diff options
Diffstat (limited to 'Documentation/hwmon/thmc50.rst')
| -rw-r--r-- | Documentation/hwmon/thmc50.rst | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/Documentation/hwmon/thmc50.rst b/Documentation/hwmon/thmc50.rst new file mode 100644 index 000000000000..cfff3885287d --- /dev/null +++ b/Documentation/hwmon/thmc50.rst @@ -0,0 +1,89 @@ +Kernel driver thmc50 +===================== + +Supported chips: + + * Analog Devices ADM1022 + + Prefix: 'adm1022' + + Addresses scanned: I2C 0x2c - 0x2e + + Datasheet: http://www.analog.com/en/prod/0,2877,ADM1022,00.html + + * Texas Instruments THMC50 + + Prefix: 'thmc50' + + Addresses scanned: I2C 0x2c - 0x2e + + Datasheet: http://www.ti.com/ + + +Author: Krzysztof Helt <krzysztof.h1@wp.pl> + +This driver was derived from the 2.4 kernel thmc50.c source file. + +Credits: + + thmc50.c (2.4 kernel): + + - Frodo Looijaard <frodol@dds.nl> + - Philip Edelbrock <phil@netroedge.com> + +Module Parameters +----------------- + +* adm1022_temp3: short array + List of adapter,address pairs to force chips into ADM1022 mode with + second remote temperature. This does not work for original THMC50 chips. + +Description +----------- + +The THMC50 implements: an internal temperature sensor, support for an +external diode-type temperature sensor (compatible w/ the diode sensor inside +many processors), and a controllable fan/analog_out DAC. For the temperature +sensors, limits can be set through the appropriate Overtemperature Shutdown +register and Hysteresis register. Each value can be set and read to half-degree +accuracy. An alarm is issued (usually to a connected LM78) when the +temperature gets higher then the Overtemperature Shutdown value; it stays on +until the temperature falls below the Hysteresis value. All temperatures are in +degrees Celsius, and are guaranteed within a range of -55 to +125 degrees. + +The THMC50 only updates its values each 1.5 seconds; reading it more often +will do no harm, but will return 'old' values. + +The THMC50 is usually used in combination with LM78-like chips, to measure +the temperature of the processor(s). + +The ADM1022 works the same as THMC50 but it is faster (5 Hz instead of +1 Hz for THMC50). It can be also put in a new mode to handle additional +remote temperature sensor. The driver use the mode set by BIOS by default. + +In case the BIOS is broken and the mode is set incorrectly, you can force +the mode with additional remote temperature with adm1022_temp3 parameter. +A typical symptom of wrong setting is a fan forced to full speed. + +Driver Features +--------------- + +The driver provides up to three temperatures: + +temp1 + - internal +temp2 + - remote +temp3 + - 2nd remote only for ADM1022 + +pwm1 + - fan speed (0 = stop, 255 = full) +pwm1_mode + - always 0 (DC mode) + +The value of 0 for pwm1 also forces FAN_OFF signal from the chip, +so it stops fans even if the value 0 into the ANALOG_OUT register does not. + +The driver was tested on Compaq AP550 with two ADM1022 chips (one works +in the temp3 mode), five temperature readings and two fans. |