first commit

Python3 version. Run this script at boot time to correct the pin settings on the 40 pin connector. All the 'special function' pins are set to special-function, and the gpio pins are set to GPIO.

gpio_fixup.py

@@ -0,0 +1,65 @@
+#!/usr/bin/python3
+
+# a program to correct the GPIO settings to match the values in the i96 bus spec
+#
+# Pat Beirne <patb@pbeirne.com> 2021
+#
+# this script applies only to the OrangePi-i96, booting from u-boot 2012.04.442
+
+from mmap import mmap
+import os, sys, time, struct
+
+# assert the i96 GPIO pins into GPIO mode
+PORTC_GPIO_MASK = 0           # no pins need changing
+PORTA_GPIO_MASK = 0x7e508000  # rda gpioA 15,20,22,25-30 (i96 gpio group)
+PORTB_GPIO_MASK = 0           # no pins need changing
+PORTD_GPIO_MASK = 0xc         # rda gpioD 2,3 (i96 gpioi group)
+PORTB_GPIO_MASK_NO_CTSRTS = 0x300  # assert B 8,9 to reuse uart2_cts,rts
+
+# clear the i96 GPIO pins to special function mode
+PORTC_SF_MASK = 0xfffffe3f  # clear bits C c6,7,8 (i96 uarts)
+PORTA_SF_MASK = 0xffff91a0  # clear bits A 0-4,6,9-11,13,14 (i96 i2c, spi, i2s)
+PORTB_SF_MASK = 0xfffffc3f  # clear bits B 6-9 (i96 i2c, uart)
+PORTD_SF_MASK = 0xFFFFFFFF  # nothing to change
+
+PORTC_IOMUX = 0x11a09008
+PORTA_IOMUX = 0x11a0900c
+PORTB_IOMUX = 0x11a09010
+PORTD_IOMUX = 0x11a09014
+
+PAGE_MASK   = ~0xFFF
+PAGE_OFFSET = 0xFFF
+
+# we must read and write 4 bytes at a time, little-endian
+def get_word(mapfile, address):
+  address &= PAGE_OFFSET
+  return struct.unpack("<L", mapfile[address:address+4])[0]
+
+def put_word(mapfile, address, data):
+  address &= PAGE_OFFSET
+  mapfile[address:address+4] = struct.pack("<L",data)
+
+if __name__ == "__main__":
+  print("OrangePi-i96 fixup GPIO pins")
+  print("Version 1.0")
+
+  try:
+    with open("/dev/mem","r+b") as m:
+      mem = mmap(m.fileno(), 32, offset = PORTC_IOMUX & PAGE_MASK)
+      # set the GPIO pins up (to 1)
+      put_word(mem, PORTC_IOMUX, get_word(mem, PORTC_IOMUX) | PORTC_GPIO_MASK)
+      put_word(mem, PORTA_IOMUX, get_word(mem, PORTA_IOMUX) | PORTA_GPIO_MASK)
+      put_word(mem, PORTB_IOMUX, get_word(mem, PORTB_IOMUX) | PORTB_GPIO_MASK)
+      put_word(mem, PORTD_IOMUX, get_word(mem, PORTD_IOMUX) | PORTD_GPIO_MASK)
+
+      # and set the special function bit down (to 0)
+      put_word(mem, PORTC_IOMUX, get_word(mem, PORTC_IOMUX) & PORTC_SF_MASK)
+      put_word(mem, PORTA_IOMUX, get_word(mem, PORTA_IOMUX) & PORTA_SF_MASK)
+      put_word(mem, PORTB_IOMUX, get_word(mem, PORTB_IOMUX) & PORTB_SF_MASK)
+
+      print("GPIO pins corrected to agree with the i96 bus spec")
+
+  except PermissionError:
+    print("failed to open /dev/mem......you must execute this script as root")
+    exit(2)
+