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Tomaz Merteljb5430a02010-01-08 14:43:04 -08001Kernel driver amc6821
2=====================
3
4Supported chips:
5 Texas Instruments AMC6821
6 Prefix: 'amc6821'
7 Addresses scanned: 0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 0x4c, 0x4d, 0x4e
8 Datasheet: http://focus.ti.com/docs/prod/folders/print/amc6821.html
9
10Authors:
11 Tomaz Mertelj <tomaz.mertelj@guest.arnes.si>
12
13
14Description
15-----------
16
17This driver implements support for the Texas Instruments amc6821 chip.
18The chip has one on-chip and one remote temperature sensor and one pwm fan
19regulator.
20The pwm can be controlled either from software or automatically.
21
22The driver provides the following sensor accesses in sysfs:
23
24temp1_input ro on-chip temperature
25temp1_min rw "
26temp1_max rw "
27temp1_crit rw "
28temp1_min_alarm ro "
29temp1_max_alarm ro "
30temp1_crit_alarm ro "
31
32temp2_input ro remote temperature
33temp2_min rw "
34temp2_max rw "
35temp2_crit rw "
36temp2_min_alarm ro "
37temp2_max_alarm ro "
38temp2_crit_alarm ro "
39temp2_fault ro "
40
41fan1_input ro tachometer speed
42fan1_min rw "
43fan1_max rw "
44fan1_fault ro "
45fan1_div rw Fan divisor can be either 2 or 4.
46
47pwm1 rw pwm1
48pwm1_enable rw regulator mode, 1=open loop, 2=fan controlled
49 by remote temperature, 3=fan controlled by
50 combination of the on-chip temperature and
51 remote-sensor temperature,
52pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3
53pwm1_auto_point1_pwm ro Hardwired to 0, shared for both
54 temperature channels.
55pwm1_auto_point2_pwm rw This value is shared for both temperature
56 channels.
57pwm1_auto_point3_pwm rw Hardwired to 255, shared for both
58 temperature channels.
59
60temp1_auto_point1_temp ro Hardwired to temp2_auto_point1_temp
61 which is rw. Below this temperature fan stops.
62temp1_auto_point2_temp rw The low-temperature limit of the proportional
63 range. Below this temperature
64 pwm1 = pwm1_auto_point2_pwm. It can go from
65 0 degree C to 124 degree C in steps of
66 4 degree C. Read it out after writing to get
67 the actual value.
68temp1_auto_point3_temp rw Above this temperature fan runs at maximum
69 speed. It can go from temp1_auto_point2_temp.
70 It can only have certain discrete values
71 which depend on temp1_auto_point2_temp and
72 pwm1_auto_point2_pwm. Read it out after
73 writing to get the actual value.
74
75temp2_auto_point1_temp rw Must be between 0 degree C and 63 degree C and
76 it defines the passive cooling temperature.
77 Below this temperature the fan stops in
78 the closed loop mode.
79temp2_auto_point2_temp rw The low-temperature limit of the proportional
80 range. Below this temperature
81 pwm1 = pwm1_auto_point2_pwm. It can go from
82 0 degree C to 124 degree C in steps
83 of 4 degree C.
84
85temp2_auto_point3_temp rw Above this temperature fan runs at maximum
86 speed. It can only have certain discrete
87 values which depend on temp2_auto_point2_temp
88 and pwm1_auto_point2_pwm. Read it out after
89 writing to get actual value.
90
91
92Module parameters
93-----------------
94
95If your board has a BIOS that initializes the amc6821 correctly, you should
96load the module with: init=0.
97
98If your board BIOS doesn't initialize the chip, or you want
99different settings, you can set the following parameters:
100init=1,
101pwminv: 0 default pwm output, 1 inverts pwm output.
102