1Kernel driver lm93 2================== 3 4Supported chips: 5 6 * National Semiconductor LM93 7 8 Prefix 'lm93' 9 10 Addresses scanned: I2C 0x2c-0x2e 11 12 Datasheet: http://www.national.com/ds.cgi/LM/LM93.pdf 13 14 * National Semiconductor LM94 15 16 Prefix 'lm94' 17 18 Addresses scanned: I2C 0x2c-0x2e 19 20 Datasheet: http://www.national.com/ds.cgi/LM/LM94.pdf 21 22 23Authors: 24 - Mark M. Hoffman <mhoffman@lightlink.com> 25 - Ported to 2.6 by Eric J. Bowersox <ericb@aspsys.com> 26 - Adapted to 2.6.20 by Carsten Emde <ce@osadl.org> 27 - Modified for mainline integration by Hans J. Koch <hjk@hansjkoch.de> 28 29Module Parameters 30----------------- 31 32* init: integer 33 Set to non-zero to force some initializations (default is 0). 34* disable_block: integer 35 A "0" allows SMBus block data transactions if the host supports them. A "1" 36 disables SMBus block data transactions. The default is 0. 37* vccp_limit_type: integer array (2) 38 Configures in7 and in8 limit type, where 0 means absolute and non-zero 39 means relative. "Relative" here refers to "Dynamic Vccp Monitoring using 40 VID" from the datasheet. It greatly simplifies the interface to allow 41 only one set of limits (absolute or relative) to be in operation at a 42 time (even though the hardware is capable of enabling both). There's 43 not a compelling use case for enabling both at once, anyway. The default 44 is "0,0". 45* vid_agtl: integer 46 A "0" configures the VID pins for V(ih) = 2.1V min, V(il) = 0.8V max. 47 A "1" configures the VID pins for V(ih) = 0.8V min, V(il) = 0.4V max. 48 (The latter setting is referred to as AGTL+ Compatible in the datasheet.) 49 I.e. this parameter controls the VID pin input thresholds; if your VID 50 inputs are not working, try changing this. The default value is "0". 51 52 53Hardware Description 54-------------------- 55 56(from the datasheet) 57 58The LM93 hardware monitor has a two wire digital interface compatible with 59SMBus 2.0. Using an 8-bit ADC, the LM93 measures the temperature of two remote 60diode connected transistors as well as its own die and 16 power supply 61voltages. To set fan speed, the LM93 has two PWM outputs that are each 62controlled by up to four temperature zones. The fancontrol algorithm is lookup 63table based. The LM93 includes a digital filter that can be invoked to smooth 64temperature readings for better control of fan speed. The LM93 has four 65tachometer inputs to measure fan speed. Limit and status registers for all 66measured values are included. The LM93 builds upon the functionality of 67previous motherboard management ASICs and uses some of the LM85's features 68(i.e. smart tachometer mode). It also adds measurement and control support 69for dynamic Vccp monitoring and PROCHOT. It is designed to monitor a dual 70processor Xeon class motherboard with a minimum of external components. 71 72LM94 is also supported in LM93 compatible mode. Extra sensors and features of 73LM94 are not supported. 74 75 76User Interface 77-------------- 78 79#PROCHOT 80^^^^^^^^ 81 82The LM93 can monitor two #PROCHOT signals. The results are found in the 83sysfs files prochot1, prochot2, prochot1_avg, prochot2_avg, prochot1_max, 84and prochot2_max. prochot1_max and prochot2_max contain the user limits 85for #PROCHOT1 and #PROCHOT2, respectively. prochot1 and prochot2 contain 86the current readings for the most recent complete time interval. The 87value of prochot1_avg and prochot2_avg is something like a 2 period 88exponential moving average (but not quite - check the datasheet). Note 89that this third value is calculated by the chip itself. All values range 90from 0-255 where 0 indicates no throttling, and 255 indicates > 99.6%. 91 92The monitoring intervals for the two #PROCHOT signals is also configurable. 93These intervals can be found in the sysfs files prochot1_interval and 94prochot2_interval. The values in these files specify the intervals for 95#P1_PROCHOT and #P2_PROCHOT, respectively. Selecting a value not in this 96list will cause the driver to use the next largest interval. The available 97intervals are (in seconds): 98 99#PROCHOT intervals: 100 0.73, 1.46, 2.9, 5.8, 11.7, 23.3, 46.6, 93.2, 186, 372 101 102It is possible to configure the LM93 to logically short the two #PROCHOT 103signals. I.e. when #P1_PROCHOT is asserted, the LM93 will automatically 104assert #P2_PROCHOT, and vice-versa. This mode is enabled by writing a 105non-zero integer to the sysfs file prochot_short. 106 107The LM93 can also override the #PROCHOT pins by driving a PWM signal onto 108one or both of them. When overridden, the signal has a period of 3.56 ms, 109a minimum pulse width of 5 clocks (at 22.5kHz => 6.25% duty cycle), and 110a maximum pulse width of 80 clocks (at 22.5kHz => 99.88% duty cycle). 