max6650.rst (2307B)
1Kernel driver max6650 2===================== 3 4Supported 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 22Authors: 23 - Hans J. Koch <hjk@hansjkoch.de> 24 - John Morris <john.morris@spirentcom.com> 25 - Claus Gindhart <claus.gindhart@kontron.com> 26 27Description 28----------- 29 30This driver implements support for the Maxim MAX6650 and MAX6651. 31 32The 2 devices are very similar, but the MAX6550 has a reduced feature 33set, e.g. only one fan-input, instead of 4 for the MAX6651. 34 35The driver is not able to distinguish between the 2 devices. 36 37The driver provides the following sensor accesses in sysfs: 38 39=============== ======= ======================================================= 40fan1_input ro fan tachometer speed in RPM 41fan2_input ro " 42fan3_input ro " 43fan4_input ro " 44fan1_target rw desired fan speed in RPM (closed loop mode only) 45pwm1_enable rw regulator mode, 0=full on, 1=open loop, 2=closed loop 46 3=off 47pwm1 rw relative speed (0-255), 255=max. speed. 48 Used in open loop mode only. 49fan1_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 54Usage notes 55----------- 56 57This driver does not auto-detect devices. You will have to instantiate the 58devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for 59details. 60 61Module parameters 62----------------- 63 64If your board has a BIOS that initializes the MAX6650/6651 correctly, you can 65simply load your module without parameters. It won't touch the configuration 66registers then. If your board BIOS doesn't initialize the chip, or you want 67different settings, you can set the following parameters: 68 69voltage_12V: 5=5V fan, 12=12V fan, 0=don't change 70prescaler: Possible values are 1,2,4,8,16, or 0 for don't change 71clock: The clock frequency in Hz of the chip the driver should assume [254000] 72 73Please have a look at the MAX6650/6651 data sheet and make sure that you fully 74understand the meaning of these parameters before you attempt to change them.