M48T86_NVRAM
((u8 *)buf)[i] = m48t86_readb(dev, M48T86_NVRAM(off + i));
m48t86_writeb(dev, ((u8 *)buf)[i], M48T86_NVRAM(off + i));
unsigned int offset0 = M48T86_NVRAM(M48T86_NVRAM_LEN - 2);
unsigned int offset1 = M48T86_NVRAM(M48T86_NVRAM_LEN - 1);