SPI: DUAL/QUAD support

[yuhang wang]

2013/7/5 Sourav Poddar <sourav.poddar at ti.com>:
> On Friday 05 July 2013 02:37 PM, yuhang wang wrote:
>>>
>>>                      if (!quad_mode)
>>>                              dra7xxx_writel(qspi, qspi->cmd |
>>> QSPI_RD_SNGL,
>>>                                              QSPI_SPI_CMD_REG);
>>>                      else
>>>                              dra7xxx_writel(qspi, qspi->cmd |
>>> QSPI_RD_QUAD,
>>>                                              QSPI_SPI_CMD_REG);
>>>                   .......
>>>                  }
>>
>> So what do you based on to set variable quad_mode.
>
> Best way should be to check for flash device id and manufacture data. Based
> on which you
> can decide whether your flash supports quad bits or not.

Perhaps I did not said it clearly. Your flash supports quad and you
set it into quad
mode. But how can your controller driver notice that. In other word,
In which way
provide this information from flash to spi controller.