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 10Authors: 11 Mark M. Hoffman <mhoffman@lightlink.com> 12 Ported to 2.6 by Eric J. Bowersox <ericb@aspsys.com> 13 Adapted to 2.6.20 by Carsten Emde <ce@osadl.org> 14 Modified for mainline integration by Hans J. Koch <hjk@linutronix.de> 15 16Module Parameters 17----------------- 18 19* init: integer 20 Set to non-zero to force some initializations (default is 0). 21* disable_block: integer 22 A "0" allows SMBus block data transactions if the host supports them. A "1" 23 disables SMBus block data transactions. The default is 0. 24* vccp_limit_type: integer array (2) 25 Configures in7 and in8 limit type, where 0 means absolute and non-zero 26 means relative. "Relative" here refers to "Dynamic Vccp Monitoring using 27 VID" from the datasheet. It greatly simplifies the interface to allow 28 only one set of limits (absolute or relative) to be in operation at a 29 time (even though the hardware is capable of enabling both). There's 30 not a compelling use case for enabling both at once, anyway. The default 31 is "0,0". 32* vid_agtl: integer 33 A "0" configures the VID pins for V(ih) = 2.1V min, V(il) = 0.8V max. 34 A "1" configures the VID pins for V(ih) = 0.8V min, V(il) = 0.4V max. 35 (The latter setting is referred to as AGTL+ Compatible in the datasheet.) 36 I.e. this parameter controls the VID pin input thresholds; if your VID 37 inputs are not working, try changing this. The default value is "0". 38 39 40Hardware Description 41-------------------- 42 43(from the datasheet) 44 45The LM93 hardware monitor has a two wire digital interface compatible with 46SMBus 2.0. Using an 8-bit ADC, the LM93 measures the temperature of two remote 47diode connected transistors as well as its own die and 16 power supply 48voltages. To set fan speed, the LM93 has two PWM outputs that are each 49controlled by up to four temperature zones. The fancontrol algorithm is lookup 50table based. The LM93 includes a digital filter that can be invoked to smooth 51temperature readings for better control of fan speed. The LM93 has four 52tachometer inputs to measure fan speed. Limit and status registers for all 53measured values are included. The LM93 builds upon the functionality of 54previous motherboard management ASICs and uses some of the LM85's features 55(i.e. smart tachometer mode). It also adds measurement and control support 56for dynamic Vccp monitoring and PROCHOT. It is designed to monitor a dual 57processor Xeon class motherboard with a minimum of external components. 58 59 60User Interface 61-------------- 62 63#PROCHOT: 64 65The LM93 can monitor two #PROCHOT signals. The results are found in the 66sysfs files prochot1, prochot2, prochot1_avg, prochot2_avg, prochot1_max, 67and prochot2_max. prochot1_max and prochot2_max contain the user limits 68for #PROCHOT1 and #PROCHOT2, respectively. prochot1 and prochot2 contain 69the current readings for the most recent complete time interval. The 70value of prochot1_avg and prochot2_avg is something like a 2 period 71exponential moving average (but not quite - check the datasheet). Note 72that this third value is calculated by the chip itself. All values range 73from 0-255 where 0 indicates no throttling, and 255 indicates > 99.6%. 74 75The monitoring intervals for the two #PROCHOT signals is also configurable. 76These intervals can be found in the sysfs files prochot1_interval and 77prochot2_interval. The values in these files specify the intervals for 78#P1_PROCHOT and #P2_PROCHOT, respectively. Selecting a value not in this 79list will cause the driver to use the next largest interval. The available 80intervals are (in seconds): 81 82#PROCHOT intervals: 0.73, 1.46, 2.9, 5.8, 11.7, 23.3, 46.6, 93.2, 186, 372 83 84It is possible to configure the LM93 to logically short the two #PROCHOT 85signals. I.e. when #P1_PROCHOT is asserted, the LM93 will automatically 86assert #P2_PROCHOT, and vice-versa. This mode is enabled by writing a 87non-zero integer to the sysfs file prochot_short. 88 89The LM93 can also override the #PROCHOT pins by driving a PWM signal onto 90one or both of them. When overridden, the signal has a period of 3.56 ms, 91a minimum pulse width of 5 clocks (at 22.5kHz => 6.25% duty cycle), and 92a maximum pulse width of 80 clocks (at 22.5kHz => 99.88% duty cycle). 