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Commit | Line | Data |
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1 | Kernel driver max6650 | |
2 | ===================== | |
3 | ||
4 | Supported chips: | |
5 | * Maxim MAX6650 | |
6 | Prefix: 'max6650' | |
7 | Addresses scanned: none | |
8 | Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf | |
9 | * Maxim MAX6651 | |
10 | Prefix: 'max6651' | |
11 | Addresses scanned: none | |
12 | Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf | |
13 | ||
14 | Authors: | |
15 | Hans J. Koch <hjk@hansjkoch.de> | |
16 | John Morris <john.morris@spirentcom.com> | |
17 | Claus Gindhart <claus.gindhart@kontron.com> | |
18 | ||
19 | Description | |
20 | ----------- | |
21 | ||
22 | This driver implements support for the Maxim MAX6650 and MAX6651. | |
23 | ||
24 | The 2 devices are very similar, but the MAX6550 has a reduced feature | |
25 | set, e.g. only one fan-input, instead of 4 for the MAX6651. | |
26 | ||
27 | The driver is not able to distinguish between the 2 devices. | |
28 | ||
29 | The driver provides the following sensor accesses in sysfs: | |
30 | ||
31 | fan1_input ro fan tachometer speed in RPM | |
32 | fan2_input ro " | |
33 | fan3_input ro " | |
34 | fan4_input ro " | |
35 | fan1_target rw desired fan speed in RPM (closed loop mode only) | |
36 | pwm1_enable rw regulator mode, 0=full on, 1=open loop, 2=closed loop | |
37 | 3=off | |
38 | pwm1 rw relative speed (0-255), 255=max. speed. | |
39 | Used in open loop mode only. | |
40 | fan1_div rw sets the speed range the inputs can handle. Legal | |
41 | values are 1, 2, 4, and 8. Use lower values for | |
42 | faster fans. | |
43 | ||
44 | Usage notes | |
45 | ----------- | |
46 | ||
47 | This driver does not auto-detect devices. You will have to instantiate the | |
48 | devices explicitly. Please see Documentation/i2c/instantiating-devices for | |
49 | details. | |
50 | ||
51 | Module parameters | |
52 | ----------------- | |
53 | ||
54 | If your board has a BIOS that initializes the MAX6650/6651 correctly, you can | |
55 | simply load your module without parameters. It won't touch the configuration | |
56 | registers then. If your board BIOS doesn't initialize the chip, or you want | |
57 | different settings, you can set the following parameters: | |
58 | ||
59 | voltage_12V: 5=5V fan, 12=12V fan, 0=don't change | |
60 | prescaler: Possible values are 1,2,4,8,16, or 0 for don't change | |
61 | clock: The clock frequency in Hz of the chip the driver should assume [254000] | |
62 | ||
63 | Please have a look at the MAX6650/6651 data sheet and make sure that you fully | |
64 | understand the meaning of these parameters before you attempt to change them. | |
65 |