linux-kernel - [PATCH 1/2] tty/serial: Add st,swap OF option to stm32-usart

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Message-Id: <20200229160507.31309-1-devik@eaxlabs.cz>
Date:   Sat, 29 Feb 2020 17:05:06 +0100
From:   Martin Devera <devik@...labs.cz>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...com>,
        linux-serial@...r.kernel.org (open list:SERIAL DRIVERS),
        linux-arm-kernel@...ts.infradead.org (moderated list:ARM/STM32
        ARCHITECTURE), linux-kernel@...r.kernel.org (open list)
Cc:     Martin Devera <devik@...labs.cz>
Subject: [PATCH 1/2] tty/serial: Add st,swap OF option to stm32-usart

STM32 F7/H7 usarts supports RX & TX pin swapping.
Add option to turn it on.
Tested on STM32MP157.

Signed-off-by: Martin Devera <devik@...labs.cz>
---
 drivers/tty/serial/stm32-usart.c | 3 ++-
 drivers/tty/serial/stm32-usart.h | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index fdcc2142aa79..8d25869a02eb 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -780,7 +780,7 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 	cr1 = USART_CR1_TE | USART_CR1_RE;
 	if (stm32_port->fifoen)
 		cr1 |= USART_CR1_FIFOEN;
-	cr2 = 0;
+	cr2 = stm32_port->swap ? USART_CR2_SWAP : 0;
 
 	/* Tx and RX FIFO configuration */
 	cr3 = readl_relaxed(port->membase + ofs->cr3);
@@ -1097,6 +1097,7 @@ static struct stm32_port *stm32_of_get_stm32_port(struct platform_device *pdev)
 
 	stm32_ports[id].hw_flow_control = of_property_read_bool(np,
 							"st,hw-flow-ctrl");
+	stm32_ports[id].swap = of_property_read_bool(np, "st,swap");
 	stm32_ports[id].port.line = id;
 	stm32_ports[id].cr1_irq = USART_CR1_RXNEIE;
 	stm32_ports[id].cr3_irq = 0;
diff --git a/drivers/tty/serial/stm32-usart.h b/drivers/tty/serial/stm32-usart.h
index 2a68bc48652e..2503a91b890c 100644
--- a/drivers/tty/serial/stm32-usart.h
+++ b/drivers/tty/serial/stm32-usart.h
@@ -275,6 +275,7 @@ struct stm32_port {
 	enum dma_cb rx_dma_cb;	 /* dma rx callback status    */
 	bool tx_dma_busy;	 /* dma tx busy               */
 	bool hw_flow_control;
+	bool swap;		 /* swap RX & TX pins */
 	bool fifoen;
 	int wakeirq;
 	struct pinctrl_state *console_pins;
-- 
2.11.0