Add Quectel lx6 GNSS driver

[nixward]

Add Quectel I2C modem backend
Add Quectel lx6 GNSS driver
Add I2C and UART lx6 variants to GNSS build_all test
Add build warning when building untested UART build variant (I only have I2C lx6 hardware)

[bjarki-andreasen]

Fantastic work! Could you add the new driver to the https://github.com/zephyrproject-rtos/zephyr/tree/main/tests/drivers/gnss/gnss_api test suite and run it as well?

[nixward]

Fantastic work! Could you add the new driver to the https://github.com/zephyrproject-rtos/zephyr/tree/main/tests/drivers/gnss/gnss_api test suite and run it as well?

Awesome, I ran the test suite on my out of tree board and made a change to now make the driver pass:

I: Turn on
*** Booting Zephyr OS build v4.1.0-7117-gdd0409b4a6b5 ***
Running TESTSUITE gnss_api
===================================================================
START - test_enabled_systems
 SKIP - test_enabled_systems in 0.001 seconds
===================================================================
START - test_fix_rate
 SKIP - test_fix_rate in 0.001 seconds
===================================================================
START - test_navigation_mode
 PASS - test_navigation_mode in 4.189 seconds
===================================================================
TESTSUITE gnss_api succeeded

------ TESTSUITE SUMMARY START ------

SUITE PASS - 100.00% [gnss_api]: pass = 1, fail = 0, skip = 2, total = 3 duration = 4.191 seconds
 - SKIP - [gnss_api.test_enabled_systems] duration = 0.001 seconds
 - SKIP - [gnss_api.test_fix_rate] duration = 0.001 seconds
 - PASS - [gnss_api.test_navigation_mode] duration = 4.189 seconds

------ TESTSUITE SUMMARY END ------

=============================================

[sonarqubecloud]

Quality Gate passed

Issues
4 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
5.3% Duplication on New Code

See analysis details on SonarQube Cloud

[bjarki-andreasen]

why include stdio?

[bjarki-andreasen]

You may want to close the pipe before disconnecting vcc, if that actually powers down the modem you could get garbage data on the UART or frame errors as the UART bus may be "floating"

[bjarki-andreasen]

For the GNSS API test suite, you may want to add CONFIG_GNSS_SATELLITES=y and configure some valid GNSS system combinations to test, see

zephyr/tests/drivers/gnss/gnss_api/boards/native_sim.conf

Lines 1 to 13 in 6c68584

	# Copyright (c) 2024 Trackunit Corporation
	# SPDX-License-Identifier: Apache-2.0
	CONFIG_GNSS_SATELLITES=y
	# GPS
	CONFIG_TEST_ENABLED_SYSTEMS_0=1
	# GPS + GLONASS
	CONFIG_TEST_ENABLED_SYSTEMS_1=3
	# GPS + GLONASS + QZSS
	CONFIG_TEST_ENABLED_SYSTEMS_2=19
	# GPS + GLONASS + GALILEO + BEIDOU + QZSS + SBAS
	CONFIG_TEST_ENABLED_SYSTEMS_3=95

for example :) Its not the most stable test in the world since it requires at least one satellite of enabled systems to be visible, but it is really good at detecting visible satellites which should not be :)