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authorLinus Torvalds <torvalds@linux-foundation.org>2013-07-04 06:56:35 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-04 06:56:35 +0400
commitddcf6600b133697adbafd96e080818bdc0dfd028 (patch)
treef382f8eaca3cc2d298542ae9599ce49884127d0e /Documentation/hwmon/g762
parentc16bfeb264decb964742067f02fdd51494e25e64 (diff)
parenta50d9a4d9ad3c71341788099d733e4151b8a511b (diff)
downloadlinux-ddcf6600b133697adbafd96e080818bdc0dfd028.tar.xz
Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull hwmon updates from Guenter Roeck: - new driver to support GMT G762/G763 pwm fan controllers - add support for DS1631, DS1721, and DS1731 to ds1621 driver - remove detect function from ds1621 driver as unreliable - bug fixes in nct6775, iio_hwmon, and adm1021 drivers - remove redundant platform_set_drvdata in various drivers - add device tree support to ina2xx driver * tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: hwmon: (ds1621) Fix temperature rounding operations hwmon: (nct6775) Drop unsupported fan alarm attributes for NCT6775 hwmon: (nct6775) Fix temperature alarm attributes Add support for GMT G762/G763 PWM fan controllers hwmon: (ina2xx) Add device tree support to pass the shunt resistor hwmon: (ds1621) Update documentation hwmon: (ds1621) Add DS1731 chip support to ds1621 driver hwmon: (iio_hwmon) add alias table hwmon: (adm1021) Do not create min sysfs attributes for LM84 hwmon: (ds1621) Remove detect function hwmon: (ds1621) Add ds1631 chip support to ds1621 driver and documentation hwmon: (ds1621) Add ds1721 update interval sysfs attribute hwmon: (ds1621) Add ds1721 chip support hwmon: (w83627ehf) Remove redundant platform_set_drvdata() hwmon: (ntc_thermistor) Remove redundant platform_set_drvdata() hwmon: (i5k_amb) Remove redundant platform_set_drvdata() hwmon: (coretemp) Remove redundant platform_set_drvdata() hwmon: (abituguru3) Remove redundant platform_set_drvdata()
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+Kernel driver g762
+==================
+
+The GMT G762 Fan Speed PWM Controller is connected directly to a fan
+and performs closed-loop or open-loop control of the fan speed. Two
+modes - PWM or DC - are supported by the device.
+
+For additional information, a detailed datasheet is available at
+http://natisbad.org/NAS/ref/GMT_EDS-762_763-080710-0.2.pdf. sysfs
+bindings are described in Documentation/hwmon/sysfs-interface.
+
+The following entries are available to the user in a subdirectory of
+/sys/bus/i2c/drivers/g762/ to control the operation of the device.
+This can be done manually using the following entries but is usually
+done via a userland daemon like fancontrol.
+
+Note that those entries do not provide ways to setup the specific
+hardware characteristics of the system (reference clock, pulses per
+fan revolution, ...); Those can be modified via devicetree bindings
+documented in Documentation/devicetree/bindings/hwmon/g762.txt or
+using a specific platform_data structure in board initialization
+file (see include/linux/platform_data/g762.h).
+
+ fan1_target: set desired fan speed. This only makes sense in closed-loop
+ fan speed control (i.e. when pwm1_enable is set to 2).
+
+ fan1_input: provide current fan rotation value in RPM as reported by
+ the fan to the device.
+
+ fan1_div: fan clock divisor. Supported value are 1, 2, 4 and 8.
+
+ fan1_pulses: number of pulses per fan revolution. Supported values
+ are 2 and 4.
+
+ fan1_fault: reports fan failure, i.e. no transition on fan gear pin for
+ about 0.7s (if the fan is not voluntarily set off).
+
+ fan1_alarm: in closed-loop control mode, if fan RPM value is 25% out
+ of the programmed value for over 6 seconds 'fan1_alarm' is
+ set to 1.
+
+ pwm1_enable: set current fan speed control mode i.e. 1 for manual fan
+ speed control (open-loop) via pwm1 described below, 2 for
+ automatic fan speed control (closed-loop) via fan1_target
+ above.
+
+ pwm1_mode: set or get fan driving mode: 1 for PWM mode, 0 for DC mode.
+
+ pwm1: get or set PWM fan control value in open-loop mode. This is an
+ integer value between 0 and 255. 0 stops the fan, 255 makes
+ it run at full speed.
+
+Both in PWM mode ('pwm1_mode' set to 1) and DC mode ('pwm1_mode' set to 0),
+when current fan speed control mode is open-loop ('pwm1_enable' set to 1),
+the fan speed is programmed by setting a value between 0 and 255 via 'pwm1'
+entry (0 stops the fan, 255 makes it run at full speed). In closed-loop mode
+('pwm1_enable' set to 2), the expected rotation speed in RPM can be passed to
+the chip via 'fan1_target'. In closed-loop mode, the target speed is compared
+with current speed (available via 'fan1_input') by the device and a feedback
+is performed to match that target value. The fan speed value is computed
+based on the parameters associated with the physical characteristics of the
+system: a reference clock source frequency, a number of pulses per fan
+revolution, etc.
+
+Note that the driver will update its values at most once per second.