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diff --git a/Documentation/hwmon/max31760.rst b/Documentation/hwmon/max31760.rst new file mode 100644 index 000000000..b1b55fb84 --- /dev/null +++ b/Documentation/hwmon/max31760.rst @@ -0,0 +1,77 @@ +.. SPDX-License-Identifier: GPL-2.0-or-later + +Kernel driver max31760 +====================== + +Supported chips: + * Analog Devices MAX31760 + + Prefix: 'max31760' + + Addresses scanned: none + + Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX31760.pdf + + +Author: Ibrahim Tilki <Ibrahim.Tilki@analog.com> + +Description +----------- + +The MAX31760 integrates temperature sensing along with precision PWM fan +control. It accurately measures its local die temperature and the remote +temperature of a discrete diode-connected transistor, such as a 2N3906, +or a thermal diode commonly found on CPUs, graphics processor units (GPUs), +and other ASICs. Multiple temperature thresholds, such as local +high/overtemperature (OT) and remote high/overtemperature, can be set by an +I2C-compatible interface. Fan speed is controlled based on the temperature +reading as an index to a 48-byte lookup table (LUT) containing +user-programmed PWM values. The flexible LUT-based architecture enables +the user to program a smooth nonlinear fan speed vs. temperature transfer +function to minimize acoustic fan noise. Two tachometer inputs allow +measuring the speeds of two fans independently. When the local or remote +OT threshold is exceeded, the SHDN pin is asserted low and can be used to +shut down the system. A dedicated ALERT pin reports that either a local or +remote high-temperature threshold has been exceeded. + +Temperature measurement range: from -55°C to 125°C + +Temperature Resolution: 11 Bits, ±0.125°C + +Please refer how to instantiate this driver: Documentation/i2c/instantiating-devices.rst + +Lookup table for auto fan control +--------------------------------- + +========= ================================= +LUT Index Name +========= ================================= +1 PWM value for T < +18°C +2 PWM value for +18°C ≤ T < +20°C +3 PWM value for +20°C ≤ T < +22°C +... ... +47 PWM value for +108°C ≤ T < +110°C +48 PWM value for T ≥ +110°C +========= ================================= + +Sysfs entries +------------- + +=============================== ================================================================================= +fan[1-2]_input Fan speed (in RPM) +fan[1-2]_enable Enable fan readings and fan fault alarms +fan[1-2]_fault Fan fault status +temp[1-2]_label "Remote" and "Local" temperature channel labels +temp[1-2]_input Temperature sensor readings (in millidegrees Celsius) +temp1_fault Remote temperature sensor fault status +temp[1-2]_max Temperature max value. Asserts "ALERT" pin when exceeded +temp[1-2]_max_alarm Temperature max alarm status +temp[1-2]_crit Temperature critical value. Asserts "SHDN" pin when exceeded +temp[1-2]_crit_alarm Temperature critical alarm status +pwm1 PWM value for direct fan control +pwm1_enable 1: direct fan control, 2: temperature based auto fan control +pwm1_freq PWM frequency in hertz +pwm1_auto_channels_temp Temperature source for auto fan control. 1: temp1, 2: temp2, 3: max(temp1, temp2) +pwm1_auto_point[1-48]_pwm PWM value for LUT point +pwm1_auto_point_temp_hyst Temperature hysteresis for auto fan control. Can be either 2000mC or 4000mC +=============================== ================================================================================= |