# Re: \[PATCH v3 4/7\] thermal/drivers/tegra: Add driver for Tegra30 thermal sensor

- From: Daniel Lezcano \<hidden\>
- Date: 2021-06-15 10:03:38 
- List: linux-pm
- Page: https://ratatoskr.run/linux-pm/2021/06/1414580
- Thread: https://ratatoskr.run/linux-devicetree/2021/05/1395821/t.md

```text

[Cc Viresh]

On 29/05/2021 19:09, Dmitry Osipenko wrote:
> All NVIDIA Tegra30 SoCs have a two-channel on-chip sensor unit which
> monitors temperature and voltage of the SoC. Sensors control CPU frequency
> throttling, which is activated by hardware once preprogrammed temperature
> level is breached, they also send signal to Power Management controller to
> perform emergency shutdown on a critical overheat of the SoC die. Add
> driver for the Tegra30 TSENSOR module, exposing it as a thermal sensor
> and a cooling device.

IMO it does not make sense to expose the hardware throttling mechanism
as a cooling device because it is not usable anywhere from the thermal
framework.

Moreover, that will collide with the thermal / cpufreq framework
mitigation (hardware sets the frequency but the software thinks the freq
is different), right ?

The hardware limiter should let know the cpufreq framework about the
frequency change.

	https://lkml.org/lkml/2021/6/8/1792

May be post the sensor without the hw limiter for now and address that
in a separate series ?

  -- Daniel

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```