USB: pl2303: clean up baud-rate handling

Clean up baud-rate handling somewhat.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index c15d64d6e1e765f7a5e5e11a9c6fca533bc51ac3..dd59c640edcc3f5bb4f5080cf416d37b0b3bfa2e 100644 (file)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -29,6 +29,7 @@
 #include <linux/uaccess.h>
 #include <linux/usb.h>
 #include <linux/usb/serial.h>
+#include <asm/unaligned.h>
 #include "pl2303.h"
 
 /*
@@ -275,65 +276,56 @@ static void pl2303_encode_baudrate(struct tty_struct *tty,
        struct usb_serial *serial = port->serial;
        struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
        int baud;
-       int baud_floor, baud_ceil;
-       int k;
+       int i;
 
-       /* NOTE: Only the values defined in baud_sup are supported !
+       /*
+        * NOTE: Only the values defined in baud_sup are supported!
         *       => if unsupported values are set, the PL2303 seems to use
         *          9600 baud (at least my PL2303X always does)
         */
        baud = tty_get_baud_rate(tty);
        dev_dbg(&port->dev, "baud requested = %d\n", baud);
-       if (baud) {
-               /* Set baudrate to nearest supported value */
-               for (k=0; k<ARRAY_SIZE(baud_sup); k++) {
-                       if (baud_sup[k] / baud) {
-                               baud_ceil = baud_sup[k];
-                               if (k==0) {
-                                       baud = baud_ceil;
-                               } else {
-                                       baud_floor = baud_sup[k-1];
-                                       if ((baud_ceil % baud)
-                                           > (baud % baud_floor))
-                                               baud = baud_floor;
-                                       else
-                                               baud = baud_ceil;
-                               }
-                               break;
-                       }
-               }
-               if (baud > 1228800) {
-                       /* type_0, type_1 only support up to 1228800 baud */
-                       if (spriv->type != HX)
-                               baud = 1228800;
-                       else if (baud > 6000000)
-                               baud = 6000000;
-               }
-               dev_dbg(&port->dev, "baud set = %d\n", baud);
-               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;
-                       }
-                       buf[0] = tmp;
+       if (!baud)
+               return;
+
+       /* Set baudrate to nearest supported value */
+       for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) {
+               if (baud_sup[i] > baud)
+                       break;
+       }
+
+       if (i == ARRAY_SIZE(baud_sup))
+               baud = baud_sup[i - 1];
+       else if (i > 0 && (baud_sup[i] - baud) > (baud - baud_sup[i - 1]))
+               baud = baud_sup[i - 1];
+       else
+               baud = baud_sup[i];
+
+       /* type_0, type_1 only support up to 1228800 baud */
+       if (spriv->type != HX)
+               baud = max_t(int, baud, 1228800);
+
+       if (baud <= 115200) {
+               put_unaligned_le32(baud, buf);
+       } else {
+               /*
+                * Apparently the formula for higher speeds is:
+                * baudrate = 12M * 32 / (2^buf[1]) / buf[0]
+                */
+               unsigned tmp = 12000000 * 32 / baud;
+               buf[3] = 0x80;
+               buf[2] = 0;
+               buf[1] = (tmp >= 256);
+               while (tmp >= 256) {
+                       tmp >>= 2;
+                       buf[1] <<= 1;
                }
+               buf[0] = tmp;
        }
 
        /* Save resulting baud rate */
-       if (baud)
-               tty_encode_baud_rate(tty, baud, baud);
+       tty_encode_baud_rate(tty, baud, baud);
+       dev_dbg(&port->dev, "baud set = %d\n", baud);
 }
 
 static void pl2303_set_termios(struct tty_struct *tty,