Hi Jonas,
On 1/15/26 2:35 PM, Jonas Karlman wrote:
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 <[email protected]>
---
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.
That seems odd to me. Why could it reach U-Boot (where the regulator
driver would then enable the regulator at voltage init-microvolt) if the
regulator was initialized too low/high out of reset? Especially for
vdd_arm, the CPU supply.
I'm not sure we'll be able to convince the DT binding people to add this
property though, it all seems like a problem related to devfreq not
being handled in U-Boot that could be resolved by configuring the
clock-tree + regulator-tree properly appropriately I guess (which is
easier said than done :) ).
We already have plenty of boards with that property (including some I
maintain... news to me :) ), one more won't hurt us, so
Reviewed-by: Quentin Schulz <[email protected]>
Thanks,
Quentin
