picow: ask at a lower level if the interface is up

[jepler]

Closes: #7072

Adafruit CircuitPython 8.0.0-beta.2-9-g5192082e64-dirty on 2022-10-17; Raspberry Pi Pico W with rp2040
>>> import wifi
>>> print(wifi.radio.ipv4_address)
None
>>> import os
>>> wifi.radio.connect(os.getenv('WIFI_SSID'), os.getenv('WIFI_PASSWORD'))
>>> print(wifi.radio.ipv4_address)
10.0.2.94

[jepler]

@BiffoBear your testing here would also be helpful. Note that this build will only have the fix for this problem, not the one for #7076.

[anecdata]

Won't this also close #6996 ?

[FoamyGuy]

I tested this successfully with a Pico W using the slightly modified version of code from the issue:

print(f"ipv4_gateway    : {wifi.radio.ipv4_gateway}")
print(f"ipv4_subnet     : {wifi.radio.ipv4_subnet}")
print(f"ipv4_address    : {wifi.radio.ipv4_address}")
print(f"ipv4_dns        : {wifi.radio.ipv4_dns}")

wifi.radio.connect(secrets["ssid"], secrets["password"])

print("---------------------")
print(f"ipv4_gateway    : {wifi.radio.ipv4_gateway}")
print(f"ipv4_subnet     : {wifi.radio.ipv4_subnet}")
print(f"ipv4_address    : {wifi.radio.ipv4_address}")
print(f"ipv4_dns        : {wifi.radio.ipv4_dns}")

With this build I do get None before connecting and real values after connecting.

When I use ctrl-c then ctrl-d to restart the script I do still have real values from the prints before the connection, but I assume it's intended to behave this way since there is no explicit disconnect action and therefore technically it's just staying connected similar to how displays do across the soft reset.

[anecdata]

Similar to @fomayguy's results, I did it in boot.py, then again in code.py:

boot.py output:
#### boot.py ####
None
None
None
None
Connecting..........
192.168.6.202
192.168.4.1
255.255.252.0
1.1.1.2

#### code.py ####
192.168.6.202
192.168.4.1
255.255.252.0
1.1.1.2
Connecting...
192.168.6.202
192.168.4.1
255.255.252.0
1.1.1.2

We should retest this when we have a code mechanism to disconnect (e.g., wifi.radio.enabled = False or wifi.radio.stop_station()) to verify that disconnection invalidates the IPv4 info and they all return None.

[jepler]

With rp2040 there's no disconnect-from-wifi call that I've been able to find, so it stays connected across soft reset. This is different than the espressif port.

[anecdata]

MicroPython has a wlan.disconnect() for Cyw43 (also p.44)
Is there a way we can use the underlying call there (not sure where it comes from)?
Otherwise we can only disconnect with hard reset or real deep sleep.

found it:
https://github.com/georgerobotics/cyw43-driver/blob/195dfcc10bb6f379e3dea45147590db2203d3c7b/src/cyw43_ctrl.c#L601

[jepler]

OK, I see _leave() now. Yes, it's worth a try.

[jepler]

(but honestly after using both wifi workflow on espressif and the never-disconnects wifi of picow -- I want wifi connections to stay across soft reset!)

[anecdata]

There are a variety of uses cases for wanting to: disconnect; turn off STA (and/or AP); even deinit wifi (we don't have that currently in either native port).

• reduce resource consumption (power, ram)
• re-initialize from code without a hard reset as an escalation when network issues arise
• disconnect from one SSID to reconnect to another
• disconnect from an multi-AP SSID to reconnect to an SSID at a specific BSSID and/or channel
• turn off STA to run AP-only (TBD future for PiCow)
• ?
• profit
;-)

Oh also, at least in the Espressif case, each time you connect to a multi-AP SSID, it will pick the best one, so roaming with a device within a multi-AP SSID area will be able to optimize the connections better. I haven't come across any info on PiCow in the context of multi-AP SSIDs.

[FoamyGuy]

Looks good to me. Thank you.