Refactors all of the serial drivers to use a shared driver class
initialization priority configuration, CONFIG_SERIAL_INIT_PRIORITY, to
allow configuring serial drivers separately from other devices. This is
similar to other driver classes like I2C and SPI.
The default is set to CONFIG_KERNEL_INIT_PRIORITY_DEVICE to preserve the
existing default initialization priority for most drivers. The one
exception is uart_lpc11u6x.c which previously used
CONFIG_KERNEL_INIT_PRIORITY_OBJECTS.
This change was motivated by an issue on the frdm_k64f board where the
serial driver was incorrectly initialized before the clock control
driver.
Signed-off-by: Maureen Helm <maureen.helm@intel.com>
Microchip XEC has been using the standard NS16550 driver.
Using the standard NS16550 driver requires extra HW programming
for XEC UART in board level and did not support XEC GIRQ interrupt
programming. We add an XEC specific driver and remove UART specific
register programming from the board level and implement interrupt
support. Also, by implementing a SoC specific driver we can add
driver PM in the future.
Signed-off-by: Scott Worley <scott.worley@microchip.com>
