1 files changed, 23 insertions, 4 deletions

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 30461fcc2206..1d33260de014 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -91,6 +91,7 @@ static const struct usb_device_id id_table[] = {
         { USB_DEVICE(SONY_VENDOR_ID, SONY_QN3USB_PRODUCT_ID) },
         { USB_DEVICE(SANWA_VENDOR_ID, SANWA_PRODUCT_ID) },
         { USB_DEVICE(ADLINK_VENDOR_ID, ADLINK_ND6530_PRODUCT_ID) },
+        { USB_DEVICE(WINCHIPHEAD_VENDOR_ID, WINCHIPHEAD_USBSER_PRODUCT_ID) },
         { }                                     /* Terminating entry */
 };
 
@@ -342,10 +343,28 @@ static void pl2303_set_termios(struct tty_struct *tty,
                                 baud = 6000000;
                 }
                 dbg("%s - baud set = %d", __func__, baud);
-                buf[0] = baud & 0xff;
-                buf[1] = (baud >> 8) & 0xff;
-                buf[2] = (baud >> 16) & 0xff;
-                buf[3] = (baud >> 24) & 0xff;
+                if (baud <= 115200) {
+                        buf[0] = baud & 0xff;
+                        buf[1] = (baud >> 8) & 0xff;
+                        buf[2] = (baud >> 16) & 0xff;
+                        buf[3] = (baud >> 24) & 0xff;
+                } else {
+                        /* apparently the formula for higher speeds is:
+                         * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
+                         */
+                        unsigned tmp = 12*1000*1000*32 / baud;
+                        buf[3] = 0x80;
+                        buf[2] = 0;
+                        buf[1] = (tmp >= 256);
+                        while (tmp >= 256) {
+                                tmp >>= 2;
+                                buf[1] <<= 1;
+                        }
+                        if (tmp > 256) {
+                                tmp %= 256;
+                        }
+                        buf[0] = tmp;
+                }
         }
 
         /* For reference buf[4]=0 is 1 stop bits */