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authorJuerg Haefliger <juergh@gmail.com>2007-06-09 10:11:16 -0400
committerMark M. Hoffman <mhoffman@lightlink.com>2007-07-19 14:22:12 -0400
commitb825037d185549825d4f35504f2085ec86037110 (patch)
tree732dfe9c84a813a3bc125d25d5e9f48c1a8b59b1 /Documentation/hwmon/dme1737
parent9431996f55f8a3c04cdcb63895cf7661e135fadb (diff)
hwmon/dme1737: Add documentation
Add documentation for the new SMSC DME1737 driver. Signed-off-by: Juerg Haefliger <juergh at gmail.com> Signed-off-by: Jean Delvare <khali@linux-fr.org>
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1Kernel driver dme1737
2=====================
3
4Supported chips:
5 * SMSC DME1737 and compatibles (like Asus A8000)
6 Prefix: 'dme1737'
7 Addresses scanned: I2C 0x2c, 0x2d, 0x2e
8 Datasheet: Provided by SMSC upon request and under NDA
9
10Authors:
11 Juerg Haefliger <juergh@gmail.com>
12
13
14Module Parameters
15-----------------
16
17* force_start: bool Enables the monitoring of voltage, fan and temp inputs
18 and PWM output control functions. Using this parameter
19 shouldn't be required since the BIOS usually takes care
20 of this.
21
22Note that there is no need to use this parameter if the driver loads without
23complaining. The driver will say so if it is necessary.
24
25
26Description
27-----------
28
29This driver implements support for the hardware monitoring capabilities of the
30SMSC DME1737 and Asus A8000 (which are the same) Super-I/O chips. This chip
31features monitoring of 3 temp sensors temp[1-3] (2 remote diodes and 1
32internal), 7 voltages in[0-6] (6 external and 1 internal) and 6 fan speeds
33fan[1-6]. Additionally, the chip implements 5 PWM outputs pwm[1-3,5-6] for
34controlling fan speeds both manually and automatically.
35
36Fan[3-6] and pwm[3,5-6] are optional features and their availability is
37dependent on the configuration of the chip. The driver will detect which
38features are present during initialization and create the sysfs attributes
39accordingly.
40
41
42Voltage Monitoring
43------------------
44
45The voltage inputs are sampled with 12-bit resolution and have internal
46scaling resistors. The values returned by the driver therefore reflect true
47millivolts and don't need scaling. The voltage inputs are mapped as follows
48(the last column indicates the input ranges):
49
50 in0: +5VTR (+5V standby) 0V - 6.64V
51 in1: Vccp (processor core) 0V - 3V
52 in2: VCC (internal +3.3V) 0V - 4.38V
53 in3: +5V 0V - 6.64V
54 in4: +12V 0V - 16V
55 in5: VTR (+3.3V standby) 0V - 4.38V
56 in6: Vbat (+3.0V) 0V - 4.38V
57
58Each voltage input has associated min and max limits which trigger an alarm
59when crossed.
60
61
62Temperature Monitoring
63----------------------
64
65Temperatures are measured with 12-bit resolution and reported in millidegree
66Celsius. The chip also features offsets for all 3 temperature inputs which -
67when programmed - get added to the input readings. The chip does all the
68scaling by itself and the driver therefore reports true temperatures that don't
69need any user-space adjustments. The temperature inputs are mapped as follows
70(the last column indicates the input ranges):
71
72 temp1: Remote diode 1 (3904 type) temperature -127C - +127C
73 temp2: DME1737 internal temperature -127C - +127C
74 temp3: Remote diode 2 (3904 type) temperature -127C - +127C
75
76Each temperature input has associated min and max limits which trigger an alarm
77when crossed. Additionally, each temperature input has a fault attribute that
78returns 1 when a faulty diode or an unconnected input is detected and 0
79otherwise.
