RE: [PATCH v4 0/5] clk: Support spread spectrum and use it in clk-scmi

Hi Stephen,

Subject: [PATCH v4 0/5] clk: Support spread spectrum and use it in clk-
scmi

Since clk-scmi.c for spread spectrum support needs some big changes,
we may need to change scmi framework to make OEM extension
in an elegant way. This will needs some time.

To patch 1-4, do you think is it ok to be in linux tree without patch 5?
If yes, I will post V5 soon with your comments in patch 2 addressed.
Otherwise I have to carry patch 1-4 in future clk-scmi patches.

Thanks,
Peng.

Since the assigned-clock-sscs property [1] has been accepted into the
device tree schema, we can now support it in the Linux clock driver.
Therefore, I’ve picked up the previously submitted work [2] titled “clk:
Support spread spectrum and use it in clk-pll144x and clk-scmi.”
As more than six months have passed since [2] was posted, I’m treating
this patchset as a new submission rather than a v3.

- Introduce clk_set_spread_spectrum to set the parameters for enabling
  spread spectrum of a clock.
- Parse 'assigned-clock-sscs' and configure it by default before using the
  clock. This property is parsed before parsing clock rate.
- Enable this feature for clk-scmi on i.MX95.

Because SCMI spec will not include spread spectrum as a standard
extension, we still need to use NXP i.MX OEM extension.

[1] https://github.com/devicetree-org/dt-schema/pull/154
[2] https://lore.kernel.org/all/20250205-clk-ssc-v2-0-
fa73083caa92@nxp.com/

Signed-off-by: Peng Fan <peng.fan@nxp.com>
---
Changes in v4:
- Add R-b for patch 1 from Brian
- Drop unecessary change in patch 4 Per Brian
- Link to v3: https://lore.kernel.org/r/20250912-clk-ssc-version1-v3-0-
fd1e07476ba1@nxp.com

Changes in v3:
- New patch 1 for dt-bindings per comment from Brian
  https://lore.kernel.org/all/aLeEFzXkPog_dt2B@x1/ (local)
  This might not be good to add a new dt-binding file in v3. But this is
  quite a simple file that just has four macros to encode modulation
  method. So hope this is fine for DT maintainers.
- Add Brain's R-b for patch 2
- New patch 3 to add Kunit test per Brain. Since Brain helped
  draft part of the code, I added Co-developed-by tag from Brain.
- Link to v2: https://lore.kernel.org/r/20250901-clk-ssc-version1-v2-0-
1d0a486dffe6@nxp.com

Changes in v2:
- Simplify the code in patch 2 per Dan Carpenter and Brian Masney
- Rebased to next-20250829
- Link to v1: https://lore.kernel.org/r/20250812-clk-ssc-version1-v1-0-
cef60f20d770@nxp.com

---
Peng Fan (5):
      dt-bindings: clock: Add spread spectrum definition
      clk: Introduce clk_hw_set_spread_spectrum
      clk: conf: Support assigned-clock-sscs
      clk: Add KUnit tests for assigned-clock-sscs
      clk: scmi: Support Spread Spectrum for NXP i.MX95

 drivers/clk/Makefile                               |   6 +
 drivers/clk/clk-conf.c                             |  69 ++++++++++++
 drivers/clk/clk-scmi.c                             |  64 ++++++++++-
 drivers/clk/clk.c                                  |  26 +++++
 drivers/clk/clk_test.c                             | 121 ++++++++++++++++++++-
 drivers/clk/kunit_clk_assigned_rates.h             |  10 ++
 drivers/clk/kunit_clk_assigned_rates_multiple.dtso |   6 +
 ...kunit_clk_assigned_rates_multiple_consumer.dtso |   6 +
 drivers/clk/kunit_clk_assigned_rates_one.dtso      |   3 +
 .../clk/kunit_clk_assigned_rates_one_consumer.dtso |   3 +
 .../clk/kunit_clk_assigned_rates_u64_multiple.dtso |   6 +
 ...t_clk_assigned_rates_u64_multiple_consumer.dtso |   6 +
 drivers/clk/kunit_clk_assigned_rates_u64_one.dtso  |   3 +
 .../kunit_clk_assigned_rates_u64_one_consumer.dtso |   3 +
 drivers/clk/kunit_clk_assigned_sscs_null.dtso      |  16 +++
 .../clk/kunit_clk_assigned_sscs_null_consumer.dtso |  20 ++++
 drivers/clk/kunit_clk_assigned_sscs_without.dtso   |  15 +++
 .../kunit_clk_assigned_sscs_without_consumer.dtso  |  19 ++++
 drivers/clk/kunit_clk_assigned_sscs_zero.dtso      |  12 ++
 .../clk/kunit_clk_assigned_sscs_zero_consumer.dtso |  16 +++
 include/dt-bindings/clock/clock.h                  |  14 +++
 include/linux/clk-provider.h                       |  22 ++++
 include/linux/scmi_protocol.h                      |   5 +
 23 files changed, 464 insertions(+), 7 deletions(-)
---
base-commit: 8941e75c0f122fdd76dc54ed45c4ce917587e006
change-id: 20250812-clk-ssc-version1-acf6f6efbd96

Best regards,
--
Peng Fan [off-list ref]