+--- a/drivers/serial/8250.c
++++ b/drivers/serial/8250.c
+@@ -302,9 +302,9 @@ static const struct serial8250_config ua
+ },
+ };
+
+-#if defined (CONFIG_SERIAL_8250_AU1X00)
++#if defined (CONFIG_SERIAL_8250_AU1X00) || defined (CONFIG_SERIAL_8250_RT288X)
+
+-/* Au1x00 UART hardware has a weird register layout */
++/* Au1x00 and RT288x UART hardware has a weird register layout */
+ static const u8 au_io_in_map[] = {
+ [UART_RX] = 0,
+ [UART_IER] = 2,
+@@ -422,7 +422,7 @@ static unsigned int mem32_serial_in(stru
+ return readl(p->membase + offset);
+ }
+
+-#ifdef CONFIG_SERIAL_8250_AU1X00
++#if defined(CONFIG_SERIAL_8250_AU1X00) || defined(CONFIG_SERIAL_8250_RT288X)
+ static unsigned int au_serial_in(struct uart_port *p, int offset)
+ {
+ offset = map_8250_in_reg(p, offset) << p->regshift;
+@@ -503,7 +503,7 @@ static void set_io_from_upio(struct uart
+ p->serial_out = mem32_serial_out;
+ break;
+
+-#ifdef CONFIG_SERIAL_8250_AU1X00
++#if defined (CONFIG_SERIAL_8250_AU1X00) || defined (CONFIG_SERIAL_8250_RT288X)
+ case UPIO_AU:
+ p->serial_in = au_serial_in;
+ p->serial_out = au_serial_out;
+@@ -535,7 +535,7 @@ serial_out_sync(struct uart_8250_port *u
+ switch (p->iotype) {
+ case UPIO_MEM:
+ case UPIO_MEM32:
+-#ifdef CONFIG_SERIAL_8250_AU1X00
++#if defined (CONFIG_SERIAL_8250_AU1X00) || defined (CONFIG_SERIAL_8250_RT288X)
+ case UPIO_AU:
+ #endif
+ case UPIO_DWAPB:
+@@ -573,8 +573,8 @@ static inline void _serial_dl_write(stru
+ serial_outp(up, UART_DLM, value >> 8 & 0xff);
+ }
+
+-#if defined(CONFIG_SERIAL_8250_AU1X00)
+-/* Au1x00 haven't got a standard divisor latch */
++#if defined (CONFIG_SERIAL_8250_AU1X00) || defined (CONFIG_SERIAL_8250_RT288X)
++/* Au1x00 and RT288x haven't got a standard divisor latch */
+ static int serial_dl_read(struct uart_8250_port *up)
+ {
+ if (up->port.iotype == UPIO_AU)
+@@ -781,22 +781,19 @@ static int size_fifo(struct uart_8250_po
+ */
+ static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
+ {
+- unsigned char old_dll, old_dlm, old_lcr;
++ unsigned char old_lcr;
++ unsigned int old_dl;
+ unsigned int id;
+
+ old_lcr = serial_inp(p, UART_LCR);
+ serial_outp(p, UART_LCR, UART_LCR_DLAB);
+
+- old_dll = serial_inp(p, UART_DLL);
+- old_dlm = serial_inp(p, UART_DLM);
++ old_dl = serial_dl_read(p);
+
+- serial_outp(p, UART_DLL, 0);
+- serial_outp(p, UART_DLM, 0);
++ serial_dl_write(p, 0);
++ id = serial_dl_read(p);
+
+- id = serial_inp(p, UART_DLL) | serial_inp(p, UART_DLM) << 8;
+-
+- serial_outp(p, UART_DLL, old_dll);
+- serial_outp(p, UART_DLM, old_dlm);
++ serial_dl_write(p, old_dl);
+ serial_outp(p, UART_LCR, old_lcr);
+
+ return id;
+@@ -2596,7 +2593,7 @@ static void serial8250_config_port(struc
+ if (flags & UART_CONFIG_TYPE)
+ autoconfig(up, probeflags);
+
+-#ifdef CONFIG_SERIAL_8250_AU1X00
++#if defined (CONFIG_SERIAL_8250_AU1X00) || defined (CONFIG_SERIAL_8250_RT288X)
+ /* if access method is AU, it is a 16550 with a quirk */
+ if (up->port.type == PORT_16550A && up->port.iotype == UPIO_AU)
+ up->bugs |= UART_BUG_NOMSR;
+--- a/drivers/serial/Kconfig
++++ b/drivers/serial/Kconfig
+@@ -266,6 +266,14 @@ config SERIAL_8250_AU1X00
+ say Y to this option. The driver can handle up to 4 serial ports,
+ depending on the SOC. If unsure, say N.
+
++config SERIAL_8250_RT288X
++ bool "Ralink RT288x/RT305x serial port support"
++ depends on SERIAL_8250 != n && (SOC_RT288X || SOC_RT305X)
++ 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.
++
+ config SERIAL_8250_RM9K
+ bool "Support for MIPS RM9xxx integrated serial port"
+ depends on SERIAL_8250 != n && SERIAL_RM9000
+--- a/include/linux/serial_core.h
++++ b/include/linux/serial_core.h
+@@ -284,7 +284,7 @@ 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 */
+ #define UPIO_DWAPB (6) /* DesignWare APB UART */
+ #define UPIO_RM9000 (7) /* RM9000 type IO */