diff options
author | Jiri Slaby <jslaby@suse.cz> | 2021-06-10 12:02:44 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-06-15 15:03:26 +0300 |
commit | 654ee49b7e0883e660be6e6e20876fc4cbdaadd1 (patch) | |
tree | 9e14c689a306e390ec13537316ad3e3166062c43 /drivers/tty/tty_ioctl.c | |
parent | fb524360f52228201b56149a138369da505141a2 (diff) |
tty: make tty_get_{char,frame}_size available
Many tty drivers contain code to compute bits count depending on termios
cflags. So extract this code from serial core to two separate tty helper
functions:
* tty_get_char_size -- only size of a character, without flags,
* tty_get_frame_size -- complete size of a frame including flags.
In the next patch, calls to these new functions replace many copies of
this code.
Note that we accept only cflag as a parameter. That's because some
callers like pch_uart_startup or sunsab_console_setup don't have at hand
termios which we could pass around.
Cc: Joe Perches <joe@perches.com>
Cc: Johan Hovold <johan@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20210610090247.2593-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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 |