rcrecv-kmod

FreeBSD kernel module for GPIO remote control receiver

About

The kernel driver reads a sequence of pulses from a remote control receiver (e.g., mx-rm-5v) and tries to decode it into a number. This number can be read from a character device or received by ioctl() as a remote control code. The driver also generates poll(2) and kqueue(2) events informing the user process about the presence of new code for it.

It is possible to read additional information about the last code it received using a ioctl() call (such as a timestamp or a pulse duration. See rcrecv.h and ./bin/ folder for examples).

The driver also stores the additional information about the code in kernel variables, which can be accessed with sysctl(8):

dev.rcrecv.0.tolerance: 60
dev.rcrecv.0.pulse_duration: 326
dev.rcrecv.0.proto: 1
dev.rcrecv.0.bit_length: 24
dev.rcrecv.0.value: 9776792
dev.rcrecv.0.last_time: 1422135711828
dev.rcrecv.0.%parent: simplebus0
dev.rcrecv.0.%pnpinfo: name=rcrecv@0 compat=rcrecv
dev.rcrecv.0.%location:
dev.rcrecv.0.%driver: rcrecv
dev.rcrecv.0.%desc: GPIO Remote Control Receiver module

Installation

You will need the FreeBSD sources to build the driver. You can copy it or mount usb-flash with it or mount it as NFS share from another PC to /usr/src as I did - It doesn't matter - all these methods will work fine. Run this commands from driver directory (If Your platform haven't DTS enabled You can skip the first line to keep opt_platform.h empty):

% echo "#define FDT 1" > opt_platform.h
% make
% sudo make install

Now You installed the driver You also need to define the receiver as a device. You can do it either by FDT-overlay or by device.hints.

FDT-overlay based setup

Go to ./fdt-overlay folder and choose an example of .dtso overlay that suits Your system best. Copy it to a name without .sample tail and edit it. Lines to pay attention to:

compatible =
pins =
gpios =

Obviously You have to define the pin You want to connect the receiver to. You also have to set correctly the compatibility string (The simplest way to do this is to take the one from Your other overlays).

To build and install Your new overlay run:

% make
% sudo make install

All You have to do now is to add the name of the new fdt-blob to /boot/loader.conf so that it is automatically loaded on system reboot (It's extension can be omitted):

fdt_overlays="your,other,overlays,sun8i-h3-rcrecv-gpio"

device.hints based pin setup

For not DTS-compatible system You can setup the device by editing a file /boot/device.hints. By example, for a device on pin 13:

hint.rcrecv.0.at="gpiobus0"
hint.rcrecv.0.compatible="rcrecv"
hint.rcrecv.0.pin_list="13"
### Optional. 60% is default tolerance value
hint.rcrecv.0.default-tolerance="60"

After changes are made You need to reboot Your system - kenv command changes the variables ok but it seems they does not be honored on already running system anyway.

Status

Tested on Orange PI PC, Orange PI Zero, Raspberry Pi 2b, Raspberry Pi 4b. Works like a charm for me.

Thanks

Suat Özgür (aka sui77) for rc-switch