20005cc58d
The fan can be stopped by writing "3" to pwm1_enable in sysfs. Add devicetree property for early initialization of the fan controller to prevent overheating, for example when resetting the board while the fan was completely turned off. Also improve error reporting, I2C failures were ignored while writing new values. Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
66 lines
2.1 KiB
Plaintext
66 lines
2.1 KiB
Plaintext
Kernel driver max6650
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=====================
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Supported chips:
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* Maxim MAX6650
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Prefix: 'max6650'
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Addresses scanned: none
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Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf
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* Maxim MAX6651
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Prefix: 'max6651'
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Addresses scanned: none
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Datasheet: http://pdfserv.maxim-ic.com/en/ds/MAX6650-MAX6651.pdf
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Authors:
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Hans J. Koch <hjk@hansjkoch.de>
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John Morris <john.morris@spirentcom.com>
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Claus Gindhart <claus.gindhart@kontron.com>
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Description
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-----------
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This driver implements support for the Maxim MAX6650 and MAX6651.
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The 2 devices are very similar, but the MAX6550 has a reduced feature
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set, e.g. only one fan-input, instead of 4 for the MAX6651.
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The driver is not able to distinguish between the 2 devices.
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The driver provides the following sensor accesses in sysfs:
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fan1_input ro fan tachometer speed in RPM
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fan2_input ro "
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fan3_input ro "
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fan4_input ro "
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fan1_target rw desired fan speed in RPM (closed loop mode only)
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pwm1_enable rw regulator mode, 0=full on, 1=open loop, 2=closed loop
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3=off
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pwm1 rw relative speed (0-255), 255=max. speed.
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Used in open loop mode only.
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fan1_div rw sets the speed range the inputs can handle. Legal
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values are 1, 2, 4, and 8. Use lower values for
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faster fans.
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Usage notes
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-----------
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This driver does not auto-detect devices. You will have to instantiate the
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devices explicitly. Please see Documentation/i2c/instantiating-devices for
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details.
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Module parameters
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-----------------
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If your board has a BIOS that initializes the MAX6650/6651 correctly, you can
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simply load your module without parameters. It won't touch the configuration
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registers then. If your board BIOS doesn't initialize the chip, or you want
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different settings, you can set the following parameters:
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voltage_12V: 5=5V fan, 12=12V fan, 0=don't change
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prescaler: Possible values are 1,2,4,8,16, or 0 for don't change
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clock: The clock frequency in Hz of the chip the driver should assume [254000]
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Please have a look at the MAX6650/6651 data sheet and make sure that you fully
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understand the meaning of these parameters before you attempt to change them.
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