GP_GPIO_PUP_PDN_CNTRL_REG0
val = bcm2835_gpio_rd(pc, GP_GPIO_PUP_PDN_CNTRL_REG0 + (offset * 4));
value = bcm2835_gpio_rd(pc, GP_GPIO_PUP_PDN_CNTRL_REG0 + (off * 4));
bcm2835_gpio_wr(pc, GP_GPIO_PUP_PDN_CNTRL_REG0 + (off * 4), value);