From: Jiri Slaby <jirislaby@kernel.org>
To: Joe Perches <joe@perches.com>, gregkh@linuxfoundation.org
Cc: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 34/35] tty: make tty_get_byte_size available
Date: Thu, 6 May 2021 09:19:32 +0200 [thread overview]
Message-ID: <949f77aa-2429-3fe9-9163-5a7b2c5c499a@kernel.org> (raw)
In-Reply-To: <ef1bd57095e941560530be43806791966a6735ad.camel@perches.com>
On 06. 05. 21, 9:16, Joe Perches wrote:
> On Wed, 2021-05-05 at 11:19 +0200, Jiri Slaby wrote:
>> Many tty drivers contain code to compute bits count depending on termios
>> cflags. So extract this code from serial core to a separate tty helper
>> function called tty_get_byte_size.
> []
>> diff --git a/drivers/tty/tty_ioctl.c b/drivers/tty/tty_ioctl.c
> []
>> +/**
>> + * tty_get_byte_size - get size of a byte
>> + * @cflag: termios cflag value
>> + * @account_flags: account for start and stop bits, second stop bit (if
>> + * set), and parity (if set)
>> + *
>> + * Get the size of a byte in bits depending on @cflag. Depending on
>> + * @account_flags parameter, the result also accounts start and stop bits,
>> + * the second stop bit, and parity bit.
>> + */
>> +unsigned char tty_get_byte_size(unsigned int cflag, bool account_flags)
>> +{
>> + unsigned char bits = account_flags ? 2 : 0;
>> +
>> + /* byte size and parity */
>> + switch (cflag & CSIZE) {
>> + case CS5:
>> + bits += 5;
>> + break;
>> + case CS6:
>> + bits += 6;
>> + break;
>> + case CS7:
>> + bits += 7;
>> + break;
>> + case CS8:
>> + default:
>> + bits += 8;
>> + break;
>> + }
>> +
>> + if (account_flags && (cflag & CSTOPB))
>> + bits++;
>> +
>> + if (account_flags && (cflag & PARENB))
>> + bits++;
>> +
>> + return bits;
>> +}
>> +EXPORT_SYMBOL_GPL(tty_get_byte_size);
>
> Perhaps clearer not testing account_flags multiple times.
Right. Originally, I had account_start_stop, account_stop, and
account_parity parameters. But they were either all false or all true.
So I unified them to account_flags, but the code remained overly complex.
> unsigned char tty_get_byte_size(unsigned int cflag, bool account_flags)
> {
> unsigned char bits;
>
> /* byte size and parity */
> switch (cflag & CSIZE) {
> case CS5:
> bits = 5;
> break;
> case CS6:
> bits = 6;
> break;
> case CS7:
> bits = 7;
> break;
> case CS8:
> default:
> bits = 8;
> break;
> }
>
> if (account_flags) {
> bits += 2; /* start/stop bits */
>
> if (cflag & CSTOPB)
> bits++;
>
> if (cflag & PARENB)
> bits++;
> }
>
> return bits;
> }
>
>
thanks,
--
js
suse labs
next prev parent reply other threads:[~2021-05-06 7:19 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-05 9:18 [PATCH 00/35] tty cleanup for 5.14 Jiri Slaby
2021-05-05 9:18 ` [PATCH 01/35] tty: remove broken r3964 line discipline Jiri Slaby
2021-05-05 9:26 ` Greg KH
2021-05-05 9:18 ` [PATCH 02/35] n_tty: remove n_tty_receive_char wrapper Jiri Slaby
2021-05-05 9:18 ` [PATCH 03/35] n_tty: remove n_tty_receive_char_fast Jiri Slaby
2021-05-05 9:18 ` [PATCH 04/35] n_tty: drop n_tty_receive_buf_fast Jiri Slaby
2021-05-05 9:18 ` [PATCH 05/35] n_tty: drop parmrk_dbl from n_tty_receive_char Jiri Slaby
2021-05-05 9:18 ` [PATCH 06/35] n_tty: move lnext handling Jiri Slaby
2021-05-05 9:19 ` [PATCH 07/35] n_tty: make n_tty_receive_char_special return void Jiri Slaby
2021-05-05 9:19 ` [PATCH 08/35] n_tty: do only one cp dereference in n_tty_receive_buf_standard Jiri Slaby
2021-05-05 9:19 ` [PATCH 09/35] n_tty: invert TTY_NORMAL condition " Jiri Slaby
2021-05-05 9:19 ` [PATCH 10/35] n_tty: remove superfluous return from n_tty_receive_signal_char Jiri Slaby
2021-05-05 9:19 ` [PATCH 11/35] tty: make fp of tty_ldisc_ops::receive_buf{,2} const Jiri Slaby
2021-05-05 9:19 ` [PATCH 12/35] tty: cumulate and document tty_struct::flow* members Jiri Slaby
