serial: ralink: adds support for the serial core found on ralink wisoc

The MIPS based Ralink WiSoC platform has 1 or more 8250 compatible serial cores.
To make them work we require the same quirks that are used by AU1x00.

Signed-off-by: John Crispin <blogic@openwrt.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 12 insertions, 4 deletions

diff --git a/drivers/tty/serial/8250/8250.c b/drivers/tty/serial/8250/8250.c
index 24939ca3eedc..0efc815a4968 100644
--- a/drivers/tty/serial/8250/8250.c
+++ b/drivers/tty/serial/8250/8250.c
@@ -317,9 +317,9 @@ static void default_serial_dl_write(struct uart_8250_port *up, int value)
         serial_out(up, UART_DLM, value >> 8 & 0xff);
 }
 
-#ifdef CONFIG_MIPS_ALCHEMY
+#if defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_SERIAL_8250_RT288X)
 
-/* Au1x00 UART hardware has a weird register layout */
+/* Au1x00/RT288x UART hardware has a weird register layout */
 static const u8 au_io_in_map[] = {
         [UART_RX]  = 0,
         [UART_IER] = 2,
@@ -440,7 +440,7 @@ static void set_io_from_upio(struct uart_port *p)
                 p->serial_out = mem32_serial_out;
                 break;
 
-#ifdef CONFIG_MIPS_ALCHEMY
+#if defined(CONFIG_MIPS_ALCHEMY) || defined(CONFIG_SERIAL_8250_RT288X)
         case UPIO_AU:
                 p->serial_in = au_serial_in;
                 p->serial_out = au_serial_out;
diff --git a/drivers/tty/serial/8250/Kconfig b/drivers/tty/serial/8250/Kconfig
index d31f4c63d4ba..2ef9537bcb2c 100644
--- a/drivers/tty/serial/8250/Kconfig
+++ b/drivers/tty/serial/8250/Kconfig
@@ -276,3 +276,11 @@ config SERIAL_8250_EM
           Selecting this option will add support for the integrated serial
           port hardware found on the Emma Mobile line of processors.
           If unsure, say N.
+
+config SERIAL_8250_RT288X
+        bool "Ralink RT288x/RT305x/RT3662/RT3883 serial port support"
+        depends on SERIAL_8250 && (SOC_RT288X || SOC_RT305X || SOC_RT3883)
+        help
+          If you have a Ralink RT288x/RT305x SoC based board and want to use the
+          serial port, say Y to this option. The driver can handle up to 2 serial
+          ports. If unsure, say N.
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index 82aebc8ff77f..d97142159e0f 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -134,7 +134,7 @@ struct uart_port {
 #define UPIO_HUB6               (1)
 #define UPIO_MEM                (2)
 #define UPIO_MEM32              (3)
-#define UPIO_AU                 (4)                     /* Au1x00 type IO */
+#define UPIO_AU                 (4)                     /* Au1x00 and RT288x type IO */
 #define UPIO_TSI                (5)                     /* Tsi108/109 type IO */
 
         unsigned int            read_status_mask;       /* driver specific */