CPU cooling api's How To
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Written by Amit Daniel Kachhap <amit.kachhap at linaro.org>

Updated: 13 Dec 2011

Copyright (c)  2011 Samsung Electronics Co., Ltd(http://www.samsung.com)

0. Introduction

The generic cpu cooling(freq clipping, cpuhotplug) provides
registration/unregistration api's to the user. The binding of the cooling
devices to the trip types is left for the user. The registration api's returns
the cooling device pointer.

1. cpufreq cooling api's

1.1 cpufreq registration api's
1.1.1 struct thermal_cooling_device *cpufreq_cooling_register(
	struct freq_pctg_table *tab_ptr, unsigned int tab_size,
	const struct cpumask *mask_val)

    This interface function registers the cpufreq cooling device with the name
	"thermal-cpufreq".

    tab_ptr: The table containing the percentage of frequency to be clipped for
    each cooling state.
	.freq_clip_pctg[NR_CPUS]:Percentage of frequency to be clipped for each
	 cpu.
	.polling_interval: polling interval for this cooling state.
    tab_size: the total number of cooling state.
    mask_val: all the allowed cpu's where frequency clipping can happen.

1.1.2 void cpufreq_cooling_unregister(void)

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


1.2 cpuhotplug registration api's

1.2.1 struct thermal_cooling_device *cpuhotplug_cooling_register(
	const struct cpumask *mask_val)

    This interface function registers the cpuhotplug cooling device with the name
	"thermal-cpuhotplug".

    mask_val: all the allowed cpu's which can be hotplugged out.

1.1.2 void cpuhotplug_cooling_unregister(void)

    This interface function unregisters the "thermal-cpuhotplug" cooling device.