Hi Adrian,
On 31.08.2017 14:41, Adrian Hunter wrote:
On 31/08/17 12:38, Stefan Roese wrote:
Hi Andy, Hi Adrian,
On 04.07.2017 15:53, Andy Shevchenko wrote:
On Tue, 2017-07-04 at 14:53 +0200, Stefan Roese wrote:
Hi,
we are currently investigating, if its possible to connect a SDIO
device (WLAN module) to the SD-card interface "SD3" of the BayTrail
SoC instead of the SDIO interface "SD2". The BayTrail manual states,
that the SDIO interface is capable of connecting SDIO devices. Is
this also possible for the SD-card interface "SD3", even if its not
explicitly mentioned in the manual? If not, why is this not possible?
Any insight on this would be really helpful.
Hmm... I have no documentation for SD/SDIO/eMMC for BayTrail except the
public one. Internally I found some charts that shows similarities
between two. So, taking that into consideration I would suggest to try
it out on real hardware (MinnowBoard MAX, for example), only impediment
I can see is the absence of support in the drivers in Linux OS. If you
need it only in U-Boot, you perhaps may fix it easily.
P.S. Adrian on vacation.
I hope your vacation was great!
Sorry for getting back to this, but I would really like to get some
more feedback on this. Perhaps Adrian has some additional comments
about the SDIO usage of the SD interface (SD3 - PCI Device ID 0x0f16)
on BayTrail.
I'm now running latest mainline Linux on this board and am trying to
get the Linux MMC / SDIO subsystem to just detect a device on this
SD PCI interface. For this I have added quite a bit of debug code to
the MMC / SDIO code to see, if any device is detected on the SDIO
port. But all command queries return timeout as far as I can tell.
I would usually interpret that to mean the SDIO card is not turned on.
Yes, this is of course possible - or some signal issues while
level-shifting etc. I've also thought of this possibility. One of the
next things to do, will be to measure some of the signals.
Adrian, do you have some additional information, if this mode of
operation is possible at all on this SD-card interface, even if
its not explicitly mentioned in the BayTrail datasheet?
I have used removable SDIO cards in SD slots before. It should work.
Sorry, but I need to double-check on this. You have successfully used
some SDIO cards in this "SD-card-only controller" (as stated in the
datasheet) on BayTrail?
Do you b y any chance remember, which SDIO card you have tested with?
Or do you
have some suggestions, how I could test such a basic SDIO connection
(without integrating of the WLAN driver first) in the simplest way?
Only to try a removable SDIO card.
Thats not possible on this board, as this WLAN module is soldered.
But I might find some other / alternative board, to test this. Let
me check on this...
Thanks,
Stefan
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