[PATCH v3 0/2] cpufreq: spacemit: Add cpufreq support for K1 SoC

[Shuwei Wu]

This series enables CPU frequency scaling for the SpacemiT K1 SoC.

K1 has two CPU cluster clocks but one shared CPU voltage rail. Add a
small K1-specific cpufreq driver so the two clocks and the shared OPP
transition can be handled together.

Tested on Banana Pi BPI-F3. The system boots with all eight CPUs online,
the K1 cpufreq driver registers one policy for CPUs 0-7, and both CPU
cluster clocks follow the selected cpufreq rate.

~ # cat /sys/devices/system/cpu/online
0-7

~ # ls /sys/devices/system/cpu/cpufreq
policy0

~ # cat /sys/devices/system/cpu/cpufreq/policy0/affected_cpus
0 1 2 3 4 5 6 7

~ # cat /sys/devices/system/cpu/cpufreq/policy0/scaling_available_frequencies
614400 819000 1000000 1228800 1600000

With the userspace governor:
----------------------------------------------------------------------------
Frequency    | scaling_cur | cpu_c0_core | cpu_c1_core | Real    | User
(kHz)        | (kHz)       | (Hz)        | (Hz)        | (s)     | (s)
-------------+-------------+-------------+-------------+---------+----------
1,600,000    | 1,600,000   | 1600000000  | 1600000000  | 1.80s   | 1.80s
1,228,800    | 1,228,800   | 1228800000  | 1228800000  | 2.33s   | 2.33s
1,000,000    | 1,000,000   | 1000000000  | 1000000000  | 2.88s   | 2.87s
  819,000    |   819,000   |  819200000  |  819200000  | 3.53s   | 3.52s
  614,400    |   614,400   |  614400000  |  614400000  | 4.72s   | 4.72s
----------------------------------------------------------------------------

Signed-off-by: Shuwei Wu <shuwei.wu at mailbox.org>
---
Changes in v3:
- Add a K1-specific cpufreq driver for the shared-rail, dual-clock topology
- Use one shared CPU OPP table and one cpufreq policy for all CPUs
- Link to v2: https://lore.kernel.org/r/20260410-shadow-deps-v2-0-4e16b8c0f60e@mailbox.org

Changes in v2:
- Move OPP tables to dedicated k1-opp.dtsi
- Enable OPP only on BPI-F3 with cpu-supply present
- Link to v1: https://lore.kernel.org/r/20260308-shadow-deps-v1-0-0ceb5c7c07eb@mailbox.org

---
Shuwei Wu (2):
      cpufreq: spacemit: Add K1 cpufreq driver
      riscv: dts: spacemit: Add cpu scaling for K1 SoC

 arch/riscv/boot/dts/spacemit/k1-bananapi-f3.dts |  35 +++-
 arch/riscv/boot/dts/spacemit/k1-opp.dtsi        |  70 +++++++
 arch/riscv/boot/dts/spacemit/k1.dtsi            |   8 +
 drivers/cpufreq/Kconfig                         |   4 +
 drivers/cpufreq/Kconfig.riscv                   |  15 ++
 drivers/cpufreq/Makefile                        |   3 +
 drivers/cpufreq/cpufreq-dt-platdev.c            |   2 +
 drivers/cpufreq/spacemit-k1-cpufreq.c           | 251 ++++++++++++++++++++++++
 8 files changed, 387 insertions(+), 1 deletion(-)
---
base-commit: 5164e95565d3fd508ca8a95351323f5716dfb695
change-id: 20260307-shadow-deps-3582a78aa756
prerequisite-patch-id: 154bd4f720ce5065d58b988de8f273207b44572e
prerequisite-message-id: <20260206-spacemit-p1-v4-0-8f695d93811e at riscstar.com>
prerequisite-patch-id: 5da3e75b18291a5540d4f66d7a0600fb8975ef62
prerequisite-patch-id: bcf41917414ecef8cf743095d130f6004c32f6a5
prerequisite-patch-id: cfe3800f8c791ec4c63e070af9628e88e0fc31b9
prerequisite-message-id: <20260305-k1-clk-fix-v1-1-abca85d6e266 at mailbox.org>
prerequisite-patch-id: 7c7fb9f87dba019ece4c97c45750349a7cd28f3a

Best regards,
-- 
Shuwei Wu <shuwei.wu at mailbox.org>