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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.
*/
#include "common.h"
#include "fan.h"
#ifndef CONFIG_FAN_RPM_CUSTOM
/* This is the default implementation. It's only called over [0,100].
* Convert the percentage to a target RPM. We can't simply scale all
* the way down to zero because most fans won't turn that slowly, so
* we'll map [1,100] => [FAN_MIN,FAN_MAX], and [0] => "off".
*/
int pwm_fan_percent_to_rpm(int pct)
{
int rpm;
if (!pct)
rpm = 0;
else
rpm = ((pct - 1) * CONFIG_FAN_RPM_MAX +
(100 - pct) * CONFIG_FAN_RPM_MIN) / 99;
return rpm;
}
#endif /* CONFIG_FAN_RPM_CUSTOM */
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