71 lines
2.5 KiB
ReStructuredText
71 lines
2.5 KiB
ReStructuredText
Kernel driver mlxreg-fan
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========================
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Provides FAN control for the next Mellanox systems:
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- QMB700, equipped with 40x200GbE InfiniBand ports;
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- MSN3700, equipped with 32x200GbE or 16x400GbE Ethernet ports;
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- MSN3410, equipped with 6x400GbE plus 48x50GbE Ethernet ports;
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- MSN3800, equipped with 64x1000GbE Ethernet ports;
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Author: Vadim Pasternak <vadimp@mellanox.com>
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These are the Top of the Rack systems, equipped with Mellanox switch
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board with Mellanox Quantum or Spectrume-2 devices.
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FAN controller is implemented by the programmable device logic.
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The default registers offsets set within the programmable device is as
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following:
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======================= ====
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pwm1 0xe3
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fan1 (tacho1) 0xe4
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fan2 (tacho2) 0xe5
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fan3 (tacho3) 0xe6
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fan4 (tacho4) 0xe7
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fan5 (tacho5) 0xe8
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fan6 (tacho6) 0xe9
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fan7 (tacho7) 0xea
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fan8 (tacho8) 0xeb
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fan9 (tacho9) 0xec
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fan10 (tacho10) 0xed
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fan11 (tacho11) 0xee
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fan12 (tacho12) 0xef
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======================= ====
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This setup can be re-programmed with other registers.
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Description
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-----------
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The driver implements a simple interface for driving a fan connected to
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a PWM output and tachometer inputs.
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This driver obtains PWM and tachometers registers location according to
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the system configuration and creates FAN/PWM hwmon objects and a cooling
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device. PWM and tachometers are sensed through the on-board programmable
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device, which exports its register map. This device could be attached to
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any bus type, for which register mapping is supported.
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Single instance is created with one PWM control, up to 12 tachometers and
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one cooling device. It could be as many instances as programmable device
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supports.
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The driver exposes the fan to the user space through the hwmon's and
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thermal's sysfs interfaces.
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/sys files in hwmon subsystem
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-----------------------------
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================= == ===================================================
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fan[1-12]_fault RO files for tachometers TACH1-TACH12 fault indication
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fan[1-12]_input RO files for tachometers TACH1-TACH12 input (in RPM)
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pwm1 RW file for fan[1-12] target duty cycle (0..255)
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================= == ===================================================
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/sys files in thermal subsystem
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-------------------------------
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================= == ====================================================
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cur_state RW file for current cooling state of the cooling device
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(0..max_state)
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max_state RO file for maximum cooling state of the cooling device
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================= == ====================================================
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