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. > 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. > 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. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
