[PATCH V2 1/2] spi: dual and quad support(device tree)

[yuhang wang]

Hi, Pekon

What about the comment below, do I still need to check the mode before setting.

>> You missed out comments provided earlier..
>> http://lists.infradead.org/pipermail/linux-mtd/2013-August/048374.html
>>
>> Remember .. this compatibility check is between spi_device->mode
>> v/s spi_master->mode_bits. This is different from ur V3 patch
>> which checks for spi_transfer->tx_nbits v/s spi_device->mode.
>>
>> + if ((xfer->tx_nbits == SPI_NBITS_DUAL) &&
>> + !(spi->mode & (SPI_TX_DUAL | SPI_TX_QUAD)))
>> + return -EINVAL;
>> + if ((xfer->tx_nbits == SPI_NBITS_QUAD) &&
>> + !(spi->mode & SPI_TX_QUAD))
>> + return -EINVAL;
>>
>>
> Sorry for my mis-understanding. But here I want to regard DUAL / QUAD
> mode just as other mode, such as CPHA, CPOL and so on. To other mode,
> spi framework didn't do such check, example:
> ---------------------------------------------------------------------------------
> /* Mode (clock phase/polarity/etc.) */
> if (of_find_property(nc, "spi-cpha", NULL))
>     spi->mode |= SPI_CPHA;
> if (of_find_property(nc, "spi-cpol", NULL))
>     spi->mode |= SPI_CPOL;
> ---------------------------------------------------------------------------------
>
> Spi framework do this check in spi_setup as follow:
> ---------------------------------------------------------------------------------
> bad_bits = spi->mode & ~spi->master->mode_bits;
> if (bad_bits) {
>     dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
>           bad_bits);
>     return -EINVAL;
> }
> ---------------------------------------------------------------------------------
> So to keep that consistant, I don't think it is necessary to add the
> check when setting the mode.
>
> Best regards