diff options
| author | Johan Hovold <johan@kernel.org> | 2021-01-21 11:29:22 +0100 |
|---|---|---|
| committer | Johan Hovold <johan@kernel.org> | 2021-01-26 16:17:01 +0100 |
| commit | 55317e22391ffc5aa297c3a617c8c3302fb184b6 (patch) | |
| tree | 970fa630d9ab5851bf85e4511eb5932cbd49eeef /drivers/usb | |
| parent | 0d05d7d913892cd093acc5a0ac884ebab9fda67c (diff) | |
| download | linux-55317e22391ffc5aa297c3a617c8c3302fb184b6.tar.bz2 | |
USB: serial: xr: fix B0 handling
Fix up B0 handling which should leave the baud rate unchanged and
specifically not report back a non-B0 rate when B0 is requested; must
temporarily disable hardware flow control so that RTS can be deasserted;
and should reassert DTR/RTS when moving from B0.
Fixes: c2d405aa86b4 ("USB: serial: add MaxLinear/Exar USB to Serial driver")
Signed-off-by: Johan Hovold <johan@kernel.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/serial/xr_serial.c | 23 |
1 files changed, 14 insertions, 9 deletions
diff --git a/drivers/usb/serial/xr_serial.c b/drivers/usb/serial/xr_serial.c index f67e7dba9509..483d07dee19d 100644 --- a/drivers/usb/serial/xr_serial.c +++ b/drivers/usb/serial/xr_serial.c @@ -341,8 +341,11 @@ static int xr_set_baudrate(struct tty_struct *tty, u16 tx_mask, rx_mask; int ret; - baud = clamp(tty->termios.c_ospeed, XR21V141X_MIN_SPEED, - XR21V141X_MAX_SPEED); + baud = tty->termios.c_ospeed; + if (!baud) + return 0; + + baud = clamp(baud, XR21V141X_MIN_SPEED, XR21V141X_MAX_SPEED); divisor = XR_INT_OSC_HZ / baud; idx = ((32 * XR_INT_OSC_HZ) / baud) & 0x1f; tx_mask = xr21v141x_txrx_clk_masks[idx].tx; @@ -399,7 +402,8 @@ static int xr_set_baudrate(struct tty_struct *tty, } static void xr_set_flow_mode(struct tty_struct *tty, - struct usb_serial_port *port) + struct usb_serial_port *port, + struct ktermios *old_termios) { u8 flow, gpio_mode; int ret; @@ -411,7 +415,7 @@ static void xr_set_flow_mode(struct tty_struct *tty, /* Set GPIO mode for controlling the pins manually by default. */ gpio_mode &= ~XR21V141X_UART_MODE_GPIO_MASK; - if (C_CRTSCTS(tty)) { + if (C_CRTSCTS(tty) && C_BAUD(tty) != B0) { dev_dbg(&port->dev, "Enabling hardware flow ctrl\n"); gpio_mode |= XR21V141X_UART_MODE_RTS_CTS; flow = XR21V141X_UART_FLOW_MODE_HW; @@ -438,6 +442,11 @@ static void xr_set_flow_mode(struct tty_struct *tty, xr_uart_enable(port); xr_set_reg_uart(port, XR21V141X_REG_GPIO_MODE, gpio_mode); + + if (C_BAUD(tty) == B0) + xr_dtr_rts(port, 0); + else if (old_termios && (old_termios->c_cflag & CBAUD) == B0) + xr_dtr_rts(port, 1); } static void xr_set_termios(struct tty_struct *tty, @@ -493,11 +502,7 @@ static void xr_set_termios(struct tty_struct *tty, if (ret) return; - /* If baud rate is B0, clear DTR and RTS */ - if (C_BAUD(tty) == B0) - xr_dtr_rts(port, 0); - - xr_set_flow_mode(tty, port); + xr_set_flow_mode(tty, port, old_termios); } static int xr_open(struct tty_struct *tty, struct usb_serial_port *port) |