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058bc104f7
linux/drivers/tty/serial
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Lukas Wunner 058bc104f7 serial: 8250: Generalize rs485 software emulation 
Commit e490c9144c ("tty: Add software emulated RS485 support for 8250")
introduced support to use RTS as an rs485 Transmit Enable signal.
So far the only drivers taking advantage of it are 8250_omap.c and
8250_of.c.

We're about to make use of the feature in 8250_bcm2835aux.c as well.
The bcm2835aux differs from omap chips by inverting the meaning of RTS
in the MCR register.  Moreover, omap achieves half-duplex mode by
disabling the RX interrupt and clearing the RX FIFO when TX stops.
The bcm2835aux requires disabling the receiver instead.

Support these behavioral differences by generalizing the rs485 emulation:
Introduce ->rs485_start_tx() and ->rs485_stop_tx() callbacks in struct
uart_8250_port, provide generic implementations containing the existing
code and use them as callbacks in 8250_omap.c and 8250_of.c.

start_tx_rs485() is idempotent in that it recognizes whether RTS is
already asserted.  Achieve the same by introducing a tx_stopped flag in
struct uart_8250_em485.  This may even perform a little better on arches
where memory access is faster than mmio access.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Matwey V. Kornilov <matwey@sai.msu.ru>
Link: https://lore.kernel.org/r/5ac0464ae4414708e723a1e0d52b0c1b2bd41b9b.1582895077.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-03-07 09:52:02 +01:00
..
8250 serial: 8250: Generalize rs485 software emulation 2020-03-07 09:52:02 +01:00
cpm_uart tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
jsm tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
21285.c tty: serial: 21285: stop using the unused[] variable from struct uart_port 2019-12-19 20:10:28 +01:00
altera_jtaguart.c
altera_uart.c
amba-pl010.c tty/serial: Migrate amba-pl01* to use has_sysrq 2019-12-18 15:04:44 +01:00
amba-pl011.c tty/serial: Migrate amba-pl01* to use has_sysrq 2019-12-18 15:04:44 +01:00
amba-pl011.h
apbuart.c tty/serial: Migrate apbuart to use has_sysrq 2019-12-18 15:04:44 +01:00
apbuart.h
ar933x_uart.c serial: ar933x_uart: add RS485 support 2020-03-06 13:26:26 +01:00
arc_uart.c tty/serial: Migrate arc_uart to use has_sysrq 2019-12-18 15:04:45 +01:00
atmel_serial.c tty: serial: atmel_serial: Drop GPIO includes 2020-03-06 13:16:16 +01:00
atmel_serial.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
bcm63xx_uart.c tty/serial: Migrate bcm63xx_uart to use has_sysrq 2019-12-18 15:04:43 +01:00
clps711x.c tty/serial: Migrate clps711x to use has_sysrq 2019-12-18 15:04:46 +01:00
digicolor-usart.c tty/serial: digicolor: Fix digicolor-usart already registered warning 2019-06-10 19:08:31 +02:00
dz.c TTY/Serial driver updates for 5.6-rc1 2020-01-29 10:13:27 -08:00
dz.h
earlycon-arm-semihost.c
earlycon-riscv-sbi.c tty/serial: use uart_console_write in the RISC-V SBL early console 2019-01-23 15:41:50 -08:00
earlycon.c serial: earlycon: prefer EARLYCON_DECLARE() variant 2020-03-07 09:52:01 +01:00
efm32-uart.c tty: serial: efm32: fix spelling mistake "reserverd" -> "reserved" 2020-02-19 11:38:58 +01:00
fsl_linflexuart.c tty/serial: Migrate fsl_linflexuart to use has_sysrq 2019-12-18 15:04:48 +01:00
fsl_lpuart.c tty: serial: fsl_lpuart: drop earlycon entry for i.MX8QXP 2020-01-06 20:22:36 +01:00
icom.c tty: serial: Remove call to memset after pci_alloc_consistent 2019-09-04 12:43:44 +02:00
icom.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
ifx6x60.c serial: ifx6x60: add missed pm_runtime_disable 2019-11-18 12:47:06 +01:00
ifx6x60.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
imx.c tty: imx serial: Implement support for reversing TX and RX polarity 2020-03-06 13:26:26 +01:00
ip22zilog.c tty/serial: Migrate ip22zilog to use has_sysrq 2019-12-18 15:04:50 +01:00
ip22zilog.h
Kconfig tty: serial: make SERIAL_SPRD not depend on ARCH_SPRD 2020-03-06 13:31:20 +01:00
kgdb_nmi.c tty/serial: kgdb_nmi: use true,false for bool variable 2020-01-14 14:34:04 +01:00
kgdboc.c kgdboc: Use for_each_console() helper 2020-02-10 12:34:43 -08:00
lantiq.c tty: serial: lantiq: Drop GPIO include 2020-03-06 13:16:16 +01:00
lpc32xx_hs.c TTY/Serial driver changes for 5.4-rc1 2019-09-18 10:50:47 -07:00