80
81
82Fan Monitoring
83--------------
84
85Fan RPMs are measured with 16-bit resolution. The chip provides inputs for 6
86fan tachometers. All 6 inputs have an associated min limit which triggers an
87alarm when crossed. Fan inputs 1-4 provide type attributes that need to be set
88to the number of pulses per fan revolution that the connected tachometer
89generates. Supported values are 1, 2, and 4. Fan inputs 5-6 only support fans
90that generate 2 pulses per revolution. Fan inputs 5-6 also provide a max
91attribute that needs to be set to the maximum attainable RPM (fan at 100% duty-
92cycle) of the input. The chip adjusts the sampling rate based on this value.
93
94
95PWM Output Control
96------------------
97
98This chip features 5 PWM outputs. PWM outputs 1-3 are associated with fan
99inputs 1-3 and PWM outputs 5-6 are associated with fan inputs 5-6. PWM outputs
1001-3 can be configured to operate either in manual or automatic mode by setting
101the appropriate enable attribute accordingly. PWM outputs 5-6 can only operate
102in manual mode, their enable attributes are therefore read-only. When set to
103manual mode, the fan speed is set by writing the duty-cycle value to the
104appropriate PWM attribute. In automatic mode, the PWM attribute returns the
105current duty-cycle as set by the fan controller in the chip. All PWM outputs
106support the setting of the output frequency via the freq attribute.
107
108In automatic mode, the chip supports the setting of the PWM ramp rate which
109defines how fast the PWM output is adjusting to changes of the associated
110temperature input. Associating PWM outputs to temperature inputs is done via
111temperature zones. The chip features 3 zones whose assignments to temperature
112inputs is static and determined during initialization. These assignments can
113be retrieved via the zone[1-3]_auto_channels_temp attributes. Each PWM output
114is assigned to one (or hottest of multiple) temperature zone(s) through the
115pwm[1-3]_auto_channels_zone attributes. Each PWM output has 3 distinct output
116duty-cycles: full, low, and min. Full is internally hard-wired to 255 (100%)
117and low and min can be programmed via pwm[1-3]_auto_point1_pwm and
118pwm[1-3]_auto_pwm_min, respectively. The thermal thresholds of the zones are
119programmed via zone[1-3]_auto_point[1-3]_temp and
120zone[1-3]_auto_point1_temp_hyst:
121
122 pwm[1-3]_auto_point2_pwm full-speed duty-cycle (255, i.e., 100%)
123 pwm[1-3]_auto_point1_pwm low-speed duty-cycle
124 pwm[1-3]_auto_pwm_min min-speed duty-cycle
125
126 zone[1-3]_auto_point3_temp full-speed temp (all outputs)
127 zone[1-3]_auto_point2_temp full-speed temp
128 zone[1-3]_auto_point1_temp low-speed temp
129 zone[1-3]_auto_point1_temp_hyst min-speed temp
130
131The chip adjusts the output duty-cycle linearly in the range of auto_point1_pwm
132to auto_point2_pwm if the temperature of the associated zone is between
133auto_point1_temp and auto_point2_temp. If the temperature drops below the
134auto_point1_temp_hyst value, the output duty-cycle is set to the auto_pwm_min
135value which only supports two values: 0 or auto_point1_pwm. That means that the
136fan either turns completely off or keeps spinning with the low-speed
137duty-cycle. If any of the temperatures rise above the auto_point3_temp value,
138all PWM outputs are set to 100% duty-cycle.
139
140Following is another representation of how the chip sets the output duty-cycle
141based on the temperature of the associated thermal zone:
142
143 Duty-Cycle Duty-Cycle
144 Temperature Rising Temp Falling Temp
145 ----------- ----------- ------------
146 full-speed full-speed full-speed
147
148 < linearly adjusted duty-cycle >
149
150 low-speed low-speed low-speed
151 min-speed low-speed
152 min-speed min-speed min-speed
153 min-speed min-speed
154
155
156Sysfs Attributes
157----------------
158
159Following is a list of all sysfs attributes that the driver provides, their
160permissions and a short description:
161
162Name Perm Description
163---- ---- -----------
164cpu0_vid RO CPU core reference voltage in
165 millivolts.
166vrm RW Voltage regulator module version
167 number.
168
169in[0-6]_input RO Measured voltage in millivolts.
