serial: Allow uart_get_rs485_mode() to return errno

We're about to amend uart_get_rs485_mode() to support a GPIO pin for
rs485 bus termination.  Retrieving the GPIO descriptor may fail, so
allow uart_get_rs485_mode() to return an errno and change all callers
to check for failure.

The GPIO descriptor is going to be stored in struct uart_port.  Pass
that struct to uart_get_rs485_mode() in lieu of a struct device and
struct serial_rs485, both of which are directly accessible from struct
uart_port.

A few drivers call uart_get_rs485_mode() before setting the struct
device pointer in struct uart_port.  Shuffle those calls around where
necessary.

[Heiko Stuebner did the ar933x_uart.c portion, hence his Signed-off-by.]

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lukas Wunner 2020-05-12 14:40:02 +02:00 committed by Greg Kroah-Hartman
parent e0a851fe6b
commit c150c0f362
9 changed files with 33 additions and 14 deletions

View file

@ -472,5 +472,5 @@ extern int uart_handle_break(struct uart_port *port);
(cflag) & CRTSCTS || \
!((cflag) & CLOCAL))
void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf);
int uart_get_rs485_mode(struct uart_port *port);
#endif /* LINUX_SERIAL_CORE_H */