linux/drivers/tty
Jan Kundrát d584b65c0d serial: max310x: use a batch write op for UART transmit
The transmit register supports batched writes. The key is simply to keep
sending additional bytes up to the FIFO size in the same SPI
transaction with the CS pin still being held low.

This duplicates the regmap infrastructure to a certain extent. There are
some provisions for multiple writes in there, but there does not appear
to be any support for those writes which are destined to the *same*
register (and also no standard for SPI bus transfers of these, anyway).

This patch does not solve every case (if the UART xmit circular buffer
wraps around, we're still doing two SPI transactions), but at least
it's not one-byte-per-transaction anymore.

This change does not touch the receive path at this time. Doing that in
the generic case appears to be impossible in the general case, because
the chips' status register contains data about the *current* byte in the
HW's Rx FIFO. We cannot read these two registers in one go,
unfortunately.

Signed-off-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-12-19 09:59:02 +01:00
..
hvc TTY/Serial patches for 4.15-rc1 2017-11-13 21:05:31 -08:00
ipwireless treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
serdev serdev: ttyport: do not used keyed wakeup in write_wakeup 2017-12-18 12:25:14 +01:00
serial serial: max310x: use a batch write op for UART transmit 2017-12-19 09:59:02 +01:00
vt tty: vt: replace _manual_ swap with swap macro in set_selection 2017-11-28 15:32:32 +01:00
Kconfig tty: goldfish: Enable 'earlycon' only if built-in 2017-12-15 20:27:44 +01:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
amiserial.c tty: add SPDX identifiers to all remaining files in drivers/tty/ 2017-11-08 13:08:12 +01:00
bfin_jtag_comm.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
cyclades.c treewide: Switch DEFINE_TIMER callbacks to struct timer_list * 2017-11-21 15:57:05 -08:00
ehv_bytechan.c tty: ehv_bytechan: fix spelling mistake 2017-11-08 14:27:10 +01:00
goldfish.c tty: goldfish: Enable 'earlycon' only if built-in 2017-12-15 20:27:44 +01:00
isicom.c tty/isicom: Fix a possible sleep-in-atomic bug in WaitTillCardIsFree 2017-12-15 20:24:14 +01:00
metag_da.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
mips_ejtag_fdc.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
moxa.c tty: moxa: Add support for CMSPAR 2017-11-28 15:32:33 +01:00
moxa.h tty: moxa: Add support for CMSPAR 2017-11-28 15:32:33 +01:00
mxser.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
mxser.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
n_gsm.c tty: n_gsm: remove redundant pointer gsm 2017-11-28 15:32:32 +01:00
n_hdlc.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_null.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_r3964.c treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
n_tracerouter.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_tracesink.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_tracesink.h tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
n_tty.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
nozomi.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
pty.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rocket.c treewide: Switch DEFINE_TIMER callbacks to struct timer_list * 2017-11-21 15:57:05 -08:00
rocket.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
rocket_int.h License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
synclink.c treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
synclink_gt.c treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
synclinkmp.c treewide: setup_timer() -> timer_setup() 2017-11-21 15:57:07 -08:00
sysrq.c TTY/Serial patches for 4.15-rc1 2017-11-13 21:05:31 -08:00
tty_audit.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
tty_baudrate.c tty: add SPDX identifiers to all remaining files in drivers/tty/ 2017-11-08 13:08:12 +01:00
tty_buffer.c tty: add SPDX identifiers to all remaining files in drivers/tty/ 2017-11-08 13:08:12 +01:00
tty_io.c tty: add SPDX identifiers to all remaining files in drivers/tty/ 2017-11-08 13:08:12 +01:00
tty_ioctl.c tty: add SPDX identifiers to all remaining files in drivers/tty/ 2017-11-08 13:08:12 +01:00
tty_jobctrl.c tty: add SPDX identifiers to all remaining files in drivers/tty/ 2017-11-08 13:08:12 +01:00
tty_ldisc.c TTY/Serial patches for 4.15-rc1 2017-11-13 21:05:31 -08:00
tty_ldsem.c tty: Remove redundant license text 2017-11-08 13:08:12 +01:00
tty_mutex.c License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
tty_port.c tty: add SPDX identifiers to all remaining files in drivers/tty/ 2017-11-08 13:08:12 +01:00
vcc.c tty: vcc: Convert timers to use timer_setup() 2017-11-04 12:01:54 +01:00