| Hans-Juergen Koch | d20620d | 2007-05-08 17:22:00 +0200 | [diff] [blame] | 1 | Kernel driver max6650 |
| 2 | ===================== |
| 3 | |
| 4 | Supported chips: |
| 5 | * Maxim 6650 / 6651 |
| 6 | Prefix: 'max6650' |
| Jean Delvare | 67b670f | 2011-05-25 20:43:32 +0200 | [diff] [blame^] | 7 | Addresses scanned: none |
| Hans-Juergen Koch | d20620d | 2007-05-08 17:22:00 +0200 | [diff] [blame] | 8 | Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf |
| 9 | |
| 10 | Authors: |
| Hans J. Koch | f99e0e9 | 2010-11-18 12:27:34 -0800 | [diff] [blame] | 11 | Hans J. Koch <hjk@hansjkoch.de> |
| Hans-Juergen Koch | d20620d | 2007-05-08 17:22:00 +0200 | [diff] [blame] | 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 | |
| Jean Delvare | 67b670f | 2011-05-25 20:43:32 +0200 | [diff] [blame^] | 39 | Usage notes |
| 40 | ----------- |
| 41 | |
| 42 | This driver does not auto-detect devices. You will have to instantiate the |
| 43 | devices explicitly. Please see Documentation/i2c/instantiating-devices for |
| 44 | details. |
| 45 | |
| Hans-Juergen Koch | d20620d | 2007-05-08 17:22:00 +0200 | [diff] [blame] | 46 | Module parameters |
| 47 | ----------------- |
| 48 | |
| 49 | If your board has a BIOS that initializes the MAX6650/6651 correctly, you can |
| 50 | simply load your module without parameters. It won't touch the configuration |
| 51 | registers then. If your board BIOS doesn't initialize the chip, or you want |
| 52 | different settings, you can set the following parameters: |
| 53 | |
| 54 | voltage_12V: 5=5V fan, 12=12V fan, 0=don't change |
| 55 | prescaler: Possible values are 1,2,4,8,16, or 0 for don't change |
| 56 | clock: The clock frequency in Hz of the chip the driver should assume [254000] |
| 57 | |
| 58 | Please have a look at the MAX6650/6651 data sheet and make sure that you fully |
| 59 | understand the meaning of these parameters before you attempt to change them. |
| 60 | |