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linux-next/include/linux/clock_cooling.h

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thermal: introduce clock cooling device This patch introduces a new thermal cooling device based on common clock framework. The original motivation to write this cooling device is to be able to cool down thermal zones using clocks that feed co-processors, such as GPUs, DSPs, Image Processing Co-processors, etc. But it is written in a way that it can be used on top of any clock. The implementation is pretty straight forward. The code creates a thermal cooling device based on a pair of a struct device and a clock name. The struct device is assumed to be usable by the OPP layer. The OPP layer is used as source of the list of possible frequencies. The (cpufreq) frequency table is then used as a map from frequencies to cooling states. Cooling states are indexes to the frequency table. The logic sits on top of common clock framework, specifically on clock pre notifications. Any PRE_RATE_CHANGE is hijacked, and the transition is only allowed when the new rate is within the thermal limit (cooling state -> freq). When a thermal cooling device state transition is requested, the clock is also checked to verify if the current clock rate is within the new thermal limit. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Mike Turquette <mturquette@linaro.org> Cc: Nishanth Menon <nm@ti.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Len Brown <len.brown@intel.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: linux-pm@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2014-01-06 21:04:18 +08:00
/*
* linux/include/linux/clock_cooling.h
*
* Copyright (C) 2014 Eduardo Valentin <edubezval@gmail.com>
*
* Copyright (C) 2013 Texas Instruments Inc.
* Contact: Eduardo Valentin <eduardo.valentin@ti.com>
*
* Highly based on cpu_cooling.c.
* Copyright (C) 2012 Samsung Electronics Co., Ltd(http://www.samsung.com)
* Copyright (C) 2012 Amit Daniel <amit.kachhap@linaro.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#ifndef __CPU_COOLING_H__
#define __CPU_COOLING_H__
#include <linux/of.h>
#include <linux/thermal.h>
#include <linux/cpumask.h>
#ifdef CONFIG_CLOCK_THERMAL
/**
* clock_cooling_register - function to create clock cooling device.
* @dev: struct device pointer to the device used as clock cooling device.
* @clock_name: string containing the clock used as cooling mechanism.
*/
struct thermal_cooling_device *
clock_cooling_register(struct device *dev, const char *clock_name);
/**
* clock_cooling_unregister - function to remove clock cooling device.
* @cdev: thermal cooling device pointer.
*/
void clock_cooling_unregister(struct thermal_cooling_device *cdev);
unsigned long clock_cooling_get_level(struct thermal_cooling_device *cdev,
unsigned long freq);
#else /* !CONFIG_CLOCK_THERMAL */
static inline struct thermal_cooling_device *
clock_cooling_register(struct device *dev, const char *clock_name)
{
return NULL;
}
static inline
void clock_cooling_unregister(struct thermal_cooling_device *cdev)
{
}
static inline
unsigned long clock_cooling_get_level(struct thermal_cooling_device *cdev,
unsigned long freq)
{
return THERMAL_CSTATE_INVALID;
}
#endif /* CONFIG_CLOCK_THERMAL */
#endif /* __CPU_COOLING_H__ */
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