From: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
When specifying flag SER_RS485_RTS_ON_SEND in RS485 configuration,
we get the following warning after commit 4afeced55baa ("serial: core:
fix sanitizing check for RTS settings"):
invalid RTS setting, using RTS_AFTER_SEND instead
This results in SER_RS485_RTS_AFTER_SEND being set and the
driver always write to the register field SC16IS7XX_EFCR_RTS_INVERT_BIT,
which breaks some hardware using these chips.
The hardware supports both RTS_ON_SEND and RTS_AFTER_SEND modes, so fix
this by announcing support for RTS_ON_SEND.
Signed-off-by: Hugo Villeneuve <hvilleneuve@xxxxxxxxxxxx>
Suggested-by: Konstantin Pugin <ria.freelander@xxxxxxxxx>
Link: https://lore.kernel.org/lkml/20240422133219.2710061-2-ria.freelander@xxxxxxxxx
---
This patch was part of a series to add support for a new EXAR variant by
Konstantin, but the final version was never submitted. I need this patch
for a new revision of our board which has reverse RTS signal compared to the
old revision.
---
drivers/tty/serial/sc16is7xx.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index ad88a33a504f..9d0c971e49f5 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -1473,7 +1473,7 @@ static int sc16is7xx_setup_mctrl_ports(struct sc16is7xx_port *s,
}
static const struct serial_rs485 sc16is7xx_rs485_supported = {
- .flags = SER_RS485_ENABLED | SER_RS485_RTS_AFTER_SEND,
+ .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1, /* Not supported but keep returning -EINVAL */
};
base-commit: 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b
--
2.39.5
