2 files changed, 18 insertions, 0 deletions

diff --git a/include/asm-x86/ioctls.h b/include/asm-x86/ioctls.h
index 336603512399..1a8ac45b28be 100644
--- a/include/asm-x86/ioctls.h
+++ b/include/asm-x86/ioctls.h
@@ -51,6 +51,8 @@
 #define TCSETS2         _IOW('T', 0x2B, struct termios2)
 #define TCSETSW2        _IOW('T', 0x2C, struct termios2)
 #define TCSETSF2        _IOW('T', 0x2D, struct termios2)
+#define TIOCGRS485      0x542E
+#define TIOCSRS485      0x542F
 #define TIOCGPTN        _IOR('T', 0x30, unsigned int)
                                 /* Get Pty Number (of pty-mux device) */
 #define TIOCSPTLCK      _IOW('T', 0x31, int)  /* Lock/unlock Pty */
diff --git a/include/linux/serial.h b/include/linux/serial.h
index deb714314fb1..1ea8d9265bf6 100644
--- a/include/linux/serial.h
+++ b/include/linux/serial.h
@@ -173,6 +173,22 @@ struct serial_icounter_struct {
         int reserved[9];
 };
 
+/*
+ * Serial interface for controlling RS485 settings on chips with suitable
+ * support. Set with TIOCSRS485 and get with TIOCGRS485 if supported by your
+ * platform. The set function returns the new state, with any unsupported bits
+ * reverted appropriately.
+ */
+
+struct serial_rs485 {
+        __u32   flags;                  /* RS485 feature flags */
+#define SER_RS485_ENABLED               (1 << 0)
+#define SER_RS485_RTS_ON_SEND           (1 << 1)
+#define SER_RS485_RTS_AFTER_SEND        (1 << 2)
+        __u32   delay_rts_before_send;  /* Milliseconds */
+        __u32   padding[6];             /* Memory is cheap, new structs
+                                           are a royal PITA .. */
+};
 
 #ifdef __KERNEL__
 #include <linux/compiler.h>