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diff --git a/Documentation/hwmon/lm93.rst b/Documentation/hwmon/lm93.rst new file mode 100644 index 000000000000..49d199b45b67 --- /dev/null +++ b/Documentation/hwmon/lm93.rst @@ -0,0 +1,312 @@ +Kernel driver lm93 +================== + +Supported chips: + + * National Semiconductor LM93 + + Prefix 'lm93' + + Addresses scanned: I2C 0x2c-0x2e + + Datasheet: http://www.national.com/ds.cgi/LM/LM93.pdf + + * National Semiconductor LM94 + + Prefix 'lm94' + + Addresses scanned: I2C 0x2c-0x2e + + Datasheet: http://www.national.com/ds.cgi/LM/LM94.pdf + + +Authors: + - Mark M. Hoffman <mhoffman@lightlink.com> + - Ported to 2.6 by Eric J. Bowersox <ericb@aspsys.com> + - Adapted to 2.6.20 by Carsten Emde <ce@osadl.org> + - Modified for mainline integration by Hans J. Koch <hjk@hansjkoch.de> + +Module Parameters +----------------- + +* init: integer + Set to non-zero to force some initializations (default is 0). +* disable_block: integer + A "0" allows SMBus block data transactions if the host supports them. A "1" + disables SMBus block data transactions. The default is 0. +* vccp_limit_type: integer array (2) + Configures in7 and in8 limit type, where 0 means absolute and non-zero + means relative. "Relative" here refers to "Dynamic Vccp Monitoring using + VID" from the datasheet. It greatly simplifies the interface to allow + only one set of limits (absolute or relative) to be in operation at a + time (even though the hardware is capable of enabling both). There's + not a compelling use case for enabling both at once, anyway. The default + is "0,0". +* vid_agtl: integer + A "0" configures the VID pins for V(ih) = 2.1V min, V(il) = 0.8V max. + A "1" configures the VID pins for V(ih) = 0.8V min, V(il) = 0.4V max. + (The latter setting is referred to as AGTL+ Compatible in the datasheet.) + I.e. this parameter controls the VID pin input thresholds; if your VID + inputs are not working, try changing this. The default value is "0". + + +Hardware Description +-------------------- + +(from the datasheet) + +The LM93 hardware monitor has a two wire digital interface compatible with +SMBus 2.0. Using an 8-bit ADC, the LM93 measures the temperature of two remote +diode connected transistors as well as its own die and 16 power supply +voltages. To set fan speed, the LM93 has two PWM outputs that are each +controlled by up to four temperature zones. The fancontrol algorithm is lookup +table based. The LM93 includes a digital filter that can be invoked to smooth +temperature readings for better control of fan speed. The LM93 has four +tachometer inputs to measure fan speed. Limit and status registers for all +measured values are included. The LM93 builds upon the functionality of +previous motherboard management ASICs and uses some of the LM85's features +(i.e. smart tachometer mode). It also adds measurement and control support +for dynamic Vccp monitoring and PROCHOT. It is designed to monitor a dual +processor Xeon class motherboard with a minimum of external components. + +LM94 is also supported in LM93 compatible mode. Extra sensors and features of +LM94 are not supported. + + +User Interface +-------------- + +#PROCHOT +^^^^^^^^ + +The LM93 can monitor two #PROCHOT signals. The results are found in the +sysfs files prochot1, prochot2, prochot1_avg, prochot2_avg, prochot1_max, +and prochot2_max. prochot1_max and prochot2_max contain the user limits +for #PROCHOT1 and #PROCHOT2, respectively. prochot1 and prochot2 contain +the current readings for the most recent complete time interval. The +value of prochot1_avg and prochot2_avg is something like a 2 period +exponential moving average (but not quite - check the datasheet). Note +that this third value is calculated by the chip itself. All values range +from 0-255 where 0 indicates no throttling, and 255 indicates > 99.6%. + +The monitoring intervals for the two #PROCHOT signals is also configurable. +These intervals can be found in the sysfs files prochot1_interval and +prochot2_interval. The values in these files specify the intervals for +#P1_PROCHOT and #P2_PROCHOT, respectively. Selecting a value not in this +list will cause the driver to use the next largest interval. The available +intervals are (in seconds): + +#PROCHOT intervals: + 0.73, 1.46, 2.9, 5.8, 11.7, 23.3, 46.6, 93.2, 186, 372 + +It is possible to configure the LM93 to logically short the two #PROCHOT +signals. I.e. when #P1_PROCHOT is asserted, the LM93 will automatically +assert #P2_PROCHOT, and vice-versa. This mode is enabled by writing a +non-zero integer to the sysfs file prochot_short. + +The LM93 can also