On Mon, Dec 15, 2014 at 10:27 PM, Bjorn Andersson <bjorn@xxxxxxx> wrote: > On Sun, Dec 14, 2014 at 8:48 PM, Tim Kryger <tim.kryger@xxxxxxxxx> wrote: >> On Sat, Dec 13, 2014 at 11:22 PM, Bjorn Andersson <bjorn@xxxxxxx> wrote: > [..] >>> Or simply; what is vmmc (in the code) supposed to represent? >> >> Hi Bjorn, >> >> VMMC is the supply that delivers power out to the SD card itself (aka VDD). >> >> It is not the internal power rail/power domain of the host controller >> within the SoC. >> > > Thanks for you answer Tim, I'll write up a patch for the Qualcomm > driver that add the possibility of specifying an internal supply for > the devices where that uses that. > > My only concern is that for any standard compliant sdhci driver we're > supposed to have a info printout that vmmc was not found (but vqmmc is > there). But I guess that's a matter of proper documentation and hoping > people don't pay too much attention to it? > Sorry, this is wrong. We are routing the regulators straight to vdd of the memory and should hence use vmmc to specify this. However unless I actually program 0x29 in the Qualcomm sdhci block I get no responses from the card. Which I believe is correct behavior as the SDHC specification [1] says the following about BIT(0) of 0x29: "If this bit is cleared, the Host Controller shall immediately stop driving CMD and DAT[3:0] (tri-state) and drive SDCLK to low level". So I think 52221610d is indeed incorrect. [1] https://www.sdcard.org/downloads/pls/simplified_specs/archive/partA2_300.pdf Regards, Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
