SIL164_REG8
sil164_writeb(dvo, SIL164_REG8,
ret = sil164_readb(dvo, SIL164_REG8, &ch);
sil164_writeb(dvo, SIL164_REG8, ch);
ret = sil164_readb(dvo, SIL164_REG8, &ch);
sil164_readb(dvo, SIL164_REG8, &val);