Re: [PATCH] [MTD] [CHIPS] stm_flash: new ST PSD4256G compatible flash chip driver

[Mike Frysinger <vapier.adi@gmail.com>]

On Tue, Sep 22, 2009 at 19:20, David Woodhouse wrote:
> On Tue, 2009-09-22 at 19:05 -0400, Mike Frysinger wrote:
>> the only problem i have here is with the need to 0xff pad the mfr/dev
>> id's.  any idea what's up with that ?  the device is 16bit and i set
>> my .width in my board resources to 2, but the id field is only 8bit,
>> so in 16bit mode the id is padded with 0xff instead of 0x00.
>
> Hm, odd -- but I wouldn't lose sleep over it.
>
> However, the datasheet suggests that the high byte is unspecified. Could
> it be returning the value of the flash data at that location, rather
> than a constant 0xFF? If so, we'd need to add a flag to the jedec match
> table to make it match only the low byte?
>
> Or maybe I'd make you do your own probe in that case, rather than
> polluting jedec_probe.c... :)

nah, none of the first 0x10 bytes are 0xff:
00000000  7f 1d bb 58 8f 04 4c 6d  f5 ee 55 d6 79 b4 31 51  |...X..Lm..U.y.1Q|

this is the only board ive seen that has this part, but i can do a
sampling of different revisions to make sure they're all 0xff.  if
you're ok with the small changes i mentioned, then i'll post a patch
for that (to replace the original proposed chip driver) and call it a
day.
-mike