xref: /linux/Documentation/hwmon/max31785.rst (revision 7ebd8b66dd9e5a0b65e5ee5e2b8e7ca382ec97b7)
1*7ebd8b66SMauro Carvalho ChehabKernel driver max31785
2*7ebd8b66SMauro Carvalho Chehab======================
3*7ebd8b66SMauro Carvalho Chehab
4*7ebd8b66SMauro Carvalho ChehabSupported chips:
5*7ebd8b66SMauro Carvalho Chehab
6*7ebd8b66SMauro Carvalho Chehab  * Maxim MAX31785, MAX31785A
7*7ebd8b66SMauro Carvalho Chehab
8*7ebd8b66SMauro Carvalho Chehab    Prefix: 'max31785' or 'max31785a'
9*7ebd8b66SMauro Carvalho Chehab
10*7ebd8b66SMauro Carvalho Chehab    Addresses scanned: -
11*7ebd8b66SMauro Carvalho Chehab
12*7ebd8b66SMauro Carvalho Chehab    Datasheet: https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf
13*7ebd8b66SMauro Carvalho Chehab
14*7ebd8b66SMauro Carvalho ChehabAuthor: Andrew Jeffery <andrew@aj.id.au>
15*7ebd8b66SMauro Carvalho Chehab
16*7ebd8b66SMauro Carvalho ChehabDescription
17*7ebd8b66SMauro Carvalho Chehab-----------
18*7ebd8b66SMauro Carvalho Chehab
19*7ebd8b66SMauro Carvalho ChehabThe Maxim MAX31785 is a PMBus device providing closed-loop, multi-channel fan
20*7ebd8b66SMauro Carvalho Chehabmanagement with temperature and remote voltage sensing. Various fan control
21*7ebd8b66SMauro Carvalho Chehabfeatures are provided, including PWM frequency control, temperature hysteresis,
22*7ebd8b66SMauro Carvalho Chehabdual tachometer measurements, and fan health monitoring.
23*7ebd8b66SMauro Carvalho Chehab
24*7ebd8b66SMauro Carvalho ChehabFor dual-rotor configurations the MAX31785A exposes the second rotor tachometer
25*7ebd8b66SMauro Carvalho Chehabreadings in attributes fan[5-8]_input. By contrast the MAX31785 only exposes
26*7ebd8b66SMauro Carvalho Chehabthe slowest rotor measurement, and does so in the fan[1-4]_input attributes.
27*7ebd8b66SMauro Carvalho Chehab
28*7ebd8b66SMauro Carvalho ChehabUsage Notes
29*7ebd8b66SMauro Carvalho Chehab-----------
30*7ebd8b66SMauro Carvalho Chehab
31*7ebd8b66SMauro Carvalho ChehabThis driver does not probe for PMBus devices. You will have to instantiate
32*7ebd8b66SMauro Carvalho Chehabdevices explicitly.
33*7ebd8b66SMauro Carvalho Chehab
34*7ebd8b66SMauro Carvalho ChehabSysfs attributes
35*7ebd8b66SMauro Carvalho Chehab----------------
36*7ebd8b66SMauro Carvalho Chehab
37*7ebd8b66SMauro Carvalho Chehab======================= =======================================================
38*7ebd8b66SMauro Carvalho Chehabfan[1-4]_alarm		Fan alarm.
39*7ebd8b66SMauro Carvalho Chehabfan[1-4]_fault		Fan fault.
40*7ebd8b66SMauro Carvalho Chehabfan[1-8]_input		Fan RPM. On the MAX31785A, inputs 5-8 correspond to the
41*7ebd8b66SMauro Carvalho Chehab			second rotor of fans 1-4
42*7ebd8b66SMauro Carvalho Chehabfan[1-4]_target		Fan input target
43*7ebd8b66SMauro Carvalho Chehab
44*7ebd8b66SMauro Carvalho Chehabin[1-6]_crit		Critical maximum output voltage
45*7ebd8b66SMauro Carvalho Chehabin[1-6]_crit_alarm	Output voltage critical high alarm
46*7ebd8b66SMauro Carvalho Chehabin[1-6]_input		Measured output voltage
47*7ebd8b66SMauro Carvalho Chehabin[1-6]_label		"vout[18-23]"
48*7ebd8b66SMauro Carvalho Chehabin[1-6]_lcrit		Critical minimum output voltage
49*7ebd8b66SMauro Carvalho Chehabin[1-6]_lcrit_alarm	Output voltage critical low alarm
50*7ebd8b66SMauro Carvalho Chehabin[1-6]_max		Maximum output voltage
51*7ebd8b66SMauro Carvalho Chehabin[1-6]_max_alarm	Output voltage high alarm
52*7ebd8b66SMauro Carvalho Chehabin[1-6]_min		Minimum output voltage
53*7ebd8b66SMauro Carvalho Chehabin[1-6]_min_alarm	Output voltage low alarm
54*7ebd8b66SMauro Carvalho Chehab
55*7ebd8b66SMauro Carvalho Chehabpwm[1-4]		Fan target duty cycle (0..255)
56*7ebd8b66SMauro Carvalho Chehabpwm[1-4]_enable		0: Full-speed
57*7ebd8b66SMauro Carvalho Chehab			1: Manual PWM control
58*7ebd8b66SMauro Carvalho Chehab			2: Automatic PWM (tach-feedback RPM fan-control)
59*7ebd8b66SMauro Carvalho Chehab			3: Automatic closed-loop (temp-feedback fan-control)
60*7ebd8b66SMauro Carvalho Chehab
61*7ebd8b66SMauro Carvalho Chehabtemp[1-11]_crit		Critical high temperature
62*7ebd8b66SMauro Carvalho Chehabtemp[1-11]_crit_alarm	Chip temperature critical high alarm
63*7ebd8b66SMauro Carvalho Chehabtemp[1-11]_input	Measured temperature
64*7ebd8b66SMauro Carvalho Chehabtemp[1-11]_max		Maximum temperature
65*7ebd8b66SMauro Carvalho Chehabtemp[1-11]_max_alarm	Chip temperature high alarm
66*7ebd8b66SMauro Carvalho Chehab======================= =======================================================
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