Commit | Line | Data |
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b5430a04 TM |
1 | Kernel driver amc6821 |
2 | ===================== | |
3 | ||
4 | Supported chips: | |
b04f2f7d | 5 | |
b5430a04 | 6 | Texas Instruments AMC6821 |
b04f2f7d | 7 | |
b5430a04 | 8 | Prefix: 'amc6821' |
b04f2f7d | 9 | |
b5430a04 | 10 | Addresses scanned: 0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 0x4c, 0x4d, 0x4e |
b04f2f7d | 11 | |
b5430a04 TM |
12 | Datasheet: http://focus.ti.com/docs/prod/folders/print/amc6821.html |
13 | ||
14 | Authors: | |
15 | Tomaz Mertelj <tomaz.mertelj@guest.arnes.si> | |
16 | ||
17 | ||
18 | Description | |
19 | ----------- | |
20 | ||
21 | This driver implements support for the Texas Instruments amc6821 chip. | |
22 | The chip has one on-chip and one remote temperature sensor and one pwm fan | |
23 | regulator. | |
24 | The pwm can be controlled either from software or automatically. | |
25 | ||
26 | The driver provides the following sensor accesses in sysfs: | |
27 | ||
b04f2f7d | 28 | ======================= == =============================================== |
b5430a04 TM |
29 | temp1_input ro on-chip temperature |
30 | temp1_min rw " | |
31 | temp1_max rw " | |
b04f2f7d | 32 | temp1_crit rw " |
b5430a04 TM |
33 | temp1_min_alarm ro " |
34 | temp1_max_alarm ro " | |
35 | temp1_crit_alarm ro " | |
36 | ||
37 | temp2_input ro remote temperature | |
38 | temp2_min rw " | |
39 | temp2_max rw " | |
b04f2f7d | 40 | temp2_crit rw " |
b5430a04 TM |
41 | temp2_min_alarm ro " |
42 | temp2_max_alarm ro " | |
43 | temp2_crit_alarm ro " | |
44 | temp2_fault ro " | |
45 | ||
b04f2f7d | 46 | fan1_input ro tachometer speed |
b5430a04 TM |
47 | fan1_min rw " |
48 | fan1_max rw " | |
b04f2f7d | 49 | fan1_fault ro " |
b5430a04 TM |
50 | fan1_div rw Fan divisor can be either 2 or 4. |
51 | ||
52 | pwm1 rw pwm1 | |
53 | pwm1_enable rw regulator mode, 1=open loop, 2=fan controlled | |
54 | by remote temperature, 3=fan controlled by | |
55 | combination of the on-chip temperature and | |
56 | remote-sensor temperature, | |
57 | pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3 | |
58 | pwm1_auto_point1_pwm ro Hardwired to 0, shared for both | |
59 | temperature channels. | |
60 | pwm1_auto_point2_pwm rw This value is shared for both temperature | |
61 | channels. | |
62 | pwm1_auto_point3_pwm rw Hardwired to 255, shared for both | |
63 | temperature channels. | |
64 | ||
65 | temp1_auto_point1_temp ro Hardwired to temp2_auto_point1_temp | |
66 | which is rw. Below this temperature fan stops. | |
67 | temp1_auto_point2_temp rw The low-temperature limit of the proportional | |
68 | range. Below this temperature | |
69 | pwm1 = pwm1_auto_point2_pwm. It can go from | |
70 | 0 degree C to 124 degree C in steps of | |
71 | 4 degree C. Read it out after writing to get | |
72 | the actual value. | |
73 | temp1_auto_point3_temp rw Above this temperature fan runs at maximum | |
74 | speed. It can go from temp1_auto_point2_temp. | |
75 | It can only have certain discrete values | |
76 | which depend on temp1_auto_point2_temp and | |
77 | pwm1_auto_point2_pwm. Read it out after | |
78 | writing to get the actual value. | |
79 | ||
80 | temp2_auto_point1_temp rw Must be between 0 degree C and 63 degree C and | |
81 | it defines the passive cooling temperature. | |
82 | Below this temperature the fan stops in | |
83 | the closed loop mode. | |
84 | temp2_auto_point2_temp rw The low-temperature limit of the proportional | |
85 | range. Below this temperature | |
86 | pwm1 = pwm1_auto_point2_pwm. It can go from | |
87 | 0 degree C to 124 degree C in steps | |
88 | of 4 degree C. | |
89 | ||
90 | temp2_auto_point3_temp rw Above this temperature fan runs at maximum | |
91 | speed. It can only have certain discrete | |
92 | values which depend on temp2_auto_point2_temp | |
93 | and pwm1_auto_point2_pwm. Read it out after | |
94 | writing to get actual value. | |
b04f2f7d | 95 | ======================= == =============================================== |
b5430a04 TM |
96 | |
97 | ||
98 | Module parameters | |
99 | ----------------- | |
100 | ||
101 | If your board has a BIOS that initializes the amc6821 correctly, you should | |
102 | load the module with: init=0. | |
103 | ||
104 | If your board BIOS doesn't initialize the chip, or you want | |
105 | different settings, you can set the following parameters: | |
b04f2f7d MCC |
106 | |
107 | - init=1, | |
108 | - pwminv: 0 default pwm output, 1 inverts pwm output. |