[PATCH] reset: spacemit: Fix the RCPU2 PWM reset registers

Troy Mitchell troy.mitchell at linux.spacemit.com
Tue Oct 20 18:44:15 PDT 2026


On Sat Oct 17, 2026 at 10:08 PM +08, Hung-Chun Tseng wrote:
> Every entry in k1_rcpu2_resets[] uses RCPU2_PWM9_CLK_RST, so asserting
> or deasserting the reset of any RCPU2 PWM from 0 to 8 acts on PWM9
> instead. Each PWM has its own register, RCPU2_PWMn_CLK_RST at offset
> 4 * n, as k1-syscon.h already defines.
>
> On a Milk-V Jupiter running the vendor kernel, which uses RCPU2 PWM2
> for the fan, the RCPU2 registers read:
>
>   0x00: 0x4  0x04: 0x4  0x08: 0x1  0x0c: 0x4  ...  0x24: 0x4
>
> Only PWM2's register has its reset deasserted, which matches one
> register per PWM.
>
> Use the matching register for each reset. No in-tree device tree uses
> the RCPU2 PWMs yet, so this has no effect on current boards, but it
> would break the first one that does.
>
> Build-tested only (riscv defconfig, W=1); the fix could not be tested
> at runtime, as mainline has no RCPU2 PWM node to exercise it.
>
> Fixes: c479d7cf06c3 ("reset: spacemit: add support for SpacemiT CCU resets")
> Assisted-by: claude-opus-5-5
> Signed-off-by: Hung-Chun Tseng <alan.tseng.cs at gmail.com>
Reviewed-by: Troy Mitchell <troy.mitchell at linux.spacemit.com>

-- 
Troy Mitchell

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