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Based on kernel version 3.15.4. Page generated on 2014-07-07 09:03 EST.

1	Kernel driver pc87360
2	=====================
3	
4	Supported chips:
5	  * National Semiconductor PC87360, PC87363, PC87364, PC87365 and PC87366
6	    Prefixes: 'pc87360', 'pc87363', 'pc87364', 'pc87365', 'pc87366'
7	    Addresses scanned: none, address read from Super I/O config space
8	    Datasheets: No longer available
9	
10	Authors: Jean Delvare <jdelvare@suse.de>
11	
12	Thanks to Sandeep Mehta, Tonko de Rooy and Daniel Ceregatti for testing.
13	Thanks to Rudolf Marek for helping me investigate conversion issues.
14	
15	
16	Module Parameters
17	-----------------
18	
19	* init int
20	  Chip initialization level:
21	   0: None
22	  *1: Forcibly enable internal voltage and temperature channels, except in9
23	   2: Forcibly enable all voltage and temperature channels, except in9
24	   3: Forcibly enable all voltage and temperature channels, including in9
25	
26	Note that this parameter has no effect for the PC87360, PC87363 and PC87364
27	chips.
28	
29	Also note that for the PC87366, initialization levels 2 and 3 don't enable
30	all temperature channels, because some of them share pins with each other,
31	so they can't be used at the same time.
32	
33	
34	Description
35	-----------
36	
37	The National Semiconductor PC87360 Super I/O chip contains monitoring and
38	PWM control circuitry for two fans. The PC87363 chip is similar, and the
39	PC87364 chip has monitoring and PWM control for a third fan.
40	
41	The National Semiconductor PC87365 and PC87366 Super I/O chips are complete
42	hardware monitoring chipsets, not only controlling and monitoring three fans,
43	but also monitoring eleven voltage inputs and two (PC87365) or up to four
44	(PC87366) temperatures.
45	
46	  Chip        #vin    #fan    #pwm    #temp   devid
47	
48	  PC87360     -       2       2       -       0xE1
49	  PC87363     -       2       2       -       0xE8
50	  PC87364     -       3       3       -       0xE4
51	  PC87365     11      3       3       2       0xE5
52	  PC87366     11      3       3       3-4     0xE9
53	
54	The driver assumes that no more than one chip is present, and one of the
55	standard Super I/O addresses is used (0x2E/0x2F or 0x4E/0x4F)
56	
57	Fan Monitoring
58	--------------
59	
60	Fan rotation speeds are reported in RPM (revolutions per minute). An alarm
61	is triggered if the rotation speed has dropped below a programmable limit.
62	A different alarm is triggered if the fan speed is too low to be measured.
63	
64	Fan readings are affected by a programmable clock divider, giving the
65	readings more range or accuracy. Usually, users have to learn how it works,
66	but this driver implements dynamic clock divider selection, so you don't
67	have to care no more.
68	
69	For reference, here are a few values about clock dividers:
70	
71	                slowest         accuracy        highest
72	                measurable      around 3000     accurate
73	    divider     speed (RPM)     RPM (RPM)       speed (RPM)
74	         1        1882              18           6928
75	         2         941              37           4898
76	         4         470              74           3464
77	         8         235             150           2449
78	
79	For the curious, here is how the values above were computed:
80	 * slowest measurable speed: clock/(255*divider)
81	 * accuracy around 3000 RPM: 3000^2/clock
82	 * highest accurate speed: sqrt(clock*100)
83	The clock speed for the PC87360 family is 480 kHz. I arbitrarily chose 100
84	RPM as the lowest acceptable accuracy.
85	
86	As mentioned above, you don't have to care about this no more.
87	
88	Note that not all RPM values can be represented, even when the best clock
89	divider is selected. This is not only true for the measured speeds, but
90	also for the programmable low limits, so don't be surprised if you try to
91	set, say, fan1_min to 2900 and it finally reads 2909.
