diff options
Diffstat (limited to 'drivers/usb/serial/ch341.c')
| -rw-r--r-- | drivers/usb/serial/ch341.c | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c index d10e4c4848a0..7cc36f84821f 100644 --- a/drivers/usb/serial/ch341.c +++ b/drivers/usb/serial/ch341.c @@ -63,6 +63,7 @@ #define CH341_REG_DIVISOR 0x13 #define CH341_REG_LCR 0x18 #define CH341_REG_LCR2 0x25 +#define CH341_REG_FLOW_CTL 0x27 #define CH341_NBREAK_BITS 0x01 @@ -77,6 +78,9 @@ #define CH341_LCR_CS6 0x01 #define CH341_LCR_CS5 0x00 +#define CH341_FLOW_CTL_NONE 0x00 +#define CH341_FLOW_CTL_RTSCTS 0x01 + #define CH341_QUIRK_LIMITED_PRESCALER BIT(0) #define CH341_QUIRK_SIMULATE_BREAK BIT(1) @@ -478,6 +482,28 @@ err_kill_interrupt_urb: return r; } +static void ch341_set_flow_control(struct tty_struct *tty, + struct usb_serial_port *port, + const struct ktermios *old_termios) +{ + u16 flow_ctl; + int r; + + if (C_CRTSCTS(tty)) + flow_ctl = CH341_FLOW_CTL_RTSCTS; + else + flow_ctl = CH341_FLOW_CTL_NONE; + + r = ch341_control_out(port->serial->dev, + CH341_REQ_WRITE_REG, + (CH341_REG_FLOW_CTL << 8) | CH341_REG_FLOW_CTL, + (flow_ctl << 8) | flow_ctl); + if (r < 0 && old_termios) { + tty->termios.c_cflag &= ~CRTSCTS; + tty->termios.c_cflag |= (old_termios->c_cflag & CRTSCTS); + } +} + /* Old_termios contains the original termios settings and * tty->termios contains the new setting to be used. */ @@ -546,6 +572,8 @@ static void ch341_set_termios(struct tty_struct *tty, spin_unlock_irqrestore(&priv->lock, flags); ch341_set_handshake(port->serial->dev, priv->mcr); + + ch341_set_flow_control(tty, port, old_termios); } /* @@ -632,13 +660,12 @@ restore: static int ch341_break_ctl(struct tty_struct *tty, int break_state) { - const uint16_t ch341_break_reg = - ((uint16_t) CH341_REG_LCR << 8) | CH341_REG_BREAK; + const u16 ch341_break_reg = (CH341_REG_LCR << 8) | CH341_REG_BREAK; struct usb_serial_port *port = tty->driver_data; struct ch341_private *priv = usb_get_serial_port_data(port); + u16 reg_contents; + u8 break_reg[2]; int r; - uint16_t reg_contents; - uint8_t break_reg[2]; if (priv->quirks & CH341_QUIRK_SIMULATE_BREAK) return ch341_simulate_break(tty, break_state); |