Commit 3cd66593 authored by Martin Devera's avatar Martin Devera Committed by Greg Kroah-Hartman
Browse files

tty/serial: Add rx-tx-swap OF option to stm32-usart 



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

Acked-by: default avatarFabrice Gasnier <fabrice.gasnier@foss.st.com>
Signed-off-by: default avatarMartin Devera <devik@eaxlabs.cz>
Link: https://lore.kernel.org/r/20210328154306.22674-2-devik@eaxlabs.cz


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 1b8dc398

drivers/tty/serial/stm32-usart.c

+10 −1
Original line number Diff line number Diff line
@@ -671,6 +671,12 @@ static int stm32_usart_startup(struct uart_port *port) 
	if (ret)

		return ret;



	if (stm32_port->swap) {

		val = readl_relaxed(port->membase + ofs->cr2);

		val |= USART_CR2_SWAP;

		writel_relaxed(val, port->membase + ofs->cr2);

	}



	/* RX FIFO Flush */

	if (ofs->rqr != UNDEF_REG)

		writel_relaxed(USART_RQR_RXFRQ, port->membase + ofs->rqr);
@@ -789,7 +795,7 @@ static void stm32_usart_set_termios(struct uart_port *port, 
	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);
@@ -1047,6 +1053,9 @@ static int stm32_usart_init_port(struct stm32_port *stm32port, 
	stm32port->wakeup_src = stm32port->info->cfg.has_wakeup &&

		of_property_read_bool(pdev->dev.of_node, "wakeup-source");



	stm32port->swap = stm32port->info->cfg.has_swap &&

		of_property_read_bool(pdev->dev.of_node, "rx-tx-swap");



	stm32port->fifoen = stm32port->info->cfg.has_fifo;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

drivers/tty/serial/stm32-usart.h

+4 −0
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ struct stm32_usart_offsets { 
struct stm32_usart_config {

	u8 uart_enable_bit; /* USART_CR1_UE */

	bool has_7bits_data;

	bool has_swap;

	bool has_wakeup;

	bool has_fifo;

	int fifosize;
@@ -76,6 +77,7 @@ struct stm32_usart_info stm32f7_info = { 
	.cfg = {

		.uart_enable_bit = 0,

		.has_7bits_data = true,

		.has_swap = true,

		.fifosize = 1,

	}

};
@@ -97,6 +99,7 @@ struct stm32_usart_info stm32h7_info = { 
	.cfg = {

		.uart_enable_bit = 0,

		.has_7bits_data = true,

		.has_swap = true,

		.has_wakeup = true,

		.has_fifo = true,

		.fifosize = 16,
@@ -268,6 +271,7 @@ struct stm32_port { 
	int last_res;

	bool tx_dma_busy;	 /* dma tx busy               */

	bool hw_flow_control;

	bool swap;		 /* swap RX & TX pins */

	bool fifoen;

	bool wakeup_src;

	int rdr_mask;		/* receive data register mask */