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Diffstat (limited to 'Documentation/hwmon/mlxreg-fan.rst')
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diff --git a/Documentation/hwmon/mlxreg-fan.rst b/Documentation/hwmon/mlxreg-fan.rst new file mode 100644 index 000000000000..c92b8e885f7e --- /dev/null +++ b/Documentation/hwmon/mlxreg-fan.rst @@ -0,0 +1,70 @@ +Kernel driver mlxreg-fan +======================== + +Provides FAN control for the next Mellanox systems: + +- QMB700, equipped with 40x200GbE InfiniBand ports; +- MSN3700, equipped with 32x200GbE or 16x400GbE Ethernet ports; +- MSN3410, equipped with 6x400GbE plus 48x50GbE Ethernet ports; +- MSN3800, equipped with 64x1000GbE Ethernet ports; + +Author: Vadim Pasternak <vadimp@mellanox.com> + +These are the Top of the Rack systems, equipped with Mellanox switch +board with Mellanox Quantum or Spectrume-2 devices. +FAN controller is implemented by the programmable device logic. + +The default registers offsets set within the programmable device is as +following: + +======================= ==== +pwm1 0xe3 +fan1 (tacho1) 0xe4 +fan2 (tacho2) 0xe5 +fan3 (tacho3) 0xe6 +fan4 (tacho4) 0xe7 +fan5 (tacho5) 0xe8 +fan6 (tacho6) 0xe9 +fan7 (tacho7) 0xea +fan8 (tacho8) 0xeb +fan9 (tacho9) 0xec +fan10 (tacho10) 0xed +fan11 (tacho11) 0xee +fan12 (tacho12) 0xef +======================= ==== + +This setup can be re-programmed with other registers. + +Description +----------- + +The driver implements a simple interface for driving a fan connected to +a PWM output and tachometer inputs. +This driver obtains PWM and tachometers registers location according to +the system configuration and creates FAN/PWM hwmon objects and a cooling +device. PWM and tachometers are sensed through the on-board programmable +device, which exports its register map. This device could be attached to +any bus type, for which register mapping is supported. +Single instance is created with one PWM control, up to 12 tachometers and +one cooling device. It could be as many instances as programmable device +supports. +The driver exposes the fan to the user space through the hwmon's and +thermal's sysfs interfaces. + +/sys files in hwmon subsystem +----------------------------- + +================= == =================================================== +fan[1-12]_fault RO files for tachometers TACH1-TACH12 fault indication +fan[1-12]_input RO files for tachometers TACH1-TACH12 input (in RPM) +pwm1 RW file for fan[1-12] target duty cycle (0..255) +================= == =================================================== + +/sys files in thermal subsystem +------------------------------- + +================= == ==================================================== +cur_state RW file for current cooling state of the cooling device + (0..max_state) +max_state RO file for maximum cooling state of the cooling device +================= == ==================================================== |