tici: remove hardcoded max brightness (#26859)

* tici: remove hardcoded max brightness

* fix that one

* cleanup

Co-authored-by: Comma Device <device@comma.ai>
old-commit-hash: 922bedaf47

system/hardware/tici/hardware.h

@@ -25,9 +25,11 @@ public:
   static void reboot() { std::system("sudo reboot"); };
   static void poweroff() { std::system("sudo poweroff"); };
   static void set_brightness(int percent) {
+    std::string max = util::read_file("/sys/class/backlight/panel0-backlight/max_brightness");
+
     std::ofstream brightness_control("/sys/class/backlight/panel0-backlight/brightness");
     if (brightness_control.is_open()) {
-      brightness_control << (percent * (int)(1023/100.)) << "\n";
+      brightness_control << (int)(percent * (std::stof(max)/100.)) << "\n";
       brightness_control.close();
     }
   };

system/hardware/tici/hardware.py

@@ -395,15 +395,22 @@ class Tici(HardwareBase):
 
   def set_screen_brightness(self, percentage):
     try:
+      with open("/sys/class/backlight/panel0-backlight/max_brightness") as f:
+        max_brightness = float(f.read().strip())
+
+      val = int(percentage * (max_brightness / 100.))
       with open("/sys/class/backlight/panel0-backlight/brightness", "w") as f:
-        f.write(str(int(percentage * 10.23)))
+        f.write(str(val))
     except Exception:
       pass
 
   def get_screen_brightness(self):
     try:
+      with open("/sys/class/backlight/panel0-backlight/max_brightness") as f:
+        max_brightness = float(f.read().strip())
+
       with open("/sys/class/backlight/panel0-backlight/brightness") as f:
-        return int(float(f.read()) / 10.23)
+        return int(float(f.read()) / (max_brightness / 100.))
     except Exception:
       return 0