added permissions handling and readonly mode

__email__ = "oleg@elphel.com"

__email__ = "oleg@elphel.com"

__status__ = "Released"

__status__ = "Released"

import array, fcntl

import array, fcntl, os, errno

import argparse # http://docs.python.org/2/howto/argparse.html

import argparse # http://docs.python.org/2/howto/argparse.html

IOCTL_GPIOGET = 0x8000

IOCTL_GPIOGET = 0x8000

parser = argparse.ArgumentParser()

parser = argparse.ArgumentParser()

parser.add_argument('-d', '--device', default="/dev/ttyUSB0", help='USB device. Default: /dev/ttyUSB0')

parser.add_argument('-d', '--device', default="/dev/ttyUSB0", help='USB device. Default: /dev/ttyUSB0')

parser.add_argument("gpio_value", help="hex value for GPIO. Example (GPIO[3:0]): 0xf - all 1's, 0x0 - all 0's")

parser.add_argument("gpio_value", default=None, nargs='?', help="hex value for GPIO. Example (GPIO[3:0]): 0xf - all 1's, 0x0 - all 0's. If not specified - read GPIO only")

parser.add_argument('-m', '--mask', default="0xff",help='hex value for masking out GPIO bits: 1 - enable rewrite, 0 - disable. Example (GPIO[3:0]): -m 0xf')

parser.add_argument('-m', '--mask', default="0xff",help='hex value for masking out GPIO bits: 1 - enable rewrite, 0 - disable. Example (GPIO[3:0]): -m 0xf')

args = parser.parse_args()

args = parser.parse_args()

device=args.device

device=args.device

if args.gpio_value is None:

    mask=0

    gpio=0xff

else:    

    mask = int(args.mask,0)

    mask = int(args.mask,0)

    gpio = (int(args.gpio_value,0)<<16)|mask

    gpio = (int(args.gpio_value,0)<<16)|mask

print ('Target GPIO value:'),gpio

print ('Target GPIO value: 0x%x, mask: 0x%x'%(gpio,mask))

exit (0)    

try:

try:

    fd = open(device, 'r+')

    fd = open(device, 'r+')

except:

except IOError, ioex:

    raise Exception(str(device)+' is not present')

    if (errno.errorcode[ioex.errno]=='EACCES'):

        print "\nDid you forget to use 'sudo' ?\n"

    raise Exception(str(device)+' - '+os.strerror(ioex.errno))

buf = array.array('l', [0])

buf = array.array('l', [0])

fcntl.ioctl(fd, IOCTL_GPIOGET, buf, 1)

fcntl.ioctl(fd, IOCTL_GPIOGET, buf, 1)