diff options
Diffstat (limited to 'drivers/tty/tty_ioctl.c')
| -rw-r--r-- | drivers/tty/tty_ioctl.c | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c index 75885d502749..507a25d692bb 100644 --- a/drivers/tty/tty_ioctl.c +++ b/drivers/tty/tty_ioctl.c @@ -280,6 +280,51 @@ int tty_termios_hw_change(const struct ktermios *a, const struct ktermios *b) EXPORT_SYMBOL(tty_termios_hw_change); /** + * tty_get_char_size - get size of a character + * @cflag: termios cflag value + * + * Get the size (in bits) of a character depending on @cflag's %CSIZE + * setting. + */ +unsigned char tty_get_char_size(unsigned int cflag) +{ + switch (cflag & CSIZE) { + case CS5: + return 5; + case CS6: + return 6; + case CS7: + return 7; + case CS8: + default: + return 8; + } +} +EXPORT_SYMBOL_GPL(tty_get_char_size); + +/** + * tty_get_frame_size - get size of a frame + * @cflag: termios cflag value + * + * Get the size (in bits) of a frame depending on @cflag's %CSIZE, %CSTOPB, + * and %PARENB setting. The result is a sum of character size, start and + * stop bits -- one bit each -- second stop bit (if set), and parity bit + * (if set). + */ +unsigned char tty_get_frame_size(unsigned int cflag) +{ + unsigned char bits = 2 + tty_get_char_size(cflag); + + if (cflag & CSTOPB) + bits++; + if (cflag & PARENB) + bits++; + + return bits; +} +EXPORT_SYMBOL_GPL(tty_get_frame_size); + +/** * tty_set_termios - update termios values * @tty: tty to update * @new_termios: desired new value |