1 Kernel driver max6650 2 ===================== 3 4 Supported chips: 5 6 * Maxim MAX6650 7 8 Prefix: 'max6650' 9 10 Addresses scanned: none 11 12 Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf 13 14 * Maxim MAX6651 15 16 Prefix: 'max6651' 17 18 Addresses scanned: none 19 20 Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf 21 22 Authors: 23 - Hans J. Koch <hjk@hansjkoch.de> 24 - John Morris <john.morris@spirentcom.com> 25 - Claus Gindhart <claus.gindhart@kontron.com> 26 27 Description 28 ----------- 29 30 This driver implements support for the Maxim MAX6650 and MAX6651. 31 32 The 2 devices are very similar, but the MAX6550 has a reduced feature 33 set, e.g. only one fan-input, instead of 4 for the MAX6651. 34 35 The driver is not able to distinguish between the 2 devices. 36 37 The driver provides the following sensor accesses in sysfs: 38 39 =============== ======= ======================================================= 40 fan1_input ro fan tachometer speed in RPM 41 fan2_input ro " 42 fan3_input ro " 43 fan4_input ro " 44 fan1_target rw desired fan speed in RPM (closed loop mode only) 45 pwm1_enable rw regulator mode, 0=full on, 1=open loop, 2=closed loop 46 3=off 47 pwm1 rw relative speed (0-255), 255=max. speed. 48 Used in open loop mode only. 49 fan1_div rw sets the speed range the inputs can handle. Legal 50 values are 1, 2, 4, and 8. Use lower values for 51 faster fans. 52 =============== ======= ======================================================= 53 54 Usage notes 55 ----------- 56 57 This driver does not auto-detect devices. You will have to instantiate the 58 devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for 59 details. 60 61 Module parameters 62 ----------------- 63 64 If your board has a BIOS that initializes the MAX6650/6651 correctly, you can 65 simply load your module without parameters. It won't touch the configuration 66 registers then. If your board BIOS doesn't initialize the chip, or you want 67 different settings, you can set the following parameters: 68 69 voltage_12V: 5=5V fan, 12=12V fan, 0=don't change 70 prescaler: Possible values are 1,2,4,8,16, or 0 for don't change 71 clock: The clock frequency in Hz of the chip the driver should assume [254000] 72 73 Please have a look at the MAX6650/6651 data sheet and make sure that you fully 74 understand the meaning of these parameters before you attempt to change them.
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