26 lines
1.2 KiB
Plaintext
26 lines
1.2 KiB
Plaintext
|
Device tree bindings for fan tach output connected to IRQ capable GPIO.
|
||
|
|
|
||
|
|
Required properties:
|
||
|
|
- compatible : "nvidia,gpio-tachometer"
|
||
|
|
- win-len : Duration in multiples of 100ms, for which the IRQ will be enabled
|
||
|
|
while measuring speed. Maximum allowed value is 5 seconds to avoid
|
||
|
|
possible IRQ overload at high speed.
|
||
|
|
- pulse-per-rev : Number of signals generated on the tach output pin by the motor
|
||
|
|
for one full rotation.
|
||
|
|
- gpio : GPIO pin on which tach output of the motor is connected.
|
||
|
|
|
||
|
|
Optional properties:
|
||
|
|
- schedule-delay: Time in milliseconds for the background thread to monitor the speed.
|
||
|
|
If the measured speed is 0, system shutdown will be initiated.
|
||
|
|
Time duration should be higher than win-len time.
|
||
|
|
|
||
|
|
Example:
|
||
|
|
gpio_tachometer {
|
||
|
|
compatible = "nvidia,gpio-tachometer";
|
||
|
|
win-len = <2>; /*For every measurement, take samples for 200ms*/
|
||
|
|
pulse-per-rev = <2>; /*Motor generates 2 pulses for every full rotation*/
|
||
|
|
schedule-delay = <10000>; /*Check motor speed every 10seconds and shutdown if motor is stopped*/
|
||
|
|
gpio = <&tegra_main_gpio TEGRA_MAIN_GPIO(Y, 1) 0>;
|
||
|
|
status = "okay";
|
||
|
|
};
|