Messages in this thread Patch in this message | ![/](/images/icornerl.gif) | | Date | Tue, 23 Apr 2024 14:59:10 -0400 | From | Hugo Villeneuve <> | Subject | Re: [PATCH v7 1/3] serial: sc16is7xx: announce support of SER_RS485_RTS_ON_SEND |
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On Mon, 22 Apr 2024 16:32:13 +0300 Konstantin Pugin <ria.freelander@gmail.com> wrote:
Hi Konstantin,
> The hardware supports both RTS_ON_SEND and RTS_AFTER_SEND modes, but > after the commit 4afeced55baa ("serial: core: fix sanitizing check for > RTS settings") we always end up with SER_RS485_RTS_AFTER_SEND set and > always write to the register field SC16IS7XX_EFCR_RTS_INVERT_BIT, which > breaks some hardware using these chips.
it took me a long time to properly understand what you meant in your commit message. In my setup, I have the property rs485-rts-active-low defined, and couldn't reproduce the problem. It is only after I commented this property that I got a warning about the "invalid RTS setting"... I also got it by defining rs485-rts-active-high.
I suggest the following changes to the commit message:
---- 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. ---
If you agree to these changes, feel free to add:
Tested-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Hugo.
> > Fixes: 267913ecf737 ("serial: sc16is7xx: Fill in rs485_supported") > Signed-off-by: Konstantin Pugin <ria.freelander@gmail.com> > --- > 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 03cf30e20b75..dfcc804f558f 100644 > --- a/drivers/tty/serial/sc16is7xx.c > +++ b/drivers/tty/serial/sc16is7xx.c > @@ -1449,7 +1449,7 @@ 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 */ > }; > -- > 2.34.1 > > >
-- Hugo Villeneuve
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