Add code to Encoder.QEP from PyBBIO.RotaryEncoder

Add code to use as a basis for our QEP module from:
graycatlabs/PyBBIO/bbio/libraries/RotaryEncoder/rotary_encoder.py

Author: pdp7

Adafruit_BBIO/Encoder.py

@@ -4,6 +4,15 @@
 # Adafruit_BBIO.Encoder.QEP Class
 # ===========================================================================
 
+# refers to graycatlabs/PyBBIO/bbio/libraries/RotaryEncoder/rotary_encoder.py
+# /sys/devices/platform/ocp/48302000.epwmss/48302180.eqep/position
+# /sys/devices/platform/ocp/48304000.epwmss/48304180.eqep/position
+# /sys/devices/platform/ocp/48300000.epwmss/48300180.eqep/position
+
+import os
+
+
+
 class QEP :
 
   def __init__(self, channel=1, debug=False):
@@ -16,19 +25,158 @@ def errMsg(self):
 
 # example method from Adafruit_I2C
 # TODO: delete this
-  def write8(self, reg, value):
-    "Writes an 8-bit value to the specified register/address"
-    try:
-      self.bus.write_byte_data(self.address, reg, value)
-      if self.debug:
-        print("Rotary: Wrote 0x%02X to register 0x%02X" % (value, reg))
-    except IOError as err:
-      return self.errMsg()
-
-
-if __name__ == '__main__':
-  try:
-    qep = Adafruit_BBIO.Encoder.QEP()
-    print("Default QEP channel is accessible")
-  except:
-    print("Error accessing default Rotary bus")
+#  def write8(self, reg, value):
+#    "Writes an 8-bit value to the specified register/address"
+#    try:
+#      self.bus.write_byte_data(self.address, reg, value)
+#      if self.debug:
+#        print("Rotary: Wrote 0x%02X to register 0x%02X" % (value, reg))
+#    except IOError as err:
+#      return self.errMsg()
+#
+#
+#if __name__ == '__main__':
+#  try:
+#    qep = Adafruit_BBIO.Encoder.QEP()
+#    print("Default QEP channel is accessible")
+#  except:
+#    print("Error accessing default Rotary bus")
+
+
+
+class RotaryEncoder(object):
+  OCP_PATH = "/sys/TEST/TODO/"
+  _eqep_dirs = [
+    '%s/48300000.epwmss/48300180.eqep' % OCP_PATH,
+    '%s/48302000.epwmss/48302180.eqep' % OCP_PATH,
+    '%s/48304000.epwmss/48304180.eqep' % OCP_PATH
+  ]
+  EQEP0 = 0
+  EQEP1 = 1
+  EQEP2 = 2
+  EQEP2b = 3
+    
+  def __init__(self, eqep_num):
+    '''
+    RotaryEncoder(eqep_num)
+    Creates an instance of the class RotaryEncoder. 
+    eqep_num determines which eQEP pins are set up. 
+    eqep_num can be: EQEP0, EQEP1, EQEP2 or EQEP2b based on which pins \
+    the rotary encoder is connected to.
+    '''
+    assert 0 <= eqep_num <= 3 , "eqep_num must be between 0 and 3"
+    if eqep_num == 3:
+        overlay = "PyBBIO-eqep2b"
+    	eqep_num = 2
+    else:
+    	overlay = 'PyBBIO-eqep%i' % eqep_num
+
+    pwmss_overlay = "PyBBIO-epwmss%i" % eqep_num
+    #cape_manager.load(pwmss_overlay, auto_unload=False)
+    delay(10)
+    #cape_manager.load(overlay, auto_unload=False)
+    delay(250) # Give driver time to load 
+    self.base_dir = self._eqep_dirs[eqep_num]
+    self.enable()
+    addToCleanup(self.disable)
+    
+  def enable(self):
+    '''
+    enable()
+    Turns the eQEP hardware ON
+    '''
+    enable_file = "%s/enabled" % self.base_dir
+    #return sysfs.kernelFileIO(enable_file, '1') 
+    
+  def disable(self):
+    '''
+    disable()
+    Turns the eQEP hardware OFF
+    '''
+    enable_file = "%s/enabled" % self.base_dir
+    #return sysfs.kernelFileIO(enable_file, '0')
+
+  def setAbsolute(self):
+    '''
+    setAbsolute()
+    Set mode as Absolute
+    The position starts at zero and is incremented or 
+    decremented by the encoder's movement
+    '''
+    mode_file = "%s/mode" % self.base_dir
+    #return sysfs.kernelFileIO(mode_file, '0')
+    
+  def setRelative(self):
+    '''
+    setRelative()
+    Set mode as Relative
+    The position is reset when the unit timer overflows.
+    '''
+    mode_file = "%s/mode" % self.base_dir
+    #return sysfs.kernelFileIO(mode_file, '1')
+    
+  def getMode(self):
+    '''
+    getMode()
+    Returns the mode the eQEP hardware is in.
+    '''
+    mode_file = "%s/mode" % self.base_dir
+    #return sysfs.kernelFileIO(mode_file)
+
+  def getPosition(self):
+    '''
+    getPosition()
+    Get the current position of the encoder.
+    In absolute mode, this attribute represents the current position 
+    of the encoder. 
+    In relative mode, this attribute represents the position of the 
+    encoder at the last unit timer overflow.
+    '''
+    position_file = "%s/position" % self.base_dir
+    #return sysfs.kernelFileIO(position_file)
+    
+  def setFrequency(self,freq):
+    '''
+    setFrequency(freq)
+    Set the frequency in Hz at which the driver reports new positions.
+    '''
+    period_file = "%s/period" % self.base_dir
+    #return sysfs.kernelFileIO(period_file, str(1000000000/freq))
+    
+  def setPosition(self,val):
+    ''' 
+    setPosition(value)
+    Give a new value to the current position
+    '''
+    position_file = "%s/position" % self.base_dir
+    #return sysfs.kernelFileIO(position_file, str(val))
+    
+  def zero(self):
+    '''
+    zero()s
+    Set the current position to 0
+    '''
+    return self.setPosition(0)
+
+
+#"""
+# encoder_test.py 
+# Rekha Seethamraju
+# An example to demonstrate the use of the eQEP library
+# for PyBBIO.
+# This example program is in the public domain.
+#"""
+#from bbio import *
+#from bbio.libraries.RotaryEncoder import RotaryEncoder
+#
+#encoder = RotaryEncoder(RotaryEncoder.EQEP2b)
+#
+#def setup():
+#  encoder.setAbsolute()
+#  encoder.zero()
+#  
+#def loop():
+#  print "encoder position : "+encoder.getPosition()
+#  delay(1000)
+#  
+#run(setup, loop)