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 <[email protected]>
Signed-off-by: Lukas Wunner <[email protected]>
Link: https://lore.kernel.org/r/271e814af4b0db3bffbbb74abf2b46b75add4516.1589285873.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <[email protected]>
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 92f5eba..b649a2b 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -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 */