92	
93	
94	Fan Control
95	-----------
96	
97	PWM (pulse width modulation) values range from 0 to 255, with 0 meaning
98	that the fan is stopped, and 255 meaning that the fan goes at full speed.
99	
100	Be extremely careful when changing PWM values. Low PWM values, even
101	non-zero, can stop the fan, which may cause irreversible damage to your
102	hardware if temperature increases too much. When changing PWM values, go
103	step by step and keep an eye on temperatures.
104	
105	One user reported problems with PWM. Changing PWM values would break fan
106	speed readings. No explanation nor fix could be found.
107	
108	
109	Temperature Monitoring
110	----------------------
111	
112	Temperatures are reported in degrees Celsius. Each temperature measured has
113	associated low, high and overtemperature limits, each of which triggers an
114	alarm when crossed.
115	
116	The first two temperature channels are external. The third one (PC87366
117	only) is internal.
118	
119	The PC87366 has three additional temperature channels, based on
120	thermistors (as opposed to thermal diodes for the first three temperature
121	channels). For technical reasons, these channels are held by the VLM
122	(voltage level monitor) logical device, not the TMS (temperature
123	measurement) one. As a consequence, these temperatures are exported as
124	voltages, and converted into temperatures in user-space.
125	
126	Note that these three additional channels share their pins with the
127	external thermal diode channels, so you (physically) can't use them all at
128	the same time. Although it should be possible to mix the two sensor types,
129	the documents from National Semiconductor suggest that motherboard
130	manufacturers should choose one type and stick to it. So you will more
131	likely have either channels 1 to 3 (thermal diodes) or 3 to 6 (internal
132	thermal diode, and thermistors).
133	
134	
135	Voltage Monitoring
136	------------------
137	
138	Voltages are reported relatively to a reference voltage, either internal or
139	external. Some of them (in7:Vsb, in8:Vdd and in10:AVdd) are divided by two
140	internally, you will have to compensate in sensors.conf. Others (in0 to in6)
141	are likely to be divided externally. The meaning of each of these inputs as
142	well as the values of the resistors used for division is left to the
143	motherboard manufacturers, so you will have to document yourself and edit
144	sensors.conf accordingly. National Semiconductor has a document with
145	recommended resistor values for some voltages, but this still leaves much
146	room for per motherboard specificities, unfortunately. Even worse,
147	motherboard manufacturers don't seem to care about National Semiconductor's
148	recommendations.
149	
150	Each voltage measured has associated low and high limits, each of which
151	triggers an alarm when crossed.
152	
153	When available, VID inputs are used to provide the nominal CPU Core voltage.
154	The driver will default to VRM 9.0, but this can be changed from user-space.
155	The chipsets can handle two sets of VID inputs (on dual-CPU systems), but
156	the driver will only export one for now. This may change later if there is
157	a need.
158	
159	
160	General Remarks
161	---------------
162	
163	If an alarm triggers, it will remain triggered until the hardware register
164	is read at least once. This means that the cause for the alarm may already
165	have disappeared! Note that all hardware registers are read whenever any
166	data is read (unless it is less than 2 seconds since the last update, in
167	which case cached values are returned instead). As a consequence, when
168	a once-only alarm triggers, it may take 2 seconds for it to show, and 2
169	more seconds for it to disappear.
170	
171	Monitoring of in9 isn't enabled at lower init levels (<3) because that
172	channel measures the battery voltage (Vbat). It is a known fact that
173	repeatedly sampling the battery voltage reduces its lifetime. National
174	Semiconductor smartly designed their chipset so that in9 is sampled only
175	once every 1024 sampling cycles (that is every 34 minutes at the default
176	sampling rate), so the effect is attenuated, but still present.
177	
178	
179	Limitations
180	-----------
181	
182	The datasheets suggests that some values (fan mins, fan dividers)
183	shouldn't be changed once the monitoring has started, but we ignore that
184	recommendation. We'll reconsider if it actually causes trouble.
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