111 112The sysfs files prochot1_override and prochot2_override contain boolean 113integers which enable or disable the override function for #P1_PROCHOT and 114#P2_PROCHOT, respectively. The sysfs file prochot_override_duty_cycle 115contains a value controlling the duty cycle for the PWM signal used when 116the override function is enabled. This value ranges from 0 to 15, with 0 117indicating minimum duty cycle and 15 indicating maximum. 118 119#VRD_HOT 120^^^^^^^^ 121 122The LM93 can monitor two #VRD_HOT signals. The results are found in the 123sysfs files vrdhot1 and vrdhot2. There is one value per file: a boolean for 124which 1 indicates #VRD_HOT is asserted and 0 indicates it is negated. These 125files are read-only. 126 127Smart Tach Mode (from the datasheet):: 128 129 If a fan is driven using a low-side drive PWM, the tachometer 130 output of the fan is corrupted. The LM93 includes smart tachometer 131 circuitry that allows an accurate tachometer reading to be 132 achieved despite the signal corruption. In smart tach mode all 133 four signals are measured within 4 seconds. 134 135Smart tach mode is enabled by the driver by writing 1 or 2 (associating the 136fan tachometer with a pwm) to the sysfs file fan<n>_smart_tach. A zero 137will disable the function for that fan. Note that Smart tach mode cannot be 138enabled if the PWM output frequency is 22500 Hz (see below). 139 140Manual PWM 141^^^^^^^^^^ 142 143The LM93 has a fixed or override mode for the two PWM outputs (although, there 144are still some conditions that will override even this mode - see section 14515.10.6 of the datasheet for details.) The sysfs files pwm1_override 146and pwm2_override are used to enable this mode; each is a boolean integer 147where 0 disables and 1 enables the manual control mode. The sysfs files pwm1 148and pwm2 are used to set the manual duty cycle; each is an integer (0-255) 149where 0 is 0% duty cycle, and 255 is 100%. Note that the duty cycle values 150are constrained by the hardware. Selecting a value which is not available 151will cause the driver to use the next largest value. Also note: when manual 152PWM mode is disabled, the value of pwm1 and pwm2 indicates the current duty 153cycle chosen by the h/w. 154 155PWM Output Frequency 156^^^^^^^^^^^^^^^^^^^^ 157 158The LM93 supports several different frequencies for the PWM output channels. 159The sysfs files pwm1_freq and pwm2_freq are used to select the frequency. The 160frequency values are constrained by the hardware. Selecting a value which is 161not available will cause the driver to use the next largest value. Also note 162that this parameter has implications for the Smart Tach Mode (see above). 163 164PWM Output Frequencies (in Hz): 165 12, 36, 48, 60, 72, 84, 96, 22500 (default) 166 167Automatic PWM 168^^^^^^^^^^^^^ 169 170The LM93 is capable of complex automatic fan control, with many different 171points of configuration. To start, each PWM output can be bound to any 172combination of eight control sources. The final PWM is the largest of all 173individual control sources to which the PWM output is bound. 174 175The eight control sources are: temp1-temp4 (aka "zones" in the datasheet), 176#PROCHOT 1 & 2, and #VRDHOT 1 & 2. The bindings are expressed as a bitmask 177in the sysfs files pwm<n>_auto_channels, where a "1" enables the binding, and 178a "0" disables it. The h/w default is 0x0f (all temperatures bound). 179 180 ====== =========== 181 0x01 Temp 1 182 0x02 Temp 2 183 0x04 Temp 3 184 0x08 Temp 4 185 0x10 #PROCHOT 1 186 0x20 #PROCHOT 2 187 0x40 #VRDHOT 1 188 0x80 #VRDHOT 2 189 ====== =========== 190 191The function y = f(x) takes a source temperature x to a PWM output y. This 192function of the LM93 is derived from a base temperature and a table of 12 193temperature offsets. The base temperature is expressed in degrees C in the 194sysfs files temp<n>_auto_base. The offsets are expressed in cumulative 195degrees C, with the value of offset <i> for temperature value <n> being 196contained in the file temp<n>_auto_offset<i>. E.g. if the base temperature 197is 40C: 198 199 ========== ======================= =============== ======= 200 offset # temp<n>_auto_offset<i> range pwm 201 ========== ======================= =============== ======= 202 1 0 - 25.00% 203 2 0 - 28.57% 204 3 1 40C - 41C 32.14% 205 4 1 41C - 42C 35.71% 206 5 2 42C - 44C 39.29% 207 6 2 44C - 46C 42.86% 208 7 2 48C - 50C 46.43% 209 8 2 50C - 52C 50.00% 210 9 2 52C - 54C 53.57% 211 10 2 54C - 56C 57.14% 212 11 2 56C - 58C 71.43% 213 12 2 58C - 60C 85.71% 214 - - > 60C 100.00% 215 ========== ======================= =============== ======= 216 217Valid offsets are in the range 0C <= x <= 7.5C in 0.5C increments. 