From 36162d6931aaaf56c60c2e1c77cd3cdc2eba8363 Mon Sep 17 00:00:00 2001
From: PA4WDH
Date: Sun, 28 Jul 2024 14:45:59 +0200
Subject: Add autodetection for temperature input

---
 Makefile            |   2 +-
 argparse.c          |   5 +-
 cputemp.c           | 128 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 cputemp.h           |  12 +++++
 cputemp2maxfreq.c   |  29 +++++++++++-
 generate_debug_h.sh |   2 +-
 6 files changed, 173 insertions(+), 5 deletions(-)
 create mode 100644 cputemp.c
 create mode 100644 cputemp.h

diff --git a/Makefile b/Makefile
index 77e77c6..e65cacf 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-cputemp2maxfreq: version.o debug.o sysfs.o cpufreq.o failsafe.o argparse.o logger.o
+cputemp2maxfreq: version.o debug.o sysfs.o cpufreq.o failsafe.o argparse.o logger.o cputemp.o
 
 version.h: generate_version_h.sh .git/index
 	./generate_version_h.sh > version.h
diff --git a/argparse.c b/argparse.c
index 124f3bc..1eae42b 100644
--- a/argparse.c
+++ b/argparse.c
@@ -20,7 +20,10 @@ void printhelp()
   "               Default: %ld\n"
   "-g <governor>  cpufreq governor to use, use \"keep\" to keep current governor\n"
   "               Default: %s\n"
-  "-i <file>      Input for temperature readout, usually somewhere in sysfs\n"
+  "-i <sensor>    Input for temperature readout, this can be specified as:\n"
+  "               A full path that starts with /, usually somewhere in sysfs\n"
+  "               A sensor name, for example \"Core 0\"\n"
+  "               The word \"auto\" autodetects a valid sensor\n"
   "               Default: %s\n"
   "-p <time>      Poll interval in seconds\n"
   "               Default: %d\n"
diff --git a/cputemp.c b/cputemp.c
new file mode 100644
index 0000000..559056f
--- /dev/null
+++ b/cputemp.c
@@ -0,0 +1,128 @@
+#include <stdio.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <string.h>
+#include "cputemp2maxfreq.h"
+#include "debug.h"
+#include "sysfs.h"
+#include "cputemp.h"
+
+extern struct s_config config;
+
+// Read a single hwmon directory and search for the requested sensor name
+void cputemp_read_hwmon(char *hwmon,char *sensor_name,struct s_sensor *sensor)
+{
+ DIR *hwmon_dir;
+ struct dirent *hwmon_dirent;
+ int count;
+ char buf[255];
+ int datalen;
+ char sysfs_file[255];
+ long int testdata;
+ int offset;
+
+ DEBUG1_CPUTEMP("Searching for sensors in %s\n",hwmon);
+
+ hwmon_dir=opendir(hwmon);
+ if (hwmon_dir==NULL)
+ {
+  DEBUG1_CPUTEMP("Failed to open hwmon dir\n");
+  return;
+ }
+
+ hwmon_dirent=readdir(hwmon_dir);
+ while((hwmon_dirent!=NULL) && (sensor->valid==0))
+ {
+  DEBUG3_CPUTEMP("%s\n",hwmon_dirent->d_name);
+
+// We are searching for files named "temp<number>_label"
+  if (strncmp(hwmon_dirent->d_name,"temp",4)==0)
+  {
+   DEBUG3_CPUTEMP("Found temp entry: %s\n",hwmon_dirent->d_name);
+   offset=0;
+   for(count=5;count<7;count++)
+   {
+    if (hwmon_dirent->d_name[count]=='_')
+    {
+     DEBUG3_CPUTEMP("Underscore at %d\n",count);
+     offset=count+1;
+     break;
+    }
+   }
+   if (strncmp(hwmon_dirent->d_name+offset,"label",5)==0)
+   {
+    DEBUG2_CPUTEMP("Found label %s\n",hwmon_dirent->d_name);
+    sprintf(sysfs_file,"%s/%s",hwmon,hwmon_dirent->d_name);
+
+// Read the label to see if it matches what we're looking for
+    datalen=sysfs_read_str(sysfs_file,buf,sizeof(buf));
+    if (datalen<0)
+    {
+     DEBUG2_CPUTEMP("Failed to read label\n");
+    } else {
+     DEBUG1_CPUTEMP("Label is: %s\n",buf);
+     if (strncasecmp(buf,sensor_name,255)==0)
+     {
+      DEBUG2_CPUTEMP("Label machtes our search criteria\n");
+      offset=strlen(sysfs_file)-5;
+      strncpy(sysfs_file+offset,"input",5);
+      DEBUG1_CPUTEMP("Input filename: %s\n",sysfs_file);
+
+// Validate the sensor by reading it
+      testdata=sysfs_read_long_int(sysfs_file);
+      DEBUG2_CPUTEMP("Input value: %ld\n",testdata);
+      if ((testdata>=VALID_TEMP_MIN) && (testdata<=VALID_TEMP_MAX))
+      {
+       DEBUG1_CPUTEMP("Input data is valid, marking sensor as valid\n");
+       sensor->valid=1;
+       strncpy(sensor->name,buf,sizeof(buf));
+       strncpy(sensor->filename,sysfs_file,sizeof(sysfs_file));
+      } else {
+       DEBUG1_CPUTEMP("Input data is invalid, ignoring sensor\n");
+      }
+     }
+    }
+   }
+  }
+  hwmon_dirent=readdir(hwmon_dir);
+ }
+ closedir(hwmon_dir);
+}
+
+// Find all entries under /sys/class/hwmon and check them with
+// cputemp_read_hwmon
+void cputemp_find_sensor(char *sensor_name,struct s_sensor *sensor)
+{
+ DIR *hwmon_dir;
+ struct dirent *hwmon_dirent;
+ char subdir[255];
+
+ DEBUG1_CPUTEMP("Searching for sensor %s\n",sensor_name);
+
+// Mark sensor data as invalid, it will be set valid if we find something
+ sensor->valid=0;
+
+ hwmon_dir=opendir("/sys/class/hwmon");
+ if (hwmon_dir==NULL)
+ {
+  DEBUG1_CPUTEMP("Failed to open /sys/class/hwmon, is sysfs mounted?\n");
+  return;
+ }
+
+ hwmon_dirent=readdir(hwmon_dir);
+ while((hwmon_dirent!=NULL) && (sensor->valid==0))
+ {
+  DEBUG3_CPUTEMP("Found file: %s\n",hwmon_dirent->d_name);
+
+// If the name starts with hwmon try to read it
+// Note that /sys/class/hwmon actually contains symlinks but we treat them like directories
+  if (strncmp(hwmon_dirent->d_name,"hwmon",5)==0)
+  {
+   sprintf(subdir,"/sys/class/hwmon/%s",hwmon_dirent->d_name);
+   DEBUG2_CPUTEMP("Found hwmon entry: %s\n",subdir);
+   cputemp_read_hwmon(subdir,sensor_name,sensor);
+  }
+  hwmon_dirent=readdir(hwmon_dir);
+ }
+ closedir(hwmon_dir);
+}
diff --git a/cputemp.h b/cputemp.h
new file mode 100644
index 0000000..8cd39d5
--- /dev/null
+++ b/cputemp.h
@@ -0,0 +1,12 @@
+#ifndef HAVE_CPUTEMP_H
+#define HAVE_CPUTEMP_H
+
+struct s_sensor {
+ char name[255];
+ char filename[255];
+ char valid;
+};
+
+void cputemp_find_sensor(char *sensor_name,struct s_sensor *sensor);
+
+#endif
diff --git a/cputemp2maxfreq.c b/cputemp2maxfreq.c
index 47b1f53..d3242b6 100644
--- a/cputemp2maxfreq.c
+++ b/cputemp2maxfreq.c
@@ -12,13 +12,14 @@
 #include "version.h"
 #include "argparse.h"
 #include "logger.h"
+#include "cputemp.h"
 
