CPU cooling APIs How To
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Written by Amit Daniel Kachhap <amit.kachhap@linaro.org>

Updated: 6 Jan 2015

Copyright (c)  2012 Samsung Electronics Co., Ltd(http://www.samsung.com)

0. Introduction

The generic cpu cooling(freq clipping) provides registration/unregistration APIs
to the caller. The binding of the cooling devices to the trip point is left for
the user. The registration APIs returns the cooling device pointer.

1. cpu cooling APIs

1.1 cpufreq registration/unregistration APIs
1.1.1 struct thermal_cooling_device *cpufreq_cooling_register(
	struct cpumask *clip_cpus)

    This interface function registers the cpufreq cooling device with the name
    "thermal-cpufreq-%x". This api can support multiple instances of cpufreq
    cooling devices.

   clip_cpus: cpumask of cpus where the frequency constraints will happen.

1.1.2 struct thermal_cooling_device *of_cpufreq_cooling_register(
	struct device_node *np, const struct cpumask *clip_cpus)

    This interface function registers the cpufreq cooling device with
    the name "thermal-cpufreq-%x" linking it with a device tree node, in
    order to bind it via the thermal DT code. This api can support multiple
    instances of cpufreq cooling devices.

    np: pointer to the cooling device device tree node
    clip_cpus: cpumask of cpus where the frequency constraints will happen.

1.1.3 void cpufreq_cooling_unregister(struct thermal_cooling_device *cdev)

    This interface function unregisters the "thermal-cpufreq-%x" cooling device.

    cdev: Cooling device pointer which has to be unregistered.