include/linux/devfreq_cooling.h

   1 /*
   2  * devfreq_cooling: Thermal cooling device implementation for devices using
   3  *                  devfreq
   4  *
   5  * Copyright (C) 2014-2015 ARM Limited
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * This program is distributed "as is" WITHOUT ANY WARRANTY of any
  12  * kind, whether express or implied; without even the implied warranty
  13  * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #ifndef __DEVFREQ_COOLING_H__
  18 #define __DEVFREQ_COOLING_H__
  19
  20 #include <linux/devfreq.h>
  21 #include <linux/thermal.h>
  22
  23
  24 /**
  25  * struct devfreq_cooling_power - Devfreq cooling power ops
  26  * @get_static_power:   Take voltage, in mV, and return the static power
  27  *                      in mW.  If NULL, the static power is assumed
  28  *                      to be 0.
  29  * @get_dynamic_power:  Take voltage, in mV, and frequency, in HZ, and
  30  *                      return the dynamic power draw in mW.  If NULL,
  31  *                      a simple power model is used.
  32  * @dyn_power_coeff:    Coefficient for the simple dynamic power model in
  33  *                      mW/(MHz mV mV).
  34  *                      If get_dynamic_power() is NULL, then the
  35  *                      dynamic power is calculated as
  36  *                      @dyn_power_coeff * frequency * voltage^2
  37  * @get_real_power:     When this is set, the framework uses it to ask the
  38  *                      device driver for the actual power.
  39  *                      Some devices have more sophisticated methods
  40  *                      (like power counters) to approximate the actual power
  41  *                      that they use.
  42  *                      This function provides more accurate data to the
  43  *                      thermal governor. When the driver does not provide
  44  *                      such function, framework just uses pre-calculated
  45  *                      table and scale the power by 'utilization'
  46  *                      (based on 'busy_time' and 'total_time' taken from
  47  *                      devfreq 'last_status').
  48  *                      The value returned by this function must be lower
  49  *                      or equal than the maximum power value
  50  *                      for the current state
  51  *                      (which can be found in power_table[state]).
  52  *                      When this interface is used, the power_table holds
  53  *                      max total (static + dynamic) power value for each OPP.
  54  */
  55 struct devfreq_cooling_power {
  56         unsigned long (*get_static_power)(struct devfreq *devfreq,
  57                                           unsigned long voltage);
  58         unsigned long (*get_dynamic_power)(struct devfreq *devfreq,
  59                                            unsigned long freq,
  60                                            unsigned long voltage);
  61         int (*get_real_power)(struct devfreq *df, u32 *power,
  62                               unsigned long freq, unsigned long voltage);
  63         unsigned long dyn_power_coeff;
  64 };
  65
  66 #ifdef CONFIG_DEVFREQ_THERMAL
  67
  68 struct thermal_cooling_device *
  69 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
  70                                   struct devfreq_cooling_power *dfc_power);
  71 struct thermal_cooling_device *
  72 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df);
  73 struct thermal_cooling_device *devfreq_cooling_register(struct devfreq *df);
  74 void devfreq_cooling_unregister(struct thermal_cooling_device *dfc);
  75
  76 #else /* !CONFIG_DEVFREQ_THERMAL */
  77
  78 struct thermal_cooling_device *
  79 of_devfreq_cooling_register_power(struct device_node *np, struct devfreq *df,
  80                                   struct devfreq_cooling_power *dfc_power)
  81 {
  82         return ERR_PTR(-EINVAL);
  83 }
  84
  85 static inline struct thermal_cooling_device *
  86 of_devfreq_cooling_register(struct device_node *np, struct devfreq *df)
  87 {
  88         return ERR_PTR(-EINVAL);
  89 }
  90
  91 static inline struct thermal_cooling_device *
  92 devfreq_cooling_register(struct devfreq *df)
  93 {
  94         return ERR_PTR(-EINVAL);
  95 }
  96
  97 static inline void
  98 devfreq_cooling_unregister(struct thermal_cooling_device *dfc)
  99 {
 100 }
 101
 102 #endif /* CONFIG_DEVFREQ_THERMAL */
 103 #endif /* __DEVFREQ_COOLING_H__ */