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