Merge pull request #34 from tiagocoutinho/led

Led brightness hardware events

linuxpy/led.py

@@ -62,6 +62,10 @@ def decode_triggers(text):
     return [i[1:-1] if i.startswith("[") else i for i in text.split()]
 
 
+def decode_brightness(data: bytes) -> int:
+    return int.from_bytes(data, "little")
+
+
 def split_name(fname):
     if nb_colons := fname.count(":"):
         parts = fname.split(":")
@@ -127,6 +131,17 @@ def trigger_enabled(self) -> bool:
         """Tells if the LED trigger is enabled"""
         return self.trigger != "none"
 
+    @property
+    def brightness_events_path(self):
+        return self.syspath / "brightness_hw_changed"
+
+    def __iter__(self):
+        if not self.brightness_events_path.exists():
+            raise ValueError("This LED does not support hardware events")
+        with self.brightness_events_path.open("rb", buffering=0) as fobj:
+            yield decode_brightness(fobj.read(4))
+            fobj.seek(0)
+
 
 class ULED(BaseDevice):
     """
@@ -142,10 +157,6 @@ def __init__(self, name: str, max_brightness: int = 1, **kwargs):
         self._brightness = None
         super().__init__(self.PATH, **kwargs)
 
-    @staticmethod
-    def decode(data: bytes) -> int:
-        return int.from_bytes(data, "little")
-
     def _on_open(self):
         data = struct.pack("64si", self.name.encode(), self.max_brightness)
         self._fobj.write(data)
@@ -165,14 +176,14 @@ def brightness(self) -> int:
         """Read new brightness. Blocks until brightness changes"""
         data = self.raw_read()
         if data is not None:
-            self._brightness = self.decode(data)
+            self._brightness = decode_brightness(data)
         return self._brightness
 
     def stream(self) -> Iterable[int]:
         """Infinite stream of brightness change events"""
         while True:
             data = self.read()
-            self._brightness = self.decode(data)
+            self._brightness = decode_brightness(data)
             yield self._brightness
 
 

tests/test_led.py

@@ -148,6 +148,13 @@ def _(uled=uled, uled_colored=uled_colored, uled_simple=uled_simple, uled_single
     assert len(leds) >= 4
 
 
+@skip("uled not prepared", when=not ULED_PREPARED)
+@test("led brightness events")
+def _(uled=uled):
+    led = LED.from_name(uled.name)
+    assert not led.brightness_events_path.exists()
+
+
 @skip("uled not prepared", when=not ULED_PREPARED)
 @test("uled stream")
 def _(uled=uled):