93 94The sysfs files prochot1_override and prochot2_override contain boolean 95integers which enable or disable the override function for #P1_PROCHOT and 96#P2_PROCHOT, respectively. The sysfs file prochot_override_duty_cycle 97contains a value controlling the duty cycle for the PWM signal used when 98the override function is enabled. This value ranges from 0 to 15, with 0 99indicating minimum duty cycle and 15 indicating maximum. 100 101#VRD_HOT: 102 103The LM93 can monitor two #VRD_HOT signals. The results are found in the 104sysfs files vrdhot1 and vrdhot2. There is one value per file: a boolean for 105which 1 indicates #VRD_HOT is asserted and 0 indicates it is negated. These 106files are read-only. 107 108Smart Tach Mode: 109 110(from the datasheet) 111 112 If a fan is driven using a low-side drive PWM, the tachometer 113 output of the fan is corrupted. The LM93 includes smart tachometer 114 circuitry that allows an accurate tachometer reading to be 115 achieved despite the signal corruption. In smart tach mode all 116 four signals are measured within 4 seconds. 117 118Smart tach mode is enabled by the driver by writing 1 or 2 (associating the 119the fan tachometer with a pwm) to the sysfs file fan<n>_smart_tach. A zero 120will disable the function for that fan. Note that Smart tach mode cannot be 121enabled if the PWM output frequency is 22500 Hz (see below). 122 123Manual PWM: 124 125The LM93 has a fixed or override mode for the two PWM outputs (although, there 126are still some conditions that will override even this mode - see section 12715.10.6 of the datasheet for details.) The sysfs files pwm1_override 128and pwm2_override are used to enable this mode; each is a boolean integer 129where 0 disables and 1 enables the manual control mode. The sysfs files pwm1 130and pwm2 are used to set the manual duty cycle; each is an integer (0-255) 131where 0 is 0% duty cycle, and 255 is 100%. Note that the duty cycle values 132are constrained by the hardware. Selecting a value which is not available 133will cause the driver to use the next largest value. Also note: when manual 134PWM mode is disabled, the value of pwm1 and pwm2 indicates the current duty 135cycle chosen by the h/w. 136 137PWM Output Frequency: 138 139The LM93 supports several different frequencies for the PWM output channels. 140The sysfs files pwm1_freq and pwm2_freq are used to select the frequency. The 141frequency values are constrained by the hardware. Selecting a value which is 142not available will cause the driver to use the next largest value. Also note 143that this parameter has implications for the Smart Tach Mode (see above). 144 145PWM Output Frequencies (in Hz): 12, 36, 48, 60, 72, 84, 96, 22500 (default) 146 147Automatic PWM: 148 149The LM93 is capable of complex automatic fan control, with many different 150points of configuration. To start, each PWM output can be bound to any 151combination of eight control sources. The final PWM is the largest of all 152individual control sources to which the PWM output is bound. 153 154The eight control sources are: temp1-temp4 (aka "zones" in the datasheet), 155#PROCHOT 1 & 2, and #VRDHOT 1 & 2. The bindings are expressed as a bitmask 156in the sysfs files pwm<n>_auto_channels, where a "1" enables the binding, and 157a "0" disables it. The h/w default is 0x0f (all temperatures bound). 158 159 0x01 - Temp 1 160 0x02 - Temp 2 161 0x04 - Temp 3 162 0x08 - Temp 4 163 0x10 - #PROCHOT 1 164 0x20 - #PROCHOT 2 165 0x40 - #VRDHOT 1 166 0x80 - #VRDHOT 2 167 168The function y = f(x) takes a source temperature x to a PWM output y. This 169function of the LM93 is derived from a base temperature and a table of 12 170temperature offsets. The base temperature is expressed in degrees C in the 171sysfs files temp<n>_auto_base. The offsets are expressed in cumulative 172degrees C, with the value of offset <i> for temperature value <n> being 173contained in the file temp<n>_auto_offset<i>. E.g. if the base temperature 174is 40C: 175 176 offset # temp<n>_auto_offset<i> range pwm 177 1 0 - 25.00% 178 2 0 - 28.57% 179 3 1 40C - 41C 32.14% 180 4 1 41C - 42C 35.71% 181 5 2 42C - 44C 39.29% 182 6 2 44C - 46C 42.86% 183 7 2 48C - 50C 46.43% 184 8 2 50C - 52C 50.00% 185 9 2 52C - 54C 53.57% 186 10 2 54C - 56C 57.14% 187 11 2 56C - 58C 71.43% 188 12 2 58C - 60C 85.71% 189 > 60C 100.00% 190 191Valid offsets are in the range 0C <= x <= 7.5C in 0.5C increments. 