hwmon: Add LM93 support

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

Author:

	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@linutronix.de>

Module Parameters

-----------------

(specific to LM93)

* 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".

(common among sensor drivers)

* force: short array (min = 1, max = 48)

  List of adapter,address pairs to assume to be present.  Autodetection

  of the target device will still be attempted.  Use one of the more

  specific force directives below if this doesn't detect the device.

* force_lm93: short array (min = 1, max = 48)

  List of adapter,address pairs which are unquestionably assumed to contain

  a 'lm93' chip

* ignore: short array (min = 1, max = 48)

  List of adapter,address pairs not to scan

* ignore_range: short array (min = 1, max = 48)

  List of adapter,start-addr,end-addr triples not to scan

* probe: short array (min = 1, max = 48)

  List of adapter,address pairs to scan additionally

* probe_range: short array (min = 1, max = 48)

  List of adapter,start-addr,end-addr triples to scan additionally

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.

Driver Description

------------------

This driver implements support for the National Semiconductor LM93.

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:

#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

intgers 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: 12, 36, 48, 60, 72, 84, 96, 22500 (h/w 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

Sample Configuration File

-------------------------

Here is a sample LM93 chip config for sensors.conf:

---------- cut here ----------

chip "lm93-*"

# VOLTAGE INPUTS

	# labels and scaling based on datasheet recommendations

	label in1	"+12V1"

	compute in1	@ * 12.945, @ / 12.945

	set in1_min	12 * 0.90

	set in1_max	12 * 1.10

	label in2	"+12V2"

	compute in2	@ * 12.945, @ / 12.945

	set in2_min	12 * 0.90

	set in2_max	12 * 1.10

	label in3	"+12V3"

	compute in3	@ * 12.945, @ / 12.945

	set in3_min	12 * 0.90

	set in3_max	12 * 1.10

	label in4	"FSB_Vtt"

	label in5	"3GIO"

	label in6	"ICH_Core"

	label in7	"Vccp1"

	label in8	"Vccp2"

	label in9	"+3.3V"

	set in9_min	3.3 * 0.90

	set in9_max	3.3 * 1.10

	label in10	"+5V"

	set in10_min	5.0 * 0.90

	set in10_max	5.0 * 1.10

	label in11	"SCSI_Core"

	label in12	"Mem_Core"

	label in13	"Mem_Vtt"

	label in14	"Gbit_Core"

	# Assuming R1/R2 = 4.1143, and 3.3V reference

	# -12V = (4.1143 + 1) * (@ - 3.3) + 3.3

	label in15	"-12V"

	compute in15 @ * 5.1143 - 13.57719, (@ + 13.57719) / 5.1143

	set in15_min	-12 * 0.90

	set in15_max	-12 * 1.10

	label in16	"+3.3VSB"

	set in16_min	3.3 * 0.90

	set in16_max	3.3 * 1.10

# TEMPERATURE INPUTS

	label temp1	"CPU1"

	label temp2	"CPU2"

	label temp3	"LM93"

# TACHOMETER INPUTS

	label fan1	"Fan1"

	set fan1_min	3000

	label fan2	"Fan2"

	set fan2_min	3000

	label fan3	"Fan3"

	set fan3_min	3000

	label fan4	"Fan4"

	set fan4_min	3000

# PWM OUTPUTS

	label pwm1	"CPU1"

	label pwm2	"CPU2"

	  This driver can also be built as a module.  If so, the module

	  will be called lm92.

config SENSORS_LM93

	tristate "National Semiconductor LM93 and compatibles"

	depends on HWMON && I2C

	select HWMON_VID

	help

	  If you say yes here you get support for National Semiconductor LM93

	  sensor chips.

	  This driver can also be built as a module.  If so, the module

	  will be called lm93.

config SENSORS_MAX1619

	tristate "Maxim MAX1619 sensor chip"

	depends on I2C

obj-$(CONFIG_SENSORS_LM87)	+= lm87.o

obj-$(CONFIG_SENSORS_LM90)	+= lm90.o

obj-$(CONFIG_SENSORS_LM92)	+= lm92.o

obj-$(CONFIG_SENSORS_LM93)	+= lm93.o

obj-$(CONFIG_SENSORS_MAX1619)	+= max1619.o

obj-$(CONFIG_SENSORS_MAX6650)	+= max6650.o

obj-$(CONFIG_SENSORS_PC87360)	+= pc87360.o