[PATCH] board: rockchip: Add FriendlyElec NanoPi Zero2

[Jonas Karlman]

Hi Quentin,

On 1/15/2026 1:24 PM, Quentin Schulz wrote:
> Hi Jonas,
> 
> On 1/10/26 9:53 PM, Jonas Karlman wrote:
>> The NanoPi Zero2 is a small single board computer developed by
>> FriendlyElec, based on the Rockchip RK3528A SoC.
>>
>> Add support for the FriendlyElec NanoPi Zero2 board.
>>
>> Features tested on a FriendlyElec NanoPi Zero2 2407:
>> - SD-card boot
>> - eMMC boot
>> - Ethernet
>> - USB host
>>
>> Signed-off-by: Jonas Karlman <jonas at kwiboo.se>
>> ---
>>   arch/arm/dts/rk3528-nanopi-zero2-u-boot.dtsi | 11 ++++
>>   arch/arm/mach-rockchip/rk3528/MAINTAINERS    |  6 ++
>>   configs/nanopi-zero2-rk3528_defconfig        | 64 ++++++++++++++++++++
>>   doc/board/rockchip/rockchip.rst              |  1 +
>>   4 files changed, 82 insertions(+)
>>   create mode 100644 arch/arm/dts/rk3528-nanopi-zero2-u-boot.dtsi
>>   create mode 100644 configs/nanopi-zero2-rk3528_defconfig
>>
>> diff --git a/arch/arm/dts/rk3528-nanopi-zero2-u-boot.dtsi b/arch/arm/dts/rk3528-nanopi-zero2-u-boot.dtsi
>> new file mode 100644
>> index 000000000000..3e2fbd81da17
>> --- /dev/null
>> +++ b/arch/arm/dts/rk3528-nanopi-zero2-u-boot.dtsi
>> @@ -0,0 +1,11 @@
>> +// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
>> +
>> +#include "rk3528-u-boot.dtsi"
>> +
>> +&vdd_arm {
>> +	regulator-init-microvolt = <953000>;
>> +};
>> +
>> +&vdd_logic {
>> +	regulator-init-microvolt = <900000>;
>> +};
> 
> Why? We need an explanation here to know if and when we can get rid of 
> those additions. Why aren't those in the Linux kernel tree?

All prior regulator-init-microvolt props was purged from Linux DTs some
time ago [1], instead of adding a dt-binding for this prop :/

After that change we now need to keep track of any initial microvolt
that should be set by U-Boot in -u-boot.dtsi files.

If I remember correctly these regulators may have been initialized with
too low or high voltage out of reset, and this ensure stable operation.

[1] https://lore.kernel.org/all/20230707162217.675390-1-cristian.ciocaltea@collabora.com/

Regards,
Jonas

> 
> OK to me otherwise.
> 
> Cheers,
> Quentin