XADC_REG_SEQ
ret = xadc_write_adc_reg(xadc, XADC_REG_SEQ(0), scan_mask & 0xffff);
ret = xadc_write_adc_reg(xadc, XADC_REG_SEQ(1), scan_mask >> 16);
ret = xadc_write_adc_reg(xadc, XADC_REG_SEQ(0), scan_mask & 0xffff);
ret = xadc_write_adc_reg(xadc, XADC_REG_SEQ(1), scan_mask >> 16);