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1 | Kernel driver lm93 |
2 | ================== | |
3 | ||
4 | Supported chips: | |
5 | * National Semiconductor LM93 | |
6 | Prefix 'lm93' | |
7 | Addresses scanned: I2C 0x2c-0x2e | |
8 | Datasheet: http://www.national.com/ds.cgi/LM/LM93.pdf | |
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9 | * National Semiconductor LM94 |
10 | Prefix 'lm94' | |
11 | Addresses scanned: I2C 0x2c-0x2e | |
12 | Datasheet: http://www.national.com/ds.cgi/LM/LM94.pdf | |
e46957ed | 13 | |
471c6068 | 14 | Authors: |
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15 | Mark M. Hoffman <mhoffman@lightlink.com> |
16 | Ported to 2.6 by Eric J. Bowersox <ericb@aspsys.com> | |
17 | Adapted to 2.6.20 by Carsten Emde <ce@osadl.org> | |
f99e0e98 | 18 | Modified for mainline integration by Hans J. Koch <hjk@hansjkoch.de> |
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19 | |
20 | Module Parameters | |
21 | ----------------- | |
22 | ||
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23 | * init: integer |
24 | Set to non-zero to force some initializations (default is 0). | |
25 | * disable_block: integer | |
26 | A "0" allows SMBus block data transactions if the host supports them. A "1" | |
27 | disables SMBus block data transactions. The default is 0. | |
28 | * vccp_limit_type: integer array (2) | |
29 | Configures in7 and in8 limit type, where 0 means absolute and non-zero | |
30 | means relative. "Relative" here refers to "Dynamic Vccp Monitoring using | |
31 | VID" from the datasheet. It greatly simplifies the interface to allow | |
32 | only one set of limits (absolute or relative) to be in operation at a | |
33 | time (even though the hardware is capable of enabling both). There's | |
34 | not a compelling use case for enabling both at once, anyway. The default | |
35 | is "0,0". | |
36 | * vid_agtl: integer | |
37 | A "0" configures the VID pins for V(ih) = 2.1V min, V(il) = 0.8V max. | |
38 | A "1" configures the VID pins for V(ih) = 0.8V min, V(il) = 0.4V max. | |
39 | (The latter setting is referred to as AGTL+ Compatible in the datasheet.) | |
40 | I.e. this parameter controls the VID pin input thresholds; if your VID | |
41 | inputs are not working, try changing this. The default value is "0". | |
42 | ||
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43 | |
44 | Hardware Description | |
45 | -------------------- | |
46 | ||
47 | (from the datasheet) | |
48 | ||
471c6068 | 49 | The LM93 hardware monitor has a two wire digital interface compatible with |
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50 | SMBus 2.0. Using an 8-bit ADC, the LM93 measures the temperature of two remote |
51 | diode connected transistors as well as its own die and 16 power supply | |
52 | voltages. To set fan speed, the LM93 has two PWM outputs that are each | |
53 | controlled by up to four temperature zones. The fancontrol algorithm is lookup | |
54 | table based. The LM93 includes a digital filter that can be invoked to smooth | |
55 | temperature readings for better control of fan speed. The LM93 has four | |
56 | tachometer inputs to measure fan speed. Limit and status registers for all | |
57 | measured values are included. The LM93 builds upon the functionality of | |
471c6068 | 58 | previous motherboard management ASICs and uses some of the LM85's features |
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59 | (i.e. smart tachometer mode). It also adds measurement and control support |
60 | for dynamic Vccp monitoring and PROCHOT. It is designed to monitor a dual | |
61 | processor Xeon class motherboard with a minimum of external components. | |
62 | ||
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63 | LM94 is also supported in LM93 compatible mode. Extra sensors and features of |
64 | LM94 are not supported. | |
65 | ||
e46957ed | 66 | |
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67 | User Interface |
68 | -------------- | |
69 | ||
70 | #PROCHOT: | |
71 | ||
72 | The LM93 can monitor two #PROCHOT signals. The results are found in the | |
