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/ec76679ebcb399cf10426bd7a4a154c3 With series applied on master plus below: - CONFIG_K3_OPP_LOW enabled in config - Additional helpful prints added in code - Logs shown with and without efuse register programmed for OPP_0 (Errors out if OPP_0 not found, programs OPP_LOW spec if found)
--- 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: J7200: 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 | 6 +++ arch/arm/mach-k3/j721e/j721e_init.c | 45 ++++++++++++++++++- configs/j7200_evm_r5_defconfig | 1 + drivers/misc/k3_avs.c | 34 ++++++++++++++ include/k3-avs.h | 2 + 6 files changed, 92 insertions(+), 6 deletions(-)