[PATCH v2] clk: spacemit: k3: add 1.8 GHz PLL5 and PLL8 rates

From: Troy Mitchell

Date: Mon Aug 10 2026 - 04:49:06 EST


K3 boot firmware configures the C2 and C3 CPU clock domains at
1.8 GHz. PLL5 feeds C2 and PLL8 feeds C3, but their rate tables
currently contain only the 2 GHz overclocking operating point.

Add the nominal 1.8 GHz configuration as the first entry in both
tables. This lets determine_rate() and set_rate() select the firmware
operating point while retaining 2 GHz as a supported overclocking rate.

Signed-off-by: Troy Mitchell <troy.mitchell@xxxxxxxxxxxxxxxxxx>
---
The related U-Boot change is available at:
https://github.com/spacemit-com/uboot-2022.10/commit/fb95cf3d848b771c61b5a1b3e5cbbee223faf352
---
Changes in v2:
- Drop "clk: spacemit: re-enable PLLs after init"; the PLL init issue
will be handled in a separate series.
- Send the K3 PLL5 and PLL8 1.8 GHz rate-table update as a standalone
patch.
- Clarify that 1.8 GHz is nominal and 2 GHz is an overclocking rate.
- Link to v1: https://patch.msgid.link/20260804-k3-pll5-pll8-1800mhz-v1-0-a3a75866ce32@xxxxxxxxxxxxxxxxxx

To: Michael Turquette <mturquette@xxxxxxxxxxxx>
To: Stephen Boyd <sboyd@xxxxxxxxxx>
To: Brian Masney <bmasney@xxxxxxxxxx>
To: Yixun Lan <dlan@xxxxxxxxxx>
To: Paul Walmsley <pjw@xxxxxxxxxx>
To: Palmer Dabbelt <palmer@xxxxxxxxxxx>
To: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
To: Alexandre Ghiti <alex@xxxxxxxx>
Cc: linux-clk@xxxxxxxxxxxxxxx
Cc: linux-riscv@xxxxxxxxxxxxxxxxxxx
Cc: spacemit@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/clk/spacemit/ccu-k3.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/clk/spacemit/ccu-k3.c b/drivers/clk/spacemit/ccu-k3.c
index cb0c4277f72a..e8b7ce89c2cb 100644
--- a/drivers/clk/spacemit/ccu-k3.c
+++ b/drivers/clk/spacemit/ccu-k3.c
@@ -38,6 +38,7 @@ static const struct ccu_pll_rate_tbl pll4_rate_tbl[] = {
};

static const struct ccu_pll_rate_tbl pll5_rate_tbl[] = {
+ CCU_PLLA_RATE(1800000000UL, 0x0b4b0000, 0x00000000, 0xa0458585),
CCU_PLLA_RATE(2000000000UL, 0x0b292aaa, 0x0000ab00, 0xa0558686),
};

@@ -50,6 +51,7 @@ static const struct ccu_pll_rate_tbl pll7_rate_tbl[] = {
};

static const struct ccu_pll_rate_tbl pll8_rate_tbl[] = {
+ CCU_PLLA_RATE(1800000000UL, 0x0b4b0000, 0x00000000, 0xa0458585),
CCU_PLLA_RATE(2000000000UL, 0x0b292aaa, 0x0000ab00, 0xa0558686),
};


---
base-commit: 1590cf0329716306e948a8fc29f1d3ee87d3989f
change-id: 20260802-k3-pll5-pll8-1800mhz-c81875a0a944

Best regards,
--
Troy Mitchell <troy.mitchell@xxxxxxxxxxxxxxxxxx>