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Commit | Line | Data |
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d20620de HJK |
1 | Kernel driver max6650 |
2 | ===================== | |
3 | ||
4 | Supported chips: | |
5 | * Maxim 6650 / 6651 | |
6 | Prefix: 'max6650' | |
7 | Addresses scanned: I2C 0x1b, 0x1f, 0x48, 0x4b | |
8 | Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf | |
9 | ||
10 | Authors: | |
11 | Hans J. Koch <hjk@linutronix.de> | |
12 | John Morris <john.morris@spirentcom.com> | |
13 | Claus Gindhart <claus.gindhart@kontron.com> | |
14 | ||
15 | Description | |
16 | ----------- | |
17 | ||
18 | This driver implements support for the Maxim 6650/6651 | |
19 | ||
20 | The 2 devices are very similar, but the Maxim 6550 has a reduced feature | |
21 | set, e.g. only one fan-input, instead of 4 for the 6651. | |
22 | ||
23 | The driver is not able to distinguish between the 2 devices. | |
24 | ||
25 | The driver provides the following sensor accesses in sysfs: | |
26 | ||
27 | fan1_input ro fan tachometer speed in RPM | |
28 | fan2_input ro " | |
29 | fan3_input ro " | |
30 | fan4_input ro " | |
31 | fan1_target rw desired fan speed in RPM (closed loop mode only) | |
32 | pwm1_enable rw regulator mode, 0=full on, 1=open loop, 2=closed loop | |
33 | pwm1 rw relative speed (0-255), 255=max. speed. | |
34 | Used in open loop mode only. | |
35 | fan1_div rw sets the speed range the inputs can handle. Legal | |
36 | values are 1, 2, 4, and 8. Use lower values for | |
37 | faster fans. | |
38 | ||
39 | Module parameters | |
40 | ----------------- | |
41 | ||
42 | If your board has a BIOS that initializes the MAX6650/6651 correctly, you can | |
43 | simply load your module without parameters. It won't touch the configuration | |
44 | registers then. If your board BIOS doesn't initialize the chip, or you want | |
45 | different settings, you can set the following parameters: | |
46 | ||
47 | voltage_12V: 5=5V fan, 12=12V fan, 0=don't change | |
48 | prescaler: Possible values are 1,2,4,8,16, or 0 for don't change | |
49 | clock: The clock frequency in Hz of the chip the driver should assume [254000] | |
50 | ||
51 | Please have a look at the MAX6650/6651 data sheet and make sure that you fully | |
52 | understand the meaning of these parameters before you attempt to change them. | |
53 |