wifi: let connect() take a scan result

[mikeysklar]

Stacked on #11308. Base is esp32c5-wifi-5ghz, so only the top commit is new here.

Body updated: this replaces an earlier CIRCUITPY_WIFI_BAND design, discussed above.

What

connect() accepts a Network from start_scanning_networks() and uses its
bssid and channel, so reaching a specific AP needs no second scan.

Why

On a same-SSID dual-band network an unqualified connect() lands on 2.4 GHz.
Passing the scan result reaches the 5 GHz AP without scanning twice.

Hardware tested

ESP32-C5-DevKitC-1-N8R8, 10.3.0-45-ge3bffa92b4. Connect timings, 10 trials
each, are in the comment below.

AI assistance

Claude wrote the overload and the docstring. I ran the connect timings on
hardware and checked the channel numbers myself.

[dhalbert]

The reason for a settings.toml value is to specify 2.4 vs 5 when using auto-connect.

I didn't suggest a property necessarily, it could also be an optional arg to connect() or start_ap(), which would limit the way it could change more. I don't know whether Espressif provides simultaneous dual-band connections but we should also look at the Nordic nRF7002, which is dual band.

EDIT: connect(), not start_station(), I think makes more sense.

[tannewt]

Yup, I agree with Dan. This should only impact wifi auto-connect. I think connect can be specific by BSSID or channel already. Channel is especially good because it reduces scan time a ton.

We also considered having connect take a scan result to encapsulate this info. Or maybe ScanResult could have connect() itself.

[mikeysklar]

connect() takes a Network from a scan and uses its bssid and channel.

CIRCUITPY_WIFI_BAND is gone.

As tannewt suggested channel= is much faster (7x). Same for net or bssid=.

ALL_CHANNEL_SCAN is expensive.

10 trials each (connection time measured in seconds):

Call	Mean	Range	Channel
connect(ssid, pw)	11.01	10.77-11.30	5
connect(ssid, pw, channel=149)	1.55	1.14-1.64	149
connect(ssid, pw, bssid=...)	1.62	1.59-1.64	149
connect(net, pw)	1.62	1.59-1.66	149

Scanning to get the Network costs 3.57s, so scan plus connect is 5.18s end to end.

[tannewt]

Thanks for these changes. I'd rather have a new network kwarg with it's own comment about what it does.

Is there any way to shrink the 7002 instead? I'd rather not have this not on every board.

[mikeysklar]

network= is its own kwarg

Passing both ssid and network raises TypeError.

Tested on the ESP32-C5-DevKitC-1-N8R8, 10.3.0-50-ge51d55ac3f:

Call	Result
connect(network=net, password=pw)	1.19 s, ch 149, 192.168.0.79
connect()	TypeError, 'ssid' argument required
connect(ssid=w, password=p, network=net)	TypeError, Supply either ssid or network, not both
connect(w, p, network=net)	same TypeError
connect(w, p)	connects, unchanged

ap_info after the first row reports ch 149 rssi -52 bssid b0:19:21:df:d4:02,
matching the scanned Network it was given.

Yes on the 7002. It reserves a 32 KB storage_partition nothing reads: the port's
only settings user is common-hal/_bleio/Adapter.c:351 and the board sets
CONFIG_BT=n. Giving it to slot0 ends exactly at end of flash. #11335.

[tannewt]

Thank you!