__sst_write
#define sst_write(reg,val) __sst_write(par->mmio_vbase, reg, val)
__sst_write(vbase, reg, __sst_read(vbase, reg) | val);
__sst_write(vbase, reg, __sst_read(vbase, reg) & ~val);
__sst_write(vbase, DAC_DATA, ((u32)reg << 8) | DAC_READ_CMD );
__sst_write(vbase, DAC_DATA,(((u32)reg << 8)) | (u32)val);