Re: [PATCH] arm64: dts: meson: odroid-n2: keep SD card regulator always on

From: Kevin Hilman
Date: Thu Jul 25 2019 - 19:43:07 EST

Xavier Ruppen <xruppen@xxxxxxxxx> writes:

> 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@xxxxxxxxx>

Thanks for the fix and the detailed background description.

Queued as a fix for v5.3.

Note that I also added this to the commit log, for the benefit of anyone
wanting to backport.

Fixes: c35f6dc5c377 ("arm64: dts: meson: Add minimal support for Odroid-N2")

> 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.