Makefile {tty: serial, nand: onenand}: samsung: rename to fix build warning 2019-11-18 18:49:11 +01:00
max310x.c serial: max310x: turn off transmitter before activating AutoCTS or auto transmitter flow control 2019-09-05 09:57:44 +02:00
max3100.c
mcf.c
men_z135_uart.c drivers: mcb: use symbol namespaces 2019-11-03 19:54:53 +01:00
meson_uart.c TTY/Serial driver updates for 5.6-rc1 2020-01-29 10:13:27 -08:00
milbeaut_usio.c tty/serial: Migrate milbeaut_usio to use has_sysrq 2019-12-18 15:04:51 +01:00
mpc52xx_uart.c tty/serial: mpc52xx_uart: Don't zero port->sysrq 2019-12-18 15:04:52 +01:00
mps2-uart.c serial: mps2-uart: Add parentheses around conditional in mps2_uart_shutdown 2019-01-31 19:34:10 +01:00
msm_serial.c tty: serial: msm_serial: RX SW/FIFO mode fallback 2020-01-14 14:07:51 +01:00
mux.c TTY/Serial driver updates for 5.6-rc1 2020-01-29 10:13:27 -08:00
mvebu-uart.c tty: Remove dev_err() usage after platform_get_irq() 2019-09-04 12:43:49 +02:00
mxs-auart.c tty/serial: Migrate mxs-auart to use has_sysrq 2019-12-18 15:04:53 +01:00
omap-serial.c tty/serial: Migrate omap-serial to use has_sysrq 2019-12-18 15:04:54 +01:00
owl-uart.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
pch_uart.c tty/serial: pmac_zilog: Don't check port->sysrq 2019-12-18 15:04:56 +01:00
pic32_uart.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
pic32_uart.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
pmac_zilog.c tty/serial: Migrate pmac_zilog to use has_sysrq 2019-12-18 15:04:56 +01:00
pmac_zilog.h
pnx8xxx_uart.c tty/serial: Migrate pnx8xxx_uart to use has_sysrq 2019-12-18 15:04:57 +01:00
pxa.c tty/serial: Migrate pxa to use has_sysrq 2019-12-18 15:04:57 +01:00
qcom_geni_serial.c tty: serial: qcom_geni_serial: Fix GPIO swapping with workaround 2020-03-06 13:16:20 +01:00
rda-uart.c remove ioremap_nocache and devm_ioremap_nocache 2020-01-06 09:45:59 +01:00
rp2.c
sa1100.c tty/serial: Migrate sa1100 to use has_sysrq 2019-12-18 15:04:59 +01:00
samsung_tty.c serial: samsung: Rename Exynos to lowercase 2020-01-06 20:22:33 +01:00
sb1250-duart.c TTY/Serial driver updates for 5.6-rc1 2020-01-29 10:13:27 -08:00
sc16is7xx.c serial: sc16is7xx: Replace zero-length array with flexible-array member 2020-02-13 12:00:23 -08:00
sccnxp.c tty/serial: Migrate sccnxp to use has_sysrq 2019-12-18 15:05:00 +01:00
serial_core.c serial: core: Switch to use DEVICE_ATTR_RO() 2020-02-17 17:01:54 +01:00
serial_mctrl_gpio.c serial: mctrl_gpio: Check for NULL pointer 2019-10-07 13:21:54 +02:00
serial_mctrl_gpio.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
serial_txx9.c tty/serial: Migrate serial_txx9 to use has_sysrq 2019-12-18 15:05:01 +01:00
serial-tegra.c tty: serial: tegra: Handle RX transfer in PIO mode if DMA wasn't started 2020-02-10 12:32:13 -08:00
sh-sci.c TTY/Serial driver updates for 5.6-rc1 2020-01-29 10:13:27 -08:00
sh-sci.h
sifive.c tty: Remove dev_err() usage after platform_get_irq() 2019-09-04 12:43:49 +02:00
sirfsoc_uart.c
sirfsoc_uart.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
sprd_serial.c Merge 5.5-rc3 into tty-next 2019-12-23 06:59:19 -05:00
st-asc.c tty: st-asc: switch to using devm_gpiod_get() 2020-01-10 14:01:33 +01:00
stm32-usart.c tty/serial: Migrate stm32-usart to use has_sysrq 2019-12-18 15:05:04 +01:00
stm32-usart.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
suncore.c
sunhv.c tty/serial: Migrate sunhv to use has_sysrq 2019-12-18 15:05:05 +01:00
sunsab.c tty/serial: Migrate sunsab to use has_sysrq 2019-12-18 15:05:05 +01:00
sunsab.h
sunsu.c tty/serial: Migrate sunsu to use has_sysrq 2019-12-18 15:05:06 +01:00
sunzilog.c tty/serial: Migrate sunzilog to use has_sysrq 2019-12-18 15:05:08 +01:00
sunzilog.h
tegra-tcu.c serial: Add Tegra Combined UART driver 2019-01-30 09:31:31 +01:00
timbuart.c
timbuart.h tty: serial: Use the correct style for SPDX License Identifier 2020-03-07 09:52:01 +01:00
uartlite.c Revert "serial-uartlite: Move the uart register" 2019-11-14 06:29:08 +08:00
ucc_uart.c ARM: SoC-related driver updates 2020-02-08 14:04:19 -08:00
vr41xx_siu.c tty/serial: Migrate vr41xx_siu to use has_sysrq 2019-12-18 15:05:09 +01:00
vt8500_serial.c tty/serial: Migrate vt8500_serial to use has_sysrq 2019-12-18 15:05:09 +01:00
xilinx_uartps.c serial: xilinx_uartps: set_mctrl sets RTS and DTR 2020-01-14 14:34:04 +01:00
zs.c TTY/Serial driver updates for 5.6-rc1 2020-01-29 10:13:27 -08:00
zs.h