| Message ID | 20210126135917.17545-1-johan@kernel.org |
|---|---|
| State | New |
| Headers | show |
| Series | USB: serial: ftdi_sio: fix FTX sub-integer prescaler | expand |
On Tue, Jan 26, 2021 at 02:59:17PM +0100, Johan Hovold wrote: > The most-significant bit of the sub-integer-prescaler index is set in > the high byte of the baudrate request wIndex also for FTX devices. > > This fixes rates like 1152000 which got mapped to 12 MBd. Hmm. I played around with this using an FT232H which has a 12 MHz clock so this example is off for FTX. I'll fix it up before applying. Johan
On Tue, Jan 26, 2021 at 03:11:15PM +0100, Johan Hovold wrote: > On Tue, Jan 26, 2021 at 02:59:17PM +0100, Johan Hovold wrote: > > The most-significant bit of the sub-integer-prescaler index is set in > > the high byte of the baudrate request wIndex also for FTX devices. > > > > This fixes rates like 1152000 which got mapped to 12 MBd. > > Hmm. I played around with this using an FT232H which has a 12 MHz clock > so this example is off for FTX. I'll fix it up before applying. Nope, false alarm, it still holds. Johan
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 94398f89e600..4168801b9595 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1386,8 +1386,9 @@ static int change_speed(struct tty_struct *tty, struct usb_serial_port *port) index_value = get_ftdi_divisor(tty, port); value = (u16)index_value; index = (u16)(index_value >> 16); - if ((priv->chip_type == FT2232C) || (priv->chip_type == FT2232H) || - (priv->chip_type == FT4232H) || (priv->chip_type == FT232H)) { + if (priv->chip_type == FT2232C || priv->chip_type == FT2232H || + priv->chip_type == FT4232H || priv->chip_type == FT232H || + priv->chip_type == FTX) { /* Probably the BM type needs the MSB of the encoded fractional * divider also moved like for the chips above. Any infos? */ index = (u16)((index << 8) | priv->interface);
The most-significant bit of the sub-integer-prescaler index is set in the high byte of the baudrate request wIndex also for FTX devices. This fixes rates like 1152000 which got mapped to 12 MBd. Reported-by: Vladimir <svv75@mail.ru> Link: https://bugzilla.kernel.org/show_bug.cgi?id=210351 Cc: stable@vger.kernel.org Signed-off-by: Johan Hovold <johan@kernel.org> --- drivers/usb/serial/ftdi_sio.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)