override the #PROCHOT pins by driving a PWM signal onto +one or both of them. When overridden, the signal has a period of 3.56 ms, +a minimum pulse width of 5 clocks (at 22.5kHz => 6.25% duty cycle), and +a maximum pulse width of 80 clocks (at 22.5kHz => 99.88% duty cycle). + +The sysfs files prochot1_override and prochot2_override contain boolean +integers which enable or disable the override function for #P1_PROCHOT and +#P2_PROCHOT, respectively. The sysfs file prochot_override_duty_cycle +contains a value controlling the duty cycle for the PWM signal used when +the override function is enabled. This value ranges from 0 to 15, with 0 +indicating minimum duty cycle and 15 indicating maximum. + +#VRD_HOT +^^^^^^^^ + +The LM93 can monitor two #VRD_HOT signals. The results are found in the +sysfs files vrdhot1 and vrdhot2. There is one value per file: a boolean for +which 1 indicates #VRD_HOT is asserted and 0 indicates it is negated. These +files are read-only. + +Smart Tach Mode (from the datasheet):: + + If a fan is driven using a low-side drive PWM, the tachometer + output of the fan is corrupted. The LM93 includes smart tachometer + circuitry that allows an accurate tachometer reading to be + achieved despite the signal corruption. In smart tach mode all + four signals are measured within 4 seconds. + +Smart tach mode is enabled by the driver by writing 1 or 2 (associating the +the fan tachometer with a pwm) to the sysfs file fan<n>_smart_tach. A zero +will disable the function for that fan. Note that Smart tach mode cannot be +enabled if the PWM output frequency is 22500 Hz (see below). + +Manual PWM +^^^^^^^^^^ + +The LM93 has a fixed or override mode for the two PWM outputs (although, there +are still some conditions that will override even this mode - see section +15.10.6 of the datasheet for details.) The sysfs files pwm1_override +and pwm2_override are used to enable this mode; each is a boolean integer +where 0 disables and 1 enables the manual control mode. The sysfs files pwm1 +and pwm2 are used to set the manual duty cycle; each is an integer (0-255) +where 0 is 0% duty cycle, and 255 is 100%. Note that the duty cycle values +are constrained by the hardware. Selecting a value which is not available +will cause the driver to use the next largest value. Also note: when manual +PWM mode is disabled, the value of pwm1 and pwm2 indicates the current duty +cycle chosen by the h/w. + +PWM Output Frequency +^^^^^^^^^^^^^^^^^^^^ + +The LM93 supports several different frequencies for the PWM output channels. +The sysfs files pwm1_freq and pwm2_freq are used to select the frequency. The +frequency values are constrained by the hardware. Selecting a value which is +not available will cause the driver to use the next largest value. Also note +that this parameter has implications for the Smart Tach Mode (see above). + +PWM Output Frequencies (in Hz): + 12, 36, 48, 60, 72, 84, 96, 22500 (default) + +Automatic PWM +^^^^^^^^^^^^^ + +The LM93 is capable of complex automatic fan control, with many different +points of configuration. To start, each PWM output can be bound to any +combination of eight control sources. The final PWM is the largest of all +individual control sources to which the PWM output is bound. + +The eight control sources are: temp1-temp4 (aka "zones" in the datasheet), +#PROCHOT 1 & 2, and #VRDHOT 1 & 2. The bindings are expressed as a bitmask +in the sysfs files pwm<n>_auto_channels, where a "1" enables the binding, and +a "0" disables it. The h/w default is 0x0f (all temperatures bound). + + ====== =========== + 0x01 Temp 1 + 0x02 Temp 2 + 0x04 Temp 3 + 0x08 Temp 4 + 0x10 #PROCHOT 1 + 0x20 #PROCHOT 2 + 0x40 #VRDHOT 1 + 0x80 #VRDHOT 2 + ====== =========== + +The function y = f(x) takes a source temperature x to a PWM output y. This +function of the LM93 is derived from a base temperature and a table of 12 +temperature offsets. The base temperature is expressed in degrees C in the +sysfs files temp<n>_auto_base. The offsets are expressed in cumulative +degrees C, with the value of offset <i> for temperature value <n> being +contained in the file temp<n>_auto_offset<i>. E.g. if the base temperature +is 40C: + + ========== ======================= =============== ======= + offset # temp<n>_auto_offset<i> range pwm + ========== ======================= =============== ======= + 1 0 - 25.00% + 2 0 - 28.57% + 3 1 40C - 41C 32.14% + 4 1 41C - 42C 35.71% + 5 2 42C - 44C 39.29% + 6 2 44C - 46C 42.86% + 7 2 48C - 50C 46.43% + 8 2 50C - 52C 50.00% + 9 2 52C - 54C 53.57% + 10 2 54C - 56C 57.14% + 11 2 56C - 58C 71.43% + 12 2 58C - 60C 85.71% + - - > 60C 