170in[0-6]_min RW Low limit for voltage input.
171in[0-6]_max RW High limit for voltage input.
172in[0-6]_alarm RO Voltage input alarm. Returns 1 if
173 voltage input is or went outside the
174 associated min-max range, 0 otherwise.
175
176temp[1-3]_input RO Measured temperature in millidegree
177 Celsius.
178temp[1-3]_min RW Low limit for temp input.
179temp[1-3]_max RW High limit for temp input.
180temp[1-3]_offset RW Offset for temp input. This value will
181 be added by the chip to the measured
182 temperature.
183temp[1-3]_alarm RO Alarm for temp input. Returns 1 if temp
184 input is or went outside the associated
185 min-max range, 0 otherwise.
186temp[1-3]_fault RO Temp input fault. Returns 1 if the chip
187 detects a faulty thermal diode or an
188 unconnected temp input, 0 otherwise.
189
190zone[1-3]_auto_channels_temp RO Temperature zone to temperature input
191 mapping. This attribute is a bitfield
192 and supports the following values:
193 1: temp1
194 2: temp2
195 4: temp3
196zone[1-3]_auto_point1_temp_hyst RW Auto PWM temp point1 hysteresis. The
197 output of the corresponding PWM is set
198 to the pwm_auto_min value if the temp
199 falls below the auto_point1_temp_hyst
200 value.
201zone[1-3]_auto_point[1-3]_temp RW Auto PWM temp points. Auto_point1 is
202 the low-speed temp, auto_point2 is the
203 full-speed temp, and auto_point3 is the
204 temp at which all PWM outputs are set
205 to full-speed (100% duty-cycle).
206
207fan[1-6]_input RO Measured fan speed in RPM.
208fan[1-6]_min RW Low limit for fan input.
209fan[1-6]_alarm RO Alarm for fan input. Returns 1 if fan
210 input is or went below the associated
211 min value, 0 otherwise.
212fan[1-4]_type RW Type of attached fan. Expressed in
213 number of pulses per revolution that
214 the fan generates. Supported values are
215 1, 2, and 4.
216fan[5-6]_max RW Max attainable RPM at 100% duty-cycle.
217 Required for chip to adjust the
218 sampling rate accordingly.
219
220pmw[1-3,5-6] RO/RW Duty-cycle of PWM output. Supported
221 values are 0-255 (0%-100%). Only
222 writeable if the associated PWM is in
223 manual mode.
224pwm[1-3]_enable RW Enable of PWM outputs 1-3. Supported
225 values are:
226 0: turned off (output @ 100%)
227 1: manual mode
228 2: automatic mode
229pwm[5-6]_enable RO Enable of PWM outputs 5-6. Always
230 returns 1 since these 2 outputs are
231 hard-wired to manual mode.
232pmw[1-3,5-6]_freq RW Frequency of PWM output. Supported
233 values are in the range 11Hz-30000Hz
234 (default is 25000Hz).
235pmw[1-3]_ramp_rate RW Ramp rate of PWM output. Determines how
236 fast the PWM duty-cycle will change
237 when the PWM is in automatic mode.
238 Expressed in ms per PWM step. Supported
239 values are in the range 0ms-206ms
240 (default is 0, which means the duty-
241 cycle changes instantly).
242pwm[1-3]_auto_channels_zone RW PWM output to temperature zone mapping.
243 This attribute is a bitfield and
244 supports the following values:
245 1: zone1
246 2: zone2
247 4: zone3
248 6: highest of zone[2-3]
249 7: highest of zone[1-3]
250pwm[1-3]_auto_pwm_min RW Auto PWM min pwm. Minimum PWM duty-
251 cycle. Supported values are 0 or
252 auto_point1_pwm.
253pwm[1-3]_auto_point1_pwm RW Auto PWM pwm point. Auto_point1 is the
254 low-speed duty-cycle.
255pwm[1-3]_auto_point2_pwm RO Auto PWM pwm point. Auto_point2 is the
256 full-speed duty-cycle which is hard-
257 wired to 255 (100% duty-cycle).