1Kernel driver lm93 2================== 3 4Supported 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 9 * National Semiconductor LM94 10 Prefix 'lm94' 11 Addresses scanned: I2C 0x2c-0x2e 12 Datasheet: http://www.national.com/ds.cgi/LM/LM94.pdf 13 14Authors: 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> 18 Modified for mainline integration by Hans J. Koch <hjk@hansjkoch.de> 19 20Module Parameters 21----------------- 22 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 43 44Hardware Description 45-------------------- 46 47(from the datasheet) 48 49The LM93 hardware monitor has a two wire digital interface compatible with 50SMBus 2.0. Using an 8-bit ADC, the LM93 measures the temperature of two remote 51diode connected transistors as well as its own die and 16 power supply 52voltages. To set fan speed, the LM93 has two PWM outputs that are each 53controlled by up to four temperature zones. The fancontrol algorithm is lookup 54table based. The LM93 includes a digital filter that can be invoked to smooth 55temperature readings for better control of fan speed. The LM93 has four 56tachometer inputs to measure fan speed. Limit and status registers for all 57measured values are included. The LM93 builds upon the functionality of 58previous motherboard management ASICs and uses some of the LM85's features 59(i.e. smart tachometer mode). It also adds measurement and control support 60for dynamic Vccp monitoring and PROCHOT. It is designed to monitor a dual 61processor Xeon class motherboard with a minimum of external components. 62 63LM94 is also supported in LM93 compatible mode. Extra sensors and features of 64LM94 are not supported. 65 66 67User Interface 68-------------- 69 70#PROCHOT: 71 72The LM93 can monitor two #PROCHOT signals. The results are found in the 73sysfs files prochot1, prochot2, prochot1_avg, prochot2_avg, prochot1_max, 74and prochot2_max. prochot1_max and prochot2_max contain the user limits 75for #PROCHOT1 and #PROCHOT2, respectively. prochot1 and prochot2 contain 76the current readings for the most recent complete time interval. The 77value of prochot1_avg and prochot2_avg is something like a 2 period 78exponential moving average (but not quite - check the datasheet). Note 79that this third value is calculated by the chip itself. All values range 80from 0-255 where 0 indicates no throttling, and 255 indicates > 99.6%. 81 82The monitoring intervals for the two #PROCHOT signals is also configurable. 83These intervals can be found in the sysfs files prochot1_interval and 84prochot2_interval. The values in these files specify the intervals for 85#P1_PROCHOT and #P2_PROCHOT, respectively. Selecting a value not in this 86list will cause the driver to use the next largest interval. The available 87intervals are (in seconds): 88 89#PROCHOT intervals: 0.73, 1.46, 2.9, 5.8, 11.7, 23.3, 46.6, 93.2, 186, 372 90 91It is possible to configure the LM93 to logically short the two #PROCHOT 92signals. I.e. when #P1_PROCHOT is asserted, the LM93 will automatically 93assert #P2_PROCHOT, and vice-versa. This mode is enabled by writing a 94non-zero integer to the sysfs file prochot_short. 95 96The LM93 can also override the #PROCHOT pins by driving a PWM signal onto 97one or both of them. When overridden, the signal has a period of 3.56 ms, 98a minimum pulse width of 5 clocks (at 22.5kHz => 6.25% duty cycle), and 99a maximum pulse width of 80 clocks (at 22.5kHz => 99.88% duty cycle). 100 101The sysfs files prochot1_override and prochot2_override contain boolean 102integers which enable or disable the override function for #P1_PROCHOT and 103#P2_PROCHOT, respectively. The sysfs file prochot_override_duty_cycle 104contains a value controlling the duty cycle for the PWM signal used when 105the override function is enabled. This value ranges from 0 to 15, with 0 106indicating minimum duty cycle and 15 indicating maximum. 107 108#VRD_HOT: 109 110The LM93 can monitor two #VRD_HOT signals. The results are found in the 111sysfs files vrdhot1 and vrdhot2. There is one value per file: a boolean for 112which 1 indicates #VRD_HOT is asserted and 0 indicates it is negated. These 113files are read-only. 114 115Smart 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 125Smart tach mode is enabled by the driver by writing 1 or 2 (associating the 126the fan tachometer with a pwm) to the sysfs file fan<n>_smart_tach. A zero 127will disable the function for that fan. Note that Smart tach mode cannot be 128enabled if the PWM output frequency is 22500 Hz (see below). 129 130Manual PWM: 131 132The LM93 has a fixed or override mode for the two PWM outputs (although, there 133are still some conditions that will override even this mode - see section 13415.10.6 of the datasheet for details.) The sysfs files pwm1_override 135and pwm2_override are used to enable this mode; each is a boolean integer 136where 0 disables and 1 enables the manual control mode. The sysfs files pwm1 137and pwm2 are used to set the manual duty cycle; each is an integer (0-255) 138where 0 is 0% duty cycle, and 255 is 100%. Note that the duty cycle values 139are constrained by the hardware. Selecting a value which is not available 140will cause the driver to use the next largest value. Also note: when manual 141PWM mode is disabled, the value of pwm1 and pwm2 indicates the current duty 142cycle chosen by the h/w. 143 144PWM Output Frequency: 145 146The LM93 supports several different frequencies for the PWM output channels. 