73 | sysfs files prochot1, prochot2, prochot1_avg, prochot2_avg, prochot1_max, | |
74 | and prochot2_max. prochot1_max and prochot2_max contain the user limits | |
75 | for #PROCHOT1 and #PROCHOT2, respectively. prochot1 and prochot2 contain | |
76 | the current readings for the most recent complete time interval. The | |
77 | value of prochot1_avg and prochot2_avg is something like a 2 period | |
78 | exponential moving average (but not quite - check the datasheet). Note | |
79 | that this third value is calculated by the chip itself. All values range | |
80 | from 0-255 where 0 indicates no throttling, and 255 indicates > 99.6%. | |
81 | ||
82 | The monitoring intervals for the two #PROCHOT signals is also configurable. | |
83 | These intervals can be found in the sysfs files prochot1_interval and | |
84 | prochot2_interval. The values in these files specify the intervals for | |
85 | #P1_PROCHOT and #P2_PROCHOT, respectively. Selecting a value not in this | |
86 | list will cause the driver to use the next largest interval. The available | |
471c6068 | 87 | intervals are (in seconds): |
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88 | |
89 | #PROCHOT intervals: 0.73, 1.46, 2.9, 5.8, 11.7, 23.3, 46.6, 93.2, 186, 372 | |
90 | ||
91 | It is possible to configure the LM93 to logically short the two #PROCHOT | |
92 | signals. I.e. when #P1_PROCHOT is asserted, the LM93 will automatically | |
93 | assert #P2_PROCHOT, and vice-versa. This mode is enabled by writing a | |
94 | non-zero integer to the sysfs file prochot_short. | |
95 | ||
96 | The LM93 can also override the #PROCHOT pins by driving a PWM signal onto | |
471c6068 | 97 | one or both of them. When overridden, the signal has a period of 3.56 ms, |
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98 | a minimum pulse width of 5 clocks (at 22.5kHz => 6.25% duty cycle), and |
99 | a maximum pulse width of 80 clocks (at 22.5kHz => 99.88% duty cycle). | |
100 | ||
101 | The sysfs files prochot1_override and prochot2_override contain boolean | |
471c6068 | 102 | integers which enable or disable the override function for #P1_PROCHOT and |
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103 | #P2_PROCHOT, respectively. The sysfs file prochot_override_duty_cycle |
104 | contains a value controlling the duty cycle for the PWM signal used when | |
105 | the override function is enabled. This value ranges from 0 to 15, with 0 | |
106 | indicating minimum duty cycle and 15 indicating maximum. | |
107 | ||
108 | #VRD_HOT: | |
109 | ||
110 | The LM93 can monitor two #VRD_HOT signals. The results are found in the | |
111 | sysfs files vrdhot1 and vrdhot2. There is one value per file: a boolean for | |
112 | which 1 indicates #VRD_HOT is asserted and 0 indicates it is negated. These | |
113 | files are read-only. | |
114 | ||
115 | Smart Tach Mode: | |
116 | ||
117 | (from the datasheet) | |
118 | ||
119 | If a fan is driven using a low-side drive PWM, the tachometer | |
120 | output of the fan is corrupted. The LM93 includes smart tachometer | |
121 | circuitry that allows an accurate tachometer reading to be | |
122 | achieved despite the signal corruption. In smart tach mode all | |
123 | four signals are measured within 4 seconds. | |
124 | ||
125 | Smart tach mode is enabled by the driver by writing 1 or 2 (associating the | |
126 | the fan tachometer with a pwm) to the sysfs file fan<n>_smart_tach. A zero | |
127 | will disable the function for that fan. Note that Smart tach mode cannot be | |
128 | enabled if the PWM output frequency is 22500 Hz (see below). | |
129 | ||
130 | Manual PWM: | |
131 | ||
132 | The LM93 has a fixed or override mode for the two PWM outputs (although, there | |
133 | are still some conditions that will override even this mode - see section | |
134 | 15.10.6 of the datasheet for details.) The sysfs files pwm1_override | |
135 | and pwm2_override are used to enable this mode; each is a boolean integer | |
136 | where 0 disables and 1 enables the manual control mode. The sysfs files pwm1 | |
137 | and pwm2 are used to set the manual duty cycle; each is an integer (0-255) | |
