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@linux.spacemit.com>
---
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@linux.spacemit.com

To: Michael Turquette <mturquette@baylibre.com>
To: Stephen Boyd <sboyd@kernel.org>
To: Brian Masney <bmasney@redhat.com>
To: Yixun Lan <dlan@kernel.org>
To: Paul Walmsley <pjw@kernel.org>
To: Palmer Dabbelt <palmer@dabbelt.com>
To: Albert Ou <aou@eecs.berkeley.edu>
To: Alexandre Ghiti <alex@ghiti.fr>
Cc: linux-clk@vger.kernel.org
Cc: linux-riscv@lists.infradead.org
Cc: spacemit@lists.linux.dev
Cc: linux-kernel@vger.kernel.org
---
 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@linux.spacemit.com>

Hi Troy,

On 2026-08-10 16:46, Troy Mitchell wrote:
> 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@linux.spacemit.com>
> ---
> 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@linux.spacemit.com

This make sense and looks good:

Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>

I wonder if it should be backported to stable, as users will deploy 
newer firmware.

Regards
Aurelien

-- 
Aurelien Jarno                          GPG: 4096R/1DDD8C9B
aurelien@aurel32.net                     http://aurel32.net

On Mon Aug 31, 2026 at 1:25 AM +08, Aurelien Jarno wrote:
> Hi Troy,
>
> On 2026-08-10 16:46, Troy Mitchell wrote:
>> 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@linux.spacemit.com>
>> ---
>> 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@linux.spacemit.com
>
> This make sense and looks good:
>
> Reviewed-by: Aurelien Jarno <aurelien@aurel32.net>
> Tested-by: Aurelien Jarno <aurelien@aurel32.net>
>
> I wonder if it should be backported to stable, as users will deploy 
> newer firmware.
Yes. I'll Cc: stable@vger.kernel.org in the next version.

Thanks for your tags.

-- 
Troy Mitchell