 // Set default config
 struct s_config config={
  "",             // Name of this program, set by argparse
  "conservative", // Governor
  70000,          // Temperature
- "/sys/devices/virtual/thermal/thermal_zone0/temp", // Temperature input
+ "auto",         // Temperature input
  100000,         // Frequency step
  2000000,        // Fallback frequency
  10,             // Interval
@@ -49,7 +50,7 @@ int main(int argc,char **argv)
 {
  long int diff;
  long int newfreq;
-
+ struct s_sensor sensor;
  char *transition_latency_remark;
 
  argparse(argc,argv);
@@ -98,6 +99,30 @@ int main(int argc,char **argv)
   exit(1);
  }
 
+// Autodetect temperature input if needed
+ if (config.temp_input[0]!='/')
+ {
+  if (strcmp(config.temp_input,"auto")==0)
+  {
+   DEBUG1_MAIN("Starting temperature sensor detection with name \"Package id 0\"\n");
+   cputemp_find_sensor("Package id 0",&sensor);
+  } else {
+   DEBUG1_MAIN("Starting temperature sensor detection with name \"%s\"\n",config.temp_input);
+   cputemp_find_sensor(config.temp_input,&sensor);
+  }
+  if (sensor.valid==1)
+  {
+   DEBUG1_MAIN("Found sensor \"%s\"\n",sensor.name);
+   DEBUG1_MAIN("Sensor file: %s\n",sensor.filename);
+   strncpy(config.temp_input,sensor.filename,sizeof(config.temp_input));
+   config.logger("Detection returned temperature input: %s",config.temp_input);
+   config.logger("Temperature input name: %s",sensor.name);
+  } else {
+   config.logger("Detection failed to return a valid sensor, set it using -i");
+   exit(1);
+  }
+ }
+
 // Get and validate CPU data
  cpudata.min_freq=sysfs_read_long_int("/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_min_freq");
  cpudata.max_freq=sysfs_read_long_int("/sys/devices/system/cpu/cpufreq/policy0/cpuinfo_max_freq");
diff --git a/generate_debug_h.sh b/generate_debug_h.sh
index 209495c..4049af9 100755
--- a/generate_debug_h.sh
+++ b/generate_debug_h.sh
@@ -5,7 +5,7 @@
 
 # Configuration
 DEBUG_LEVELS=4
-DEBUG_PARTS="MAIN ARGPARSE SYSFS CPUFREQ LOG"
+DEBUG_PARTS="MAIN ARGPARSE SYSFS CPUFREQ LOG CPUTEMP"
 DEBUG_HELPER_DEF=`grep -o "void .*()" debug.c | head -n 1`
 DEBUG_HELPER=${DEBUG_HELPER_DEF##* }
 HEXDUMP_HELPER_DEF=`grep -o "void .*(unsigned char \*data,int len)" debug.c`
-- 
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