1Kernel driver w83627ehf
2=======================
3
4Supported chips:
5
6  * Winbond W83627EHF/EHG (ISA access ONLY)
7
8    Prefix: 'w83627ehf'
9
10    Addresses scanned: ISA address retrieved from Super I/O registers
11
12    Datasheet: not available
13
14  * Winbond W83627DHG
15
16    Prefix: 'w83627dhg'
17
18    Addresses scanned: ISA address retrieved from Super I/O registers
19
20    Datasheet: not available
21
22  * Winbond W83627DHG-P
23
24    Prefix: 'w83627dhg'
25
26    Addresses scanned: ISA address retrieved from Super I/O registers
27
28    Datasheet: not available
29
30  * Winbond W83627UHG
31
32    Prefix: 'w83627uhg'
33
34    Addresses scanned: ISA address retrieved from Super I/O registers
35
36    Datasheet: available from www.nuvoton.com
37
38  * Winbond W83667HG
39
40    Prefix: 'w83667hg'
41
42    Addresses scanned: ISA address retrieved from Super I/O registers
43
44    Datasheet: not available
45
46  * Winbond W83667HG-B
47
48    Prefix: 'w83667hg'
49
50    Addresses scanned: ISA address retrieved from Super I/O registers
51
52    Datasheet: Available from Nuvoton upon request
53
54  * Nuvoton NCT6775F/W83667HG-I
55
56    Prefix: 'nct6775'
57
58    Addresses scanned: ISA address retrieved from Super I/O registers
59
60    Datasheet: Available from Nuvoton upon request
61
62  * Nuvoton NCT6776F
63
64    Prefix: 'nct6776'
65
66    Addresses scanned: ISA address retrieved from Super I/O registers
67
68    Datasheet: Available from Nuvoton upon request
69
70
71Authors:
72
73	- Jean Delvare <jdelvare@suse.de>
74	- Yuan Mu (Winbond)
75	- Rudolf Marek <r.marek@assembler.cz>
76	- David Hubbard <david.c.hubbard@gmail.com>
77	- Gong Jun <JGong@nuvoton.com>
78
79Description
80-----------
81
82This driver implements support for the Winbond W83627EHF, W83627EHG,
83W83627DHG, W83627DHG-P, W83627UHG, W83667HG, W83667HG-B, W83667HG-I
84(NCT6775F), and NCT6776F super I/O chips. We will refer to them collectively
85as Winbond chips.
86
87The chips implement 3 to 4 temperature sensors (9 for NCT6775F and NCT6776F),
882 to 5 fan rotation speed sensors, 8 to 10 analog voltage sensors, one VID
89(except for 627UHG), alarms with beep warnings (control unimplemented),
90and some automatic fan regulation strategies (plus manual fan control mode).
91
92The temperature sensor sources on W82677HG-B, NCT6775F, and NCT6776F are
93configurable. temp4 and higher attributes are only reported if its temperature
94source differs from the temperature sources of the already reported temperature
95sensors. The configured source for each of the temperature sensors is provided
96in tempX_label.
97
98Temperatures are measured in degrees Celsius and measurement resolution is 1
99degC for temp1 and 0.5 degC for temp2 and temp3. For temp4 and higher,
100resolution is 1 degC for W83667HG-B and 0.0 degC for NCT6775F and NCT6776F.
101An alarm is triggered when the temperature gets higher than high limit;
102it stays on until the temperature falls below the hysteresis value.
103Alarms are only supported for temp1, temp2, and temp3.
104
105Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
106triggered if the rotation speed has dropped below a programmable limit. Fan
107readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or
108128) to give the readings more range or accuracy. The driver sets the most
109suitable fan divisor itself. Some fans might not be present because they
110share pins with other functions.
111
112Voltage sensors (also known as IN sensors) report their values in millivolts.
113An alarm is triggered if the voltage has crossed a programmable minimum
114or maximum limit.
115
116The driver supports automatic fan control mode known as Thermal Cruise.
117In this mode, the chip attempts to keep the measured temperature in a
118predefined temperature range. If the temperature goes out of range, fan
119is driven slower/faster to reach the predefined range again.
