On 11/22/2012 08:33 PM, Fabio Estevam wrote:

Hi Sinan,

On Thu, Nov 22, 2012 at 7:43 PM, Sinan Akman sinan@writeme.com wrote:

...

Hi Fabio

I just tried spi nor on fsl m28evk and see :

MX28EVK U-Boot > sf probe SF: Unsupported manufacturer ff Failed to initialize SPI flash at 2:0

This is with U-Boot 2012.10 and I included #define CONFIG_SPI_FLASH_WINBOND in mx28evk.h.

Which SPI flash have you populated into mx28evk?

Hi Fabio, thanks for your reply. I guess I got blindfolded by another winbond W25X80 populated board that I used to access and now an unrelated winbond chip on this board. But this board was not populated therefore the FF readings as ID. Marek helped me to figure out and forwarded your message.

I find it interesting though that an unpopulated chip returns FFs instead of causing a timeout etc. Probing another (presumably non-existing) bus/cs value (e.g. 3:0) causes a timeout. I don't know enough about this at this point why we read FFs quietly in an unpopulated case but I would like to dig a bit more.

Thanks much for the pointers you provided.

-- sinan