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.
The semantics of defining an SSID prefix that overrides the already defined SSID exactly when and only when it is set, and then enabling dynamic SSID generation with that prefix, made handling the parameter definition unnecessarily difficult and hard to understand.
Defining a boolean option that enables dynamic SSID generation, which then simply reuses the defined SSID as a prefix, makes it much more understandable and easier to handle, especially with respect to Kconfig.
Modify the periph_temperature implementation to expose the full
resolution of the temperature sensor. The accuracy of the sensor will
likely be less than 0.25 °C, but typically temperature sensors have
a precision in the order of their resolution. Exposing the full
resolution can therefore be useful to monitor relative temperature
changes.
The sam0 rtt busy loops for 180us every time an alarm is set or
the counter is read, this propagates and leads to timing errors
on ztimer_msec that are higher than > +-1msec.
The same goes for fe310.
For RISC-V and Cortex-M-not-3, triples are known and have worked in some
configuration, but do not work at the moment and stay disabled until the
reference platforms (native, M3) have been established well.
This introduces KCONFIG_BOARD_CONFIG and KCONFIG_CPU_CONFIG variable for
boards and CPUs (including common directories) to add default
configuration files to be merged. The current approach, as it uses
Makefile.features, would include boards first, not allowing them to
override CPU configurations.