147The sysfs files pwm1_freq and pwm2_freq are used to select the frequency. The 148frequency values are constrained by the hardware. Selecting a value which is 149not available will cause the driver to use the next largest value. Also note 150that this parameter has implications for the Smart Tach Mode (see above). 151 152PWM Output Frequencies (in Hz): 12, 36, 48, 60, 72, 84, 96, 22500 (default) 153 154Automatic PWM: 155 156The LM93 is capable of complex automatic fan control, with many different 157points of configuration. To start, each PWM output can be bound to any 158combination of eight control sources. The final PWM is the largest of all 159individual control sources to which the PWM output is bound. 160 161The 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 163in the sysfs files pwm<n>_auto_channels, where a "1" enables the binding, and 164a "0" disables it. The h/w default is 0x0f (all temperatures bound). 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 175The function y = f(x) takes a source temperature x to a PWM output y. This 176function of the LM93 is derived from a base temperature and a table of 12 177temperature offsets. The base temperature is expressed in degrees C in the 178sysfs files temp<n>_auto_base. The offsets are expressed in cumulative 179degrees C, with the value of offset <i> for temperature value <n> being 180contained in the file temp<n>_auto_offset<i>. E.g. if the base temperature 181is 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 198Valid offsets are in the range 0C <= x <= 7.5C in 0.5C increments. 199 200There is an independent base temperature for each temperature channel. Note, 201however, there are only two tables of offsets: one each for temp[12] and 202temp[34]. Therefore, any change to e.g. temp1_auto_offset<i> will also 203affect temp2_auto_offset<i>. 204 205The LM93 can also apply hysteresis to the offset table, to prevent unwanted 206oscillation between two steps in the offsets table. These values are found in 207the sysfs files temp<n>_auto_offset_hyst. The value in this file has the 208same representation as in temp<n>_auto_offset<i>. 209 210If a temperature reading falls below the base value for that channel, the LM93 211will use the minimum PWM value. These values are found in the sysfs files 212temp<n>_auto_pwm_min. Note, there are only two minimums: one each for temp[12] 213and temp[34]. Therefore, any change to e.g. temp1_auto_pwm_min will also 214affect temp2_auto_pwm_min. 215 216PWM Spin-Up Cycle: 217 218A spin-up cycle occurs when a PWM output is commanded from 0% duty cycle to 219some value > 0%. The LM93 supports a minimum duty cycle during spin-up. These 220values are found in the sysfs files pwm<n>_auto_spinup_min. The value in this 221file has the same representation as other PWM duty cycle values. The 222duration of the spin-up cycle is also configurable. These values are found in 223the sysfs files pwm<n>_auto_spinup_time. The value in this file is 224the spin-up time in seconds. The available spin-up times are constrained by 225the hardware. Selecting a value which is not available will cause the driver 226to use the next largest value. 227 228Spin-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 233If the #PROCHOT or #VRDHOT signals are asserted while bound to a PWM output 234channel, the LM93 will ramp the PWM output up to 100% duty cycle in discrete 235steps. The duration of each step is configurable. There are two files, with 236one value each in seconds: pwm_auto_prochot_ramp and pwm_auto_vrdhot_ramp. 237The available ramp times are constrained by the hardware. Selecting a value 238which is not available will cause the driver to use the next largest value. 239 240Ramp Times: 0 (disabled, h/w default) to 0.75 in 0.05 second intervals 241 242Fan Boost: 243 244For each temperature channel, there is a boost temperature: if the channel 245exceeds this limit, the LM93 will immediately drive both PWM outputs to 100%. 246This limit is expressed in degrees C in the sysfs files temp<n>_auto_boost. 247There is also a hysteresis temperature for this function: after the boost 248limit is reached, the temperature channel must drop below this value before 249the boost function is disabled. This temperature is also expressed in degrees 250C in the sysfs files temp<n>_auto_boost_hyst. 251 252GPIO Pins: 253 254The LM93 can monitor the logic level of four dedicated GPIO pins as well as the 255four tach input pins. GPIO0-GPIO3 correspond to (fan) tach 1-4, respectively. 256All eight GPIOs are read by reading the bitmask in the sysfs file gpio. The 257LSB is GPIO0, and the MSB is GPIO7. 258 259 260LM93 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 309 310