All derived `feather-m0-*` boards have all features of the `feather-m0` board and `Makefile.features` of derived `feather-m0-`*` boards just include `Makefile.features` of the `feather-m0` base board. Therefore a base board definition is used in Kconfig for all `feather-m0*` boards.
With PR #17401 the Arduino feature was introduced for the `feather-m0` base board. Since all derived `feather-m0-*` boards with additional hardware modules simply include `Makefile.features` of the `feather-m0` base board, they also have this feature. However, the `Kconfig` file is defined separately for each of these boards. In PR 17401, it was forgotten to include the Arduino feature in the `Kconfig` file for the derived boards. This was not noticed because the CI did not trigger an error message.
If the WiFi interface is enabled by module `esp_wifi_any`, binary SDK libraries use the RTT. Therefore, `ztimer` must not use `periph_rtt`as backend, if the WiFi interface is enabled by module `esp_wifi_any`.
`ztimer_core` functions have to reside in IRAM for timing reasons and to be available also when the IROM cache is disabled. Although the module is called `ztimer`, its object files are generated in directory `ztimer_core`.
Previously, a default value for ESP_WIFI_PASS was intentionally defined only if DOXYGEN was also defined, to allow ESP_WIFI_PASS to be left undefined for using APs without authentication. With PR #17415 the definition was changed to always define a default value for EPS_WIFI_PASS. This made it impossible to use APs without authentication. The commit reverts this change.
The former correction factors were determined by measuring the resulting clocks without a device connected to the bus.
However, when testing the changes for low CPU clock frequencies, it was figured out that the clocks not only depend on configured register values
_i2c_hw[dev].regs->scl_low_period.period
_i2c_hw[dev].regs->scl_high_period.period
but also on the bus capacity. Obviously, the register values are not absolute times in APB clock cycles, but rather times that start as soon as the corresponding level is reached. In this case, the higher the bus capacity, the longer the period would be.
This means that the clock speed cannot be precisely controlled via the correction factors anyway. For this reason, and because the I2C implementation in ESP-IDF also does not use correction factors, they were removed.
