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[V3,4/4] serial: stm32: Add support for rs485 RX_DURING_TX output GPIO

Message ID 20221201110237.7917-4-cniedermaier@dh-electronics.com
State New
Headers show
Series [V3,1/4] dt-bindings: serial: rs485: Add GPIO controlling RX enable during TX | expand

Commit Message

Christoph Niedermaier Dec. 1, 2022, 11:02 a.m. UTC 
If a RX_DURING_TX GPIO is defined by the DT property "rs485-rx-during-tx-gpios"
this patch switches this GPIO accordingly to the RS485 flag RX_DURING_TX in user
space. Controlled by this GPIO, now the hardware is responsible for connecting
or disconnecting RX during TX.

Signed-off-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
---
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: Alexander Dahl <ada@thorsis.com>
Cc: Marek Vasut <marex@denx.de>
Cc: kernel@dh-electronics.com
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-serial@vger.kernel.org
To: linux-arm-kernel@lists.infradead.org
---
V2: - Rework of the commit message
V3: - No changes
---
 drivers/tty/serial/stm32-usart.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index a1490033aa16..0f2cca9054ba 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -226,7 +226,14 @@  static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter
 
 	stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
 
-	rs485conf->flags |= SER_RS485_RX_DURING_TX;
+	if (port->rs485_rx_during_tx_gpio) {
+		if (rs485conf->flags & SER_RS485_RX_DURING_TX)
+			gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 1);
+		else
+			gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
+	} else {
+		rs485conf->flags |= SER_RS485_RX_DURING_TX;
+	}
 
 	if (rs485conf->flags & SER_RS485_ENABLED) {
 		cr1 = readl_relaxed(port->membase + ofs->cr1);