#+TITLE: PiFanControlTUI
#+AUTHOR: A simple TUI to set your RPi5 fan curve.

* Install This
#TODO: now its not packaged, package it.

* Workings
This project's backend works by setting the following dtparams in =/boot/firmware/config.txt=. Settings require reboot to work.
The RaspberryPi 5 firmware supports up to 4 different [[https://github.com/raspberrypi/firmware/blob/4aa2a51fecb99ce16fe591391f6779174b9b5bea/boot/overlays/README#L271][thresholds]].
The backend validates the new config and only if valid it writes it to disk.

Each threshold is defined by:
1. *fan_tempN*: temperature fan activates at in millicelsius
2. *fan_tempN_hyst*: fan turns off (or to lower setting) when temperature is =fan_tempN - fan_tempN_hyst=. Also in millicelsius
3. *fan_tempN_speed*: fan speed in range [0, 255] where 255 is 100% fan speed


An example of the additions to your =/boot/firmware/config.txt:=
#+begin_src diff
[all]

+ # Auto-Generated Fan Curve parameters by PiFanUI
+ dtparam=fan_temp0=55000,fan_temp0_hyst=2000,fan_temp0_speed=90
+ dtparam=fan_temp1=65000,fan_temp1_hyst=3000,fan_temp1_speed=160
+ dtparam=fan_temp2=70000,fan_temp2_hyst=4000,fan_temp2_speed=200
+ dtparam=fan_temp3=72000,fan_temp3_hyst=5000,fan_temp3_speed=255
#+end_src


** Defaults
The following are the default values used by the firmware:
#+begin_src txt
fan_temp0               Temperature threshold (in millicelcius) for
                        1st cooling level (default 50000).

fan_temp0_hyst          Temperature hysteresis (in millicelcius) for
                        1st cooling level (default 5000).

fan_temp0_speed         Fan PWM setting for 1st cooling level (0-255,
                        default 75).

fan_temp1               Temperature threshold (in millicelcius) for
                        2nd cooling level (default 60000).

fan_temp1_hyst          Temperature hysteresis (in millicelcius) for
                        2nd cooling level (default 5000).

fan_temp1_speed         Fan PWM setting for 2nd cooling level (0-255,
                        default 125).

fan_temp2               Temperature threshold (in millicelcius) for
                        3rd cooling level (default 67500). 

fan_temp2_hyst          Temperature hysteresis (in millicelcius) for
                        3rd cooling level (default 5000).

fan_temp2_speed         Fan PWM setting for 3rd cooling level (0-255,
                        default 175).

fan_temp3               Temperature threshold (in millicelcius) for
                                4th cooling level (default 75000).

fan_temp3_hyst          Temperature hysteresis (in millicelcius) for
                        4th cooling level (default 5000).

fan_temp3_speed         Fan PWM setting for 4th cooling level (0-255,
                        default 250).

#+end_src
** Future Work
- [ ] add TUI
- [ ] add =-d, --dry-run= flag that generates a =.diff= file instead of modifying config
- [ ] support partial threshold definitions