diff options
| -rw-r--r-- | drivers/usb/serial/cp210x.c | 50 |
1 files changed, 27 insertions, 23 deletions
diff --git a/drivers/usb/serial/cp210x.c b/drivers/usb/serial/cp210x.c index 3778685c7b99..957406aac9bd 100644 --- a/drivers/usb/serial/cp210x.c +++ b/drivers/usb/serial/cp210x.c @@ -230,6 +230,7 @@ struct cp210x_serial_private { #endif u8 partnum; speed_t max_speed; + bool use_actual_rate; }; struct cp210x_port_private { @@ -457,15 +458,6 @@ struct cp210x_gpio_write { u8 state; } __packed; -static bool cp210x_is_cp2102n(struct usb_serial *serial) -{ - struct cp210x_serial_private *priv = usb_get_serial_data(serial); - - return (priv->partnum == CP210X_PARTNUM_CP2102N_QFN28) || - (priv->partnum == CP210X_PARTNUM_CP2102N_QFN24) || - (priv->partnum == CP210X_PARTNUM_CP2102N_QFN20); -} - /* * Helper to get interface number when we only have struct usb_serial. */ @@ -1036,6 +1028,23 @@ static speed_t cp210x_get_an205_rate(speed_t baud) return cp210x_an205_table1[i].rate; } +static speed_t cp210x_get_actual_rate(struct usb_serial *serial, speed_t baud) +{ + struct cp210x_serial_private *priv = usb_get_serial_data(serial); + unsigned int prescale = 1; + unsigned int div; + + baud = clamp(baud, 300u, priv->max_speed); + + if (baud <= 365) + prescale = 4; + + div = DIV_ROUND_CLOSEST(48000000, 2 * prescale * baud); + baud = 48000000 / (2 * prescale * div); + + return baud; +} + /* * CP2101 supports the following baud rates: * @@ -1072,25 +1081,17 @@ static void cp210x_change_speed(struct tty_struct *tty, baud = tty->termios.c_ospeed; /* - * This maps the requested rate to the actual rate on cp2102n, a valid - * rate on cp2102 or cp2103, or to an arbitrary rate in - * [1M, max_speed]. + * This maps the requested rate to the actual rate, a valid rate on + * cp2102 or cp2103, or to an arbitrary rate in [1M, max_speed]. * * NOTE: B0 is not implemented. */ - if (cp210x_is_cp2102n(serial)) { - int clk_div; - int prescaler; - - baud = clamp(baud, 300u, priv->max_speed); - prescaler = (baud <= 365) ? 4 : 1; - clk_div = DIV_ROUND_CLOSEST(48000000, 2 * prescaler * baud); - baud = 48000000 / (2 * prescaler * clk_div); - } else if (baud < 1000000) { + if (priv->use_actual_rate) + baud = cp210x_get_actual_rate(serial, baud); + else if (baud < 1000000) baud = cp210x_get_an205_rate(baud); - } else if (baud > priv->max_speed) { + else if (baud > priv->max_speed) baud = priv->max_speed; - } dev_dbg(&port->dev, "%s - setting baud rate to %u\n", __func__, baud); if (cp210x_write_u32_reg(port, CP210X_SET_BAUDRATE, baud)) { @@ -1524,6 +1525,7 @@ static int cp210x_port_remove(struct usb_serial_port *port) static void cp210x_init_max_speed(struct usb_serial *serial) { struct cp210x_serial_private *priv = usb_get_serial_data(serial); + bool use_actual_rate = false; speed_t max; switch (priv->partnum) { @@ -1547,6 +1549,7 @@ static void cp210x_init_max_speed(struct usb_serial *serial) case CP210X_PARTNUM_CP2102N_QFN28: case CP210X_PARTNUM_CP2102N_QFN24: case CP210X_PARTNUM_CP2102N_QFN20: + use_actual_rate = true; max = 3000000; break; default: @@ -1555,6 +1558,7 @@ static void cp210x_init_max_speed(struct usb_serial *serial) } priv->max_speed = max; + priv->use_actual_rate = use_actual_rate; } static int cp210x_attach(struct usb_serial *serial) |