120
121The mode works for fan1-fan4. Mapping of temperatures to pwm outputs is as
122follows::
123
124  temp1 -> pwm1
125  temp2 -> pwm2
126  temp3 -> pwm3 (not on 627UHG)
127  prog  -> pwm4 (not on 667HG and 667HG-B; the programmable setting is not
128		 supported by the driver)
129
130/sys files
131----------
132
133name
134	this is a standard hwmon device entry, it contains the name of
135	the device (see the prefix in the list of supported devices at
136	the top of this file)
137
138pwm[1-4]
139	this file stores PWM duty cycle or DC value (fan speed) in range:
140
141	   0 (stop) to 255 (full)
142
143pwm[1-4]_enable
144	this file controls mode of fan/temperature control:
145
146	* 1 Manual mode, write to pwm file any value 0-255 (full speed)
147	* 2 "Thermal Cruise" mode
148	* 3 "Fan Speed Cruise" mode
149	* 4 "Smart Fan III" mode
150	* 5 "Smart Fan IV" mode
151
152	SmartFan III mode is not supported on NCT6776F.
153
154	SmartFan IV mode is configurable only if it was configured at system
155	startup, and is only supported for W83677HG-B, NCT6775F, and NCT6776F.
156	SmartFan IV operational parameters can not be configured at this time,
157	and the various pwm attributes are not used in SmartFan IV mode.
158	The attributes can be written to, which is useful if you plan to
159	configure the system for a different pwm mode. However, the information
160	returned when reading pwm attributes is unrelated to SmartFan IV
161	operation.
162
163pwm[1-4]_mode
164	controls if output is PWM or DC level
165
166	* 0 DC output (0 - 12v)
167	* 1 PWM output
168
169Thermal Cruise mode
170-------------------
171
172If the temperature is in the range defined by:
173
174pwm[1-4]_target
175		   set target temperature, unit millidegree Celsius
176		   (range 0 - 127000)
177pwm[1-4]_tolerance
178		   tolerance, unit millidegree Celsius (range 0 - 15000)
179
180there are no changes to fan speed. Once the temperature leaves the interval,
181fan speed increases (temp is higher) or decreases if lower than desired.
182There are defined steps and times, but not exported by the driver yet.
183
184pwm[1-4]_min_output
185		   minimum fan speed (range 1 - 255), when the temperature
186		   is below defined range.
187pwm[1-4]_stop_time
188		   how many milliseconds [ms] must elapse to switch
189		   corresponding fan off. (when the temperature was below
190		   defined range).
191pwm[1-4]_start_output
192		   minimum fan speed (range 1 - 255) when spinning up
193pwm[1-4]_step_output
194		   rate of fan speed change (1 - 255)
195pwm[1-4]_stop_output
196		   minimum fan speed (range 1 - 255) when spinning down
197pwm[1-4]_max_output
198		   maximum fan speed (range 1 - 255), when the temperature
199		   is above defined range.
200
201Note: last six functions are influenced by other control bits, not yet exported
202      by the driver, so a change might not have any effect.
203
204Implementation Details
205----------------------
206
207Future driver development should bear in mind that the following registers have
208different functions on the 627EHF and the 627DHG. Some registers also have
209different power-on default values, but BIOS should already be loading
210appropriate defaults. Note that bank selection must be performed as is currently
211done in the driver for all register addresses.
212
213========================= =====================================================
214Register(s)		  Meaning
215========================= =====================================================
2160x49                      only on DHG, selects temperature source for AUX fan,
217			  CPU fan0
2180x4a                      not completely documented for the EHF and the DHG
219			  documentation assigns different behavior to bits 7
220			  and 6, including extending the temperature input
221			  selection to SmartFan I, not just SmartFan III.
222			  Testing on the EHF will reveal whether they are
223			  compatible or not.
2240x58                      Chip ID: 0xa1=EHF 0xc1=DHG
2250x5e                      only on DHG, has bits to enable "current mode"
226			  temperature detection and critical temperature
227			  protection
2280x45b                     only on EHF, bit 3, vin4 alarm (EHF supports 10
229			  inputs, only 9 on DHG)
2300x552                     only on EHF, vin4
2310x558                     only on EHF, vin4 high limit
2320x559                     only on EHF, vin4 low limit
2330x6b                      only on DHG, SYS fan critical temperature
2340x6c                      only on DHG, CPU fan0 critical temperature
2350x6d                      only on DHG, AUX fan critical temperature
2360x6e                      only on DHG, CPU fan1 critical temperature
2370x50-0x55 and 0x650-0x657 marked as:
238
239			    - "Test Register" for the EHF
240			    - "Reserved Register" for the DHG
241========================= =====================================================
242
243The DHG also supports PECI, where the DHG queries Intel CPU temperatures, and
244the ICH8 southbridge gets that data via PECI from the DHG, so that the
245southbridge drives the fans. And the DHG supports SST, a one-wire serial bus.
246
247The DHG-P has an additional automatic fan speed control mode named Smart Fan
248(TM) III+. This mode is not yet supported by the driver.
249