SysfsGpio: add invert attribute (active-low) to the SysfsGPIO resources

The resources SysfsGPIO, NetworkSysfsGPIO and MatchedSysfsGPIO have
been modified to have an additional optional invert (active-low) attribute
(default False) which can be used to invert the logical value used
on the gpio line.

Signed-off-by: Perry Melange <[email protected]>

Author: pmelange

labgrid/resource/base.py

@@ -42,5 +42,7 @@ class SysfsGPIO(Resource):
     """The basic SysfsGPIO contains an index
 
     Args:
-        index (int): index of target gpio line."""
+        index (int): index of target gpio line.
+        invert (bool) : optional, whether the logic level is inverted (active-low)"""
     index = attr.ib(default=None, validator=attr.validators.instance_of(int))
+    invert = attr.ib(default=False,  validator=attr.validators.instance_of(bool))

labgrid/resource/remote.py

@@ -339,7 +339,9 @@ class NetworkSysfsGPIO(NetworkResource, ManagedResource):
     manager_cls = RemotePlaceManager
 
     """The NetworkSysfsGPIO describes a remotely accessible gpio line"""
+
     index = attr.ib(validator=attr.validators.optional(attr.validators.instance_of(int)))
+    invert = attr.ib(default=False, validator=attr.validators.instance_of(bool))
     def __attrs_post_init__(self):
         self.timeout = 10.0
         super().__attrs_post_init__()

labgrid/resource/udev.py

@@ -758,8 +758,10 @@ class MatchedSysfsGPIO(USBResource):
     """The MatchedSysfsGPIO described a SysfsGPIO matched by Udev
 
     Args:
-        pin (int): gpio pin number within the matched gpiochip."""
+        pin (int): gpio pin number within the matched gpiochip.
+        invert (bool): optional, whether the logic level is inverted (active-low)"""
     pin = attr.ib(default=None, validator=attr.validators.instance_of(int))
+    invert = attr.ib(default=False, validator=attr.validators.instance_of(bool))
     index = None
 
     def __attrs_post_init__(self):