Fix #117: Rework host USB ready timeout

adafruit_hid/__init__.py

@@ -19,6 +19,12 @@
 
 # imports
 from __future__ import annotations
+import time
+
+try:
+    import supervisor
+except ImportError:
+    supervisor = None
 
 try:
     from typing import Sequence
@@ -31,17 +37,46 @@
 
 
 def find_device(
-    devices: Sequence[usb_hid.Device], *, usage_page: int, usage: int
+    devices: Sequence[usb_hid.Device],
+    *,
+    usage_page: int,
+    usage: int,
+    timeout: int = None,
 ) -> usb_hid.Device:
     """Search through the provided sequence of devices to find the one with the matching
-    usage_page and usage."""
+    usage_page and usage.
+
+    :param timeout: Time in seconds to wait for USB to become ready before timing out.
+    Defaults to None to wait indefinitely."""
+
     if hasattr(devices, "send_report"):
         devices = [devices]  # type: ignore
-    for device in devices:
+    device = None
+    for dev in devices:
         if (
-            device.usage_page == usage_page
-            and device.usage == usage
-            and hasattr(device, "send_report")
+            dev.usage_page == usage_page
+            and dev.usage == usage
+            and hasattr(dev, "send_report")
         ):
-            return device
-    raise ValueError("Could not find matching HID device.")
+            device = dev
+            break
+    if device is None:
+        raise ValueError("Could not find matching HID device.")
+
+    if supervisor is None:
+        # Blinka doesn't have supervisor (see issue Adafruit_Blinka#711), so wait
+        # one second for USB to become ready
+        time.sleep(1.0)
+    elif timeout is None:
+        # default behavior: wait indefinitely for USB to become ready
+        while not supervisor.runtime.usb_connected:
+            time.sleep(1.0)
+    else:
+        # wait up to timeout seconds for USB to become ready
+        for _ in range(timeout):
+            if supervisor.runtime.usb_connected:
+                return device
+            time.sleep(1.0)
+        raise OSError("Failed to initialize HID device. Is USB connected?")
+
+    return device

adafruit_hid/consumer_control.py

@@ -18,7 +18,6 @@
 
 # pylint: disable=wrong-import-position
 import struct
-import time
 from . import find_device
 
 try:
@@ -31,26 +30,23 @@
 class ConsumerControl:
     """Send ConsumerControl code reports, used by multimedia keyboards, remote controls, etc."""
 
-    def __init__(self, devices: Sequence[usb_hid.Device]) -> None:
+    def __init__(self, devices: Sequence[usb_hid.Device], timeout: int = None) -> None:
         """Create a ConsumerControl object that will send Consumer Control Device HID reports.
 
+        :param timeout: Time in seconds to wait for USB to become ready before timing out.
+        Defaults to None to wait indefinitely.
+
         Devices can be a sequence of devices that includes a Consumer Control device or a CC device
         itself. A device is any object that implements ``send_report()``, ``usage_page`` and
         ``usage``.
         """
-        self._consumer_device = find_device(devices, usage_page=0x0C, usage=0x01)
+        self._consumer_device = find_device(
+            devices, usage_page=0x0C, usage=0x01, timeout=timeout
+        )
 
         # Reuse this bytearray to send consumer reports.
         self._report = bytearray(2)
 
-        # Do a no-op to test if HID device is ready.
-        # If not, wait a bit and try once more.
-        try:
-            self.send(0x0)
-        except OSError:
-            time.sleep(1)
-            self.send(0x0)
-
     def send(self, consumer_code: int) -> None:
         """Send a report to do the specified consumer control action,
         and then stop the action (so it will not repeat).

adafruit_hid/keyboard.py

@@ -9,7 +9,6 @@
 * Author(s): Scott Shawcroft, Dan Halbert
 """
 
-import time
 from micropython import const
 import usb_hid
 
@@ -39,14 +38,19 @@ class Keyboard:
 
     # No more than _MAX_KEYPRESSES regular keys may be pressed at once.
 
-    def __init__(self, devices: Sequence[usb_hid.Device]) -> None:
+    def __init__(self, devices: Sequence[usb_hid.Device], timeout: int = None) -> None:
         """Create a Keyboard object that will send keyboard HID reports.
 
+        :param timeout: Time in seconds to wait for USB to become ready before timing out.
+        Defaults to None to wait indefinitely.
+
         Devices can be a sequence of devices that includes a keyboard device or a keyboard device
         itself. A device is any object that implements ``send_report()``, ``usage_page`` and
         ``usage``.
         """
-        self._keyboard_device = find_device(devices, usage_page=0x1, usage=0x06)
+        self._keyboard_device = find_device(
+            devices, usage_page=0x1, usage=0x06, timeout=timeout
+        )
 
         # Reuse this bytearray to send keyboard reports.
         self.report = bytearray(8)
@@ -65,14 +69,6 @@ def __init__(self, devices: Sequence[usb_hid.Device]) -> None:
         # No keyboard LEDs on.
         self._led_status = b"\x00"
 
-        # Do a no-op to test if HID device is ready.
-        # If not, wait a bit and try once more.
-        try:
-            self.release_all()
-        except OSError:
-            time.sleep(1)
-            self.release_all()
-
     def press(self, *keycodes: int) -> None:
         """Send a report indicating that the given keys have been pressed.
 

adafruit_hid/mouse.py

@@ -8,8 +8,6 @@
 
 * Author(s): Dan Halbert
 """
-import time
-
 from . import find_device
 
 try:
@@ -29,14 +27,19 @@ class Mouse:
     MIDDLE_BUTTON = 4
     """Middle mouse button."""
 
-    def __init__(self, devices: Sequence[usb_hid.Device]):
+    def __init__(self, devices: Sequence[usb_hid.Device], timeout: int = None) -> None:
         """Create a Mouse object that will send USB mouse HID reports.
 
+        :param timeout: Time in seconds to wait for USB to become ready before timing out.
+        Defaults to None to wait indefinitely.
+
         Devices can be a sequence of devices that includes a keyboard device or a keyboard device
         itself. A device is any object that implements ``send_report()``, ``usage_page`` and
         ``usage``.
         """
-        self._mouse_device = find_device(devices, usage_page=0x1, usage=0x02)
+        self._mouse_device = find_device(
+            devices, usage_page=0x1, usage=0x02, timeout=timeout
+        )
 
         # Reuse this bytearray to send mouse reports.
         # report[0] buttons pressed (LEFT, MIDDLE, RIGHT)
@@ -45,14 +48,6 @@ def __init__(self, devices: Sequence[usb_hid.Device]):
         # report[3] wheel movement
         self.report = bytearray(4)
 
-        # Do a no-op to test if HID device is ready.
-        # If not, wait a bit and try once more.
-        try:
-            self._send_no_move()
-        except OSError:
-            time.sleep(1)
-            self._send_no_move()
-
     def press(self, buttons: int) -> None:
         """Press the given mouse buttons.