> Date: Thu, 14 Jul 2016 19:45:32 +1000
> From: Jonathan Gray <[email protected]>
> 
> On Thu, Jul 14, 2016 at 11:34:05AM +0200, Mark Kettenis wrote:
> > > Date: Thu, 14 Jul 2016 17:53:22 +1000
> > > From: Jonathan Gray <[email protected]>
> > > 
> > > On Thu, Jul 14, 2016 at 03:20:34AM -0400, Ian Sutton wrote:
> > > > I am working on a MD PCI-E driver for the armv7/imx platform. It
> > > > attaches via FDT/simplebus, ascertaining its physical memory addresses
> > > > from the fdt structure originating from the dtb files present on the
> > > > msdos bootloader partition. The dtb files we're using now have the
> > > > cubox's 'pcie' nodes disabled via a "status=disabled" property. The
> > > > following patches fix this in the decompiled dtb outfiles:
> > > 
> > > I thought the wlan was attached to pcie but it seems it is
> > > actually an sdio device.
> > > 
> > > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/imx6qdl-microsom.dtsi
> > > 
> > > /* USDHC1 - Connected to optional BRCM Wifi/BT/FM */
> > > &usdhc1 {
> > >         pinctrl-names = "default";
> > >         pinctrl-0 = <&pinctrl_microsom_brcm_wifi 
> > > &pinctrl_microsom_usdhc1>;
> > >         bus-width = <4>;
> > >         mmc-pwrseq = <&usdhc1_pwrseq>;
> > >         keep-power-in-suspend;
> > >         no-1-8-v;
> > >         non-removable;
> > >         vmmc-supply = <&reg_brcm>;
> > >         status = "okay";
> > > };
> > 
> > WiFi over SDIO is quite common for these SoC-type systems.  The Bay
> > Trail-based ASUS EeeBook I have has a similar setup.  I suppose PCIe
> > sucks quite a bit of power even if you do proper link management.  I
> > actually believe that Broadcom's PCIe solutions are essentially SDIO
> > with a PCIe to SDIO bridge on front of them.
> > 
> > Time to investigate the
> > 
> >   sdmmc0: can't enable card
> > 
> > message I see on my CuBox-i4Pro once more.
> 
> I'd look at the no-1-8v property to start with (ommmc should be looking
> at ti,dual-volt before using 3.0v as well).
> 
> Documented as:
> 
> - no-1-8-v: when present, denotes that 1.8v card voltage is not supported on
>   this system, even if the controller claims it is.

I'll look at it, but I think the 1.8v thing doesn't apply to SDIO and
was only handled to work around an issue in the Linux sdhc code.

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