On Wed, Nov 08, 2017 at 11:32:34AM +0100, Lukas Wunner wrote:
> When a driver invokes the uart_get_rs485_mode() helper, set the RTS
> polarity to active high by default unless the newly introduced
> "rs485-rts-active-low" property was specified.
>
> omap-serial historically defaults to active low and supports an
> "rs485-rts-active-high" property to inverse the polarity. Retain that
> behavior for compatibility.
>
> Cc: Mark Jackson <mpfj@xxxxxxxxxxxxx>
> Cc: Michał Oleszczyk <oleszczyk.m@xxxxxxxxx>
> Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
> Cc: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
> Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
> ---
> drivers/tty/serial/omap-serial.c | 7 +++++--
> drivers/tty/serial/serial_core.c | 8 ++++++++
> 2 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
> index e6aadb6d02e5..7ef36c0af825 100644
> --- a/drivers/tty/serial/omap-serial.c
> +++ b/drivers/tty/serial/omap-serial.c
> @@ -1617,10 +1617,13 @@ static int serial_omap_probe_rs485(struct uart_omap_port *up,
>
> uart_get_rs485_mode(up->dev, rs485conf);
>
> - if (of_property_read_bool(np, "rs485-rts-active-high"))
> + if (of_property_read_bool(np, "rs485-rts-active-high")) {
> rs485conf->flags |= SER_RS485_RTS_ON_SEND;
> - else
> + rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
> + } else {
> + rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
> rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
> + }
>
> /* check for tx enable gpio */
> up->rts_gpio = of_get_named_gpio_flags(np, "rts-gpio", 0, &flags);
> diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
> index 548bb80223c1..64e15507a9bd 100644
> --- a/drivers/tty/serial/serial_core.c
> +++ b/drivers/tty/serial/serial_core.c
> @@ -3048,6 +3048,14 @@ void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
> rs485conf->delay_rts_after_send = 0;
> }
>
> + if (device_property_read_bool(dev, "rs485-rts-active-low")) {
> + rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
> + rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
> + } else {
> + rs485conf->flags |= SER_RS485_RTS_ON_SEND;
> + rs485conf->flags &= ~SER_RS485_RTS_AFTER_SEND;
> + }
> +
I wonder if it would be easier to understand when making that:
- rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED);
+ rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_RTS_AFTER_SEND | SER_RS485_ENABLED);
+ rs485conf->flags |= SER_RS485_RTS_ON_SEND;
...
+ if (device_property_read_bool(dev, "rs485-rts-active-low")) {
+ rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
+ rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
+ }
(together with the then needed comment updates) which would highlight
that SER_RS485_RTS_ON_SEND is the default.
imx.c has unconditional
sport->port.rs485.flags |= SER_RS485_RTS_ON_SEND;
that needs to be dropped in this patch.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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