Re: [PATCH v4 0/6] RK3588 and Rock 5B dts additions: thermal, OPP and fan

[Alexey Charkov <alchark@gmail.com>]

On Mon, May 6, 2024 at 1:37 PM Alexey Charkov <alchark@gmail.com> wrote:
>
> This enables thermal monitoring and CPU DVFS on RK3588(s), as well as
> active cooling on Radxa Rock 5B via the provided PWM fan.
>
> Some RK3588 boards use separate regulators to supply CPUs and their
> respective memory interfaces, so this is handled by coupling those
> regulators in affected boards' device trees to ensure that their
> voltage is adjusted in step.
>
> This also enables the built-in thermal sensor (TSADC) for all boards
> that don't currently have it enabled, using the default CRU based
> emergency thermal reset. This default configuration only uses on-SoC
> devices and doesn't rely on any external wiring, thus it should work
> for all devices (tested only on Rock 5B though).
>
> The boards that have TSADC_SHUT signal wired to the PMIC reset line
> can choose to override the default reset logic in favour of GPIO
> driven (PMIC assisted) reset, but in my testing it didn't work on
> Radxa Rock 5B - maybe I'm reading the schematic wrong and it doesn't
> support PMIC assisted reset after all.
>
> Fan control on Rock 5B has been split into two intervals: let it spin
> at the minimum cooling state between 55C and 65C, and then accelerate
> if the system crosses the 65C mark - thanks to Dragan for suggesting.
> This lets some cooling setups with beefier heatsinks and/or larger
> fan fins to stay in the quietest non-zero fan state while still
> gaining potential benefits from the airflow it generates, and
> possibly avoiding noisy speeds altogether for some workloads.
>
> OPPs help actually scale CPU frequencies up and down for both cooling
> and performance - tested on Rock 5B under varied loads. I've dropped
> those OPPs that cause frequency reductions without accompanying decrease
> in CPU voltage, as they don't seem to be adding much benefit in day to
> day use, while the kernel log gets a number of "OPP is inefficient" lines.
>
> Note that this submission doesn't touch the SRAM read margin updates or
> the OPP calibration based on silicon quality which the downstream driver
> does and which were mentioned in [1]. It works as it is (also confirmed by
> Sebastian in his follow-up message [2]), and it is stable in my testing on
> Rock 5B, so it sounds better to merge a simple version first and then
> extend when/if required.
>
> [1] https://lore.kernel.org/linux-rockchip/CABjd4YzTL=5S7cS8ACNAYVa730WA3iGd5L_wP1Vn9=f83RCORA@mail.gmail.com/
> [2] https://lore.kernel.org/linux-rockchip/pkyne4g2cln27dcdu3jm7bqdqpmd2kwkbguiolmozntjuiajrb@gvq4nupzna4o/
>
> Signed-off-by: Alexey Charkov <alchark@gmail.com>
> ---

Hi Heiko,

Do you think this can be merged for 6.11? Looks like there hasn't been
any new feedback in a while, and it would be good to have frequency
scaling in place for RK3588.

Please let me know if you have any reservations or if we need any
broader discussion.

Thanks a lot,
Alexey