[U-Boot] [PATCH] mx28: fix i.MX28 spi driver

[Fabio Estevam]

On 1/14/12, Matthias Fuchs <matthias.fuchs at esd.eu> wrote:
> The generic spi flash driver (drivers/mtd/spi/spi_flash.c) uses the
> spi low level driver's spi_xfer() function with len=0 to deassert the
> SPI flash' chip select. But the i.MX28 spi driver rejects this call
> due to len=0.
>
> This patch implements an exception for len=0 with the SPI_XFER_END
> flag set. This results in an extra read with the chip select being
> deasserted afterwards. There seems to be no way to deassert the signal
> by hand.
>
> Signed-off-by: Matthias Fuchs <matthias.fuchs at esd.eu>

Tested-by: Fabio Estevam <fabio.estevam at freescale.com>

Soldered a SST25VF016B on a mx28evk (and also the SPI pullups) and
verified that the flash can be erased succesfully now.

I suggest that this patch gets applied as it fixes a real issue.

Thanks,

Fabio Estevam