diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/serial/cp210x.c | 71 |
1 files changed, 57 insertions, 14 deletions
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index ad7599ed5df9..2d2d23933ba6 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -39,6 +39,8 @@ static void cp210x_get_termios(struct tty_struct *, struct usb_serial_port *port); static void cp210x_get_termios_port(struct usb_serial_port *port, unsigned int *cflagp, unsigned int *baudp); +static void cp210x_change_speed(struct tty_struct *, struct usb_serial_port *, + struct ktermios *); static void cp210x_set_termios(struct tty_struct *, struct usb_serial_port *, struct ktermios*); static int cp210x_tiocmget(struct tty_struct *); @@ -576,11 +578,62 @@ static void cp210x_get_termios_port(struct usb_serial_port *port, *cflagp = cflag; } +/* + * CP2101 supports the following baud rates: + * + * 300, 600, 1200, 1800, 2400, 4800, 7200, 9600, 14400, 19200, 28800, + * 38400, 56000, 57600, 115200, 128000, 230400, 460800, 921600 + * + * CP2102 and CP2103 support the following additional rates: + * + * 4000, 16000, 51200, 64000, 76800, 153600, 250000, 256000, 500000, + * 576000 + * + * The device will map a requested rate to a supported one, but the result + * of requests for rates greater than 1053257 is undefined (see AN205). + * + * CP2104, CP2105 and CP2110 support most rates up to 2M, 921k and 1M baud, + * respectively, with an error less than 1%. The actual rates are determined + * by + * + * div = round(freq / (2 x prescale x request)) + * actual = freq / (2 x prescale x div) + * + * For CP2104 and CP2105 freq is 48Mhz and prescale is 4 for request <= 365bps + * or 1 otherwise. + * For CP2110 freq is 24Mhz and prescale is 4 for request <= 300bps or 1 + * otherwise. + */ +static void cp210x_change_speed(struct tty_struct *tty, + struct usb_serial_port *port, struct ktermios *old_termios) +{ + u32 baud; + + baud = tty->termios->c_ospeed; + + /* This maps the requested rate to a rate valid on cp2102 or cp2103. + * + * NOTE: B0 is not implemented. + */ + baud = cp210x_quantise_baudrate(baud); + + dbg("%s - setting baud rate to %u", __func__, baud); + if (cp210x_set_config(port, CP210X_SET_BAUDRATE, &baud, + sizeof(baud))) { + dev_warn(&port->dev, "failed to set baud rate to %u\n", baud); + if (old_termios) + baud = old_termios->c_ospeed; + else + baud = 9600; + } + + tty_encode_baud_rate(tty, baud, baud); +} + static void cp210x_set_termios(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios) { unsigned int cflag, old_cflag; - u32 baud; unsigned int bits; unsigned int modem_ctl[4]; @@ -591,19 +644,9 @@ static void cp210x_set_termios(struct tty_struct *tty, cflag = tty->termios->c_cflag; old_cflag = old_termios->c_cflag; - baud = cp210x_quantise_baudrate(tty_get_baud_rate(tty)); - - /* If the baud rate is to be updated*/ - if (baud != tty_termios_baud_rate(old_termios) && baud != 0) { - dbg("%s - Setting baud rate to %d baud", __func__, - baud); - if (cp210x_set_config(port, CP210X_SET_BAUDRATE, &baud, sizeof(baud))) { - dbg("Baud rate requested not supported by device"); - baud = tty_termios_baud_rate(old_termios); - } - } - /* Report back the resulting baud rate */ - tty_encode_baud_rate(tty, baud, baud); + + if (tty->termios->c_ospeed != old_termios->c_ospeed) + cp210x_change_speed(tty, port, old_termios); /* If the number of data bits is to be updated */ if ((cflag & CSIZE) != (old_cflag & CSIZE)) { |