1 files changed, 51 insertions, 2 deletions

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 5e93e8d40f59..17c2f3276888 100644
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -31,6 +31,7 @@
 #include <linux/tty_flip.h>
 #include <linux/tty.h>
 
+#include "serial_mctrl_gpio.h"
 #include "stm32-usart.h"
 
 static void stm32_stop_tx(struct uart_port *port);
@@ -510,12 +511,29 @@ static void stm32_set_mctrl(struct uart_port *port, unsigned int mctrl)
 		stm32_set_bits(port, ofs->cr3, USART_CR3_RTSE);
 	else
 		stm32_clr_bits(port, ofs->cr3, USART_CR3_RTSE);
+
+	mctrl_gpio_set(stm32_port->gpios, mctrl);
 }
 
 static unsigned int stm32_get_mctrl(struct uart_port *port)
 {
+	struct stm32_port *stm32_port = to_stm32_port(port);
+	unsigned int ret;
+
 	/* This routine is used to get signals of: DCD, DSR, RI, and CTS */
-	return TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+	ret = TIOCM_CAR | TIOCM_DSR | TIOCM_CTS;
+
+	return mctrl_gpio_get(stm32_port->gpios, &ret);
+}
+
+static void stm32_enable_ms(struct uart_port *port)
+{
+	mctrl_gpio_enable_ms(to_stm32_port(port)->gpios);
+}
+
+static void stm32_disable_ms(struct uart_port *port)
+{
+	mctrl_gpio_disable_ms(to_stm32_port(port)->gpios);
 }
 
 /* Transmit stop */
@@ -626,6 +644,9 @@ static void stm32_shutdown(struct uart_port *port)
 	u32 val, isr;
 	int ret;
 
+	/* Disable modem control interrupts */
+	stm32_disable_ms(port);
+
 	val = USART_CR1_TXEIE | USART_CR1_TE;
 	val |= stm32_port->cr1_irq | USART_CR1_RE;
 	val |= BIT(cfg->uart_enable_bit);
@@ -764,6 +785,12 @@ static void stm32_set_termios(struct uart_port *port, struct ktermios *termios,
 		cr3 |= USART_CR3_CTSE | USART_CR3_RTSE;
 	}
 
+	/* Handle modem control interrupts */
+	if (UART_ENABLE_MS(port, termios->c_cflag))
+		stm32_enable_ms(port);
+	else
+		stm32_disable_ms(port);
+
 	usartdiv = DIV_ROUND_CLOSEST(port->uartclk, baud);
 
 	/*
@@ -898,6 +925,7 @@ static const struct uart_ops stm32_uart_ops = {
 	.throttle	= stm32_throttle,
 	.unthrottle	= stm32_unthrottle,
 	.stop_rx	= stm32_stop_rx,
+	.enable_ms	= stm32_enable_ms,
 	.break_ctl	= stm32_break_ctl,
 	.startup	= stm32_startup,
 	.shutdown	= stm32_shutdown,
@@ -960,10 +988,31 @@ static int stm32_init_port(struct stm32_port *stm32port,
 
 	stm32port->port.uartclk = clk_get_rate(stm32port->clk);
 	if (!stm32port->port.uartclk) {
-		clk_disable_unprepare(stm32port->clk);
 		ret = -EINVAL;
+		goto err_clk;
+	}
+
+	stm32port->gpios = mctrl_gpio_init(&stm32port->port, 0);
+	if (IS_ERR(stm32port->gpios)) {
+		ret = PTR_ERR(stm32port->gpios);
+		goto err_clk;
 	}
 
+	/* Both CTS/RTS gpios and "st,hw-flow-ctrl" should not be specified */
+	if (stm32port->hw_flow_control) {
+		if (mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_CTS) ||
+		    mctrl_gpio_to_gpiod(stm32port->gpios, UART_GPIO_RTS)) {
+			dev_err(&pdev->dev, "Conflicting RTS/CTS config\n");
+			ret = -EINVAL;
+			goto err_clk;
+		}
+	}
+
+	return ret;
+
+err_clk:
+	clk_disable_unprepare(stm32port->clk);
+
 	return ret;
 }