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authormerge <null@invalid>2009-01-22 13:55:32 +0000
committerAndy Green <agreen@octopus.localdomain>2009-01-22 13:55:32 +0000
commitaa6f5ffbdba45aa8e19e5048648fc6c7b25376d3 (patch)
treefbb786d0ac6f8a774fd834e9ce951197e60fbffa /Documentation/hwmon/adt7462
parentf2d78193eae5dccd3d588d2c8ea0866efc368332 (diff)
MERGE-via-pending-tracking-hist-MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141
pending-tracking-hist top was MERGE-via-stable-tracking-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040-1232632141 / fdf777a63bcb59e0dfd78bfe2c6242e01f6d4eb9 ... parent commitmessage: From: merge <null@invalid> MERGE-via-stable-tracking-hist-MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 stable-tracking-hist top was MERGE-via-mokopatches-tracking-fix-stray-endmenu-patch-1232632040 / 90463bfd2d5a3c8b52f6e6d71024a00e052b0ced ... parent commitmessage: From: merge <null@invalid> MERGE-via-mokopatches-tracking-hist-fix-stray-endmenu-patch mokopatches-tracking-hist top was fix-stray-endmenu-patch / 3630e0be570de8057e7f8d2fe501ed353cdf34e6 ... parent commitmessage: From: Andy Green <andy@openmoko.com> fix-stray-endmenu.patch Signed-off-by: Andy Green <andy@openmoko.com>
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+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.
+