1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
#!/bin/sh
#
# Copyright 2004-present Facebook. All Rights Reserved.
#
# This program file 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.
#
# You should have received a copy of the GNU General Public License
# along with this program in a file named COPYING; if not, write to the
# Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor,
# Boston, MA 02110-1301 USA
#
PWM_DIR=/sys/devices/platform/ast_pwm_tacho.0
set -e
# The PWM frequency is
# clk_source / ((2 ^ division_) * (2 * division_l) * (unit + 1))
#
# Our clk_source is 24Mhz. 4-pin fans are generally supposed to be driven with
# a 25Khz PWM control signal. Therefore we want the divisor to equal 960.
#
# We also want the unit to be as large as possible, since this controls the
# granularity with which we can modulate the PWM signal. The following
# settings allow us to set the fan from 0 to 100% in increments of 1/96th.
#
# The AST chip supports 3 different PWM clock configurations, but we only use
# type M for now.
echo 0 > $PWM_DIR/pwm_type_m_division_h
echo 5 > $PWM_DIR/pwm_type_m_division_l
echo 95 > $PWM_DIR/pwm_type_m_unit
# On wedge, there are 4 fans connected.
# Each fan has one PWM input and 2 tacho outputs.
# Here is the mapping between the fan and PWN/Tacho,
# staring from the one from the edge
# Fan 0: PWM 7, Tacho3, Tacho7
# Fan 1: PWM 6, Tacho2, Tacho6
# Fan 2: PWM 0, Tacho0, Tacho4
# Fan 3: PWM 1, Tacho1, Tacho5
# For each fan, setting the type, and 100% initially
for pwm in 0 1 6 7; do
echo 0 > $PWM_DIR/pwm${pwm}_type
echo 0 > $PWM_DIR/pwm${pwm}_rising
echo 0 > $PWM_DIR/pwm${pwm}_falling
echo 1 > $PWM_DIR/pwm${pwm}_en
done
# Enable Tach 0..7
echo 0 > $PWM_DIR/tacho0_source
echo 0 > $PWM_DIR/tacho4_source
echo 1 > $PWM_DIR/tacho1_source
echo 1 > $PWM_DIR/tacho5_source
echo 6 > $PWM_DIR/tacho2_source
echo 6 > $PWM_DIR/tacho6_source
echo 7 > $PWM_DIR/tacho3_source
echo 7 > $PWM_DIR/tacho7_source
t=0
while [ $t -le 7 ]; do
echo 1 > $PWM_DIR/tacho${t}_en
t=$((t+1))
done
|
