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Diffstat (limited to 'Documentation/hwmon/g762')
| -rw-r--r-- | Documentation/hwmon/g762 | 65 |
1 files changed, 0 insertions, 65 deletions
diff --git a/Documentation/hwmon/g762 b/Documentation/hwmon/g762 deleted file mode 100644 index 923db9c5b5bc..000000000000 --- a/Documentation/hwmon/g762 +++ /dev/null @@ -1,65 +0,0 @@ -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. |