attenuation-control: Add scripts to control the attenuation

Xmlrpc client/server application to control the digital attenuators
installed in the lava testbed.

Implements AR_VUL-64.

Signed-off-by: Thomas Klaehn <thomas.klaehn@u-blox.com>

source/attenuator/__init__.py

@@ -0,0 +1,115 @@
+import os
+import sys
+
+try:
+    from IOPi import IOPi
+except ImportError:
+    sys.path.append('mock')
+    try:
+        from IOPi import IOPi
+    except ImportError:
+        raise ImportError("IOPi not found")
+
+class Pin(object):
+    """Abstraction of pin object. Every pin object contains a gpio number and a i2c bus address."""
+    bus_address = None
+    pin_number = None
+    bus = None
+
+    def __init__(self, bus_address, pin_number):
+        """Constructor.
+
+        Args:
+            bus_address (int): i2c bus address [0x20..0x23].
+            pin_number (int): Gpio pin number.
+        """
+        self.bus_address = bus_address
+        self.pin_number = pin_number
+
+class Attenuator(object):
+    """Abstraction of ANALOG DEVICES HMC425A digital attenuator"""
+    pin = None
+
+    def __init__(self,pin_0_5db, pin_1_0db, pin_2_0db, pin_4_0db, pin_8_0db, pin_16_0db):
+        """Constructor.
+
+        Args:
+            pin_0_5db (Pin): Pin object to control the 0.5 db gpio
+            pin_1_0db (Pin): Pin object to control the 1.0 db gpio
+            pin_2_0db (Pin): Pin object to control the 2.0 db gpio
+            pin_4_0db (Pin): Pin object to control the 4.0 db gpio
+            pin_8_0db (Pin): Pin object to control the 8.0 db gpio
+            pin_16_0db (Pin): Pin object to control the 16.0 db gpio
+        """
+        if type(pin_0_5db) is not Pin:
+            raise TypeError("Wrong type for pin_0_5db")
+        if type(pin_1_0db) is not Pin:
+            raise TypeError("Wrong type for pin_1_0db")
+        if type(pin_2_0db) is not Pin:
+            raise TypeError("Wrong type for pin_2_0db")
+        if type(pin_4_0db) is not Pin:
+            raise TypeError("Wrong type for pin_4_0db")
+        if type(pin_8_0db) is not Pin:
+            raise TypeError("Wrong type for pin_8_0db")
+        if type(pin_16_0db) is not Pin:
+            raise TypeError("Wrong type for pin_16_0db")
+
+        if pin_0_5db.bus_address not in range(0x20, 0x24):
+            raise IndexError('pin_0_0db i2c bus address index out of range')
+        if pin_1_0db.bus_address not in range(0x20, 0x24):
+            raise IndexError('pin_1_0db i2c bus address index out of range')
+        if pin_2_0db.bus_address not in range(0x20, 0x24):
+            raise IndexError('pin_2_0db i2c bus address index out of range')
+        if pin_4_0db.bus_address not in range(0x20, 0x24):
+            raise IndexError('pin_4_0db i2c bus address index out of range')
+        if pin_8_0db.bus_address not in range(0x20, 0x24):
+            raise IndexError('pin_8_0db i2c bus address index out of range')
+        if pin_16_0db.bus_address not in range(0x20, 0x24):
+            raise IndexError('pin_16_0db i2c bus address index out of range')
+
+        if pin_0_5db.pin_number not in range(1, 17):
+            raise IndexError('pin_0_5db pin number index out of range')
+        if pin_1_0db.pin_number not in range(1, 17):
+            raise IndexError('pin_1_0db pin number index out of range')
+        if pin_2_0db.pin_number not in range(1, 17):
+            raise IndexError('pin_2_0db pin number index out of range')
+        if pin_4_0db.pin_number not in range(1, 17):
+            raise IndexError('pin_4_0db pin number index out of range')
+        if pin_8_0db.pin_number not in range(1, 17):
+            raise IndexError('pin_8_0db pin number index out of range')
+        if pin_16_0db.pin_number not in range(1, 17):
+            raise IndexError('pin_16_0db pin number index out of range')
+
+        self.pin = [pin_0_5db, pin_1_0db, pin_2_0db, pin_4_0db, pin_8_0db, pin_16_0db]
+
+        for pin in self.pin:
+            pin.bus = IOPi(pin.bus_address)
+            pin.bus.set_pin_direction(pin.pin_number, 0)
+            pin.bus.write_pin(pin.pin_number, 0)
+
+    def set_attenuation(self, attenuation):
+        """Set attenuation.
+
+        Args:
+            attenuation (float): Value of attenuation to be set [0..31.5]
+        """
+        if attenuation < 0:
+            attenuation = 0
+        elif attenuation > 31.5:
+            attenuation = 31.5
+
+        max_single_value = 16 * 2
+        attenuation *= 2
+        switch_pin = [1 for i in range(6)]
+        index = 5
+
+        while index >= 0:
+            if attenuation - max_single_value >= 0:
+                attenuation -= max_single_value
+                switch_pin[index] = 0
+            max_single_value /= 2
+            index -= 1
+
+        for i in range(0, len(switch_pin)):
+            bus = IOPi(self.pin[i].bus_address)
+            bus.write_pin(self.pin[i].pin_number, switch_pin[i])