion.m in Sources */,
 				89148EA315E2543D00A073EE /* NSFileManager+DirectoryLocations.m in Sources */,
+				B5A4D43B293A62F90084C50B /* IOKitSensor.m in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};