2021-05-05 9:19 ` [PATCH 13/35] tty: cumulate and document tty_struct::ctrl* members Jiri Slaby
2021-05-05 9:19 ` [PATCH 14/35] tty: set tty_ldisc_ops::num statically Jiri Slaby
2021-05-05 9:19 ` [PATCH 15/35] n_gsm: use goto-failpaths in gsm_init Jiri Slaby
2021-05-05 9:19 ` [PATCH 16/35] tty: make tty_ldisc_ops a param in tty_unregister_ldisc Jiri Slaby
2021-05-05 9:19 ` [PATCH 17/35] tty: drop tty_ldisc_ops::refcount Jiri Slaby
2021-05-05 9:19 ` [PATCH 18/35] tty: no checking of tty_unregister_ldisc Jiri Slaby
2021-05-05 9:19 ` [PATCH 19/35] tty: return void from tty_unregister_ldisc Jiri Slaby
2021-05-05 9:19 ` [PATCH 20/35] ti-st: use goto-failpath in st_core_init Jiri Slaby
2021-05-05 9:19 ` [PATCH 21/35] ti-st: use tty_write_room Jiri Slaby
2021-05-05 9:19 ` [PATCH 22/35] tty: make tty_operations::write_room return uint Jiri Slaby
2021-05-05 9:25 ` Geert Uytterhoeven
2021-05-05 10:34 ` Anton Ivanov
2021-05-05 10:43 ` David Sterba
2021-05-05 11:53 ` Max Filippov
2021-05-05 12:15 ` Alex Elder
2021-05-10 11:27 ` Laurentiu Tudor
2021-05-05 9:19 ` [PATCH 23/35] USB: serial: make usb_serial_driver::write_room " Jiri Slaby
2021-05-19 9:07 ` Johan Hovold
2021-05-05 9:19 ` [PATCH 24/35] tty: make tty_buffer_space_avail " Jiri Slaby
2021-05-05 9:19 ` [PATCH 25/35] tty: remove tty_operations::chars_in_buffer for non-buffering Jiri Slaby
2021-05-05 11:51 ` Max Filippov
2021-05-06 5:47 ` Jiri Slaby
2021-05-06 5:56 ` Greg KH
2021-05-05 9:19 ` [PATCH 26/35] tty: make tty_operations::chars_in_buffer return uint Jiri Slaby
2021-05-05 10:34 ` Anton Ivanov
2021-05-05 10:43 ` David Sterba
2021-05-05 9:19 ` [PATCH 27/35] serial: make usb_serial_driver::chars_in_buffer " Jiri Slaby
2021-05-19 9:09 ` Johan Hovold
2021-05-05 9:19 ` [PATCH 28/35] nozomi: simplify ntty_chars_in_buffer Jiri Slaby
2021-05-05 9:19 ` [PATCH 29/35] USB: serial: digi_acceleport, simplify digi_chars_in_buffer Jiri Slaby
2021-05-19 9:11 ` Johan Hovold
2021-05-05 9:19 ` [PATCH 30/35] tty: remove empty tty_operations::flush_buffer Jiri Slaby
2021-05-05 9:19 ` [PATCH 31/35] tty: remove empty tty_operations::set_termios Jiri Slaby
2021-05-05 10:34 ` Anton Ivanov
2021-05-05 9:19 ` [PATCH 32/35] isdn: capi, remove optional tty ops Jiri Slaby
2021-05-05 9:19 ` [PATCH 33/35] isdn: capi, drop useless pr_debugs Jiri Slaby
2021-05-05 9:19 ` [PATCH 34/35] tty: make tty_get_byte_size available Jiri Slaby
2021-05-06 7:16 ` Joe Perches
2021-05-06 7:19 ` Jiri Slaby [this message]
[not found] ` <CAHp75Vfq6ABW7ukwaKmZOF2DszmuHD28S=wcLcFowvRdXTnWmg@mail.gmail.com>
2021-05-06 8:31 ` Jiri Slaby
2021-05-06 9:33 ` Andy Shevchenko
2021-05-06 8:35 ` Joe Perches
2021-05-10 7:00 ` [PATCH v2 " Jiri Slaby
2021-05-10 9:47 ` Johan Hovold
2021-05-13 7:24 ` Jiri Slaby
2021-05-13 9:41 ` Johan Hovold
2021-05-05 9:19 ` [PATCH 35/35] tty: make use of tty_get_byte_size Jiri Slaby
2021-05-10 9:59 ` Johan Hovold
2021-05-13 15:04 ` [PATCH 00/35] tty cleanup for 5.14 Greg KH
2021-05-13 16:20 ` Johan Hovold
2021-05-13 16:29 ` Greg KH
2021-05-14 8:11 ` Johan Hovold
2021-06-10 9:02 ` [PATCH v3 1/4] tty: make tty_get_{char,frame}_size available Jiri Slaby
2021-06-10 9:02 ` [PATCH v3 2/4] mxs-auart: redefine AUART_LINECTRL_WLEN to accept bits count Jiri Slaby
2021-06-10 9:02 ` [PATCH v3 3/4] cypress_m8: switch data_bits to real character bits Jiri Slaby
2021-06-10 9:02 ` [PATCH v3 4/4] tty: make use of tty_get_{char,frame}_size Jiri Slaby
2021-06-10 15:15 ` Alex Elder
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=949f77aa-2429-3fe9-9163-5a7b2c5c499a@kernel.org \
--to=jirislaby@kernel.org \
--cc=gregkh@linuxfoundation.org \
--cc=joe@perches.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-serial@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).