138 | where 0 is 0% duty cycle, and 255 is 100%. Note that the duty cycle values | |
139 | are constrained by the hardware. Selecting a value which is not available | |
140 | will cause the driver to use the next largest value. Also note: when manual | |
141 | PWM mode is disabled, the value of pwm1 and pwm2 indicates the current duty | |
142 | cycle chosen by the h/w. | |
143 | ||
144 | PWM Output Frequency: | |
145 | ||
146 | The LM93 supports several different frequencies for the PWM output channels. | |
147 | The sysfs files pwm1_freq and pwm2_freq are used to select the frequency. The | |
148 | frequency values are constrained by the hardware. Selecting a value which is | |
149 | not available will cause the driver to use the next largest value. Also note | |
150 | that this parameter has implications for the Smart Tach Mode (see above). | |
151 | ||
471c6068 | 152 | PWM Output Frequencies (in Hz): 12, 36, 48, 60, 72, 84, 96, 22500 (default) |
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153 | |
154 | Automatic PWM: | |
155 | ||
156 | The LM93 is capable of complex automatic fan control, with many different | |
157 | points of configuration. To start, each PWM output can be bound to any | |
158 | combination of eight control sources. The final PWM is the largest of all | |
159 | individual control sources to which the PWM output is bound. | |
160 | ||
161 | The eight control sources are: temp1-temp4 (aka "zones" in the datasheet), | |
162 | #PROCHOT 1 & 2, and #VRDHOT 1 & 2. The bindings are expressed as a bitmask | |
163 | in the sysfs files pwm<n>_auto_channels, where a "1" enables the binding, and | |
471c6068 | 164 | a "0" disables it. The h/w default is 0x0f (all temperatures bound). |
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165 | |
166 | 0x01 - Temp 1 | |
167 | 0x02 - Temp 2 | |
168 | 0x04 - Temp 3 | |
169 | 0x08 - Temp 4 | |
170 | 0x10 - #PROCHOT 1 | |
171 | 0x20 - #PROCHOT 2 | |
172 | 0x40 - #VRDHOT 1 | |
173 | 0x80 - #VRDHOT 2 | |
174 | ||
175 | The function y = f(x) takes a source temperature x to a PWM output y. This | |
176 | function of the LM93 is derived from a base temperature and a table of 12 | |
177 | temperature offsets. The base temperature is expressed in degrees C in the | |
178 | sysfs files temp<n>_auto_base. The offsets are expressed in cumulative | |
179 | degrees C, with the value of offset <i> for temperature value <n> being | |
180 | contained in the file temp<n>_auto_offset<i>. E.g. if the base temperature | |
181 | is 40C: | |
182 | ||
183 | offset # temp<n>_auto_offset<i> range pwm | |
184 | 1 0 - 25.00% | |
185 | 2 0 - 28.57% | |
186 | 3 1 40C - 41C 32.14% | |
187 | 4 1 41C - 42C 35.71% | |
188 | 5 2 42C - 44C 39.29% | |
189 | 6 2 44C - 46C 42.86% | |
190 | 7 2 48C - 50C 46.43% | |
191 | 8 2 50C - 52C 50.00% | |
192 | 9 2 52C - 54C 53.57% | |
193 | 10 2 54C - 56C 57.14% | |
194 | 11 2 56C - 58C 71.43% | |
195 | 12 2 58C - 60C 85.71% | |
196 | > 60C 100.00% | |
197 | ||
198 | Valid offsets are in the range 0C <= x <= 7.5C in 0.5C increments. | |
199 | ||
200 | There is an independent base temperature for each temperature channel. Note, | |
201 | however, there are only two tables of offsets: one each for temp[12] and | |
202 | temp[34]. Therefore, any change to e.g. temp1_auto_offset<i> will also | |
203 | affect temp2_auto_offset<i>. | |
204 | ||
205 | The LM93 can also apply hysteresis to the offset table, to prevent unwanted | |
206 | oscillation between two steps in the offsets table. These values are found in | |
207 | the sysfs files temp<n>_auto_offset_hyst. The value in this file has the | |
208 | same representation as in temp<n>_auto_offset<i>. | |
209 | ||
210 | If a temperature reading falls below the base value for that channel, the LM93 | |
211 | will use the minimum PWM value. These values are found in the sysfs files | |
212 | temp<n>_auto_pwm_min. Note, there are only two minimums: one each for temp[12] | |
213 | and temp[34]. Therefore, any change to e.g. temp1_auto_pwm_min will also | |
214 | affect temp2_auto_pwm_min. | |
215 | ||
216 | PWM Spin-Up Cycle: | |
217 | ||
