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/* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* Fan control module for Chrome EC */
#ifndef __CROS_EC_FAN_H
#define __CROS_EC_FAN_H
struct fan_conf {
unsigned int flags;
/* Hardware channel number (the meaning is chip-specific) */
int ch;
/* Active-high power_good input GPIO, or -1 if none */
int pgood_gpio;
/* Active-high power_enable output GPIO, or -1 if none */
int enable_gpio;
};
struct fan_rpm {
/* rpm_min is to keep turning. rpm_start is to begin turning */
int rpm_min;
int rpm_start;
int rpm_max;
};
/* Characteristic of each physical fan */
struct fan_t {
const struct fan_conf *conf;
const struct fan_rpm *rpm;
};
/* Values for .flags field */
/* Enable automatic RPM control using tach input */
#define FAN_USE_RPM_MODE (1 << 0)
/* Require a higher duty cycle to start up than to keep running */
#define FAN_USE_FAST_START (1 << 1)
/* The list of fans is instantiated in board.c. */
extern struct fan_t fans[];
/* For convenience */
#define FAN_CH(fan) fans[fan].conf->ch
/**
* Set the amount of active cooling needed. The thermal control task will call
* this frequently, and the fan control logic will attempt to provide it.
*
* @param fan Fan number (index into fans[])
* @param pct Percentage of cooling effort needed (0 - 100)
*/
void fan_set_percent_needed(int fan, int pct);
/**
* This function translates the percentage of cooling needed into a target RPM.
* The default implementation should be sufficient for most needs, but
* individual boards may provide a custom version if needed (see config.h).
*
* @param fan Fan number (index into fans[])
* @param pct Percentage of cooling effort needed (always in [0,100])
* Return Target RPM for fan
*/
int fan_percent_to_rpm(int fan, int pct);
/**
* These functions require chip-specific implementations.
*/
/* Enable/Disable the fan controller */
void fan_set_enabled(int ch, int enabled);
int fan_get_enabled(int ch);
/* Fixed pwm duty cycle (0-100%) */
void fan_set_duty(int ch, int percent);
int fan_get_duty(int ch);
/* Enable/Disable automatic RPM control using tach feedback */
void fan_set_rpm_mode(int ch, int rpm_mode);
int fan_get_rpm_mode(int ch);
/* Set the target for the automatic RPM control */
void fan_set_rpm_target(int ch, int rpm);
int fan_get_rpm_actual(int ch);
int fan_get_rpm_target(int ch);
/* Is the fan stalled when it shouldn't be? */
int fan_is_stalled(int ch);
/**
* STOPPED means not spinning.
*
* When setting fan rpm, some implementations in chip layer (npcx and it83xx)
* is to adjust fan pwm duty steps by steps. In this period, fan_status will
* be marked as CHANGING. After change is done, fan_status will become LOCKED.
*
* In the period of changing pwm duty, if it's trying to increase/decrease duty
* even when duty is already in upper/lower bound. Then this action won't work,
* and fan_status will be marked as FRUSTRATED.
*
* For other implementations in chip layer (mchp and mec1322), there is no
* changing period. So they don't have CHANGING status.
* Just return status as LOCKED in normal spinning case, return STOPPED when
* not spinning, return FRUSTRATED when the related flags (which is read from
* chip's register) is set.
*/
enum fan_status {
FAN_STATUS_STOPPED = 0,
FAN_STATUS_CHANGING = 1,
FAN_STATUS_LOCKED = 2,
FAN_STATUS_FRUSTRATED = 3
};
enum fan_status fan_get_status(int ch);
/* Initialize the HW according to the desired flags */
void fan_channel_setup(int ch, unsigned int flags);
#endif /* __CROS_EC_FAN_H */
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