Hi,

On Mon, May 18, 2015 at 8:01 PM, Chen-Yu Tsai <[email protected]> wrote:

> Hi,
>
> On Mon, May 18, 2015 at 12:08 AM, Lawrence Y <[email protected]> wrote:
> > Hi,
> >
> > I'm not sure if it is my sdcard, my A31 hummingboard device, or
> something I
> > am doing wrong, but I've been trying to boot an A31 hummingbird from an
> > sdcard using the kernel from the sunxi-next branch at
> >
> > https://github.com/mripard/linux
> > 33da8d2 - Merge tag 'ib-mfd-regulator-v4.2' into sunxi-next
> >
> > and ran into a problem where the kernel would hang while waiting for the
> > root device /dev/mmcblk0p2
> >
> > If I use the sun6i-a31-hummingbird.dtb built from the linux mainline the
> > sdcard will boot the root file system correctly, but if I use the
> > sun6i-a31-hummingbird.dtb from sunxi-next the kernel will hang while
> waiting
> > for /dev/mmcblk0p2.
> >
> > I ran a git bisect and narrowed down the commit that causes the problem
> I am
> > seeing to
> >
> > commit bab03561224baa536b98f1d137d2b6b5dd159763
> > Date:   Tue Mar 10 19:59:21 2015 +0800
> >
> >     ARM: dts: sun6i: hummingbird: Add AXP221 regulator nodes
> >
> >     This patch adds the AXP221 regulators. Only the ones directly used
> >     on the board are added.
> >
> > Please let me know if there is anything I can do to help fix this
> problem,
> > if it really is a problem.  I have an A31 hummingbird available for
> testing.
>
> The latest commit you pointed to merges AXP221 support with regulators.
> The Hummingbird A31 dts was also updated with the new regulator nodes.
>
> Do you have AXP20X MFD and regulator support enabled?
> CONFIG_MFD_AXP20X and CONFIG_REGULATOR_AXP20X should be y.
>
>
> ChenYu
>

I tested with the sunxi_defconfig and confirmed that

CONFIG_INPUT_AXP20X_PEK=y
CONFIG_MFD_AXP20X=y
CONFIG_REGULATOR_AXP20X=y

are set in the .config file by the sunxi_defconfig and was used when the
root file system on the mmc card is not detected during the boot.

I did some more experimenting and found that if I change the vmmc-supply
for the mmc0 in the dts from vcc_3v0 to reg_vcc3v0 the root file system on
the sdcard will boot properly

@@ -119,7 +119,7 @@
 &mmc0 {
        pinctrl-names = "default";
        pinctrl-0 = <&mmc0_pins_a>, <&mmc0_cd_pin_hummingbird>;
-       vmmc-supply = <&vcc_3v0>;
+       vmmc-supply = <&reg_vcc3v0>;
        bus-width = <4>;
        cd-gpios = <&pio 0 8 GPIO_ACTIVE_HIGH>; /* PA8 */
        cd-inverted;

I am going to try Han's suggestion of using the vcc_3v3 when I get a chance
to see if that makes it better.

Lawrence

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