WebUSB implementation #2862
WebUSB implementation #2862
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| @@ -417,6 +417,10 @@ impl<'a, 'd, D: Driver<'d>> InterfaceAltBuilder<'a, 'd, D> { | |||
| self.builder.config_descriptor.write(descriptor_type, descriptor); | |||
| } | |||
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| pub fn bos_capability(&mut self, capability_type: u8, capability: &[u8]) { | |||
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This is the only piece I had to add to the builder. I'm not sure if this is the best spot to add it but I needed a way to add BOS capabilities within the interface API.
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Nice! Is there a reason for allocating in/out endpoints and echoing of webusb packets? AFAIK webusb only needs descriptors, it doesn't use endpoints and doesn't send/receive any data. You use webusb descriptors to throw a notification linking to URL and then use other protocols for communication (CDC, DFU, etc). |
Hey, thank you so much for giving this a look! WebUSB does indeed support data transfer and endpoints (see https://wicg.github.io/webusb/#device-usage). The endpoints I implemented here enable the The creation of exactly these two endpoints is indeed kind of arbitrary. There might be the need for only a read or only a write endpoint on the device (or even more endpoints). However, with the current API (the |
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Just to keep the conversation going, I unleashed this PR out of draft mode, added all the documentation and improved the API around the URL a bit. Let me know what you think :) |
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Please someone correct me if I am wrong, but normally you would use a regular USB class (i.e. CDC-ACM, HID, DFU etc), which defines protocol and USB endpoints that it uses. You then add WebUSB descriptors just for the OS notification and redirection to your URL, no additional endpoints are used for this. When you connect to your USB device from browser, you get a raw USB API, where you can access all device endpoints belonging to all classes that your device has. |
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I did some more reading and I think you are correct. While most of the implementations I've found use endpoints to initiate transfers for illustration purposes, they are definitely not required. I'll try to move the endpoints creation to the example and put them onto another interface. |
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Ok, I removed all the additional endpoints from the capability implementation itself and moved them to the example. Only change is that they live on interface 1 now which is created in the example itself. |
This adds the WebUSB implementation as per https://wicg.github.io/webusb/, using one in-endpoint and one out-endpoint as well as an example for the RP2040 to illustrate this capability.
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I created an implementation for the WebUSB spec that can be found here: https://wicg.github.io/webusb/.
This is a rough draft and I just wanted to get a feel for whether you'd be willing to consider this functionality as a part of embassy.
I tried to stay as close to the current class implementations as possible and use existing APIs as much as I could (there's a notable exception -
bos_capability, see the comment below).If you feel like this would be a valuable addition, I'll clean it up a bit more and add documentation for it.