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The Radxa Rock comes with IR sensor(between the uSD card and USB otg port). This page describes how to use and configure the remote to work properly on RR. You can do this in two ways:

  • Modify the IR kernel driver - low level hacking, working on Linux and Android since they are based the same kernel
  • Modify the Android key mapping if you use android - user space hacking

Kernel Level

The IR driver only supports NEC Encode format. Below is the instructions of how to add you IR remote to send the right key code in Linux kernel.

There is just one file related "kernel/drivers/input/remotectl/rkxx_remotectl.c"

Do as follows

1、Add an array as follow:

 static struct rkxx_remote_key_table remote_key_table_41C8[] = {
                {0x38, KEY_VOLUMEUP},
                {0xb8, KEY_VOLUMEDOWN},
                {0x58, KEY_MENU},
                {0xd0, KEY_REPLY},
                {0x48, KEY_BACK},
                {0x98, KEY_BACK},
                {0x50, KEY_UP},
                {0x30, KEY_DOWN},
                {0xc8, KEY_LEFT},
                {0xc0, KEY_RIGHT},
                {0x40, KEY_REPLY},
                {0x80, KEY_SEARCH},

The first column is the IR key value,the second column is the corresponding key code.

2、Add one item in

  static struct rkxx_remotectl_button remotectl_button[]

For example:

        .usercode = 0x41c8, /* need to get the usercode in next step */
        .nbuttons = 12,    /* number of buttons */
        .key_table = &remote_key_table_41C8[0], /* key table */

The first is usercode, every IR has a usercode; the second is the number of buttons, the third is the address of the array we added in the 1st step.

How to get the usercode and IR key value

In the remotectl_do_something func

       case RMC_USERCODE:
            ddata->scanData <<= 1;
            ddata->count ++;
            if ((TIME_BIT1_MIN < ddata->period) && (ddata->period < TIME_BIT1_MAX)){
                ddata->scanData |= 0x01;
            if (ddata->count == 0x10){//16 bit user code
               // printk("u=0x%x\n",((ddata->scanData)&0xFFFF));                if (remotectl_keybdNum_lookup(ddata)){
                    ddata->state = RMC_GETDATA;
                    ddata->scanData = 0;
                    ddata->count = 0;
                   ddata->state = RMC_PRELOAD;

Uncomment the printk code to get the usercode,then add remotectl_button array with the usercode and the buttons number

       case RMC_GETDATA:
            ddata->count ++;
            ddata->scanData <<= 1;
            if ((TIME_BIT1_MIN < ddata->period) && (ddata->period < TIME_BIT1_MAX)){
                ddata->scanData |= 0x01;
            if (ddata->count == 0x10){
               // printk(KERN_ERR "d=%x\n",(ddata->scanData&0xFFFF));                if ((ddata->scanData&0x0ff) == ((~ddata->scanData >> 8)&0x0ff)){
                    if (remotectl_keycode_lookup(ddata)){
                        ddata->press = 1;

Uncomment the printk code ,you can get the IR key value


  1. The printk output is in hex(0x) format, the first two number is we needed ,the last two number is just used for checking, we can ignore it.
  2. Don't leave much printing log in code, it will make in the ir not work.

Android Key Remapping

/system/usr/keylayout/rkxx-remotectl.kl is a file mapping scancodes(linux) to keycodes(android). you can add the item to match your IR- remocon's key. Here are some mistakes someone has met.

1) Number KEY doesn't work.(Map's Items is wrote wrong)

//Wrong Code
key 1    KEY_1
key 2    KEY_2
key 3    KEY_3
key 4    KEY_4 
key 5    KEY_5
key 6    KEY_6
key 7    KEY_7
key 8    KEY_8
key 9    KEY_9
key 0    KEY_0
//Right Code
key 1    ESCAPE
key 2    1               //NOTE  is 1  not 2
key 3    2
key 4    3 
key 5    4
key 6    5
key 7    6
key 8    7
key 9    8
key 10   9    
key 11   0