diff options
| author | Florian Zumbiehl <florz@florz.de> | 2018-05-20 02:23:12 +0200 |
|---|---|---|
| committer | Johan Hovold <johan@kernel.org> | 2018-05-22 10:08:05 +0200 |
| commit | 7041d9c3f01b365daa50340a5d2dce84a09ea813 (patch) | |
| tree | 439804d40c9b17948675344eb1b38d7ecac8a5f3 /drivers/usb | |
| parent | 7b0c6b38c4f9f9736ccd41363b3cfd7143e1f823 (diff) | |
| download | linux-7041d9c3f01b365daa50340a5d2dce84a09ea813.tar.gz | |
USB: serial: pl2303: add support for tx xon/xoff flow control
Support hardware-level Xon/Xoff flow control in transmit direction with
pl2303.
I only know how to get the hardware to do IXON/!IXANY with ^S/^Q as control
characters, so I preserve the old behaviour for all other cases.
Signed-off-by: Florian Zumbiehl <florz@florz.de>
[ johan: rewrite logic using pl2303_termios_change() helper ]
Signed-off-by: Johan Hovold <johan@kernel.org>
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/serial/pl2303.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c index 46dd09da2434..5d1a1931967e 100644 --- a/drivers/usb/serial/pl2303.c +++ b/drivers/usb/serial/pl2303.c @@ -533,6 +533,17 @@ static int pl2303_set_line_request(struct usb_serial_port *port, return 0; } +static bool pl2303_termios_change(const struct ktermios *a, const struct ktermios *b) +{ + bool ixon_change; + + ixon_change = ((a->c_iflag ^ b->c_iflag) & (IXON | IXANY)) || + a->c_cc[VSTART] != b->c_cc[VSTART] || + a->c_cc[VSTOP] != b->c_cc[VSTOP]; + + return tty_termios_hw_change(a, b) || ixon_change; +} + static void pl2303_set_termios(struct tty_struct *tty, struct usb_serial_port *port, struct ktermios *old_termios) { @@ -544,7 +555,7 @@ static void pl2303_set_termios(struct tty_struct *tty, int ret; u8 control; - if (old_termios && !tty_termios_hw_change(&tty->termios, old_termios)) + if (old_termios && !pl2303_termios_change(&tty->termios, old_termios)) return; buf = kzalloc(7, GFP_KERNEL); @@ -662,6 +673,9 @@ static void pl2303_set_termios(struct tty_struct *tty, pl2303_vendor_write(serial, 0x0, 0x41); else pl2303_vendor_write(serial, 0x0, 0x61); + } else if (I_IXON(tty) && !I_IXANY(tty) && START_CHAR(tty) == 0x11 && + STOP_CHAR(tty) == 0x13) { + pl2303_vendor_write(serial, 0x0, 0xc0); } else { pl2303_vendor_write(serial, 0x0, 0x0); } |