faster power measurement

system/hardware/hardwared.py

@@ -96,6 +96,23 @@ def touch_thread(end_event):
       time.sleep(DT_HW)
 
 
+def power_sample_thread(end_event):
+  """5.6Hz SOM power via FG IADC direct mode."""
+  try:
+    HARDWARE.init_fast_power()
+    while not end_event.is_set():
+      try:
+        i_ua = HARDWARE.fast_ibat_ua()
+        v_mv = HARDWARE.fast_vbat_mv()
+        p = v_mv * i_ua / 1e9
+        statlog.sample("som_power_draw", p)
+        statlog.sample("power_draw", p)
+      except Exception:
+        pass
+  finally:
+    HARDWARE.stop_fast_power()
+
+
 def hw_state_thread(end_event, hw_queue):
   """Handles non critical hardware state, and sends over queue"""
   count = 0
@@ -472,6 +489,7 @@ def main():
 
   if TICI:
     threads.append(threading.Thread(target=touch_thread, args=(end_event,)))
+    threads.append(threading.Thread(target=power_sample_thread, args=(end_event,)))
 
   for t in threads:
     t.start()

system/hardware/tici/hardware.py

@@ -317,6 +317,50 @@ def get_current_power_draw(self):
   def get_som_power_draw(self):
     return (self.read_param_file("/sys/class/power_supply/bms/voltage_now", int) * self.read_param_file("/sys/class/power_supply/bms/current_now", int) / 1e12)
 
+  # fast power measurement: FG IADC direct mode (5.6Hz, 488uA resolution)
+  # PMI8998 FG normally converts IBATT every 1.47s. ALG_DIRECT_MODE triggers
+  # the 15-bit delta-sigma IADC on demand
+
+  def _spmi_write(self, addr, val):
+    regmap = '/sys/kernel/debug/regmap/spmi0-02'
+    with open(f'{regmap}/address', 'w') as f:
+      f.write(hex(addr))
+    with open(f'{regmap}/count', 'w') as f:
+      f.write('1')
+    with open(f'{regmap}/data', 'w') as f:
+      f.write(hex(val))
+
+  def _spmi_read16(self, addr):
+    regmap = '/sys/kernel/debug/regmap/spmi0-02'
+    with open(f'{regmap}/address', 'w') as f:
+      f.write(hex(addr))
+    with open(f'{regmap}/count', 'w') as f:
+      f.write('2')
+    with open(f'{regmap}/data') as f:
+      d = f.read().strip().split('\n')
+    return int(d[1].split(':')[1], 16) << 8 | int(d[0].split(':')[1], 16)
+
+  def fast_vbat_mv(self):
+    return self.read_param_file("/sys/class/power_supply/bms/voltage_now", int) / 1e3
+
+  def fast_ibat_ua(self):
+    self._spmi_write(0x41D0, 0xA5)
+    self._spmi_write(0x41E5, 0x12)
+    self._spmi_write(0x41D0, 0xA5)
+    self._spmi_write(0x41E5, 0x16)
+    time.sleep(0.170)
+    raw = self._spmi_read16(0x41AE)
+    signed = raw if raw < 0x8000 else raw - 0x10000
+    return signed * 488281 // 1000
+
+  def init_fast_power(self):
+    self._spmi_write(0x41D0, 0xA5)
+    self._spmi_write(0x41E5, 0x12)
+
+  def stop_fast_power(self):
+    self._spmi_write(0x41D0, 0xA5)
+    self._spmi_write(0x41E5, 0x20)
+
   def shutdown(self):
     os.system("sudo poweroff")