192 193There is an independent base temperature for each temperature channel. Note, 194however, there are only two tables of offsets: one each for temp[12] and 195temp[34]. Therefore, any change to e.g. temp1_auto_offset<i> will also 196affect temp2_auto_offset<i>. 197 198The LM93 can also apply hysteresis to the offset table, to prevent unwanted 199oscillation between two steps in the offsets table. These values are found in 200the sysfs files temp<n>_auto_offset_hyst. The value in this file has the 201same representation as in temp<n>_auto_offset<i>. 202 203If a temperature reading falls below the base value for that channel, the LM93 204will use the minimum PWM value. These values are found in the sysfs files 205temp<n>_auto_pwm_min. Note, there are only two minimums: one each for temp[12] 206and temp[34]. Therefore, any change to e.g. temp1_auto_pwm_min will also 207affect temp2_auto_pwm_min. 208 209PWM Spin-Up Cycle: 210 211A spin-up cycle occurs when a PWM output is commanded from 0% duty cycle to 212some value > 0%. The LM93 supports a minimum duty cycle during spin-up. These 213values are found in the sysfs files pwm<n>_auto_spinup_min. The value in this 214file has the same representation as other PWM duty cycle values. The 215duration of the spin-up cycle is also configurable. These values are found in 216the sysfs files pwm<n>_auto_spinup_time. The value in this file is 217the spin-up time in seconds. The available spin-up times are constrained by 218the hardware. Selecting a value which is not available will cause the driver 219to use the next largest value. 220 221Spin-up Durations: 0 (disabled, h/w default), 0.1, 0.25, 0.4, 0.7, 1.0, 222 2.0, 4.0 223 224#PROCHOT and #VRDHOT PWM Ramping: 225 226If the #PROCHOT or #VRDHOT signals are asserted while bound to a PWM output 227channel, the LM93 will ramp the PWM output up to 100% duty cycle in discrete 228steps. The duration of each step is configurable. There are two files, with 229one value each in seconds: pwm_auto_prochot_ramp and pwm_auto_vrdhot_ramp. 230The available ramp times are constrained by the hardware. Selecting a value 231which is not available will cause the driver to use the next largest value. 232 233Ramp Times: 0 (disabled, h/w default) to 0.75 in 0.05 second intervals 234 235Fan Boost: 236 237For each temperature channel, there is a boost temperature: if the channel 238exceeds this limit, the LM93 will immediately drive both PWM outputs to 100%. 239This limit is expressed in degrees C in the sysfs files temp<n>_auto_boost. 240There is also a hysteresis temperature for this function: after the boost 241limit is reached, the temperature channel must drop below this value before 242the boost function is disabled. This temperature is also expressed in degrees 243C in the sysfs files temp<n>_auto_boost_hyst. 244 245GPIO Pins: 246 247The LM93 can monitor the logic level of four dedicated GPIO pins as well as the 248four tach input pins. GPIO0-GPIO3 correspond to (fan) tach 1-4, respectively. 249All eight GPIOs are read by reading the bitmask in the sysfs file gpio. The 250LSB is GPIO0, and the MSB is GPIO7. 251 252 253LM93 Unique sysfs Files 254----------------------- 255 256 file description 257 ------------------------------------------------------------- 258 259 prochot<n> current #PROCHOT % 260 261 prochot<n>_avg moving average #PROCHOT % 262 263 prochot<n>_max limit #PROCHOT % 264 265 prochot_short enable or disable logical #PROCHOT pin short 266 267 prochot<n>_override force #PROCHOT assertion as PWM 268 269 prochot_override_duty_cycle 270 duty cycle for the PWM signal used when 271 #PROCHOT is overridden 272 273 prochot<n>_interval #PROCHOT PWM sampling interval 274 275 vrdhot<n> 0 means negated, 1 means asserted 276 277 fan<n>_smart_tach enable or disable smart tach mode 278 279 pwm<n>_auto_channels select control sources for PWM outputs 280 281 pwm<n>_auto_spinup_min minimum duty cycle during spin-up 282 283 pwm<n>_auto_spinup_time duration of spin-up 284 285 pwm_auto_prochot_ramp ramp time per step when #PROCHOT asserted 286 287 pwm_auto_vrdhot_ramp ramp time per step when #VRDHOT asserted 288 289 temp<n>_auto_base temperature channel base 290 291 temp<n>_auto_offset[1-12] 292 temperature channel offsets 293 294 temp<n>_auto_offset_hyst 295 temperature channel offset hysteresis 296 297 temp<n>_auto_boost temperature channel boost (PWMs to 100%) limit 298 299 temp<n>_auto_boost_hyst temperature channel boost hysteresis 300 301 gpio input state of 8 GPIO pins; read-only 302 303