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USB: pl2303: use divisors for unsupported baud rates

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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>
This commit is contained in:
Lauri Hintsala 2014-08-13 15:02:53 +03:00 committed by Johan Hovold
parent 69e273c0b0
commit 399aa9a75a
1 changed files with 7 additions and 6 deletions
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13
drivers/usb/serial/pl2303.c
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@ -162,6 +162,9 @@ static const struct pl2303_type_data pl2303_type_data[TYPE_COUNT] = {
.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 @@ static void pl2303_encode_baud_rate(struct tty_struct *tty,
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);