75 lines · plain
1Kernel driver max66502=====================3 4Supported chips:5 6 * Maxim MAX66507 8 Prefix: 'max6650'9 10 Addresses scanned: none11 12 Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf13 14 * Maxim MAX665115 16 Prefix: 'max6651'17 18 Addresses scanned: none19 20 Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf21 22Authors:23 - Hans J. Koch <hjk@hansjkoch.de>24 - John Morris <john.morris@spirentcom.com>25 - Claus Gindhart <claus.gindhart@kontron.com>26 27Description28-----------29 30This driver implements support for the Maxim MAX6650 and MAX6651.31 32The 2 devices are very similar, but the MAX6550 has a reduced feature33set, 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 RPM41fan2_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 loop46 3=off47pwm1 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. Legal50 values are 1, 2, 4, and 8. Use lower values for51 faster fans.52=============== ======= =======================================================53 54Usage notes55-----------56 57This driver does not auto-detect devices. You will have to instantiate the58devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for59details.60 61Module parameters62-----------------63 64If your board has a BIOS that initializes the MAX6650/6651 correctly, you can65simply load your module without parameters. It won't touch the configuration66registers then. If your board BIOS doesn't initialize the chip, or you want67different settings, you can set the following parameters:68 69voltage_12V: 5=5V fan, 12=12V fan, 0=don't change70prescaler: Possible values are 1,2,4,8,16, or 0 for don't change71clock: 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 fully74understand the meaning of these parameters before you attempt to change them.75