Re: using mmc2 on panda [was: Regression 3.11-rc1: omap4panda:no usb and consequently no ethernet]

From: Arend van Spriel
Date: Wed Oct 02 2013 - 05:04:10 EST


On 10/01/2013 03:19 PM, Balaji T K wrote:
Hi Roger,

It has been a while, but I would like to pickup this thread. We
have a couple of pandaboards used as test setup. These have an
SDIO adapter hooked up to expansion connector A using MMC2. I have
attached the patch file (just ignore platform_data stuff). Now on
one board it works, but not for the other. I suspect a board issue
so listing the two types that we use:

PandaBoard rev A2 (dmesg: OMAP4430 ES2.1): works
PandaBoardES rev B1 (dmesg: OMAP4460 ES1.1): nope

Any hints for me.

Does your PandaboardES have the WLAN chip (U4) mounted? If yes, how
do you isolate
it from your external SDIO adapter?

On my 4460 board in front of me U4 is not populated, but U3 is (the
TiWi thing).


OK, just realized that the expansion connector uses different pads
for MMC2. However, you still
need to make sure that the other pins (connected to on board WLAN
chip) are not muxed as MMC2.

I think Luciano added DT patches for on-board WLAN and it uses MMC5
if I am not mistaken(?). Attached are the dmesg logs of the two boards.

Right. WLAN is supposed to use MMC5. But if you don't have Luca's
patches, can you please ensure that those pins are muxed either as
safe mode
or as MMC5? Default seems to be safe mode, but you should cross check.

Also in your patches you have set mmc2-clk to PIN_INPUT_PULLUP
Shouldn't it be PIN_OUTPUT?

Still I have no clue why it works on 4430 and not on 4460. Are you
using the same bootloader image on both boards?

if you are using vaux1, can you check the voltage levels,

From dmesg you attached,
vaux1 is set to 1.8V on omap4430 and to 2.8V on OMAP4460

4430
[ 2.425750] VAUX1_6030: 1000 <--> 3000 mV at 1800 mV

4460
[ 2.244262] VAUX1_6030: 1000 <--> 3000 mV at 2800 mV

Nice catch. Not sure whether this is an issue, but worth looking into.

Can you also check with MMC_DEBUG enabled for any clues.

building....

cheers,
-roger
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