serial: 8250: Add rs485 emulation to 8250_dw
From: Heiko Stuebner <heiko@...> Date: Wed, 18 Mar 2020 15:19:21 +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. So I've marked the patch doing this as DTR pin as RFC but that patch isn't needed for the other core functionality, so could also be left out. 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. [0] Link: https://lore.kernel.org/linux-serial/20180601124021.102970-1-giulio.benetti@micronovasrl.com/ Giulio Benetti (4): serial: 8250: Make em485_rts_after_send() set mctrl according to rts state. serial: 8250: Handle case port doesn't have TEMT interrupt using em485. serial: 8250_dw: add em485 support serial: 8250_dw: allow enable rs485 at boot time Heiko Stuebner (3): serial: 8250: add serial_in_poll_timeout helper serial: 8250: Start rs485 after registering port if rs485 is enabled in probe serial: 8250: handle DTR in rs485 emulation drivers/tty/serial/8250/8250.h | 36 ++++++++++++++++++++- drivers/tty/serial/8250/8250_core.c | 9 ++++++ drivers/tty/serial/8250/8250_dw.c | 35 +++++++++++++++++++- drivers/tty/serial/8250/8250_of.c | 2 +- drivers/tty/serial/8250/8250_omap.c | 2 +- drivers/tty/serial/8250/8250_port.c | 50 +++++++++++++++++++++++------ include/linux/serial_8250.h | 1 + 7 files changed, 121 insertions(+), 14 deletions(-) -- 2.24.1
Patches in this set
- [0001] serial: 8250: Make em485_rts_after_send() set mctrl (raw)
- [0002] serial: 8250: add serial_in_poll_timeout helper (raw)
- [0003] serial: 8250: Handle case port doesn't have TEMT (raw)
- [0004] serial: 8250: Start rs485 after registering port if rs485 (raw)
- [0005] serial: 8250: handle DTR in rs485 emulation (raw)
- [0006] serial: 8250_dw: add em485 support (raw)
- [0007] serial: 8250_dw: allow enable rs485 at boot time (raw)
Statistics
- 7 individual patches
- 121 lines added
- 14 lines removed