[PATCH 2/4] serial: core: Add option to control rs485 RX_DURING_TX by a GPIO

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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




[Index of Archives]     [Kernel Newbies]     [Security]     [Netfilter]     [Bugtraq]     [Linux PPP]     [Linux FS]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Samba]     [Video 4 Linux]     [Linmodem]     [Device Mapper]     [Linux Kernel for ARM]

  Powered by Linux