[Request for insight] Android set_player_leds info?

[LeeNX]

Is your feature request related to a problem? Please describe.
Looking for info or insight on how the android_set_player_leds is enabled? Basically looking to find out what would be needed to add to the Gatt Descriptor to work with bluepad32.

I was thinking something like:

// ------------------------------------------------- Player 1 to 4 leds
  REPORT_COUNT(1),     0x04,          //   REPORT_COUNT (4) ; 4 bits (Player 1, Player 2, Player 3, Player 4)
  REPORT_SIZE(1),      0x01,          //   REPORT_SIZE (1)
  USAGE_PAGE(1),       0x08,          //   USAGE_PAGE (LEDs)
  USAGE_MINIMUM(1),    0x61,          //   USAGE_MINIMUM (0x61) ; Player 1
  USAGE_MAXIMUM(1),    0x64,          //   USAGE_MAXIMUM (0x64) ; Player 4
  HIDOUTPUT(1),        0x02,          //   OUTPUT (Data,Var,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)
  REPORT_COUNT(1),     0x01,          //   REPORT_COUNT (1) ; 4 bits (Padding)
  REPORT_SIZE(1),      0x04,          //   REPORT_SIZE (4)
  HIDOUTPUT(1),        0x01,          //   OUTPUT (Const,Array,Abs,No Wrap,Linear,Preferred State,No Null Position,Non-volatile)

Been looking for an implementation that I could use or mimic so that I could add to the ESP32-BLE-Gamepad library, but not yet found anything that I can use, might just be a poor programming skills.

I found the function uni_hid_parser_android_set_player_leds in uni_hid_parser_android.c, but I can't see how it's enabled.

[ricardoquesada]

yes, uni_hid_parser_android_set_player_leds() is disabled because I couldn't make it work in any Android controller.

You can try to enable it by changing the #if 0 to #if 1 here: https://github.com/ricardoquesada/bluepad32/blob/main/src/components/bluepad32/parser/uni_hid_parser_android.c#L222

and then try setting the correct report_id... but that will only work with BR/EDR controllers.

For BLE controllers you will need to change that with something like hids_client_send_write_report(...).

Search in the Bluepad32 for hids_client_send_write_report to see how it is being used by the other BLE drivers

[LeeNX]

Thanks @ricardoquesada, for your time, insight and understanding.

I did think that function was disabled, but normally see a debug env or something. Again, apologies for my poor coding skills.

I will investigate hids_client_send_write_report. In my testings for HID report writing, I was able to get my PoC accepting and acting on a HID report, but have not been able to get any service to register GATT service to a function.

Maybe nobody has made a device that is a good reference design via BLE only? I was hoping that if the correct Gatt Descriptor was in place, it would just be picked up, but my research has shown that software like SDL are tied to VID:PID associated implementations, like XInput for XBox and Playstation devices.

If you see or know of anything that is worth sharing, please let me know.

[ricardoquesada]

I think you are in the right direction, but I got confused with the terminology.

What you need to do, is to define an "Input report" in the "HID descriptor".

I guess, just a guess, that on the gamepad then you should receive a sort of "Gatt service hid report" event.

That's my guess.

[LeeNX]

Thanks @ricardoquesada for your input, no pun intended ;-) That might have been more funny in my head.

I might have abuse the terminology trying to sound like I know what I am doing, but I am just guessing.

I think the input report is the standard why the HID is setup for buttons, I think it's an output which will create report means as an example:
from https://github.com/lemmingDev/ESP32-BLE-Gamepad/blob/11ee6e927df7c8bef37b2cdc36eb798e5173c15f/BleGamepad.cpp#L426

        // INPUT (Data,Var,Abs)
        tempHidReportDescriptor[hidReportDescriptorSize++] = 0x81;
        tempHidReportDescriptor[hidReportDescriptorSize++] = 0x02;

or https://github.com/DJm00n/ControllersInfo/blob/82c1d04494df9886b0f35f77e2435b5e3938575b/stadiacontroller/stadiacontroller_bluetoothle_hid_report_descriptor.txt#L107

85 05          (GLOBAL) REPORT_ID          0x05 (5)  
06 0F00        (GLOBAL) USAGE_PAGE         0x000F Physical Interface Device Page 
09 97          (LOCAL)  USAGE              0x000F0097 DC Enable Actuators (Selector)  
75 10          (GLOBAL) REPORT_SIZE        0x10 (16) Number of bits per field  
95 02          (GLOBAL) REPORT_COUNT       0x02 (2) Number of fields  
27 FFFF0000    (GLOBAL) LOGICAL_MAXIMUM    0x0000FFFF (65535)  
91 02          (MAIN)   OUTPUT             0x00000002 (2 fields x 16 bits) 0=Data 1=Variable 0=Absolute 0=NoWrap 0=Linear 0=PrefState 0=NoNull 0=NonVolatile 0=Bitmap  <-- Error: PHYSICAL_MINIMUM is undefined
C0           (MAIN)   END_COLLECTION     Application 

thou you may be looking at it from the host view vs where I am been looking at it from the device view.

Rather let me update my PoC and make a build with some tests and see where we get.

Mind if I poke you further? Have not found anywhere else that has offered feedback.

Thanks a ton.

Two things that I don't understand or can track in the code, is how does the HID descriptor is parsed and then used to expose the feature set of the gamepad/device connected.