This patch provides a generic GPIO variable for the use of the rs485
feature RX_DURING_TX controlled by a GPIO. The GPIO is defined by the
devicetree property "rs485-rx-during-tx-gpios". To use it in a low
level serial driver, the evaluation of this variable must be
implemented there accordingly.
Signed-off-by: Christoph Niedermaier <cniedermaier@xxxxxxxxxxxxxxxxxx>
---
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jirislaby@xxxxxxxxxx>
Cc: Marek Vasut <marex@xxxxxxx>
Cc: Linux Team <linux-imx@xxxxxxx>
To: linux-serial@xxxxxxxxxxxxxxx
To: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
---
drivers/tty/serial/serial_core.c | 12 ++++++++++++
include/linux/serial_core.h | 1 +
2 files changed, 13 insertions(+)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 179ee199df34..63150d922aa1 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -3410,6 +3410,7 @@ int uart_get_rs485_mode(struct uart_port *port)
struct device *dev = port->dev;
u32 rs485_delay[2];
int ret;
+ int rx_during_tx_gpio_flag;
ret = device_property_read_u32_array(dev, "rs485-rts-delay",
rs485_delay, 2);
@@ -3458,6 +3459,17 @@ int uart_get_rs485_mode(struct uart_port *port)
if (port->rs485_term_gpio)
port->rs485_supported.flags |= SER_RS485_TERMINATE_BUS;
+ rx_during_tx_gpio_flag = (rs485conf->flags & SER_RS485_RX_DURING_TX) ?
+ GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
+ port->rs485_rx_during_tx_gpio = devm_gpiod_get_optional(dev,
+ "rs485-rx-during-tx",
+ rx_during_tx_gpio_flag);
+ if (IS_ERR(port->rs485_rx_during_tx_gpio)) {
+ ret = PTR_ERR(port->rs485_rx_during_tx_gpio);
+ port->rs485_rx_during_tx_gpio = NULL;
+ return dev_err_probe(dev, ret, "Cannot get rs485-rx-during-tx-gpios\n");
+ }
+
return 0;
}
EXPORT_SYMBOL_GPL(uart_get_rs485_mode);
diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h
index d657f2a42a7b..b4cdeb6e952a 100644
--- a/include/linux/serial_core.h
+++ b/include/linux/serial_core.h
@@ -579,6 +579,7 @@ struct uart_port {
struct serial_rs485 rs485;
struct serial_rs485 rs485_supported; /* Supported mask for serial_rs485 */
struct gpio_desc *rs485_term_gpio; /* enable RS485 bus termination */
+ struct gpio_desc *rs485_rx_during_tx_gpio; /* Controls RS485 Rx enable during Tx */
struct serial_iso7816 iso7816;
void *private_data; /* generic platform data pointer */
};
--
2.11.0
