diff options
| author | Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de> | 2011-07-22 10:41:15 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2011-08-08 12:34:48 -0700 |
| commit | 0ee404ccf1c63aa25363940d474c3c03f8d7e882 (patch) | |
| tree | a59624c6f19fa45254546cd15f9fb0d3572ca523 /drivers/usb/serial/ftdi_sio.c | |
| parent | 17d3e145a4ad680b3d1b1c30d0696a5bbb2b65c4 (diff) | |
usb: serial: ftdi_sio.c: For the FT232H FTDI_SIO_SET_BAUDRATE_REQUEST, index needs to be shifted too
the recent addition of the FT232H showed that baudrate was set wrong. See
gmane.linux.usb.general: "[ftdi_sio] FT232H support". With the old code,
the MSB of the 4 encoded fractional divider bits and more important the
clock predivider bits got lost. Adding the FT232H to the code patch were
these bits are shifted solves the problem. I verified baud rates with a
scope now.
I suspect, that the BM device probably needs these bits shifted too. But
there is no predivider bit, so this is not obvious, and a missing MSB of the
encoded fractional divider only shifts the resulting baudrate minimal.
The AM has only 3 bits of encoded fractional divider, so it is not impacted.
I have no BM device to test, so I only added a comment and left the code for
the BM untouched.
Signed-off-by: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/serial/ftdi_sio.c')
| -rw-r--r-- | drivers/usb/serial/ftdi_sio.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/usb/serial/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c index 9afb3614373..7d42f61bd7a 100644 --- a/drivers/usb/serial/ftdi_sio.c +++ b/drivers/usb/serial/ftdi_sio.c @@ -1205,7 +1205,10 @@ static int change_speed(struct tty_struct *tty, struct usb_serial_port *port) urb_index_value = get_ftdi_divisor(tty, port); urb_value = (__u16)urb_index_value; urb_index = (__u16)(urb_index_value >> 16); - if (priv->interface) { /* FT2232C */ + if ((priv->chip_type == FT2232C) || (priv->chip_type == FT2232H) || + (priv->chip_type == FT4232H) || (priv->chip_type == FT232H)) { + /* Probably the BM type needs the MSB of the encoded fractional + * divider also moved like for the chips above. Any infos? */ urb_index = (__u16)((urb_index << 8) | priv->interface); } |