Totally forgot to add the OverlayManager code in the last commit. This update is for #10

CHIP_IO/OverlayManager.py

@@ -0,0 +1,192 @@
+import os
+import shutil
+import time
+
+DEBUG = False
+
+OVERLAYINSTALLPATH = "/lib/firmware/chip_io"
+OVERLAYCONFIGPATH  = "/sys/kernel/config/device-tree/overlays"
+CUSTOMOVERLAYFILEPATH = ""
+
+PWMSYSFSPATH = "/sys/class/pwm/pwmchip0"
+I2C1SYSFSPATH = "/sys/class/i2c-dev/i2c-1"
+
+# LOADED VARIABLES
+# DO NOT MODIFY BY HAND WHEN USING
+# AS IT COULD BREAK FUNCTIONALITY
+_LOADED = {
+  "I2C1" : False,
+  "SPI2" : False,
+  "PWM0" : False,
+  "CUST" : False
+}
+
+_OVERLAYS = {
+  "I2C1" : "chip-i2c1.dtbo",
+  "SPI2" : "chip-spi2.dtbo",
+  "PWM0" : "chip-pwm0.dtbo",
+  "CUST" : ""
+}
+
+_FOLDERS = {
+  "I2C1" : "chip-i2c",
+  "SPI2" : "chip-spi",
+  "PWM0" : "chip-pwm",
+  "CUST" : "chip-cust"
+}
+
+def enable_debug():
+    global DEBUG
+    DEBUG = True
+
+def get_i2c_loaded():
+    """
+     get_i2c_loaded - Returns True/False based upon if the i2c-1 Overlay is loaded
+    """
+    global _LOADED
+    return _LOADED["I2C1"]
+
+def get_spi_loaded():
+    """
+     get_spi_loaded - Returns True/False based upon if the spi2 Overlay is loaded
+    """
+    global _LOADED
+    return _LOADED["SPI2"]
+
+def get_pwm_loaded():
+    """
+     get_pwm_loaded - Returns True/False based upon if the pwm0 Overlay is loaded
+    """
+    global _LOADED
+    return _LOADED["PWM0"]
+
+def get_custom_loaded():
+    """
+     get_custom_loaded - Returns True/False based upon if a Custom Overlay is loaded
+    """
+    global _LOADED
+    return _LOADED["CUST"]
+
+def _set_overlay_verify(name, overlay_path, config_path):
+    """
+     _set_overlay_verify - Function to load the overlay and verify it was setup properly
+    """
+    global DEBUG
+    # VERIFY PATH IS NOT THERE
+    if os.path.exists(config_path):
+        print("Config path already exists! Not moving forward")
+        print("config_path: {0}".format(config_path))
+        return -1
+    
+    # MAKE THE CONFIGURATION PATH
+    os.makedirs(config_path)
+
+    # CAT THE OVERLAY INTO THE CONFIG FILESYSTEM
+    with open(config_path + "/dtbo", 'wb') as outfile:
+        with open(overlay_path, 'rb') as infile:
+            shutil.copyfileobj(infile, outfile)
+
+    # SLEEP TO ENABLE THE KERNEL TO DO ITS JOB
+    time.sleep(0.2)
+
+    # VERIFY
+    if name == "PWM0":
+        if os.path.exists(PWMSYSFSPATH):
+            if DEBUG:
+                print("PWM IS LOADED!")
+            return 0
+        else:
+            if DEBUG:
+                print("ERROR LOAIDNG PWM0")
+            return 1
+    elif name == "I2C1":
+        if os.path.exists(I2C1SYSFSPATH):
+            if DEBUG:
+                print("I2C-1 IS LOADED!")
+            return 0
+        else:
+            if DEBUG:
+                print("ERROR LOADING I2C-1")
+            return 1
+
+def load(overlay, path=""):
+    """
+     load - Load a DTB Overlay
+
+     Inputs:
+      overlay - Overlay Key: I2C1, SPI2, PWM0, CUST
+      path    - Full Path to where the custom overlay is stored
+
+     Returns:
+      0 - Successful Load
+      1 - Unsuccessful Load
+      2 - Overlay was previously set
+    """
+    global DEBUG
+    global _LOADED
+    if DEBUG:
+        print("LOAD OVERLAY")
+        print("OVERLAY: {0}".format(overlay))
+        print("PATH:    {0}".format(path))
+    # SEE IF OUR OVERLAY NAME IS IN THE KEYS
+    if overlay.upper() in _OVERLAYS.keys():
+        cpath = OVERLAYCONFIGPATH + "/" + _FOLDERS[overlay.upper()]
+        if DEBUG:
+            print("VALID OVERLAY")
+            print("CONFIG PATH:  {0}".format(cpath))
+        # CHECK TO SEE IF WE HAVE A PATH FOR CUSTOM OVERLAY
+        if overlay.upper() == "CUST" and path == "":
+            raise ValueError("Path must be specified for Custom Overlay Choice")
+        elif overlay.upper() == "CUST" and _LOADED[overlay.upper()]:
+            print("Custom Overlay already loaded")
+            return 2
+        elif overlay.upper() == "CUST":
+            opath = OVERLAYINSTALLPATH + "/" + _OVERLAYS[overlay.upper()]
+            print("Custom Overlay not implemented yet")
+            return 1
+
+        # SET UP THE OVERLAY PATH FOR OUR USE
+        if overlay.upper() != "CUST":
+            opath = OVERLAYINSTALLPATH + "/" + _OVERLAYS[overlay.upper()]
+        else:
+            opath = path
+        if DEBUG:
+            print("OVERLAY PATH: {0}".format(opath))
+
+        if overlay.upper() == "PWM0" and _LOADED[overlay.upper()]:
+            print("PWM0 Overlay already loaded")
+            return 2
+
+        if overlay.upper() == "I2C1" and _LOADED[overlay.upper()]:
+            print("I2C1 Overlay already loaded")
+            return 2
+
+        if overlay.upper() == "SPI2" and _LOADED[overlay.upper()]:
+            print("SPI2 Overlay already loaded")
+            return 2
+
+        # LOAD THE OVERLAY
+        errc = _set_overlay_verify(overlay.upper(), opath, cpath)
+        if DEBUG:
+            print("ERRC: {0}".format(errc))
+        if errc == 0:
+            _LOADED[overlay.upper()] = True
+
+    else:
+        raise ValueError("Invalid Overlay name specified! Choose between: I2C1, SPI2, PWM0, CUST")
+
+def unload(overlay):
+    global DEBUG
+    global _LOADED
+    if DEBUG:
+        print("UNLOAD OVERLAY")
+        print(overlay)
+    # SEE IF OUR OVERLAY NAME IS IN THE KEYS
+    if overlay.upper() in _OVERLAYS.keys():
+        # BRUTE FORCE REMOVE AS THE DIRECTORY CONTAINS FILES
+        os.system('rmdir \"{}\"'.format(OVERLAYCONFIGPATH + "/" + _FOLDERS[overlay.upper()]))
+        _LOADED[overlay.upper()] = False
+    else:
+        raise ValueError("Invalid Overlay name specified! Choose between: I2C1, SPI2, PWM0, CUST")
+        
+