open_input
open_input(NULL, argv[1]);
open_input(dir_name, "include/linux/input.h");
open_input(dir_name, "include/uapi/linux/input-event-codes.h");
open_input(spk_dir_name, "spk_priv_keyinfo.h");
int (*open_input) (struct snd_mpu401 * mpu);
if (mpu->open_input) {
err = mpu->open_input(mpu);
if (mpu->open_input && mpu->close_input)
mpu->open_input = snd_msnd_mpu401_open;
mpu->open_input = mpu401_open;
mpu->open_input = snd_sonicvibes_midi_input_open;