serial: 8250: Add rs485 emulation to 8250_dw
From: Heiko Stuebner <heiko@...> Date: Wed, 25 Mar 2020 22:37:32 +0100
This series tries to revive the work of Giulio Benetti from 2018 [0] which seemed to have stalled at that time. The board I needed that on also had the additional caveat that it uses non-standard pins for DE/RE so needed gpio mctrl layer as well and even more special needed to control the RE pin manually not as part of it being connected to the DE signal as seems to be the standard. The first 3 patches are taken from Lukas Wunner's repository with work he wants to submit after 5.7-rc1. Patches needed adaptions from their 4.19 base of course, so no guarantes I did that correctly ;-) . I just need the change in the rs485_mode handling as base. So as suggested by Andy this series is meant as a base for discussions to show how my 8250_dw rs485 support fits onto the more recent codebase and find more issues earlier. Changes in v2: - move to recent rs485 improvements in tty-next - added a capability for TEMT interrupt presence - external gpio for optional receiver-enable handling - timeout polling via the generic readx_poll_timeout Changes from the 2018 submission include: - add timeout when waiting for fifos to clear using a new helper - move on-boot enablement of the rs485 mode to after registering the port. This saves having to copy the em485 struct as done originally, which also ran into spinlock-debug warnings when testing and also makes it actually possible to use the mctrl gpio layer for non-standard gpios. *** BLURB HERE *** Giulio Benetti (2): serial: 8250: Handle implementations not having TEMT interrupt using em485 serial: 8250_dw: add em485 support Heiko Stuebner (2): dt-bindings: serial: Add binding for rs485 receiver enable GPIO serial: 8250: Support separate rs485 rx-enable GPIO Lukas Wunner (3): serial: Allow uart_get_rs485_mode() to return errno dt-bindings: serial: Add binding for rs485 bus termination GPIO serial: 8250: Support rs485 bus termination GPIO .../devicetree/bindings/serial/rs485.yaml | 8 ++++ drivers/tty/serial/8250/8250.h | 1 + drivers/tty/serial/8250/8250_bcm2835aux.c | 2 +- drivers/tty/serial/8250/8250_core.c | 4 +- drivers/tty/serial/8250/8250_dw.c | 3 ++ drivers/tty/serial/8250/8250_of.c | 2 + drivers/tty/serial/8250/8250_omap.c | 2 +- drivers/tty/serial/8250/8250_port.c | 41 +++++++++++++++--- drivers/tty/serial/ar933x_uart.c | 6 ++- drivers/tty/serial/atmel_serial.c | 6 ++- drivers/tty/serial/fsl_lpuart.c | 5 ++- drivers/tty/serial/imx.c | 6 ++- drivers/tty/serial/omap-serial.c | 4 +- drivers/tty/serial/serial_core.c | 43 ++++++++++++++++++- drivers/tty/serial/stm32-usart.c | 8 ++-- include/linux/serial_core.h | 4 +- 16 files changed, 124 insertions(+), 21 deletions(-) -- 2.24.1
Patches in this set
- [0001] serial: Allow uart_get_rs485_mode() to return errno (raw)
- [0002] dt-bindings: serial: Add binding for rs485 bus (raw)
- [0003] serial: 8250: Support rs485 bus termination GPIO (raw)
- [0004] serial: 8250: Handle implementations not having TEMT (raw)
- [0005] dt-bindings: serial: Add binding for rs485 receiver (raw)
- [0006] serial: 8250: Support separate rs485 rx-enable GPIO (raw)
- [0007] serial: 8250_dw: add em485 support (raw)
Statistics
- 7 individual patches
- 124 lines added
- 21 lines removed