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Linux/Documentation/hwmon/w83627ehf.rst

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  1 Kernel driver w83627ehf
  2 =======================
  3 
  4 Supported 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 
 71 Authors:
 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 
 79 Description
 80 -----------
 81 
 82 This driver implements support for the Winbond W83627EHF, W83627EHG,
 83 W83627DHG, W83627DHG-P, W83627UHG, W83667HG, W83667HG-B, W83667HG-I
 84 (NCT6775F), and NCT6776F super I/O chips. We will refer to them collectively
 85 as Winbond chips.
 86 
 87 The chips implement 3 to 4 temperature sensors (9 for NCT6775F and NCT6776F),
 88 2 to 5 fan rotation speed sensors, 8 to 10 analog voltage sensors, one VID
 89 (except for 627UHG), alarms with beep warnings (control unimplemented),
 90 and some automatic fan regulation strategies (plus manual fan control mode).
 91 
 92 The temperature sensor sources on W82677HG-B, NCT6775F, and NCT6776F are
 93 configurable. temp4 and higher attributes are only reported if its temperature
 94 source differs from the temperature sources of the already reported temperature
 95 sensors. The configured source for each of the temperature sensors is provided
 96 in tempX_label.
 97 
 98 Temperatures are measured in degrees Celsius and measurement resolution is 1
 99 degC for temp1 and 0.5 degC for temp2 and temp3. For temp4 and higher,
100 resolution is 1 degC for W83667HG-B and 0.0 degC for NCT6775F and NCT6776F.
101 An alarm is triggered when the temperature gets higher than high limit;
102 it stays on until the temperature falls below the hysteresis value.
103 Alarms are only supported for temp1, temp2, and temp3.
104 
105 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
106 triggered if the rotation speed has dropped below a programmable limit. Fan
107 readings can be divided by a programmable divider (1, 2, 4, 8, 16, 32, 64 or
108 128) to give the readings more range or accuracy. The driver sets the most
109 suitable fan divisor itself. Some fans might not be present because they
110 share pins with other functions.
111 
112 Voltage sensors (also known as IN sensors) report their values in millivolts.
113 An alarm is triggered if the voltage has crossed a programmable minimum
114 or maximum limit.
115 
116 The driver supports automatic fan control mode known as Thermal Cruise.
117 In this mode, the chip attempts to keep the measured temperature in a
118 predefined temperature range. If the temperature goes out of range, fan
119 is driven slower/faster to reach the predefined range again.
120 
121 The mode works for fan1-fan4. Mapping of temperatures to pwm outputs is as
122 follows::
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 
133 name
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 
138 pwm[1-4]
139         this file stores PWM duty cycle or DC value (fan speed) in range:
140 
141            0 (stop) to 255 (full)
142 
143 pwm[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 
163 pwm[1-4]_mode
164         controls if output is PWM or DC level
165 
166         * 0 DC output (0 - 12v)
167         * 1 PWM output
168 
169 Thermal Cruise mode
170 -------------------
171 
172 If the temperature is in the range defined by:
173 
174 pwm[1-4]_target
175                    set target temperature, unit millidegree Celsius
176                    (range 0 - 127000)
177 pwm[1-4]_tolerance
178                    tolerance, unit millidegree Celsius (range 0 - 15000)
179 
180 there are no changes to fan speed. Once the temperature leaves the interval,
181 fan speed increases (temp is higher) or decreases if lower than desired.
182 There are defined steps and times, but not exported by the driver yet.
183 
184 pwm[1-4]_min_output
185                    minimum fan speed (range 1 - 255), when the temperature
186                    is below defined range.
187 pwm[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).
191 pwm[1-4]_start_output
192                    minimum fan speed (range 1 - 255) when spinning up
193 pwm[1-4]_step_output
194                    rate of fan speed change (1 - 255)
195 pwm[1-4]_stop_output
196                    minimum fan speed (range 1 - 255) when spinning down
197 pwm[1-4]_max_output
198                    maximum fan speed (range 1 - 255), when the temperature
199                    is above defined range.
200 
201 Note: 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 
204 Implementation Details
205 ----------------------
206 
207 Future driver development should bear in mind that the following registers have
208 different functions on the 627EHF and the 627DHG. Some registers also have
209 different power-on default values, but BIOS should already be loading
210 appropriate defaults. Note that bank selection must be performed as is currently
211 done in the driver for all register addresses.
212 
213 ========================= =====================================================
214 Register(s)               Meaning
215 ========================= =====================================================
216 0x49                      only on DHG, selects temperature source for AUX fan,
217                           CPU fan0
218 0x4a                      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.
224 0x58                      Chip ID: 0xa1=EHF 0xc1=DHG
225 0x5e                      only on DHG, has bits to enable "current mode"
226                           temperature detection and critical temperature
227                           protection
228 0x45b                     only on EHF, bit 3, vin4 alarm (EHF supports 10
229                           inputs, only 9 on DHG)
230 0x552                     only on EHF, vin4
231 0x558                     only on EHF, vin4 high limit
232 0x559                     only on EHF, vin4 low limit
233 0x6b                      only on DHG, SYS fan critical temperature
234 0x6c                      only on DHG, CPU fan0 critical temperature
235 0x6d                      only on DHG, AUX fan critical temperature
236 0x6e                      only on DHG, CPU fan1 critical temperature
237 0x50-0x55 and 0x650-0x657 marked as:
238 
239                             - "Test Register" for the EHF
240                             - "Reserved Register" for the DHG
241 ========================= =====================================================
242 
243 The DHG also supports PECI, where the DHG queries Intel CPU temperatures, and
244 the ICH8 southbridge gets that data via PECI from the DHG, so that the
245 southbridge drives the fans. And the DHG supports SST, a one-wire serial bus.
246 
247 The 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.

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