Jetpack/kernel/nvidia/Documentation/devicetree/bindings/thermal/tegra-pwm-fan.txt
dchvs 75c7968d30 Add Jetpack 4.4.1 sources
Jetson Xavier NX, Jetson TX2 Series, Jetson AGX Xavier Series, Jetson Nano, Jetson TX1 [L4T 32.4.4]
2021-01-19 20:45:17 -06:00

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Bindings for a fan connected to the PWM lines
Properties details:
- compatible : "pwm-fan"
- pwms : the PWM that is used to control the PWM fan
- shared_data
- active_steps : Entries for references in active_rpm[], active_pwm[], active_rru[], active_rrd[]
- active_rru : This value is kept on added to cur_pwm till it reaches at
next active step from the table. This is repeated until cur_pwm
value reaches target_pwm
- active_rrd : This value is kept on subtracted from cur_pwm till it reaches at
previous active step from the table. This is repeated until cur_pwm
value reaches target_pwm
- state_cap_lookup : Index to refer in active_pwm[]
- pwm_period : To derive duty cycle
- pwm_id : Assigned PWM controller id to tegra fan
Same as mentioned id in pwms. In pwms, the id starts from 1
pwm_id in pfsd, the id starts from 0
- step_time : Time taken for each step during rru/rrd
- state_cap : Capping state value out of available active_steps
- active_pwm_max : Max pwm value (256)
- pwm_gpio : GPIO pin used for pwm
Example:
pwm_fan_shared_data: pfsd {
status = "okay";
num_resources = <0>;
active_steps = <10>;
active_rpm = <0 1000 2000 3000 4000 5000 6000 7000 10000 11000>;
active_rru = <40 2 1 1 1 1 1 1 1 1>;
active_rrd = <40 2 1 1 1 1 1 1 1 1>;
state_cap_lookup = <2 2 2 2 3 3 3 4 4 4>;
pwm_period = <45334>;
pwm_id = <3>;
step_time = <100>; /* mesecs */
state_cap = <7>;
active_pwm_max = <256>;
pwm_gpio = <&tegra_aon_gpio TEGRA_AON_GPIO(V, 6) GPIO_ACTIVE_LOW>; /* TEGRA_MAIN_GPIO_PV6 */
};
pwm-fan {
status = "okay";
compatible = "pwm-fan";
#pwm-cells = <1>;
pwms = <&tegra_pwm4 0 45334>;
shared_data = <&pwm_fan_shared_data>;
active_pwm = <0 80 120 160 255 255 255 255 255 255>;
};
};