zephyr

Primary Git Repository for the Zephyr Project. Zephyr is a new generation, scalable, optimized, secure RTOS for multiple hardware architectures.

bluetooth bluetooth-le embedded embedded-c iot mcu microcontroller real-time rtos zephyr zephyr-rtos zephyros

History

Titouan Christophe c525e7a0a5 usb: device_next: add new MIDI 2.0 device class This adds a new USB device class (based on usb/device_next) that implements revision 2.0 of the MIDIStreaming interface, a sub-class of the USB audio device class. In practice, the MIDI interface is much more simple and has little in common with Audio, so it makes sense to have it as a separate class driver. MIDI inputs and outputs are configured through the device tree, under a node `compatible = "zephyr,usb-midi"`. As per the USB-MIDI2.0 spec, a single usb-midi interface can convey up to 16 Universal MIDI groups, comprising 16 channels each. Data is carried from/to the host via so-called Group Terminals, that are organized in Group Terminal Blocks. They are represented as children of the usb-midi interface in the device tree. From the Zephyr application programmer perspective, MIDI data is exchanged with the host through the device associated with the `zephyr,usb-midi` interface, using the following API: * Send a Universal MIDI Packet to the host: `usb_midi_send(device, pkt)` * Universal MIDI Packets from the host are delivered to the function passed in `usb_midi_set_ops(device, &{.rx_packet_cb = handler})` Compliant USB-MIDI 2.0 devices are required to expose a USB-MIDI1.0 interface as alt setting 0, and the 2.0 interface on alt setting 1. To avoid the extra complexity of generating backward compatible USB descriptors and translating Universal MIDI Packets from/to the old USB-MIDI1.0 format, this driver generates an empty MIDI1.0 interface (without any input/output); and therefore will only be able to exchange MIDI data when the host has explicitely enabled MIDI2.0 (alt setting 1). This implementation is based on the following documents, which are referred to in the inline comments: * `midi20`: Universal Serial Bus Device Class Definition for MIDI Devices Release 2.0 https://www.usb.org/sites/default/files/USB%20MIDI%20v2_0.pdf * `ump112`: Universal MIDI Packet (UMP) Format and MIDI 2.0 Protocol With MIDI 1.0 Protocol in UMP Format Document Version 1.1.2 https://midi.org/universal-midi-packet-ump-and-midi-2-0-protocol-specification Signed-off-by: Titouan Christophe <moiandme@gmail.com>		5 months ago
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codec.h	api: codec: Extend API	10 months ago
dmic.h	include/zephyr: Add 'version' and 'since' tag to groups	1 year ago
midi.h	usb: device_next: add new MIDI 2.0 device class	5 months ago