[PATCH v6] arm64: dts: rockchip: Fix SD card init on rk3399-nanopi4

[Christian Kohlschütter]

Am 18.07.2022 um 14:05 schrieb Christian Kohlschütter <christian at kohlschutter.com>:
> 
>> Am 18.07.2022 um 14:04 schrieb Christian Kohlschütter <christian at kohlschutter.com>:
>> 
>> mmc/SD-card initialization may fail on NanoPi R4S with
>> "mmc1: problem reading SD Status register" /
>> "mmc1: error -110 whilst initialising SD card"
>> either on cold boot or after a reboot.
> ...
> Walking back on my claim in the commit message that no further patches are needed for the u-boot integration to work.
> Other than that, the actual patch is unchanged.

I can no longer verify that the v6 patch actually increases use_count to 2.

At this point, I don't have a purely device tree-based fix that works reliably, therefore necessitating the code changes in regulator/core.c.
If anyone of you knows a way to reliably increase vcc3v0_sd's use_count ("cat /sys/kernel/debug/regulator/vcc3v0_sd/use_count") to at least 2, then we can remove the regulator-always-on statement.