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-rw-r--r--drivers/usb/serial/pl2303.c40
1 files changed, 38 insertions, 2 deletions
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 4cbe59c4ae7..82055b07e02 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -528,6 +528,12 @@ static void pl2303_set_termios(struct tty_struct *tty,
int baud;
int i;
u8 control;
+ const int baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400, 3600,
+ 4800, 7200, 9600, 14400, 19200, 28800, 38400,
+ 57600, 115200, 230400, 460800, 614400,
+ 921600, 1228800, 2457600, 3000000, 6000000 };
+ int baud_floor, baud_ceil;
+ int k;
dbg("%s - port %d", __func__, port->number);
@@ -573,9 +579,39 @@ static void pl2303_set_termios(struct tty_struct *tty,
dbg("%s - data bits = %d", __func__, buf[6]);
}
+ /* For reference buf[0]:buf[3] baud rate value */
+ /* 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);
- dbg("%s - baud = %d", __func__, baud);
+ dbg("%s - baud requested = %d", __func__, 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 (priv->type != HX)
+ baud = 1228800;
+ else if (baud > 6000000)
+ baud = 6000000;
+ }
+ dbg("%s - baud set = %d", __func__, baud);
buf[0] = baud & 0xff;
buf[1] = (baud >> 8) & 0xff;
buf[2] = (baud >> 16) & 0xff;
@@ -648,7 +684,7 @@ static void pl2303_set_termios(struct tty_struct *tty,
pl2303_vendor_write(0x0, 0x0, serial);
}
- /* FIXME: Need to read back resulting baud rate */
+ /* Save resulting baud rate */
if (baud)
tty_encode_baud_rate(tty, baud, baud);