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author | Mauro Carvalho Chehab <mchehab+samsung@kernel.org> | 2019-04-17 12:46:29 +0300 |
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committer | Guenter Roeck <linux@roeck-us.net> | 2019-04-17 20:37:23 +0300 |
commit | 7ebd8b66dd9e5a0b65e5ee5e2b8e7ca382ec97b7 (patch) | |
tree | 9db30159bd32bec125c7d49e80a79bb7c4da0c8e /Documentation/hwmon/adt7462.rst | |
parent | b04f2f7d387b3160883c2a1f5e2285483a791e82 (diff) | |
download | linux-7ebd8b66dd9e5a0b65e5ee5e2b8e7ca382ec97b7.tar.xz |
docs: hwmon: Add an index file and rename docs to *.rst
Now that all files were converted to ReST format, rename them
and add an index.
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'Documentation/hwmon/adt7462.rst')
-rw-r--r-- | Documentation/hwmon/adt7462.rst | 70 |
1 files changed, 70 insertions, 0 deletions
diff --git a/Documentation/hwmon/adt7462.rst b/Documentation/hwmon/adt7462.rst new file mode 100644 index 000000000000..139e19696188 --- /dev/null +++ b/Documentation/hwmon/adt7462.rst @@ -0,0 +1,70 @@ +Kernel driver adt7462 +===================== + +Supported chips: + + * Analog Devices ADT7462 + + Prefix: 'adt7462' + + Addresses scanned: I2C 0x58, 0x5C + + Datasheet: Publicly available at the Analog Devices website + +Author: Darrick J. Wong + +Description +----------- + +This driver implements support for the Analog Devices ADT7462 chip family. + +This chip is a bit of a beast. It has 8 counters for measuring fan speed. It +can also measure 13 voltages or 4 temperatures, or various combinations of the +two. See the chip documentation for more details about the exact set of +configurations. This driver does not allow one to configure the chip; that is +left to the system designer. + +A sophisticated control system for the PWM outputs is designed into the ADT7462 +that allows fan speed to be adjusted automatically based on any of the three +temperature sensors. Each PWM output is individually adjustable and +programmable. Once configured, the ADT7462 will adjust the PWM outputs in +response to the measured temperatures without further host intervention. This +feature can also be disabled for manual control of the PWM's. + +Each of the measured inputs (voltage, temperature, fan speed) has +corresponding high/low limit values. The ADT7462 will signal an ALARM if +any measured value exceeds either limit. + +The ADT7462 samples all inputs continuously. The driver will not read +the registers more often than once every other second. Further, +configuration data is only read once per minute. + +Special Features +---------------- + +The ADT7462 have a 10-bit ADC and can therefore measure temperatures +with 0.25 degC resolution. + +The Analog Devices datasheet is very detailed and describes a procedure for +determining an optimal configuration for the automatic PWM control. + +The driver will report sensor labels when it is able to determine that +information from the configuration registers. + +Configuration Notes +------------------- + +Besides standard interfaces driver adds the following: + +* PWM Control + +* pwm#_auto_point1_pwm and temp#_auto_point1_temp and +* pwm#_auto_point2_pwm and temp#_auto_point2_temp - + + - point1: Set the pwm speed at a lower temperature bound. + - point2: Set the pwm speed at a higher temperature bound. + +The ADT7462 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 temp#_max. |