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References: <20190719192954.26481-1-xruppen@gmail.com> <eadcf7ef-4aad-fa4f-3b1b-a5238f394b1e@baylibre.com>
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From:   Anand Moon <linux.amoon@gmail.com>
Date:   Wed, 24 Jul 2019 11:00:26 +0530
Message-ID: <CANAwSgTbvQO5qum1K3q8+J=WO4yLjadnZSZYf_AAhbf+CJm92Q@mail.gmail.com>
Subject: Re: [PATCH] arm64: dts: meson: odroid-n2: keep SD card regulator
 always on
To:     Neil Armstrong <narmstrong@baylibre.com>
Cc:     Xavier Ruppen <xruppen@gmail.com>,
        Kevin Hilman <khilman@baylibre.com>,
        Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
        linux-amlogic@lists.infradead.org,
        Linux Kernel <linux-kernel@vger.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>
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Hi All,

On Mon, 22 Jul 2019 at 12:51, Neil Armstrong <narmstrong@baylibre.com> wrote:
>
> On 19/07/2019 21:29, Xavier Ruppen wrote:
> > When powering off the Odroid N2, the tflash_vdd regulator is
> > automatically turned off by the kernel. This is a problem
> > when issuing the "reboot" command while using an SD card.
> > The boot ROM does not power this regulator back on, blocking
> > the reboot process at the boot ROM stage, preventing the
> > SD card from being detected.
> >
> > Adding the "regulator-always-on" property fixes the problem.
> >
> > Signed-off-by: Xavier Ruppen <xruppen@gmail.com>
> > ---
> >
> > Here is what the boot ROM output looks like without this patch:
> >
> >     [root@alarm ~]# reboot
> >     [...]
> >     [   24.275860] shutdown[1]: All loop devices detached.
> >     [   24.278864] shutdown[1]: Detaching DM devices.
> >     [   24.287105] kvm: exiting hardware virtualization
> >     [   24.318776] reboot: Restarting system
> >     bl31 reboot reason: 0xd
> >     bl31 reboot reason: 0x0
> >     system cmd  1.
> >     G12B:BL:6e7c85:7898ac;FEAT:E0F83180:2000;POC:F;RCY:0;
> >     EMMC:800;NAND:81;SD?:0;SD:400;USB:8;LOOP:1;EMMC:800;
> >     NAND:81;SD?:0;SD:400;USB:8;LOOP:2;EMMC:800;NAND:81;
> >     SD?:0;SD:400;USB:8;LOOP:3; [...]
> >
> > Other people can be seen having this problem on the odroid
> > forum [1].
> >
> > The cause of the problem was found by Martin Blumenstingl
> > on #linux-amlogic. We may want to add his Suggested-by tag
> > if he agrees.
> >
> > [1] https://forum.odroid.com/viewtopic.php?f=176&t=33993
> >
> >  arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts b/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts
> > index 81780ffcc7f0..4e916e1f71f7 100644
> > --- a/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts
> > +++ b/arch/arm64/boot/dts/amlogic/meson-g12b-odroid-n2.dts
> > @@ -53,6 +53,7 @@
> >
> >               gpio = <&gpio_ao GPIOAO_8 GPIO_ACTIVE_HIGH>;
> >               enable-active-high;
> > +             regulator-always-on;
> >       };
> >
> >       tf_io: gpio-regulator-tf_io {
> >
>
> Surely solves the situation, thanks !
>
> please add a comment on top of "regulator-always-on" to explain why we always enable it,
> note we should always enable it in case of watchdog reboot or other uncontrolled reset,
> this regulator must never be disabled.
>
> Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
>
> Thanks,
> Neil
>

I am afraid this did not fix the issue I was also facing with
Archlinux on Odroid N2 using mainline u-boot.
Here is the log of at my end using latest mainline u-boot with Neil's patches.

[0] https://pastebin.com/HNmeY5uF

Well this issue also persist with eMMC not getting detected after reboot
If I try to change the dts to fix the sdcard.

I am checking this should we enable regulator-boot-on option but still no luck.

Best Regards
-Anand