On Wed, May 24, 2023, at 10:34, Jacky Huang wrote: > On 2023/5/24 下午 03:42, Jiri Slaby wrote: >> On 16. 05. 23, 9:52, Jacky Huang wrote: >>> +static void ma35d1serial_config_port(struct uart_port *port, int flags) >>> +{ >>> + /* >>> + * Driver core for serial ports forces a non-zero value for port >>> type. >>> + * Write an arbitrary value here to accommodate the serial core >>> driver, >>> + * as ID part of UAPI is redundant. >>> + */ >>> + port->type = 1; >> >> So this 1 translates to PORT_8250. Why not to use it directly? Or >> something more saner like PORT_16550A? >> > It's not actually 8250 or 16550A. > Can we add the following definition to > 'include/uapi/linux/serial_core.h' and use PORT_MA35 instead? > > #define PORT_MA35 124 This was already in a previous version, until Greg commented that it was probably not needed: https://lore.kernel.org/lkml/20fc81c9-5517-ce1e-639a-3b425cf27759@xxxxxxxxx/ Since leaving port->type at PORT_UNKNOWN doesn't work, and almost all other drivers have something in serial_core.h, it's probably best to do the same here. Checking the other drivers showed that drivers/tty/serial/lantiq.c is currently the only exception, it defines PORT_LTQ_ASC locally, which causes a conflict with PORT_SPRD. Arnd