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.
imx contains a line to set the default RTS polarity to active high,
it is now superfluous and hence deleted.
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: Rafael Gago Castano <rgc@xxxxxx>
Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Cc: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
---
Changes v1 -> v2:
- Rework uart_get_rs485_mode() to unconditionally set up the flags
for active-high polarity, then change them only if active-low
polarity was configured in the device properties. (Uwe)
- Drop line from imx.c which unconditionally sets the RTS_ON_SEND
bit. Previously this change was made in patch [5/5]. (Uwe)
drivers/tty/serial/imx.c | 1 -
drivers/tty/serial/omap-serial.c | 7 +++++--
drivers/tty/serial/serial_core.c | 13 ++++++++++---
3 files changed, 15 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index f0a14fe4c12f..30e885ac00db 100644
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -2078,7 +2078,6 @@ static int serial_imx_probe(struct platform_device *pdev)
sport->port.fifosize = 32;
sport->port.ops = &imx_pops;
sport->port.rs485_config = imx_rs485_config;
- sport->port.rs485.flags |= SER_RS485_RTS_ON_SEND;
sport->port.flags = UPF_BOOT_AUTOCONF;
setup_timer(&sport->timer, imx_timeout, (unsigned long)sport);
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 227347548fff..56e683373d6d 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1613,10 +1613,13 @@ 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 a59184a7afb0..f57969de2f1c 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3036,16 +3036,23 @@ void uart_get_rs485_mode(struct device *dev, struct serial_rs485 *rs485conf)
}
/*
- * clear full-duplex and enabled flags to get to a defined state with
- * the two following properties.
+ * Clear full-duplex and enabled flags, set RTS polarity to active high
+ * to get to a defined state with the following properties:
*/
- rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED);
+ rs485conf->flags &= ~(SER_RS485_RX_DURING_TX | SER_RS485_ENABLED |
+ SER_RS485_RTS_AFTER_SEND);
+ rs485conf->flags |= SER_RS485_RTS_ON_SEND;
if (device_property_read_bool(dev, "rs485-rx-during-tx"))
rs485conf->flags |= SER_RS485_RX_DURING_TX;
if (device_property_read_bool(dev, "linux,rs485-enabled-at-boot-time"))
rs485conf->flags |= SER_RS485_ENABLED;
+
+ if (device_property_read_bool(dev, "rs485-rts-active-low")) {
+ rs485conf->flags &= ~SER_RS485_RTS_ON_SEND;
+ rs485conf->flags |= SER_RS485_RTS_AFTER_SEND;
+ }
}
EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
--
2.11.0
--
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