commit 399aa9a75ad372b301e5050f3653a297a767fdc4
author Lauri Hintsala <lauri.hintsala@bluegiga.com> Wed Aug 13 15:02:53 2014 +0300
committer Johan Hovold <johan@kernel.org> Mon Sep 01 12:04:17 2014 +0200
tree 9738bb249a31ba13cba86866cf641bdc915d7f7a
parent 69e273c0b0a3c337a521d083374c918dc52c666f

USB: pl2303: use divisors for unsupported baud rates

Use direct method for supported baud rates, otherwise use divisors.
Limit baud rate to 12 Mbaud with HX type.

This change has been tested to work with PL-2303HX at 115200, 500000,
1000000, 2000000, 2500000, 3000000 and 4000000 baud rates.

Signed-off-by: Lauri Hintsala <lauri.hintsala@bluegiga.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

drivers/usb/serial/pl2303.c

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index e9bad92..0f872e6 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -162,6 +162,9 @@
 		.max_baud_rate =	1228800,
 		.quirks =		PL2303_QUIRK_LEGACY,
 	},
+	[TYPE_HX] = {
+		.max_baud_rate =	12000000,
+	},
 };
 
 static int pl2303_vendor_read(struct usb_serial *serial, u16 value,
@@ -395,16 +398,14 @@
 	if (spriv->type->max_baud_rate)
 		baud = min_t(speed_t, baud, spriv->type->max_baud_rate);
 	/*
-	 * Set baud rate to nearest supported value.
-	 *
-	 * NOTE: Baud rate 500k can only be set using divisors.
+	 * Use direct method for supported baud rates, otherwise use divisors.
 	 */
 	baud_sup = pl2303_get_supported_baud_rate(baud);
 
-	if (baud == 500000)
-		baud = pl2303_encode_baud_rate_divisor(buf, baud);
+	if (baud == baud_sup)
+		baud = pl2303_encode_baud_rate_direct(buf, baud);
 	else
-		baud = pl2303_encode_baud_rate_direct(buf, baud_sup);
+		baud = pl2303_encode_baud_rate_divisor(buf, baud);
 
 	/* Save resulting baud rate */
 	tty_encode_baud_rate(tty, baud, baud);