xref: /linux/Documentation/hwmon/max31785.rst (revision 7ebd8b66dd9e5a0b65e5ee5e2b8e7ca382ec97b7)
14d420a6aSAndrew JefferyKernel driver max31785
24d420a6aSAndrew Jeffery======================
34d420a6aSAndrew Jeffery
44d420a6aSAndrew JefferySupported chips:
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64d420a6aSAndrew Jeffery  * Maxim MAX31785, MAX31785A
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84d420a6aSAndrew Jeffery    Prefix: 'max31785' or 'max31785a'
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104d420a6aSAndrew Jeffery    Addresses scanned: -
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124d420a6aSAndrew Jeffery    Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
134d420a6aSAndrew Jeffery
144d420a6aSAndrew JefferyAuthor: Andrew Jeffery <andrew@aj.id.au>
154d420a6aSAndrew Jeffery
164d420a6aSAndrew JefferyDescription
174d420a6aSAndrew Jeffery-----------
184d420a6aSAndrew Jeffery
194d420a6aSAndrew JefferyThe Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel fan
204d420a6aSAndrew Jefferymanagement with temperature and remote voltage sensing. Various fan control
214d420a6aSAndrew Jefferyfeatures are provided, including PWM frequency control, temperature hysteresis,
224d420a6aSAndrew Jefferydual tachometer measurements, and fan health monitoring.
234d420a6aSAndrew Jeffery
24cf583b42SAndrew JefferyFor dual-rotor configurations the MAX31785A exposes the second rotor tachometer
25cf583b42SAndrew Jefferyreadings in attributes fan[5-8]_input. By contrast the MAX31785 only exposes
26cf583b42SAndrew Jefferythe slowest rotor measurement, and does so in the fan[1-4]_input attributes.
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284d420a6aSAndrew JefferyUsage Notes
294d420a6aSAndrew Jeffery-----------
304d420a6aSAndrew Jeffery
314d420a6aSAndrew JefferyThis driver does not probe for PMBus devices. You will have to instantiate
324d420a6aSAndrew Jefferydevices explicitly.
334d420a6aSAndrew Jeffery
344d420a6aSAndrew JefferySysfs attributes
354d420a6aSAndrew Jeffery----------------
364d420a6aSAndrew Jeffery
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384d420a6aSAndrew Jefferyfan[1-4]_alarm		Fan alarm.
394d420a6aSAndrew Jefferyfan[1-4]_fault		Fan fault.
40cf583b42SAndrew Jefferyfan[1-8]_input		Fan RPM. On the MAX31785A, inputs 5-8 correspond to the
41cf583b42SAndrew Jeffery			second rotor of fans 1-4
4256ad86b4SAndrew Jefferyfan[1-4]_target		Fan input target
434d420a6aSAndrew Jeffery
444d420a6aSAndrew Jefferyin[1-6]_crit		Critical maximum output voltage
454d420a6aSAndrew Jefferyin[1-6]_crit_alarm	Output voltage critical high alarm
464d420a6aSAndrew Jefferyin[1-6]_input		Measured output voltage
474d420a6aSAndrew Jefferyin[1-6]_label		"vout[18-23]"
484d420a6aSAndrew Jefferyin[1-6]_lcrit		Critical minimum output voltage
494d420a6aSAndrew Jefferyin[1-6]_lcrit_alarm	Output voltage critical low alarm
504d420a6aSAndrew Jefferyin[1-6]_max		Maximum output voltage
514d420a6aSAndrew Jefferyin[1-6]_max_alarm	Output voltage high alarm
524d420a6aSAndrew Jefferyin[1-6]_min		Minimum output voltage
534d420a6aSAndrew Jefferyin[1-6]_min_alarm	Output voltage low alarm
544d420a6aSAndrew Jeffery
5556ad86b4SAndrew Jefferypwm[1-4]		Fan target duty cycle (0..255)
5656ad86b4SAndrew Jefferypwm[1-4]_enable		0: Full-speed
5756ad86b4SAndrew Jeffery			1: Manual PWM control
5856ad86b4SAndrew Jeffery			2: Automatic PWM (tach-feedback RPM fan-control)
5956ad86b4SAndrew Jeffery			3: Automatic closed-loop (temp-feedback fan-control)
6056ad86b4SAndrew Jeffery
614d420a6aSAndrew Jefferytemp[1-11]_crit		Critical high temperature
624d420a6aSAndrew Jefferytemp[1-11]_crit_alarm	Chip temperature critical high alarm
634d420a6aSAndrew Jefferytemp[1-11]_input	Measured temperature
644d420a6aSAndrew Jefferytemp[1-11]_max		Maximum temperature
654d420a6aSAndrew Jefferytemp[1-11]_max_alarm	Chip temperature high alarm
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