218 | A spin-up cycle occurs when a PWM output is commanded from 0% duty cycle to | |
219 | some value > 0%. The LM93 supports a minimum duty cycle during spin-up. These | |
220 | values are found in the sysfs files pwm<n>_auto_spinup_min. The value in this | |
221 | file has the same representation as other PWM duty cycle values. The | |
222 | duration of the spin-up cycle is also configurable. These values are found in | |
223 | the sysfs files pwm<n>_auto_spinup_time. The value in this file is | |
224 | the spin-up time in seconds. The available spin-up times are constrained by | |
225 | the hardware. Selecting a value which is not available will cause the driver | |
226 | to use the next largest value. | |
227 | ||
228 | Spin-up Durations: 0 (disabled, h/w default), 0.1, 0.25, 0.4, 0.7, 1.0, | |
229 | 2.0, 4.0 | |
230 | ||
231 | #PROCHOT and #VRDHOT PWM Ramping: | |
232 | ||
233 | If the #PROCHOT or #VRDHOT signals are asserted while bound to a PWM output | |
234 | channel, the LM93 will ramp the PWM output up to 100% duty cycle in discrete | |
235 | steps. The duration of each step is configurable. There are two files, with | |
236 | one value each in seconds: pwm_auto_prochot_ramp and pwm_auto_vrdhot_ramp. | |
237 | The available ramp times are constrained by the hardware. Selecting a value | |
238 | which is not available will cause the driver to use the next largest value. | |
239 | ||
240 | Ramp Times: 0 (disabled, h/w default) to 0.75 in 0.05 second intervals | |
241 | ||
242 | Fan Boost: | |
243 | ||
244 | For each temperature channel, there is a boost temperature: if the channel | |
245 | exceeds this limit, the LM93 will immediately drive both PWM outputs to 100%. | |
246 | This limit is expressed in degrees C in the sysfs files temp<n>_auto_boost. | |
247 | There is also a hysteresis temperature for this function: after the boost | |
248 | limit is reached, the temperature channel must drop below this value before | |
249 | the boost function is disabled. This temperature is also expressed in degrees | |
250 | C in the sysfs files temp<n>_auto_boost_hyst. | |
251 | ||
252 | GPIO Pins: | |
253 | ||
254 | The LM93 can monitor the logic level of four dedicated GPIO pins as well as the | |
255 | four tach input pins. GPIO0-GPIO3 correspond to (fan) tach 1-4, respectively. | |
256 | All eight GPIOs are read by reading the bitmask in the sysfs file gpio. The | |
257 | LSB is GPIO0, and the MSB is GPIO7. | |
258 | ||
259 | ||
260 | LM93 Unique sysfs Files | |
261 | ----------------------- | |
262 | ||
263 | file description | |
264 | ------------------------------------------------------------- | |
265 | ||
266 | prochot<n> current #PROCHOT % | |
267 | ||
268 | prochot<n>_avg moving average #PROCHOT % | |
269 | ||
270 | prochot<n>_max limit #PROCHOT % | |
271 | ||
272 | prochot_short enable or disable logical #PROCHOT pin short | |
273 | ||
274 | prochot<n>_override force #PROCHOT assertion as PWM | |
275 | ||
276 | prochot_override_duty_cycle | |
277 | duty cycle for the PWM signal used when | |
278 | #PROCHOT is overridden | |
279 | ||
280 | prochot<n>_interval #PROCHOT PWM sampling interval | |
281 | ||
282 | vrdhot<n> 0 means negated, 1 means asserted | |
283 | ||
284 | fan<n>_smart_tach enable or disable smart tach mode | |
285 | ||
286 | pwm<n>_auto_channels select control sources for PWM outputs | |
287 | ||
288 | pwm<n>_auto_spinup_min minimum duty cycle during spin-up | |
289 | ||
290 | pwm<n>_auto_spinup_time duration of spin-up | |
291 | ||
292 | pwm_auto_prochot_ramp ramp time per step when #PROCHOT asserted | |
293 | ||
294 | pwm_auto_vrdhot_ramp ramp time per step when #VRDHOT asserted | |
295 | ||
296 | temp<n>_auto_base temperature channel base | |
297 | ||
298 | temp<n>_auto_offset[1-12] | |
299 | temperature channel offsets | |
300 | ||
301 | temp<n>_auto_offset_hyst | |
302 | temperature channel offset hysteresis | |
303 | ||
304 | temp<n>_auto_boost temperature channel boost (PWMs to 100%) limit | |
305 | ||
306 | temp<n>_auto_boost_hyst temperature channel boost hysteresis | |
307 | ||
308 | gpio input state of 8 GPIO pins; read-only | |
309 |