218 219There is an independent base temperature for each temperature channel. Note, 220however, there are only two tables of offsets: one each for temp[12] and 221temp[34]. Therefore, any change to e.g. temp1_auto_offset<i> will also 222affect temp2_auto_offset<i>. 223 224The LM93 can also apply hysteresis to the offset table, to prevent unwanted 225oscillation between two steps in the offsets table. These values are found in 226the sysfs files temp<n>_auto_offset_hyst. The value in this file has the 227same representation as in temp<n>_auto_offset<i>. 228 229If a temperature reading falls below the base value for that channel, the LM93 230will use the minimum PWM value. These values are found in the sysfs files 231temp<n>_auto_pwm_min. Note, there are only two minimums: one each for temp[12] 232and temp[34]. Therefore, any change to e.g. temp1_auto_pwm_min will also 233affect temp2_auto_pwm_min. 234 235PWM Spin-Up Cycle 236^^^^^^^^^^^^^^^^^ 237 238A spin-up cycle occurs when a PWM output is commanded from 0% duty cycle to 239some value > 0%. The LM93 supports a minimum duty cycle during spin-up. These 240values are found in the sysfs files pwm<n>_auto_spinup_min. The value in this 241file has the same representation as other PWM duty cycle values. The 242duration of the spin-up cycle is also configurable. These values are found in 243the sysfs files pwm<n>_auto_spinup_time. The value in this file is 244the spin-up time in seconds. The available spin-up times are constrained by 245the hardware. Selecting a value which is not available will cause the driver 246to use the next largest value. 247 248Spin-up Durations: 249 0 (disabled, h/w default), 0.1, 0.25, 0.4, 0.7, 1.0, 2.0, 4.0 250 251#PROCHOT and #VRDHOT PWM Ramping 252^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 253 254If the #PROCHOT or #VRDHOT signals are asserted while bound to a PWM output 255channel, the LM93 will ramp the PWM output up to 100% duty cycle in discrete 256steps. The duration of each step is configurable. There are two files, with 257one value each in seconds: pwm_auto_prochot_ramp and pwm_auto_vrdhot_ramp. 258The available ramp times are constrained by the hardware. Selecting a value 259which is not available will cause the driver to use the next largest value. 260 261Ramp Times: 262 0 (disabled, h/w default) to 0.75 in 0.05 second intervals 263 264Fan Boost 265^^^^^^^^^ 266 267For each temperature channel, there is a boost temperature: if the channel 268exceeds this limit, the LM93 will immediately drive both PWM outputs to 100%. 269This limit is expressed in degrees C in the sysfs files temp<n>_auto_boost. 270There is also a hysteresis temperature for this function: after the boost 271limit is reached, the temperature channel must drop below this value before 272the boost function is disabled. This temperature is also expressed in degrees 273C in the sysfs files temp<n>_auto_boost_hyst. 274 275GPIO Pins 276^^^^^^^^^ 277 278The LM93 can monitor the logic level of four dedicated GPIO pins as well as the 279four tach input pins. GPIO0-GPIO3 correspond to (fan) tach 1-4, respectively. 280All eight GPIOs are read by reading the bitmask in the sysfs file gpio. The 281LSB is GPIO0, and the MSB is GPIO7. 282 283 284LM93 Unique sysfs Files 285----------------------- 286 287=========================== =============================================== 288file description 289=========================== =============================================== 290prochot<n> current #PROCHOT % 291prochot<n>_avg moving average #PROCHOT % 292prochot<n>_max limit #PROCHOT % 293prochot_short enable or disable logical #PROCHOT pin short 294prochot<n>_override force #PROCHOT assertion as PWM 295prochot_override_duty_cycle duty cycle for the PWM signal used when 296 #PROCHOT is overridden 297prochot<n>_interval #PROCHOT PWM sampling interval 298vrdhot<n> 0 means negated, 1 means asserted 299fan<n>_smart_tach enable or disable smart tach mode 300pwm<n>_auto_channels select control sources for PWM outputs 301pwm<n>_auto_spinup_min minimum duty cycle during spin-up 302pwm<n>_auto_spinup_time duration of spin-up 303pwm_auto_prochot_ramp ramp time per step when #PROCHOT asserted 304pwm_auto_vrdhot_ramp ramp time per step when #VRDHOT asserted 305temp<n>_auto_base temperature channel base 306temp<n>_auto_offset[1-12] temperature channel offsets 307temp<n>_auto_offset_hyst temperature channel offset hysteresis 308temp<n>_auto_boost temperature channel boost (PWMs to 100%) 309 limit 310temp<n>_auto_boost_hyst temperature channel boost hysteresis 311gpio input state of 8 GPIO pins; read-only 312=========================== =============================================== 313