From: Johan Hovold johan@kernel.org
commit 979d9cbe75b922ab1695b8ad5576115774f72e62 upstream.
The latest chip family (HXN) apparently does not support setting the line speed using divisors and instead needs to use the direct encoding scheme for all rates.
This specifically enables 50, 110, 134, 200 bps and other rates not supported by the original chip type.
Fixes: ebd09f1cd417 ("USB: serial: pl2303: add support for PL2303HXN") Cc: stable@vger.kernel.org # 5.5 Cc: Charles Yeh charlesyeh522@gmail.com Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/serial/pl2303.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/drivers/usb/serial/pl2303.c +++ b/drivers/usb/serial/pl2303.c @@ -183,6 +183,7 @@ struct pl2303_type_data { speed_t max_baud_rate; unsigned long quirks; unsigned int no_autoxonxoff:1; + unsigned int no_divisors:1; };
struct pl2303_serial_private { @@ -209,6 +210,7 @@ static const struct pl2303_type_data pl2 }, [TYPE_HXN] = { .max_baud_rate = 12000000, + .no_divisors = true, }, };
@@ -571,8 +573,12 @@ static void pl2303_encode_baud_rate(stru baud = min_t(speed_t, baud, spriv->type->max_baud_rate); /* * Use direct method for supported baud rates, otherwise use divisors. + * Newer chip types do not support divisor encoding. */ - baud_sup = pl2303_get_supported_baud_rate(baud); + if (spriv->type->no_divisors) + baud_sup = baud; + else + baud_sup = pl2303_get_supported_baud_rate(baud);
if (baud == baud_sup) baud = pl2303_encode_baud_rate_direct(buf, baud);