USB: pl2303: refactor baud-rate table lookup

Refactor supported baud-rate table lookup.

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 8d792af..9a95b92 100644 (file)
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -311,31 +311,19 @@ static int pl2303_set_control_lines(struct usb_serial_port *port, u8 value)
        return retval;
 }
 
-static void pl2303_encode_baud_rate(struct tty_struct *tty,
-                                       struct usb_serial_port *port,
-                                       u8 buf[4])
+/*
+ * Returns the nearest supported baud rate.
+ */
+static speed_t pl2303_get_supported_baud_rate(speed_t baud)
 {
-       const speed_t baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400, 3600,
-                                4800, 7200, 9600, 14400, 19200, 28800, 38400,
-                                57600, 115200, 230400, 460800, 500000, 614400,
-                                921600, 1228800, 2457600, 3000000, 6000000 };
+       static const speed_t baud_sup[] = {
+               75, 150, 300, 600, 1200, 1800, 2400, 3600, 4800, 7200, 9600,
+               14400, 19200, 28800, 38400, 57600, 115200, 230400, 460800,
+               500000, 614400, 921600, 1228800, 2457600, 3000000, 6000000
+       };
 
-       struct usb_serial *serial = port->serial;
-       struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
-       speed_t baud;
-       int i;
+       unsigned i;
 
-       /*
-        * 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 = %u\n", baud);
-       if (!baud)
-               return;
-
-       /* Set baud rate to nearest supported value */
        for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) {
                if (baud_sup[i] > baud)
                        break;
@@ -348,6 +336,29 @@ static void pl2303_encode_baud_rate(struct tty_struct *tty,
        else
                baud = baud_sup[i];
 
+       return baud;
+}
+
+static void pl2303_encode_baud_rate(struct tty_struct *tty,
+                                       struct usb_serial_port *port,
+                                       u8 buf[4])
+{
+       struct usb_serial *serial = port->serial;
+       struct pl2303_serial_private *spriv = usb_get_serial_data(serial);
+       speed_t baud;
+
+       baud = tty_get_baud_rate(tty);
+       dev_dbg(&port->dev, "baud requested = %u\n", baud);
+       if (!baud)
+               return;
+       /*
+        * Set baud rate to nearest supported value.
+        *
+        * NOTE: If unsupported values are set directly, the PL2303 seems to
+        *       use 9600 baud.
+        */
+       baud = pl2303_get_supported_baud_rate(baud);
+
        if (spriv->type->max_baud_rate)
                baud = min_t(speed_t, baud, spriv->type->max_baud_rate);