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/* Copyright 2013 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
/* MEC1322 fan control module. */
/* This assumes 2-pole fan. For each rotation, 5 edges are measured. */
#include "fan.h"
#include "registers.h"
#include "util.h"
/* Maximum tach reading/target value */
#define MAX_TACH 0x1fff
/* Tach target value for disable fan */
#define FAN_OFF_TACH 0xfff8
/*
* RPM = (n - 1) * m * f * 60 / poles / TACH
* n = number of edges = 5
* m = multiplier defined by RANGE = 2 in our case
* f = 32.768K
* poles = 2
*/
#define RPM_TO_TACH(rpm) MIN((7864320 / MAX((rpm), 1)), MAX_TACH)
#define TACH_TO_RPM(tach) (7864320 / MAX((tach), 1))
static int rpm_setting;
static int duty_setting;
static int in_rpm_mode = 1;
static void clear_status(void)
{
/* Clear DRIVE_FAIL, FAN_SPIN, and FAN_STALL bits */
MEC1322_FAN_STATUS = 0x23;
}
void fan_set_enabled(int ch, int enabled)
{
if (in_rpm_mode) {
if (enabled)
fan_set_rpm_target(ch, rpm_setting);
else
MEC1322_FAN_TARGET = FAN_OFF_TACH;
} else {
if (enabled)
fan_set_duty(ch, duty_setting);
else
MEC1322_FAN_SETTING = 0;
}
clear_status();
}
int fan_get_enabled(int ch)
{
if (in_rpm_mode)
return (MEC1322_FAN_TARGET & 0xff00) != 0xff00;
else
return !!MEC1322_FAN_SETTING;
}
void fan_set_duty(int ch, int percent)
{
if (percent < 0)
percent = 0;
else if (percent > 100)
percent = 100;
duty_setting = percent;
MEC1322_FAN_SETTING = percent * 255 / 100;
clear_status();
}
int fan_get_duty(int ch)
{
return duty_setting;
}
int fan_get_rpm_mode(int ch)
{
return !!(MEC1322_FAN_CFG1 & BIT(7));
}
void fan_set_rpm_mode(int ch, int rpm_mode)
{
if (rpm_mode)
MEC1322_FAN_CFG1 |= BIT(7);
else
MEC1322_FAN_CFG1 &= ~BIT(7);
clear_status();
}
int fan_get_rpm_actual(int ch)
{
if ((MEC1322_FAN_READING >> 8) == 0xff)
return 0;
else
return TACH_TO_RPM(MEC1322_FAN_READING >> 3);
}
int fan_get_rpm_target(int ch)
{
return rpm_setting;
}
void fan_set_rpm_target(int ch, int rpm)
{
rpm_setting = rpm;
MEC1322_FAN_TARGET = RPM_TO_TACH(rpm) << 3;
clear_status();
}
enum fan_status fan_get_status(int ch)
{
uint8_t sts = MEC1322_FAN_STATUS;
if (sts & (BIT(5) | BIT(1)))
return FAN_STATUS_FRUSTRATED;
if (fan_get_rpm_actual(ch) == 0)
return FAN_STATUS_STOPPED;
return FAN_STATUS_LOCKED;
}
int fan_is_stalled(int ch)
{
uint8_t sts = MEC1322_FAN_STATUS;
if (fan_get_rpm_actual(ch)) {
MEC1322_FAN_STATUS = 0x1;
return 0;
}
return sts & 0x1;
}
void fan_channel_setup(int ch, unsigned int flags)
{
/*
* Fan configuration 1 register:
* 0x80 = bit 7 = RPM mode (0x00 if FAN_USE_RPM_MODE not set)
* 0x20 = bits 6:5 = min 1000 RPM, multiplier = 2
* 0x08 = bits 4:3 = 5 edges, 2 poles
* 0x03 = bits 2:0 = 400 ms update time
*
* Fan configuration 2 register:
* 0x00 = bit 6 = Ramp control disabled
* 0x00 = bit 5 = Glitch filter enabled
* 0x18 = bits 4:3 = Using both derivative options
* 0x02 = bits 2:1 = error range is 50 RPM
* 0x00 = bits 0 = normal polarity
*/
if (flags & FAN_USE_RPM_MODE)
MEC1322_FAN_CFG1 = 0xab;
else
MEC1322_FAN_CFG1 = 0x2b;
MEC1322_FAN_CFG2 = 0x1a;
clear_status();
}
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