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From:   Anand Moon <linux.amoon@gmail.com>
Date:   Wed, 24 Jul 2019 14:30:01 +0530
Message-ID: <CANAwSgSwDQdT60N87GrOWNDP0_ZvKnYsKg5QPVP0jJvQ8rKzpg@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 Neil,

On Wed, 24 Jul 2019 at 12:19, Neil Armstrong <narmstrong@baylibre.com> wrote:
>
> Hi Anand,
>
> On 24/07/2019 07:30, Anand Moon wrote:
> > 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.
>
> Seems to be a separate issue, could we start a separate thread with all your
> setup (branch, git SHAa, configs, board setup, ...) for this ?
>
> Thanks,
> Neil
>

Ok sorry for the noise.

Best Regards
-Anand