add cpu frequency driver

app/cpu/drivers/sys.go

@@ -0,0 +1,67 @@
+package drivers
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"sort"
+	"strconv"
+	"strings"
+)
+
+type SysDriver struct{}
+
+func NewSysDriver() *SysDriver {
+	return &SysDriver{}
+}
+
+func (r *SysDriver) ReadClockSensors() ([]ClockSensor, error) {
+	// Glob directly targets scaling_cur_freq for all numerical CPU core paths
+	freqFiles, err := filepath.Glob("/sys/devices/system/cpu/cpu[0-9]*/cpufreq/scaling_cur_freq")
+	if err != nil {
+		return nil, fmt.Errorf("failed to glob cpufreq files: %w", err)
+	}
+
+	clockSensors := []ClockSensor{}
+
+	for _, path := range freqFiles {
+		// Example path: /sys/devices/system/cpu/cpu0/cpufreq/scaling_cur_freq
+		// Extract core ID from path segments
+		parts := strings.Split(path, "/")
+		if len(parts) < 6 {
+			continue
+		}
+
+		// Parse "cpu0" -> 0
+		cpuDir := parts[5]
+		coreIDStr := strings.TrimPrefix(cpuDir, "cpu")
+		coreID, err := strconv.Atoi(coreIDStr)
+		if err != nil {
+			continue
+		}
+
+		// Read frequency in kHz directly from the matched file path
+		data, err := os.ReadFile(path)
+		if err != nil {
+			continue
+		}
+
+		khz, err := strconv.ParseFloat(strings.TrimSpace(string(data)), 64)
+		if err != nil {
+			continue
+		}
+
+		clockSensors = append(clockSensors, ClockSensor{
+			path:         path,
+			Name:         coreID,
+			FrequencyGHz: khz / 1000000.0, // Convert KHz to GHz
+		})
+	}
+
+	// Guarantee numerical order by core ID
+	sort.Slice(clockSensors, func(i, j int) bool {
+		return clockSensors[i].Name < clockSensors[j].Name
+	})
+
+	return clockSensors, nil
+}