from migen import *
from migen.build.generic_platform import *


def _eem_signal(i):
    n = "d{}".format(i)
    if i == 0:
        n += "_cc"
    return n


def _eem_pin(eem, i, pol):
    return "eem{}:{}_{}".format(eem, _eem_signal(i), pol)


def default_iostandard(eem):
    return IOStandard("LVDS_25")


def diff_io(eem, iostandard=default_iostandard):
    return [("dio{}".format(eem), i,
        Subsignal("p", Pins(_eem_pin(eem, i, "p"))),
        Subsignal("n", Pins(_eem_pin(eem, i, "n"))),
        iostandard(eem))
        for i in range(8)]


def generate_pads(platform, eem):
    platform.add_extension(diff_io(eem))