Re: [PATCH v3] mtd: spi-nor: Add support for Cypress cy15x104q

[<Tudor.Ambarus@xxxxxxxxxxxxx>]

On Friday, April 24, 2020 9:56:26 AM EEST Sascha Hauer wrote:
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> The Cypress cy15b104q and cy15v104q are 4Mbit serial SPI F-RAM devices.
> Add support for them to the spi-nor driver.
> 
> The actual Device ID of this chip is 7f 7f 7f 7f 7f 7f c2 2c 04. That is
> six times the continuation code 7f followed by c2 for Ramtron.
> Unfortunately the chip sends the Device ID in reversed order, so the
> continuation code is not at the beginning, but instead at the end. Even
> more unfortunate is that when reading further the chip sends more 7f
> codes which means we are not even able to count the continuation codes.
> We can only hope that this reversed Device ID will never match any other
> devices ID.
> 
> Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>

Collisions are improbable as of now, the solution from above is good
enough. In case of future collisions one can introduce an INFO9 macro,
with the downsize that struct flash_info would grow and we have lots of
flashes. A more elegant solution would be to introduce dedicated
flash ID tables for each bank in JESP106BA.

Amended commit description with the above text and applied. Thanks.


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