100.00% + ========== ======================= =============== ======= + +Valid offsets are in the range 0C <= x <= 7.5C in 0.5C increments. + +There is an independent base temperature for each temperature channel. Note, +however, there are only two tables of offsets: one each for temp[12] and +temp[34]. Therefore, any change to e.g. temp1_auto_offset<i> will also +affect temp2_auto_offset<i>. + +The LM93 can also apply hysteresis to the offset table, to prevent unwanted +oscillation between two steps in the offsets table. These values are found in +the sysfs files temp<n>_auto_offset_hyst. The value in this file has the +same representation as in temp<n>_auto_offset<i>. + +If a temperature reading falls below the base value for that channel, the LM93 +will use the minimum PWM value. These values are found in the sysfs files +temp<n>_auto_pwm_min. Note, there are only two minimums: one each for temp[12] +and temp[34]. Therefore, any change to e.g. temp1_auto_pwm_min will also +affect temp2_auto_pwm_min. + +PWM Spin-Up Cycle +^^^^^^^^^^^^^^^^^ + +A spin-up cycle occurs when a PWM output is commanded from 0% duty cycle to +some value > 0%. The LM93 supports a minimum duty cycle during spin-up. These +values are found in the sysfs files pwm<n>_auto_spinup_min. The value in this +file has the same representation as other PWM duty cycle values. The +duration of the spin-up cycle is also configurable. These values are found in +the sysfs files pwm<n>_auto_spinup_time. The value in this file is +the spin-up time in seconds. The available spin-up times are constrained by +the hardware. Selecting a value which is not available will cause the driver +to use the next largest value. + +Spin-up Durations: + 0 (disabled, h/w default), 0.1, 0.25, 0.4, 0.7, 1.0, 2.0, 4.0 + +#PROCHOT and #VRDHOT PWM Ramping +^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +If the #PROCHOT or #VRDHOT signals are asserted while bound to a PWM output +channel, the LM93 will ramp the PWM output up to 100% duty cycle in discrete +steps. The duration of each step is configurable. There are two files, with +one value each in seconds: pwm_auto_prochot_ramp and pwm_auto_vrdhot_ramp. +The available ramp times are constrained by the hardware. Selecting a value +which is not available will cause the driver to use the next largest value. + +Ramp Times: + 0 (disabled, h/w default) to 0.75 in 0.05 second intervals + +Fan Boost +^^^^^^^^^ + +For each temperature channel, there is a boost temperature: if the channel +exceeds this limit, the LM93 will immediately drive both PWM outputs to 100%. +This limit is expressed in degrees C in the sysfs files temp<n>_auto_boost. +There is also a hysteresis temperature for this function: after the boost +limit is reached, the temperature channel must drop below this value before +the boost function is disabled. This temperature is also expressed in degrees +C in the sysfs files temp<n>_auto_boost_hyst. + +GPIO Pins +^^^^^^^^^ + +The LM93 can monitor the logic level of four dedicated GPIO pins as well as the +four tach input pins. GPIO0-GPIO3 correspond to (fan) tach 1-4, respectively. +All eight GPIOs are read by reading the bitmask in the sysfs file gpio. The +LSB is GPIO0, and the MSB is GPIO7. + + +LM93 Unique sysfs Files +----------------------- + +=========================== =============================================== +file description +=========================== =============================================== +prochot<n> current #PROCHOT % +prochot<n>_avg moving average #PROCHOT % +prochot<n>_max limit #PROCHOT % +prochot_short enable or disable logical #PROCHOT pin short +prochot<n>_override force #PROCHOT assertion as PWM +prochot_override_duty_cycle duty cycle for the PWM signal used when + #PROCHOT is overridden +prochot<n>_interval #PROCHOT PWM sampling interval +vrdhot<n> 0 means negated, 1 means asserted +fan<n>_smart_tach enable or disable smart tach mode +pwm<n>_auto_channels select control sources for PWM outputs +pwm<n>_auto_spinup_min minimum duty cycle during spin-up +pwm<n>_auto_spinup_time duration of spin-up +pwm_auto_prochot_ramp ramp time per step when #PROCHOT asserted +pwm_auto_vrdhot_ramp ramp time per step when #VRDHOT asserted +temp<n>_auto_base temperature channel base +temp<n>_auto_offset[1-12] temperature channel offsets +temp<n>_auto_offset_hyst temperature channel offset hysteresis +temp<n>_auto_boost temperature channel boost (PWMs to 100%) + limit +temp<n>_auto_boost_hyst temperature channel boost hysteresis +gpio input state of 8 GPIO pins; read-only +=========================== =============================================== |
