STROBE
const u32 STROBE = 1<<17;
gpio_bits(0x20000, STROBE); /* STROBE high */
gpio_bits(0x20000, ~STROBE); /* STROBE low */
portman_write_command(pm, command | STROBE);
portman_write_command(pm, cmdout | STROBE); /* Write address+IE+Strobe. */
portman_write_command(pm, command | STROBE);
parport_write_control(p, RXDATA0 | STROBE); /* Write Strobe=1 to command reg. */