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Diffstat (limited to 'Documentation/hwmon/adt7470')
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diff --git a/Documentation/hwmon/adt7470 b/Documentation/hwmon/adt7470 deleted file mode 100644 index fe68e18a0c8d..000000000000 --- a/Documentation/hwmon/adt7470 +++ /dev/null @@ -1,90 +0,0 @@ -Kernel driver adt7470 -===================== - -Supported chips: - * Analog Devices ADT7470 - Prefix: 'adt7470' - Addresses scanned: I2C 0x2C, 0x2E, 0x2F - Datasheet: Publicly available at the Analog Devices website - -Author: Darrick J. Wong - -Description ------------ - -This driver implements support for the Analog Devices ADT7470 chip. There may -be other chips that implement this interface. - -The ADT7470 uses the 2-wire interface compatible with the SMBus 2.0 -specification. Using an analog to digital converter it measures up to ten (10) -external temperatures. It has four (4) 16-bit counters for measuring fan speed. -There are four (4) PWM outputs that can be used to control fan speed. - -A sophisticated control system for the PWM outputs is designed into the ADT7470 -that allows fan speed to be adjusted automatically based on any of the ten -temperature sensors. Each PWM output is individually adjustable and -programmable. Once configured, the ADT7470 will adjust the PWM outputs in -response to the measured temperatures with further host intervention. This -feature can also be disabled for manual control of the PWM's. - -Each of the measured inputs (temperature, fan speed) has corresponding high/low -limit values. The ADT7470 will signal an ALARM if any measured value exceeds -either limit. - -The ADT7470 samples all inputs continuously. A kernel thread is started up for -the purpose of periodically querying the temperature sensors, thus allowing the -automatic fan pwm control to set the fan speed. The driver will not read the -registers more often than once every 5 seconds. Further, configuration data is -only read once per minute. - -Special Features ----------------- - -The ADT7470 has a 8-bit ADC and is capable of measuring temperatures with 1 -degC resolution. - -The Analog Devices datasheet is very detailed and describes a procedure for -determining an optimal configuration for the automatic PWM control. - -Configuration Notes -------------------- - -Besides standard interfaces driver adds the following: - -* PWM Control - -* pwm#_auto_point1_pwm and pwm#_auto_point1_temp and -* pwm#_auto_point2_pwm and pwm#_auto_point2_temp - - -point1: Set the pwm speed at a lower temperature bound. -point2: Set the pwm speed at a higher temperature bound. - -The ADT7470 will scale the pwm between the lower and higher pwm speed when -the temperature is between the two temperature boundaries. PWM values range -from 0 (off) to 255 (full speed). Fan speed will be set to maximum when the -temperature sensor associated with the PWM control exceeds -pwm#_auto_point2_temp. - -The driver also allows control of the PWM frequency: - -* pwm1_freq - -The PWM frequency is rounded to the nearest one of: - -* 11.0 Hz -* 14.7 Hz -* 22.1 Hz -* 29.4 Hz -* 35.3 Hz -* 44.1 Hz -* 58.8 Hz -* 88.2 Hz -* 1.4 kHz -* 22.5 kHz - -Notes ------ - -The temperature inputs no longer need to be read periodically from userspace in -order for the automatic pwm algorithm to run. This was the case for earlier -versions of the driver. |