[PATCH v3 0/5] Add OPP_LOW support for J7200

[Aniket Limaye]

This series adds OPP_LOW spec data in k3_avs driver and enables a config
option to select the OPP_LOW performance point.

J7200 SOC supports OPP_LOW and OPP_NOM as two Operating Performance
Points as per (7.5 Operating Performance Points) section in the
Datasheet [0].
- A72SS/MSMC at 2 GHz/1GHz operation must use OPP_NOM.
- A72SS/MSMC at 1 GHz/500 MHz operation can use OPP_NOM or OPP_LOW
  voltage (though OPP_LOW voltage is recommended to reduce power
  consumption).

The actual OPP voltage for the device is read from the efuse and
updated in k3_avs_probe().

The default j7200 devicetree and k3_avs driver set OPP_NOM spec
frequency and voltage.

In the board init file, if K3_OPP_LOW config is enabled, Check if
OPP_LOW AVS voltage read from efuse is valid and update frequency (A72
and MSMC) and voltage (VDD_CPU) as per the OPP_LOW spec.

[0]: https://www.ti.com/lit/gpn/dra821u  (J7200 Datasheet)

Test logs:
https://gist.github.com/aniket-l/328ad93ed60c2419ed7be9f85e6b6075
- With series applied on master and CONFIG_K3_OPP_LOW enabled in
  j7200_evm_r5_defconfig
- Logs shown with and without efuse register programmed for OPP_0
  (Errors out if OPP_0 not found, programs OPP_LOW spec if found)
- Voltage update verified using 'i2c md 0x4c 0xe' in u-boot
- Frequency update verified using 'k3conf clock dump' in linux

---
v4:
* Manorit
- Update function name to k3_avs_check_opp and update description
- Move Kconfig definition to arch/arm/mach-k3/r5/Kconfig

- Update commit messages
- Fixup patch styling problems
- In previous versions, fdt_fixup_a72ss_clock_frequency() assumed a
  fixed order of assigned-clock-rates in the DT to update clk freqs.
  This may not always be a valid assumption. So, add a new function
  get_clock_index_by_dev_id() to search the indices for A72 CPU and MSMC
  clk IDs and then use that index to update the clock rates in place.
- Link to v3: https://lore.kernel.org/u-boot/20241116071615.839623-1-a-limaye@ti.com/

v3:
* Manorit
- Use more descriptive name for fdt_fixup_a72ss_clock_frequency()
  and make function static.
- Move error prints (with error codes) before else conditions. Helps
  with code readability to map error print with the function.
- Remove k3_avs_set_opp() from board_init_f altogether. Reasoning being
  that the value being set through k3_avs_set_opp() will anyway be
  (correctly) overridden by the k3_avs_notify_freq() call later in the
  boot process, when a72 freq is actually set from clk_k3.

- Add msmc clock at the end to preserve current ordering of core and gtc
  clocks
- Add Kconfig dependency on K3_AVS0 and Update commit msg to make it
  more clear

- Link to v2: https://lore.kernel.org/u-boot/20241023130033.1826413-1-a-limaye@ti.com/

v2:
* Neha
- Fix indentation
- Updates to commit msgs

- Re-format patches 3/5 and 4/5 with logical changes in each patch

- Link to v1: https://lore.kernel.org/u-boot/20241017062911.2241167-1-a-limaye@ti.com/


Reid Tonking (5):
  arm: dts: k3-j7200-r5-common: Add msmc clk to a72 node
  misc: k3_avs: Add OPP_LOW voltage and frequency to vd_data
  misc: k3_avs: Check validity of efuse voltage data
  arm: mach-k3: j721e-init.c: Add support for CONFIG_K3_OPP_LOW
  configs: j7200_evm_r5_defconfig: Define K3_OPP_LOW

 .../arm/dts/k3-j7200-r5-common-proc-board.dts | 10 ++---
 arch/arm/mach-k3/Kconfig                      |  7 ++++
 arch/arm/mach-k3/j721e/j721e_init.c           | 41 ++++++++++++++++++-
 configs/j7200_evm_r5_defconfig                |  1 +
 drivers/misc/k3_avs.c                         | 34 +++++++++++++++
 include/k3-avs.h                              |  2 +
 6 files changed, 89 insertions(+), 6 deletions(-)

-- 
2.47.0