USE_TINYUSB_HOST check is needed on Pico's to compile

[tuulikauri]

Describe the bug
Fails to compile on Pico2W (I assume also on Pico, PicoW, and Pico2) if using TinyUSB Host mode.

To Reproduce
Using earle philhower core and Arduino IDE.
In Arduino IDE Tools->USB Stack menu
Select Adafruit TinyUSB Host (Native) as the USB Stack setting
Compile any project.
Control-Surface tries to use TinyUSBDevice.mounted(); but it fails to compile as this isn't found (it's not a USB device when its in host mode, and the check for USE_TINYUSB passes).

This is the fix; add a check for !defined(USE_TINYUSB_HOST) here:
Arduino\libraries\Control_Surface\src\MIDI_Interfaces\PicoUSBInit.hpp Line 16:
defined(USE_TINYUSB) && !defined(CS_USB_MIDI_NOT_SUPPORTED) && !defined(USE_TINYUSB_HOST)

With this change to the library, the code compiles in TinyUSB Host mode on a Pico 2W.

Expected behavior
Compiles.

Code
This is the fix; add !defined(USE_TINYUSB_HOST) here:
Arduino\libraries\Control_Surface\src\MIDI_Interfaces\PicoUSBInit.hpp Line 16:
defined(USE_TINYUSB) && !defined(CS_USB_MIDI_NOT_SUPPORTED) && !defined(USE_TINYUSB_HOST)

Sorry I don't have time to do a PR with this fix right now and I'm starting to forget so thought it's better to leave this brief and incomplete note here. I intend to come back to this with a PR for the fix.

[tttapa]

Thanks for the report! Let me know if you need help with the PR.

Possibly off-topic, but proper USB Host MIDI support is something I never got around to, unfortunately. There's rudimentary support on Teensy, but not enough other boards actually have the low-level software support for it. Once the low-level support is there, interfacing it with the existing Control Surface infrastructure should be fairly straightforward, though: https://tttapa.github.io/Control-Surface/Doxygen/d7/d5f/Custom-USB-MIDI-Backend_8ino-example.html

[tuulikauri]

proper USB Host MIDI support

Yeah I have a USB-Host project working, and wanted to add Bluetooth; Control-Surface seemed like a great way to not have to wrangle it myself on the Pico 2W :D I'm using EZ_USB_MIDI_HOST. If the licenses are compatible maybe it can be merged in, as once I fixed the compile check and added #define CS_USB_MIDI_NOT_SUPPORTED to my *.ino project file it works (fwiw, I dont think this define in my ino does anything... Arduino IDE does not pass macros into library files, but rather compiles them all separately... but it makes me feel good lol because it appears that is checked in parts of the library to skip USB support). I don't fully know what I have removed; the TinyUSBDevice.mounted(); check and associated code seems somewhat important, and probably some equivalent should be added for Host mode as part of adding host mode.

I'm a bit reluctant to submit my hack as a proper PR, as-is. Right now it just disables USB support in the Control-Surface's USB library entirely if the compiler is in Host mode. Perhaps with a change to throw a helpful compiler error would be a good enough temp fix for now.

#if defined(USE_TINYUSB_HOST)
#error "Control Surface doesnt support USB Host mode. Compile with Tools->USB Stack->
Adafruit TinyUSB mode instead to enable USB Device functions."
#endif // could be in all functions that call USB functions, and the USE_TINYUSB_HOST could block out all USB functions

Not having USB Host through Control-Surface is fine for my project; the USB-Host is for I/O to an off-the-shelf MIDI controller, but that MIDI is actually completely isolated as it's acting as an interface panel vs MIDI notes I might need to send to other devices. And there's Serial DIN MIDI I/O for actual MIDI note data; and now, thanks to CS, Bluetooth I/O!